WO2015165492A1

WO2015165492A1 - Method for preparing an animal feed supplement composition

Info

Publication number: WO2015165492A1
Application number: PCT/EP2014/058631
Authority: WO
Inventors: Angelo Lauwaerts; Dieter ULRICHTS; Mia Laget
Original assignee: Taminco
Priority date: 2014-04-28
Filing date: 2014-04-28
Publication date: 2015-11-05

Abstract

The animal feed supplement composition comprises one or more feed supplement substances including at least one choline feed supplement substance. To prepare the feed supplement composition, the particles of a particulate absorbent carrier are allowed to absorb an aqueous solution of the choline feed supplement substance. In accordance with the invention, the absorbent particles are allowed to absorb also at least one medium chain fatty acid feed supplement substance, which may be a salt dissolved in water or a free fatty acid. The absorbent carrier may be an organic carrier, such as corn cob, or an inorganic carrier, in particular a silica material. The combination of the choline feed supplement substance and the medium chain fatty acid feed supplement substance enables to improve the flow properties of the product either in its dry state or after having been exposed to humid conditions. A higher load of active ingredients can also be obtained more easily.

Description

"Method for preparing an animal feed supplement composition"

The present invention relates to a method for preparing an animal feed supplement composition comprising one or more feed supplement substances including at least one choline feed supplement substance. To prepare the feed supplement composition, a liquid comprising at least the choline feed supplement substance dissolved in water is provided and the particles of a particulate absorbent carrier are allowed to absorb the choline feed supplement substance contained in said liquid.

Choline feed supplement substances, in particular choline chloride, are already used for a long time in the formulation of animal feed supplement compositions. Choline is a water-soluble essential nutrient. It is usually grouped within the B-complex vitamins and requires dietary intake to remain healthy. It is used on a large scale in the animal feed industry as a feed additive, especially for chickens where it accelerates growth. Choline is often used as a 75% aqueous solution of choline chloride because the anhydrous form of this choline salt is highly hygroscopic (deliquescent). It however also exists as a powder. A carrier free choline chloride powder can for example be made, as disclosed in WO 2010/072842, by spray drying a choline chloride solution wherein a small amount of stearate has been dissolved and by mixing the obtained powder with more stearate. This way of producing choline chloride powder enables to achieve a high choline chloride concentration but is quite complex and expensive and requires moreover the use of stearates.

As disclosed for example in US 4 775 540 and in

US 5 766 668 an aqueous choline chloride solution can also be applied onto a carrier, in particular onto silica or organic carriers, for example onto corn cob powder or rice husks. Silica carriers are described as being absorbent carriers that may contain from 15 to 25 wt.% residual water whilst still having a good flowability. These products therefore do not need to be dried. The products employing organic carriers are less expensive but usually need to be dried to a water content of 1 -2%.

Silica carrier materials that are suited for absorbing choline chloride solutions, in particular precipitated silica materials, are also described for example in US 6 960 251 and in US 7 153 521 . A drawback of silica materials is however that they are relatively expensive so that it is important to be able to absorb as much as possible of the active ingredients. Although an aqueous choline chloride solution contains a relatively small amount of water, the absorption thereof by the precipitated silica material is limited by the amount of water that can be absorbed by the silica material whilst still remaining free flowing. The silica material disclosed in US 7 153 521 was for example loaded with 64 to 68% of choline chloride solution, corresponding thus to a load of about 50% of choline chloride. A same choline chloride load of about 50% is described in US 6 960 251 . Also the chloline chloride products on a silica carrier which are presently on the market have standard a choline chloride load of about 50%.

A problem of choline chloride containing powders is indeed that, due to the very hygroscopic nature of choline chloride, these powders tend to lump or even cake and hence become less free flowing, or even difficult to pour, when they come into contact with moisture, for example when they come into contact with the free atmosphere. Another drawback is that when a premix is made from these choline powders with other feed additives such as vitamins, in particular vitamins A, E and/or K₃, the presence of choline chloride in the premix makes the premix more hygroscopic. The premix thus absorbes more water which has a negative impact on the flowability of the premix and on the stability of the vitamins contained in the premix. In their article "Stability of vitamins in premixes", Gabrijela Tavcar-Kalcher and Anton Vergust describe for example that the presence of choline chloride in a vitamin premix reduces the retention of vitamin A and E after storage of the premix for 3, 6 and 12 months. This effect was more pronounced for vitamin K₃.. After 12 months of storage, the presence of choline chloride in the premix reduced the retention of vitamin K₃ from 80% to 9%. In view of these negative effects of the presence of choline in premixes, choline is often added directly to the final feed.

Just as choline, medium chain fatty acids (MCFA's), i.e. fatty acids having a carbon chain length of from 6 to 12 carbon atoms, are already used for a long time in the formulation of animal feed supplement compositions. US 3 564 098 (1971 ) discloses for example the use of C5 to C1 1 free fatty acids as growth promoters for animals. Different possibilities are described in this US patent for adding the free fatty acids to the feed. They can be added for example as the pure compounds or as an adsorbate on silica gel, oatmeal, soybean meal or on ion-exchange resins. US 3 564 098 also discloses other materials which can be incorporated in the feed such as different vitamins including choline.

EP 0 089 376 (1983) discloses the use of salts of fatty acids, including the salts of MCFA's, as growth promoting substances. It more particularly describes that these fatty acids are good alternatives for the antibiotics used extensively in the past for producing livestock, poultry and fish efficiently in a shorter period of time and also with smaller amounts of feed. Just as US 3 564 098, it also mentions other additives that can be added to the feed, in particular choline.

A problem with MCFA's is that they are difficult to formulate in a feed supplement composition which meets all of the desired objects such as a quite large amount of the active ingredient, avoiding bad organoleptic properties like an unpleasant odour and taste and achieving physical properties which allow the feed supplement composition to be easily mixed, in the correct amounts, with the other components of the feed or with other components of a feed premix. When it is a particulate feed supplement composition, i.e. a feed supplement composition consisting of small solids particles, the feed supplement composition should preferably have good flow properties so that it can be dosed easily. In order to reduce the unpleasant odour of medium chain fatty acids, which could restrain the animals from consuming the feed, they are preferably not incorporated as a free fatty acid in the feed supplement composition but instead for example as a salt as disclosed for example in WO 00/36928.

As disclosed in the prior art section of WO 2009/002558 liquid organic acids, in particular medium chain fatty acids, can be absorbed on dry absorbent chemical carriers. The dry absorbent carrier system should be capable of being used in a manner that will reduce the vapour pressure of the volatile components within the liquid feed additives. Fumed silica is mentioned as a carrier which has already been used for a long time as absorbent for desired liquid animal feed additives. Fumed silica is highly absorbent but a drawback of fumed silica is that it is also quite expensive.

In the invention as disclosed in WO 2009/002558 use is therefore made of a much cheaper carrier material, more particularly of dried citrus peels. The dried citrus peel carrier is made to absorb liquid feed supplements including different organic and medium chain fatty acids. Choline is also mentioned as a possible liquid feed supplement that may be put on the citrus carrier. When fatty acids, in particular short chain fatty acids, are put on the carrier, they are added as free acid in combination with a salt thereof in order to reduce the bad odour of the free acids. It was indeed found that the presence of such a salt reduces the vapour pressure, and thus the smell, of the acid in the solution. The salt can for example be obtained by ammoniating a portion of the acid. In the examples of WO 2009/002558 a solution of 65% propionic acid is for example ammoniated to pH 4.5. Since this is still lower than the pKa of propionic acid, most of the propionic acid is still present as free acid. This free acid is miscible with the water contained in the liquid whilst the ammonium salt dissolves therein.

A drawback of the feed supplement composition disclosed in WO 2009/002558 is that notwithstanding the fact that the liquid absorbed by the organic carrier comprises water the feed supplement should remain "dry". The amount of water in the liquid feed supplement absorbed by the carrier should therefore be kept sufficiently small. This means that only a small portion of the fatty acids contained therein can be converted into a salt as these salts are not liquid, in contrast to the free fatty acids, and thus need to be dissolved in the water present in the liquid. The term "dry" is moreover used in a very broad meaning in WO 2009/002558. The limit of a dry material is indeed defined therein as the condition up to the point where free liquid is observed on the sides of the test blender and is no longer absorbed onto the chemical carrier. The obtained product, which is not dried, contains thus a relatively large amount of water, and also of liquid acids. A drawback of this product is that the "dry" product has only a limited free flowability. An angle of repose of less than 40 degrees, which is described in WO 2009/002558 as indicating a free flowing composition, is still quite large.

An object of the present invention is to provide a new animal feed supplement composition, and a new method for preparing it, which has advantageous effects compared to the above described prior art compositions containing either medium chain fatty acids or a choline salt absorbed on a carrier. As defined in claim 1 , the method according to the present invention comprises the steps of providing a particulate absorbent carrier consisting of absorbent particles; providing a liquid which comprises at least said choline feed supplement substance dissolved in water; and allowing the particles of the absorbent carrier to absorb said choline feed supplement substance contained in said liquid. The method according to the invention is characterised in that the particles of the absorbent carrier are allowed to absorb also at least one medium chain fatty acid feed supplement substance which comprises a medium chain fatty acid group having a chain length of 6 to 12 carbon atoms so that substantially each of the particles of the animal feed supplement composition comprises the MCFA feed supplement substance and the choline feed supplement substance. This medium chain fatty acid feed supplement substance may be the same as or different from the choline feed supplement substance. When it is the same, it comprises a choline salt of the medium chain fatty acid. The animal feed supplement composition of the present invention, which is obtainable by the claimed method, comprises a particulate carrier, the particles of which, or preferably substantially each of the particles of which, have absorbed one or more feed supplement substances including at least one choline feed supplement substance and at least one medium chain fatty acid feed supplement substance.

According to the invention it has been found, on the one hand, that there is an almost linear relationship between the amount of water absorbed by the feed supplement composition (water uptake) after a predetermined period of time in a humid atmosphere and the choline feed supplement substance content of the feed supplement composition, expressed as % by dry weight of choline cations. On the other hand, it has been found that the medium chain fatty acid substance content of the feed supplement composition, expressed as % by dry weight of medium chain fatty acid equivalents, has substantially no effect on the water uptake. An advantage of the present invention is thus that by replacing part of the choline in the feed supplement composition by one or more fatty acids, the water uptake of the feed supplement composition is reduced. This reduction of the water uptake is obtained by means of valuable feed additives (MCFA feed supplement substances) which otherwise have to be dosed separately either directly or indirectly via a premix (with vitamins) into the feed. A first advantage of the reduced water uptake is that, when being exposed to the free atmosphere, the feed supplement composition remains flowable for a longer period of time since its water content increases less quickly. Moreover, its final moisture content is lower. When added to a premix, the risk of lumping is therefore smaller. Due to the lower equilibrium moisture content of the particles or even lumps of the feed supplement composition in the premix, it also has a smaller effect on the stability of the vitamins which are in contact with the particles or lumps of this relatively humid feed supplement composition.

In the method of the present invention the particles of the carrier are allowed to absorb both the choline feed supplement substance and the medium chain fatty acid feed supplement substance. The feed supplement composition of the present invention is thus not a mixture of absorbent carrier particles having absorbed the choline feed supplement substance and of absorbent carrier particles having absorbed the medium chain fatty acid feed supplement substance. It has indeed been found that such a mixture, which has a same average composition, has a same water uptake but, after having been exposed to a humid atmosphere, it consists of particles that have absorbed almost no water and particles that have absorbed a large amount of water, in particular to such an extent that they are swollen. The present inventor have found moreover quite by surprise that such a mixture of different particles has considerably worse flow properties than particles which have absorbed both the choline feed supplement substance and the medium chain fatty acid feed supplement substance. The mixture of the two types of particles is thus also more susceptible to lumping or caking. Moreover, when incorporated in a premix containing vitamins, the humid swollen carrier particles may form wet spots where the stability of the vitamins is negatively affected by the humid conditions caused by the high choline concentration.

In accordance with the present invention it has also been found that the combination of the medium chain fatty acid feed supplement substance and the choline feed supplement substance on the same carrier particles enables to improve the flow properties of the particulate feed supplement composition compared to a feed supplement composition which only contains one of these feed supplement substances.

In this respect, the animal feed supplement composition has preferably a choline feed supplement substance content, expressed in parts by weight of choline cations per 100 parts by weight of the feed supplement composition, and a medium chain fatty acid feed supplement substance content, expressed in parts by weight of medium chain fatty acid equivalents per 100 parts by weight of the feed supplement composition, in a ratio which is equal to or larger than 10/90, preferably equal to or larger than 15/85 and which is more preferably equal to or larger than 18/82 parts by weight of choline cations per parts by weight of medium chain fatty acid equivalents but equal to or smaller than 60/40, preferably equal to or smaller than 50/50 and which is more preferably equal to or smaller than 46/54 parts by weight of choline cations per parts by weight of medium chain fatty acid equivalents.

In a preferred embodiment of the method according to the present invention, the absorbent carrier is dried to produce a dry feed supplement composition having preferably a water content of less than 15 wt.%, more preferably of less than 10 wt.% and most preferably of less than 5 wt.%.

By drying the feed supplement composition, the flow properties of the feed supplement composition are improved. Due to the fact that part of the choline feed supplement substance has been replaced by the medium chain fatty acid feed supplement substance, the feed supplement composition absorbs less water, so that when the feed supplement composition is exposed to atmospheric conditions, it remains free or easy flowing for a longer period of time, in particular when the choline feed supplement substance has been replaced partially by the medium chain fatty acid feed supplement substance on substantially each of the carrier particles of the feed supplement composition. Due to the drying step, the absorbed water, which contained the feed supplement substances, has no effect on the flowability of the dried composition. Consequently, the carrier can be allowed to absorb a maximum of liquid before being dried. A larger amount of feed supplement substances can thus be applied on the carrier. This applies in particular to salts of medium chain fatty acids which have, compared to for example choline salts, a much lower solubility.

In a first particular embodiment of the method according to the present invention, the liquid which is absorbed by the absorbent particles of the carrier and which contains the choline feed supplement substance also contains the medium chain fatty acid feed supplement substance. In this embodiment, the medium chain fatty acid feed supplement substance is preferably a salt of a medium chain fatty acid which can be dissolved in the aqueous liquid containing the dissolved choline feed supplement substance.

Salts of medium chain fatty acids are preferred over the free fatty acids in view of their reduced odour compared to the odour of free fatty acids. Compared to free fatty acids, the salts thereof are much less volatile so that the carriers having absorbed these salts can be dried at higher temperatures without risk of losing part of these salts. This is in particular the case when no silica carriers are used, but instead cheaper organic carriers which bind free fatty acids less strongly than silica carriers. An advantage of dissolving both the choline and the MCFA feed supplement substance in said liquid is that, as a result of the higher solubility of choline feed supplement substances in water, a higher total concentration of feed supplement substances (choline and MCFA feed supplement substances) can be achieved more easily in the liquid which is to be absorbed by the absorbent carrier (i.e. without requiring heating or less heating of this liquid). As a result thereof, a higher total load of feed supplement substances can also be achieved more easily on the carrier compared to a feed supplement composition which only comprises the MCFA feed supplement substance absorbed on the carrier.

A preferred embodiment of the method according to the present invention comprises the step of producing the liquid which is absorbed by the absorbent carrier. In this step, an aqueous solution of at least one choline salt is provided and a medium chain fatty acid compound, which comprises the same medium fatty acid group as said medium chain fatty acid feed supplement substance, is added thereto. The medium chain fatty acid compound which is added to the choline salt solution is in particular a free fatty acid or a fatty acid salt. When added as a free fatty acid, the free fatty acid is preferably neutralized by adding an inorganic base to the choline salt solution, in particular sodium, potassium, ammonium, calcium and/or magnesium hydroxide.

Preferably, the liquid which is absorbed by the absorbent carrier has a pH higher than 5.0, preferably higher than 6.0 and more preferably higher than 6.8. In this way, this liquid is substantially free of free fatty acid. In a preferred embodiment of the method according to the invention, the pH of said liquid is lower than 12, preferably lower than 1 1 .

An advantage of this preferred embodiment is that the choline present in the composition is more stable, and is more particularly less subjected to decomposition with the formation of trimethylamine (TMA), especially when drying the composition, but also after the drying step, so that the formation of TMA, which can give some smell, can be avoided.

In a further preferred embodiment of the method according to the invention said liquid has a medium chain fatty acid feed supplement substance content, expressed in parts by weight of medium chain fatty acid equivalents per 100 parts by weight of liquid and a content of medium chain fatty acid feed supplement substances having a MCFA group with a chain length of less than nine, preferably of less than eight, carbon atoms, expressed in parts by weight of medium chain fatty acid equivalents per 100 parts by weight of liquid, which comprises between 20 and 90 wt.%, preferably between 30 and 80 wt.% of said medium chain fatty acid feed supplement substance content.

The combination of shorter MCFA's with longer MCFA's is advantageous in view of achieving broader antimicrobial effects. Moreover, the use of a feed supplement substance which comprises a medium chain fatty acid group having a carbon chain of less than nine, preferably of less than eight carbon atoms has the important advantage that it has a higher solubility in the liquid which is absorbed by the carrier so that a higher load can more easily be obtained. It also has been found quite surprisingly that the shorter the fatty acid chain, the greater the positive effect of the medium chain fatty acid feed supplement substance on the flow properties of the feed supplement composition.

In a second particular embodiment of the method according to the present invention, the choline feed supplement substance is contained in said liquid whilst the medium chain fatty acid feed supplement substance is contained in a further liquid, different from the liquid which contains the choline feed supplement substance. The absorbent particles are allowed to absorb both liquids.

An advantage of this embodiment is that the further liquid, i.e. the liquid containing the medium chain fatty acid feed supplement, doesn't have to be an aqueous liquid but may for example be an organic liquid. The further liquid can consist for example of the free medium chain fatty acid, or can consist more generally for at least 50 % by weight, preferably for at least 70 % by weight and more preferably for at least 90 % by weight of free (i.e. undissociated) medium chain fatty acid.

This second particular embodiment is especially advantageous when use is made of a silica carrier, in particular of a precipitated silica carrier. Such silica carriers can indeed easily absorb quite large amounts of the medium chain fatty acid feed supplement substance, in particular when the medium chain fatty acid feed supplement substance is a free fatty acid (organic liquid instead of an aqueous solution).

Preferably, the particles of the absorbent carrier are allowed to absorb first the further liquid containing the medium chain fatty acid feed supplement substance and subsequently the liquid containing the choline feed supplement substance.

An advantage of this embodiment is that when the further liquid is an oily organic liquid, containing in particular no water or less than 10 wt.% of water, it can be absorbed more easily, in a relatively large amount, by the absorbent particles which have not yet absorbed the choline feed supplement substance, and which therefore also have a lower water content.

The present invention also relates to an animal feed supplement composition which is obtainable, in particular obtained, by a method according to the invention and which comprises a particulate carrier consisting of particles having preferably each absorbed one or more feed supplement substances including at least one choline feed supplement substance and at least one medium chain fatty acid feed supplement which comprises a medium chain fatty acid group having a chain length of 6 to 12 carbon atoms and which may be the same as or different from said choline feed supplement substance.

Other particularities and advantages of the invention will become apparent from the following description of some particular embodiments of the method and of the animal feed supplement composition according to the present invention. Reference is made in the examples to the annexed drawings wherein:

Figure 1 is a graph showing the water uptake of the final products obtained in Examples 1 to 5 over time;

Figure 2 is a graph showing the water uptake of a product comprising a mixture of corn cob particles loaded with choline chloride and corn cob particles loaded with C7/C9 sodium carboxylates and of a product according to the invention comprising corn cob particles loaded with a mixture of choline chloride and C7/C9 sodium carboxylates;

Figure 3 is an enlarged picture of the corn cob particles which are loaded with the mixture of choline chloride and C7/C9 sodium carboxylates; and

Figure 4 is an enlarged picture of the mixture of corn cob particles loaded with choline chloride and of corn cob particles loaded with the C7/C9 sodium carboxylates.

The present invention relates to an animal feed supplement composition comprising feed supplement substances absorbed onto a particulate carrier and to a method for producing this feed supplement composition. The feed supplement substances comprise at least one medium chain fatty acid (MCFA) feed supplement substance and at least one choline feed supplement substance. These two feed supplement substances may be different from one another, but may also be the same, in which case they comprise a choline salt of the medium chain fatty acid. In the present specification and claims, when mention is made of the (or of said) MCFA feed supplement substance, this refers to the MCFA feed supplement substance if there is only one MCFA feed supplement or to at least one, and preferably to all, of the MCFA feed supplement substances if there is more than one MCFA feed supplement substance. The same goes for the choline feed supplement substance. When mention is made in the present specification and claims of the (or of said) choline feed supplement substance, this refers to the choline feed supplement substance if there is only one choline feed supplement or to at least one, and preferably to all, of the choline feed supplement substances if there is more than one choline feed supplement substance.

The MCFA feed supplements comprise a medium chain fatty acid group which has a chain length of 6 to 12 carbon atoms, i.e. it is a C6, C7, C8, C9, C10, C1 1 or C12 fatty acid group. The fatty acid group can be branched, in particular for a part thereof, for example when the fatty acid groups are made synthetically, in which case all the carbon atoms fatty acid group are counted for determining the chain length. The fatty acid group is however usually not branched. The fatty acid group can be saturated or unsaturated but it preferably saturated. The fatty acid group of the MCFA feed supplement substance is in particular not an unsaturated C6 fatty acid group, and comprises in particular no sorbate group.

The MCFA feed supplement substance can be the free medium chain fatty acid, i.e. the MCFA group provided with a hydrogen atom to form an undissociated carboxylic acid group. The MCFA feed supplement substance can also be an ester or an amide of the medium chain fatty acid, in particular a glyceride, preferably a monoglyceride, of the MCFA. The MCFA feed supplement substance is however preferably a salt, for example a sodium, potassium, ammonium, calcium, magnesium and/or choline salt.

The choline feed supplement substance is a salt comprising a choline cation. Examples of such salts are choline chloride, choline citrate, choline bitartrate, choline bicarbonate, choline sulphate, choline phosphate, choline carboxylates.

The feed supplement composition of the present invention may contain different of the above described MCFA feed supplement substances and/or choline feed supplement substances. In view of the lower volatility of fatty acid salts, compared to free fatty acids, and the higher solubility thereof in water, one or more of the MCFA feed supplement substances are preferably a salt, in particular so that at least 70 wt.%, preferably at least 80 wt.% and more preferably at least 90 wt.% of the MCFA and choline feed supplement substances are a salt.

Moreover, the feed supplement composition of the present invention preferably contains no or only a limited amount of free medium chain fatty acids in acid form. In particular, the feed supplement composition is free of free medium chain fatty acids in acid form or has a free medium chain fatty acid content in acid form which is less than 30%, preferably less than 20% and more preferably less than 10% of its medium chain fatty acid feed supplement substance content, expressed in parts by weight of medium chain fatty acid equivalents per 100 parts by dry weight of the feed supplement composition.

In a preferred embodiment, the feed supplement composition comprises at least one MCFA feed supplement substance which has a MCFA group with a chain length of less than nine, preferably of less than eight carbon atoms, the MCFA group being in other words in this preferred embodiment a C6, C7 or C8 MCFA group, or preferably a C6 or a C7 MCFA group. In particular, the feed supplement composition has a content of MCFA feed supplement substances having a MCFA group with a chain length of less than nine, preferably of less than eight carbon atoms, expressed in parts by weight of medium chain fatty acid equivalents (i.e. of hexanoic and/or heptanoic acid) per 100 parts by dry weight of the feed supplement composition, which comprises between 20 and 90 wt.%, preferably between 30 and 80 wt.% of its MCFA feed supplement substance content, expressed in parts by weight of MCFA equivalents per 100 parts by dry weight of the feed supplement composition. An advantage of such shorter MCFA feed supplement substances is that the solubility of the salts thereof is higher in water and that they enable to achieve better flow properties.

As described hereabove, the choline feed supplement substance may be a choline salt of a medium chain fatty acid. However, the feed supplement composition is preferably free of choline carboxylates or has a choline carboxylate content, expressed in parts by weight of choline carboxylate per 100 parts by dry weight of the feed supplement composition, which is less than 30%, preferably less than 20% and more preferably less than 10% of its total choline feed supplement substance content, expressed in parts by weight of choline feed supplement substances per 100 parts by dry weight of the feed supplement composition. An advantage of this preferred embodiment is that the use of choline salts different from choline carboxylates, enables to achieve better flow properties.

The feed supplement composition preferably contains the MCFA and the choline in certain mutual ratio's. More particularly, it has preferably a choline feed supplement substance content, expressed in parts by weight of choline cations per 100 parts by dry weight of the feed supplement composition, and a medium chain fatty acid feed supplement substance content, expressed in parts by weight of medium chain fatty acid equivalents per 100 parts by dry weight of the feed supplement composition, in a ratio which is equal to or larger than 10/90, preferably equal to or larger than 15/85 and which is more preferably equal to or larger than 18/82 parts by weight of choline cations per parts by weight of medium chain fatty acid equivalents but equal to or smaller than 60/40, preferably equal to or smaller than 50/50 and which is more preferably equal to or smaller than 46/54 parts by weight of choline cations per parts by weight of medium chain fatty acid equivalents.

In addition to the feed supplement substances, the animal feed supplement composition of the present invention comprises a particulate carrier consisting of absorbent particles onto which the feed supplement substances are absorbed. All of the particles have preferably absorbed all of the feed supplement substances contained in the feed supplement composition. The feed supplement composition is therefore preferably not a mixture of absorbent particles having absorbed the choline feed supplement substance and of absorbent particles having absorbed the MCFA feed supplement substance.

The carrier is an edible carrier. It can be an inorganic carrier, in particular a carrier comprising silica powder, diatomaceous earths and/or clays such as kaolin and bentonite. The inorganic carrier preferably comprises a silica material, more preferably a precipitated silica material. Such precipitated silica materials are for example disclosed in US 6 960 251 and in US 7 153 521 , the description and definition of a precipitated silica material given in these US patents being included in the present specification by way of reference.

The carrier can also be an organic carrier and comprises for example a ground vegetable or animal material, or a mixture thereof, such as particulate corn cob, rice chaffs, rice meal, beet cossettes, extracted palm kernel meal, corn meal, cereal bran, extracted soybean meal, feather meal, fish meal and/or bone meal. Preferred carriers are ground corn cob, wheat bran and rice hulls or mixtures thereof.

Due to the presence of the carrier, the amount of MCFA and choline feed supplement substance in the feed supplement composition is less high than in so-called carrier free feed supplement compositions. Nevertheless, relatively high total amounts of MCFA and choline feed supplement substances can be achieved. The feed supplement composition preferably comprises in total at least 30 wt.%, preferably at least 35 wt.% and more preferably at least 40 wt.% of the MCFA and choline feed supplement substances on the total dry weight of the dry feed supplement composition. Due to the fact that these feed supplement substances have to be absorbed onto the carrier, the feed supplement composition contains in total usually less than 80 wt.% and in particular less than 70 wt.% of the MCFA and choline feed supplement substances on the total dry weight of the dry feed supplement composition.

For preparing the feed supplement composition, a particulate absorbent carrier is provided, for example silica powder or ground corn cob. This carrier consists of small individual solid particles. The feed supplement substances, in particular the MCFA and the choline feed supplement substances, are provided in a liquid form and the absorbent particles of the carrier are allowed to absorb the liquid or liquids containing these feed supplement substances.

The choline feed supplement substance is a salt that is dissolved in water. The MCFA feed supplement substance can be a free fatty acid. Free MCFA's have a relatively low melting point and can thus be applied directly, in liquid form, onto the carrier. This can be done before, after or partially before and partially after the carrier has absorbed the liquid that contains the choline feed supplement substance. The carrier having absorbed the choline feed supplement substance can be dried first before applying the MCFA feed supplement substance. Due to the fact that the liquid MCFA contains no or substantially no water, and the choline feed supplement substance can be dissolved in a small amount of water (for example in case of a 75 wt.% choline chloride solution), it is possible to applying both onto the absorbent carrier particles without having to dry the obtained product. The liquid MCFA is preferably applied first onto the carrier particles and subsequently the aqueous choline feed supplement solution. Since no drying is required, there is no risk that the MCFA will evaporate during the drying process.

Since inorganic carriers such as silica powders, in particular precipitated silica carriers, can absorb more water than organic carriers, and can also absorb MCFA's more strongly, they are preferably used when the MCFA feed supplement substance is a free fatty acid. They can indeed absorb the water from the aqueous choline solution whilst still remaining dry and maintaining their flow properties. Moreover, it has been found that a silica carrier having absorbed MCFA's can be dried without losing the MCFA's by evaporation. A bad smell of the feed supplement composition can also be avoided, especially in case of a silica carrier, in particular by adding a flavouring agent.

Organic carriers, in particular animal or vegetal carriers such as ground corn cob, are considerably less expensive than silica carriers. They have however to be dried to remain free or easy flowing. The MCFA can be applied also as a liquid composed of the free fatty acid onto the absorbent particles of such organic carriers. However, since they have to be dried after having absorbed the aqueous choline solution, the MCFA feed supplement substance is preferably also applied as a salt dissolved in water. Such a salt is indeed less volatile than the corresponding free fatty acid and also doesn't cause such a bad smell so that flavouring agents are not needed. The carrier therefore also doesn't need to be able to bind strongly to the MCFA feed supplement so that any organic carrier, which can absorb a sufficient amount of the aqueous liquid, is suitable.

The choline feed supplement substance and the MCFA feed supplement substance can be added in separate liquids to the carrier particles, i.e. respectively in a liquid and in a further liquid. As explained hereabove, the particles of the absorbent carrier are preferably allowed to absorb first the liquid containing the MCFA feed supplement substance and subsequently the liquid containing the choline feed supplement substance (which may optionally contain a part of the MCFA feed supplement substance in the form of a water soluble salt). The liquid containing the MCFA feed supplement substance comprises this MCFA feed supplement substance preferably in the form of an undissociated free fatty acid and preferably consists for at least 50 % by weight, more preferably for at least 70 % by weight and most preferably for at least 90 % by weight of undissociated free MCFA (or MCFA's).

The particles of the carrier are preferably allowed to absorb such an amount of the liquid containing the choline feed supplement substance and of the further liquid containing the MCFA feed supplement substance that the feed supplement composition, in particular substantially each of the absorbent particles thereof, comprises these feed supplement substances in the mutual ratio's described hereabove.

Instead of applying the feed supplement substances by means of different liquids onto the carrier particles, they are preferably applied by means of one single aqueous liquid so that they can be applied easily in one step (which does not exclude that they are applied in two steps onto the carrier particles, preferably with an intermediate drying step, in order to be able to achieve a higher feed supplement substance load on the particles). The feed supplement substances, in particular the MCFA and choline feed supplement substances, are thus preferably provided in a liquid that contains water wherein the feed supplement substances are at least partially dissolved. The particulate absorbent carrier is brought in contact with this liquid and is allowed to absorb it. The different feed supplement substances are thus intimately mixed on the carrier.

The liquid which is to be absorbed by the carrier can be made in different ways.

In a first step an aqueous solution of at least one choline salt, for example choline chloride, is provided. Such solutions are readily available, for example 75% choline chloride solutions. To this solution a MCFA compound, which comprises the same MCFA group as the MCFA feed supplement substance which is to be provided on the carrier, is added.

This MCFA compound can be an ester or an amide of the MCFA. When it is not miscible or not soluble in the aqueous solution, an emulsion can be made for example by means of emulsifiers. The MCFA can also be the free MCFA itself, i.e. in acid form. Since the solubility of the free fatty acid is low in the aqueous solution, it is also possible to make an emulsion of the fatty acid and the aqueous choline solution. This emulsion can then be applied onto the carrier.

Preferably, however, the free fatty acid is neutralised in the aqueous choline solution by adding a base thereto, in particular sodium, potassium, calcium and/or magnesium hydroxide or ammonium. The base is preferably added to the aqueous solution after having added the free fatty acid thereto. It has been found that in this way a solution of the choline salt and of the in situ produced MCFA salt can easily be obtained.

Instead of producing the MCFA salt in situ in the aqueous solution, it can also be added as such to that solution, preferably after having dissolved it in water. The MCFA salt which is added is preferably a sodium, potassium, ammonium, calcium and/or magnesium salt of the MCFA. In accordance with the invention, it has been found that the presence of a MCFA salt on the carrier, in combination with a choline salt, enables to achieve better flow properties, and enables in particular to achieve an easy or even a free flowing powder having a flow factor index ff larger than 4, preferably larger than 5, more preferably larger than 6 and most preferably larger than 7. An additional advantage of a MCFA salt is that it is not or at least much less volatile than the corresponding MCFA so that it is not lost during drying, even not on organic carriers, and so that it causes less odour problems than free fatty acids.

The choline salt solution preferably comprises choline chloride, choline citrate or choline bitartrate. Other salts are however also possible such as choline bicarbonate, choline sulphate, choline phosphate and choline carboxylates. The choline salt may in particular comprise a choline salt of a MCFA. This salt can be produced by adding a MCFA to a choline base (choline hydroxide) solution or by using MCFA as acid, instead of HCI, during the production of choline. This choline carboxylate solution can be applied as such to the absorbent carrier but, if more MCFA is needed in the feed supplement composition, additional MCFA can be added to this solution, either as a free fatty acid (subsequently neutralised by means of a base) or as a salt. This additional MCFA may be the same as or different from the MCFA of the choline carboxylate.

As explained hereabove, the feed supplement composition preferably contains no or only a limited amount of choline carboxylates. Indeed, compared to choline carboxylates other choline salts were found to enable to achieve better flow properties.

The liquid which is applied onto the absorbent carrier has preferably a pH higher than 5.0, more preferably higher than 6.0 and most preferably higher than 6.8. An advantage of such a relatively high pH is that when the liquid comprises a MCFA salt, most of the MCFA is in its dissociated (anionic) form so that substantially no free fatty acid will be present on the carrier. The pH of the liquid absorbed by the carrier is however preferably lower than 12 and more preferably lower than 1 1 . It has indeed been found that at higher pH values choline decomposes more quickly with the formation of volatile trimethylamine.

To achieve the above-described preferred choline/MCFA ratios without having to apply an additional liquid that contain the choline feed supplement substance and/or the MCFA feed supplement substance, the liquid absorbed by the carrier is composed to have a choline feed supplement substance content, expressed in parts by weight of choline cations per 100 parts by weight of liquid, and a MCFA feed supplement substance content, expressed in parts by weight of MCFA equivalents per 100 parts by weight of liquid, in a ratio which is equal to or larger than 10/90, preferably equal to or larger than 15/85 and which is more preferably equal to or larger than 18/82 parts by weight of choline cations per parts by weight of MCFA equivalents. The ratio between the choline feed supplements substance content and the MCFA feed substance content of the liquid is moreover preferably equal to or smaller than 60/40, preferably equal to or smaller than 50/50 and which is more preferably equal to or smaller than 46/54 parts by weight of choline cations per parts by weight of MCFA equivalents.

With respect to the chain length of the MCFA's, it has been found by the present inventors that salts of shorter chain MCFA's, having a chain length of less than nine, preferably of less than eight carbon atoms, i.e. six or seven carbon atoms, have not only a higher solubility in water but provide also for better flow properties. In this respect, the liquid absorbed by the carrier is provided with such an amount of MCFA feed supplement substances which have a MCFA group with a chain length of less than nine, preferably of less than eight carbon atoms, expressed in parts by weight of MCFA equivalents per 100 parts by weight of liquid, which comprises between 20 and 90 wt.%, preferably between 30 and 80 wt.% of the total MCFA feed supplement substance content of the liquid, expressed in parts by weight of MCFA equivalents per 100 parts by weight of liquid.

An important feature of the feed supplement composition is its water uptake, i.e. the amount of water the feed supplement composition absorbs when being in contact with an atmosphere that contains moisture for a predetermined period of time. When adding the feed supplement composition to a premix containing vitamins, this is important to avoid a too high humidity at the location of the particles of the feed supplement composition, and to avoid lumping or caking of the premix. Avoiding a too high water uptake within a short period of time, for example within a few hours, is also important in view of the fact that flowability of the composition becomes worse when its water content increases. Due to the fact that in the feed supplement composition of the present patent application part of the choline feed supplement is replaced by one or more MCFA's feed supplements, the water uptake is reduced preferably to such an extent that the composition remains easy or free flowable for at least a few hours, or preferably even for a day (or for a few days).

The different particles of the carrier should preferably be allowed to absorb both the choline feed supplement substance and the MCFA feed supplement substance. As a matter of fact it has been found that, although the water uptake after a predetermined number of hours in a humid atmosphere depends merely on the (average) choline content of the feed supplement composition, the flowability of the feed supplement is negatively affected when the choline and MCFA feed supplement substances are not uniformly distributed over the particles of the carrier. In particular, the flowability of particles having each absorbed the choline and the MCFA feed supplement substance is considerably better, after having been kept for a few days in a humid atmosphere, than the flowability of a mixture of the same particles having absorbed only the choline feed supplement substance and of particles having absorbed only the MCFA feed supplement substance same and kept for a same number of hours in the same humid atmosphere. Consequently, in the feed supplement composition of the present invention, the choline and the MCFA feed supplement substances are preferably substantially uniformly distributed over the carrier particles, i.e. each of the carrier particles has substantially a same concentration of these feed supplement substances.

In order to enable to dose the feed supplement composition easily and correctly to the feed or to a premix, the feed supplement composition should preferably be free flowing or at least easy flowing. These properties can be determined for example with a Brookfield powder flow tester of Brookfield Engineering Laboratories Inc. as described in the Manual No. M09-1200-C0213. As disclosed in that manual, the standard classification of powder flowability uses the flow factor index ff, which indicates a linear relationship between the major principal consolidation stress σι and the unconfined failure strength o_c. The different powder flowabilities are indicated in Table 1 .

Table 1 : Standard classification of powder flowability

When using a highly absorbent carrier, such as a silica gel material which strongly absorbs liquids, a relatively high amount of water and/or liquid feed supplement substances (such as free fatty acids and fatty acid esters and amides) can be absorbed without having a too large negative effect on the flowability of the feed supplement composition. In a preferred embodiment of the method according to the present invention cheaper, less absorbent particulate carriers are however used, in particular organic carriers which are of vegetal or animal origine. Only a limited amount of liquid can be absorbed thereon and lumping or caking of the composition occurs more quickly.

In a preferred embodiment of the method according to the present invention, the absorbent carrier which has absorbed the liquid containing the feed supplement substances is therefore dried. Different drying techniques can be used, in particular fluid bed drying techniques wherein the feed supplement is dried by means of a heated air stream. The feed supplement composition is in particular dried until it has a water content of less than 15 wt.%, preferably of less than 10 wt.% and more preferably of less than 5 wt.%. In practice, the feed supplement is preferably dried to a water content of between 1 and 2 wt.%. After the drying step, the composition is packaged in a hermetically sealed packaging to prevent absorption of moisture from the atmosphere.

The following examples are intended to illustrate the present invention and not to limit it thereto. As carrier use was made in these examples of corn cob which was ground so that its particle size was between 200 and 800 μηη.

EXPERIMENTS WITH CORN COB AS CARRIER

Example 1 (comparative): Preparation of sodium carboxylate on corn cobs

Example 1.1 : C7/C9 sodium carboxylates (50% load)

A 50/50 w/w mixture of heptanoic acid and nonanoic acid was used for the preparation of sodium carboxylate. A sodium hydroxide solution was neutralized with this mixture. Because of the low solubility of sodium carboxylate, water was added to obtain a solution. The final solution contained 41 wt.% sodium carboxylate.

First, 70 g corn cobs were soaked in 256 g of the sodium carboxylate solution to obtain a 60 % load. After soaking, the mixture was too wet to dry in a fluid bed drier. A second test was done by soaking 70 g of corn cobs in 171 g of sodium carboxylate solution to obtain a 50% load. In this test, it was no problem to dry the product in a fluid bed drier. The product was dried during 1 hour in a fluid bed drier at 70 °C.

Example 1.2: C7/C9 sodium carboxylates (60% load)

Example 1 .1 was repeated (50/50 C7/C9) but the final solution was made at a higher temperature of 60°C so that a higher concentration of sodium carboxylate could be obtained. The corn cob carrier was allowed to absorb this solution to achieve a load of 60 %.

Example 2 (comparative): Preparation of choline chloride on corn cobs (60% load)

Choline chloride was put industrially on corn cobs with a final load of 60 % wt. choline chloride. This dry choline chloride on corn cobs was produced by adding 140 g of 75 % choline chloride solution to 70 g of corn cobs and drying during 1 hour in a fluid bed drier at 70 °C. Theoretically, 60 % wt. choline chloride was present on the corn cobs. Example 3: Preparation of choline carboxylate on corn cobs (58% load)

A 50/50 w/w mixture of heptanoic acid and nonanoic acid was used for the preparation of the choline carboxylate. Choline base was neutralized with this mixture. When analyzing the mixture, 60.2 wt.% choline carboxylate was found. The mixture contained 25 wt.% of choline cations and 35 wt.% of MCFA equivalents so that the ratio between the choline cations content and the MCFA equivalents content was equal to about 42/58.

In the lab, a dry product was produced by adding 163 g of choline carboxylate solution to 70 g of corn cobs and drying during 1 hour in a fluid bed drier at 70 °C. Theoretically, 58 wt.% choline carboxylate was present on the corn cobs.

Example 4: Preparation of choline carboxylate - sodium carboxylate mixtures on corn cobs

The 60.2 wt.% choline carboxylate solution of Example 3 was mixed in different ratios with the 41 wt% sodium carboxylate solution of comparative Example 1 . The ground corn cob was soaked with these mixtures and dried for 1 hour in a fluid bed drier at 70 °C.

Example 4.1 80/20 choline carboxylate - sodium carboxylate (50% load)

320 g of the 60.2 wt.% choline carboxylate solution and 122 g of the 41 wt.% sodium carboxylate solution were mixed to have a mixture containing 80/20 choline carboxylate - sodium carboxylate on dry matter. The mixture therefore contained 43.6 wt.% of choline carboxylate and 1 1 .3 wt.% of sodium carboxylate (in total 54.9 wt.% of active ingredients).

First, 70 g of corn cobs were soaked in 181 g of the mixture to obtain a 60 % load. After soaking, the product was too wet to dry in a fluid bed drier. A second test was done by soaking 70 g corn cobs in 121 g of the mixture to obtain a 50 % load. In this last test, it was no problem to dry the product in a fluid bed drier. The product was dried during 1 hour in a fluid bed drier at 70 °C. The final product contained theoretically 16.7 wt.% of choline cations and 31 .8 wt.% of MCFA equivalents so that the ratio between the choline cations content and the MCFA equivalents content was equal to about 34/66.

Example 4.2 50/50 choline carboxylate - sodium carboxylate (50% load)

155 g of the 60.2 % choline carboxylate solution and 244 g of the 41 % sodium carboxylate solution were mixed to have a mixture containing 50/50 choline carboxylate - sodium carboxylate. The mixture therefore contained 23.4 wt.% of choline carboxylate and 25.1 wt.% of sodium carboxylate (in total 48.5 wt.% of active ingredients).

First, 70 g of corn cobs were soaked in 210 g of the mixture to obtain a 60 % load. After soaking, the product was too wet to dry in a fluid bed drier. A second test was done by soaking 70 g of corn cobs in 140 g of the mixture to obtain a 50 % load. In this last test, it was no problem to dry the product in a fluid bed drier. The product was dried during 1 hour in a fluid bed drier at 70 °C.

The final product contained theoretically 10.2 wt.% of choline cations and 36.3 wt.% of MCFA equivalents so that the ratio between the choline cations content and the MCFA equivalents content was equal to about 22/78.

Example 4.320/80 choline carboxylate - sodium carboxylate (50% load)

50 g of the 60.2 % choline carboxylate solution and 394 g of the 41 % sodium carboxylate solution were mixed to have a mixture containing 20/80 choline carboxylate - sodium carboxylate on dry matter. The mixture therefore contained 6.8 wt.% of choline carboxylate and 36.4 wt.% of sodium carboxylate (in total 43.2 wt.% of active ingredients). First, 70 g of corn cobs were soaked in 240.8 g of the mixture to obtain a 60 % load. After soaking, the product was too wet to dry in a fluid bed drier. A second test was done by soaking 70 g of corn cobs in 160.5 g of the mixture to obtain a 50 % load. In this last test, it was no problem to dry the product in a fluid bed drier. The product was dried during 1 hour in a fluid bed drier at 70 °C.

The final product contained theoretically 3.3 wt.% of choline cations and 40.9 wt.% of MCFA equivalents so that the ratio between the choline cations content and the MCFA equivalents content was equal to about 7/93.

Example 5: Preparation of choline chloride - sodium carboxylate mixtures on corn cobs

The 41 wt% sodium carboxylate solution of comparative Example 1 was mixed in different ratios with a commercially available 75 wt.% choline chloride solution. The ground corn cob was soaked with these mixtures and dried for 1 hour in a fluid bed drier at 70 °C.

Example 5.1 80/20 choline chloride - sodium carboxylate (60% load)

267 g of the 75 % choline chloride solution and 122 g of the

41 % sodium carboxylate solution were mixed to have a mixture containing 80/20 choline chloride - sodium carboxylate on dry matter. The mixture therefore contained 51 .5 wt.% of choline chloride and 12.9 wt.% of sodium carboxylate (in total 64.4 wt.% of active ingredients).

70 g of corn cobs were soaked in 210 g of the mixture to obtain a 60 % load. After soaking, the product was dried in a fluid bed drier for 1 hour at 70 °C.

The final product contained theoretically 35.8 wt.% of choline cations and 10.3 wt.% of MCFA equivalents so that the ratio between the choline cations content and the MCFA equivalents content was equal to about 78/22.

Example 5.2 50/50 choline chloride - sodium carboxylate (60% load)

134 g of the 75 % choline chloride solution and 244 g of the

41 % sodium carboxylate solution were mixed to have a mixture containing 50/50 choline chloride - sodium carboxylate on dry matter. The mixture therefore contained 26.6 wt.% of choline chloride and 26.5 wt.% of sodium carboxylate (in total 53.1 wt.% of active ingredients).

70 g of corn cobs were soaked in 234 g of the mixture to obtain a 60 % load. After soaking, the product was dried in a fluid bed drier for 1 hour at 70 °C.

The final product contained theoretically 22.4 wt.% of choline cations and 25.9 wt.% of MCFA equivalents so that the ratio between the choline cations content and the MCFA equivalents content was equal to about 46/54.

Example 5.320/80 choline chloride - sodium carboxylate (50% load)

50 g of the 75 % choline chloride solution and 366 g of the 41 % sodium carboxylate solution were mixed to have a mixture containing 20/80 choline chloride - sodium carboxylate on dry matter. The mixture therefore contained 9.0 wt.% of choline chloride and 36.1 wt.% of sodium carboxylate (in total 45.1 wt.% of active ingredients).18/82

First, 70 g of corn cobs were soaked in 233 g of the mixture to obtain a 60 % load. After soaking, the product was too wet to dry in a fluid bed drier. A second test was done by soaking 70 g corn cobs in 156 g of the mixture to obtain a 50 % load. In this last test, it was no problem to dry the product in a fluid bed drier. The product was dried during 1 hour in a fluid bed drier at 70 °C. The final product contained theoretically 7.5 wt.% of choline cations and 34.5 wt.% of MCFA equivalents so that the ratio between the choline cations content and the MCFA equivalents content was equal to about 18/82.

Example 5.420/80 choline chloride - sodium carboxylate (60% load)

Example 5.3 was repeated but the final solution was made at a higher temperature of 60°C so that a higher concentration of choline chloride and sodium carboxylate could be obtained. The corn cob carrier was allowed to absorb this solution to achieve a load of 60 %. Just as in Example 5.3 the ratio between the choline cations content and the MCFA equivalents content was equal to about 18/82.

Example 5.5 10/90 choline chloride - sodium carboxylate (60% load)

The 75 % choline chloride solution and the 41 % sodium carboxylate solution were mixed to have a mixture containing 10/90 choline chloride - sodium carboxylate on dry matter. The ratio between the choline cations content and the MCFA equivalents content was equal to about 8/92. By heating the solution a higher concentration could be obtained therein enabling to achieve a total load of 60%.

Example 5.6 30/70 choline chloride - sodium carboxylate (60% load)

The 75 % choline chloride solution and the 41 % sodium carboxylate solution were mixed to have a mixture containing 30/70 choline chloride - sodium carboxylate on dry matter. The ratio between the choline cations content and the MCFA equivalents content was equal to about 27/73. By heating the solution a higher concentration could be obtained therein enabling to achieve a total load of 60%. Testing of the water uptake of Examples 1 to 5.3 and of corn cob

The samples prepared in Examples 1 to 5, and a sample comprising only the ground corn cob, were put in an oven for 1 hour at 60 °C to evaporate most of the water present. Of each product, 1 g was put in an aluminum cup and was put in a desiccator with a saturated NaCI-solution. This solution keeps the relative humidity of the atmosphere in the desiccator at 75%.

The flowability of the samples was tested visually over time. This visual method only allowed to determine whether the samples were flowing. A visually flowable sample is indicated in Table 1 by a "+" whilst a less flowable sample was indicated with a In Table 1 the choline cation contents and the MCFA equivalent contents are also indicated, as well as the sodium and chloride contents.

Table 1 : Visual flowing properties of water uptake samples over time

It can be seen that ground corn cobs are visually flowable and remain flowable when the different compositions have been put thereon. However, when the composition comprises only choline chloride, it looses after two to four hours its flowing properties. This process can be slowed down by replacing a portion of the choline salt by a medium chain fatty acid salt. The lower the choline cation content, the longer the feed supplement composition remains flowable. In Examples 5.1 and 5.2 the flowability of the feed supplement composition was already considerably improved (flowable for more than 4 hours) by a reduced choline cation/MCFA equivalents ratio of respectively 78/22 and 46/54. By further reducing this ratio, the composition can be maintained for a longer period of time flowable, and remained flowable in the case of Example 5.3, with a choline cation/MCFA equivalents ratio of 18/82, for a period of time which was longer than 168 hours.

The water uptake of the samples was measured by the increase in weight over time. The graph in Figure 1 represents the water uptake of the samples over time.

It can be seen that the water uptake depends on the amount of choline in the formulation. The more choline present, the more water the composition absorbs. For the compositions of Examples 1 .1 , 4.1 , 4.2, 4.3 and 5.3, which remained flowable even after 168 hours, the water uptake remained below 23%.

Examples 5.7 and 5.8: Comparison of the water uptake and flowabilitv after being exposed to humid conditions of a mixture of 70 wt.% of the product of comp. Ex. 1.1 and 30 wt.% of the product of comp. Ex. 2 with a product according to the invention containing the same carrier and the same amount of feed supplement substances.

A mixture containing 70 wt.% of the product of comp. Ex. 1 .1 (50/50 C7/C9 sodium carboxylates on carrier) and 30 wt.% of the product of comp. Ex. 2 (choline chloride on carrier) was made (Ex. 5.7: not according to the invention). An aqueous solution of the same sodium carboxylates and of choline chloride was made and was put on the same corn cob carrier (Ex. 5.8). Both products had the same average composition. The two samples, and a sample of comp. Ex. 1 .1 and one of comp. Ex. 2, were put in an oven for 1 hour at 60 °C to evaporate most of the water present. Of each product, 1 g was put in an aluminum cup and was put in a chamber having a humidity content of 70%.

The water uptake of the samples was measured by the increase in weight over time. The graph in Figure 2 represents the water uptake of the samples over time.

It can be seen that the water uptake depends again on the amount of choline in the formulation. The more choline present, the more water the composition absorbs. It can also be seen that the water uptake of the product according to the invention (Ex. 5.8) is substantially the same as the water uptake of the mixture of the carrier particles containing only the choline feed supplement substance and the carrier particles containing only the mixture of the MCFA feed supplement substances (mixture of C7 and C9 MCFA's) (Ex. 5.7). After having been exposed for one day to the humid atmosphere, both products could however be distinguished visually (see the enlarged pictures in Figures 3 and 4) from one another due to the fact that the mixture of particles containing only the choline feed supplement substance and of particles containing only the MCFA feed supplement substances clearly contained particles that are darker and more swollen by having absorbed a larger amount of moisture. Those more swollen particles formed also stuck together in aggregates as can be seen in the enlarged picture of Figure 4. The flowability of both products was also measured, in the way described hereunder. The flowability of the product of the present invention (Ex. 5.8) was considerably better than the flowability of the mixture of the particles which were loaded with the choline feed supplement substance and the particles which were loaded with the MCFA feed supplement substances (Ex. 5.7). The product of Example 5.8 was indeed still easy flowing after being exposed to the humid conditions (flow factor index ff equal to 5.9) whilst the product of Example 5.7 became cohesive (ff = 3.8) after the water uptake.

Testing of the flow properties

Examples 1.2, 2, 5.1 , 5.2, 5.4, 5.5 and 5.6 and of corn cob: Choline chloride/sodium carboxylates mixtures (60% load)

With the use of the Brookfield powder flow tester, the flowability of the powders could be examined. The operating instruction of this powder flow tester can be found back in the Manual No. M09- 1200-C0213 of the Brookfield Engineering Laboratories, Inc. The flowability was an important parameter for the final product.

The flow was expressed in flow functions. A certain stress was applied to the sample with a metal ring and this ring rotated. Depending on the strength that was required to turn the ring, the flowing could be determined. The flow functions were compared with standard flow functions. In Table 2 the flow factor indexes ff are indicated as calculated for the last value (highest value of the major principal consolidation stress).

Table 2: Flow factor indexes ff for the different examples with a 60% load of choline chloride/sodium carboxylates (50/50 C7/C9) mixtures on corn cob

Example ff Choline cations/MCFA Load

equivalents ratio

Corn cob 5.3 - -

Ex. 1 .2 5.6 0/100 60%

Ex. 5.5 4.8 8/92 60% Ex. 5.4 1 1 .1 18/82 60%

Ex. 5.6 9.1 27/73 60%

Ex. 5.2 12.5 46/54 60%

Ex. 5.1 4.8 78/22 60%

Ex. 2 5.0 100/0 60%

In Table 2 it can be seen that pure corn cob and corn cob loaded with sodium carboxylate or with choline chloride are easy flowing, and remain at least easy flowing when using mixtures of choline chloride and sodium carboxylate. Surprisingly, an intermediate mixtures of choline chloride and sodium carboxylate, having a choline cations/MCFA equivalents ratio higher than 8/92 but lower than 78/22, had a much better flowability and was clearly free flowing (having a flow factor index larger than 10).

Examples 4.1 , 4.2 and 4.3: Choline carboxylates as initial product

The flow factor indexes of the products starting with choline carboxylate are indicated in Table 3. Table 3: Flow factor indexes ff for the different examples with choline carboxylate on corn cob either alone or in combination with sodium carboxylates (50/50 C7/C9) mixtures

Example ff Choline cations/MCFA Load

equivalents ratio

Ex. 3 2.3 42/58 60%

Ex. 4.1 2.8 34/66 50%

Ex. 4.2 3.6 22/78 50%

Ex. 4.3 4.2 7/93 50% It can be seen that by using choline carboxylate instead on choline chloride, the flow properties were worse but the products were still visually flowable. As indicated in Table 1 they remained flowable for a long time, certainly for Example 4.1 containing choline carboxylate in combination with a minor amount of sodium carboxylate. When more sodium carboxylate was loaded on the carrier (Examples 4.2 and 4.3) the flowability was improved somewhat.

Stability during drying

An extra drying was performed on the dry product on corn cobs in the fluid bed drier at 70 °C. The product was made with a 50/50 mixture of choline chloride and a sodium carboxylate mixture containing 50/50 C7/C9. There were no significant weight % variations and the product stayed stable as shown in Table 4.

Table 4: Analysis results of the dried product

The same product was dried for 5 minutes in an oven at 160 °C. As it can be observed in Table 5, the weight percentages increased. This means that carrier material has been converted to CO₂ and water. The product remained stable when an extra drying step was performed. Table 5: analysis results of the dried product

Example 6: Influence of chain length on flow properties

Corn cob was loaded with a 50/50 weight by weight mixture of choline chloride and one sodium carboxylate to achieve a final load of 60%. Four sodium carboxylates (C7, C8, C9, and C10) were used. The flow properties of the corn cob samples loaded with those different choline chloride/sodium carboxylate mixtures were tested in the powder flow tester. In Table 6 the flow factor indexes ff are indicated as calculated for the last value (highest value of the major principal consolidation stress).

Table 6: Flow factor indexes ff for the examples of 50/50 mixtures of choline chloride with different sodium carboxylates on corn cob

The flow properties improved with decreasing chain length. The flow properties of the sodium C10 carboxylate product were comparable with those of choline on corn (60%).

Three samples with different ratios of sodium heptanoate and sodium nonanoate (3:1 , 1 :1 , and 1 :3) were also tested in the powder flow tester. Corn cob was loaded with a 50/50 weight by weight mixture of choline chloride and the sodium carboxylate mixture (C7/C9 fatty acid equivalent weight ratio's of 3:1 , 1 :1 and 1 :3). The flow properties of the corn cob samples loaded with those different choline chloride/sodium carboxylates mixtures were tested in the powder flow tester. In Table 7 the flow factor indexes ff are indicated as calculated for the last value (highest value of the major principal consolidation stress).

Table 7: Flow factor indexes ff for the examples of 50/50 mixtures of choline chloride and C7-C9 sodium carboxylate mixtures with different C7/C9 ratio's on corn cob

It can be seen that a higher C7/C9 ratio results in a somewhat higher flow factor index.

Example 7: Influence of load on flow properties

To check the influence of the load, i.e. of the total amount of the choline and the MCFA feed supplement substances (salts) in the dry product, 3 different formulations on corn cob were made:

- Ex. 7.1 : 50/50 choline chloride / sodium carboxylate (50/50 C7/C9) 60% on corn cob

- Ex. 7.2: 50/50 choline chloride / sodium carboxylate (50/50 C7/C9) 40% on corn cob

- Ex. 7.3: 50/50 choline chloride / sodium carboxylate (50/50 C7/C9) 20% on corn cob

The sodium carboxylate was a 50/50 mixture (expressed in parts by weight of fatty acid equivalent) of sodium heptanoate and sodium nonanoate. The flowability of the samples was measured with the Powder Flow Tester. In Table 8 the flow factor indexes ff are indicated as calculated for the last value (highest value of the major principal consolidation stress).

Table 8: Flow factor indexes ff for the examples of 50/50 mixtures of choline chloride and a 50/50 C7-C9 sodium carboxylate mixture with different loads on corn cob

It can be seen that the higher the load, the better the flow properties.

Influence of the chain length of the carboxylates on the solubility

The chain length may influence the solubility of the product. The pure sodium salt of the carboxylates could be dissolved at room temperature at the following concentrations:

Sodium heptanoate 40.5 %

Sodium octanoate 33.7 %

Sodium nonanoate 31 .0 %

Sodium decanoate 29.9 %

When comparing the solution prepared in Example 1 with those of Examples 5.1 to 5.3 (all prepared at a same temperature), it can be seen that a higher concentration of active ingredients can be achieved in the solution containing MCFA salts and choline salt (in total between 45.1 and 64.4 wt.% of active ingredients) compared to a solution which only contains the MCFA salts (containing 41 wt.% of the MCFA salts as active ingredients). The carrier can thus absorb more active ingredients in one soaking step and requires less drying.

By using a higher amount of a MCFA having a lower chain length in a mixture of different MCFA's, a higher concentration of active ingredients can also be achieved. Three formulations (tested in Examples 6.5 to 6.7) were made with ratios 3:1 ; 1 :1 ; 1 :3 for the combination of Na- heptanoate and Na-nonanoate (NaC7/NaC9), to check the influence of the ratio on the solubility at room temperature. The solution also contained choline chloride in a 50/50 weight ratio with the sodium carboxylates. Table 9 shows whether the resulting mixture is liquid or not.

Table 9: Solubility (at room temperature) of a 50/50 weight by weight mixture of choline chloride and of different MCFA salt mixtures at different concentrations of the total active ingredients

A further test was performed with a 50/50 distribution of NaC7/NaC9. A solution with a concentration of 45 % (choline chloride + sodium carboxylates) could be made (at 60 °C instead of at room temperature). Using this solution, only 50% active product could be put on corn. When synthesizing at 80 °C, a solution with a concentration of 50 % could be made and 60 % active could be put on corn cob. When using a 65/35 distribution of NaC7/NaC9, a solution with a concentration of 50 % could be made at 60 °C. Using this solution, 60% active product could be put on corn cob. This product had a flow factor index of 10.0.

Since the MCFA salts which have a lower chain length, in particular a chain length of less than nine, preferably of less than eight carbon atoms, are better soluble in water so that a solution with a higher concentration of these MCFA's can be put on the carrier, and since those MCFA salts enable moreover to achieve better flow properties, the feed supplement compositions of the present invention preferably comprise such MCFA salts, in particular in combination with a MCFA salt that has a longer chain length in view of the additional microbiological effects offered by such longer MCFA.

In summary, the 50/50 Choline Chloride - Sodium Carboxylate was a stable formulation after synthesis and during drying. The chain length of the carboxylates in the formulation influences the solubility and the flowing properties. The solubility was a key factor which determines the load that can be put on carrier in one run. The carboxylates influence the flowing properties: a shorter chain made the product more free-flowing than a longer chain. The flow properties were also influenced by the load on the carrier material: a higher load resulted in better flowing properties.

EXPERIMENTS WITH SILICA AS CARRIER

In the following examples a precipitated silica carrier was used as carrier. The silica carrier material had a specific surface area of between 150 and 200 m²/g and a residue on a sieve of 45 μιτι of less than 0.5%.

Example 8: Formulation of choline chloride and free MCFA's on precipitated silica carrier

Example 8.1 : 30/70 choline chloride - MCFA's (50/50 C7/C9)

In the corn cob examples, tests with mixtures of 30% CC and 70% MCFA's (50% C7 and 50% C9 acid) were performed. In this example, the silica carrier was first made to absorb a liquid consisting of a 50/50 mixture of heptanoic and nonanoic acid by adding this liquid to the carrier while mixing. After all the acid is absorbed, a 78% choline chloride solution (in water) was added to the carrier while mixing. Different loads were applied onto the silica carrier. The flowability of the obtained products was evaluated visually. The results are shown in Table 1 . In this table a visually flowable product was indicated with a "+" whilst products that are no longer visually flowable are indicated with a

Table 10: Flowability of the silica carrier loaded with different amounts of free MCFA's and a 78% choline chloride solution

Example 8.2: Other ratio's choline chloride - MCFA's

This example illustrates that the combination of silica with fatty acids delivers extra freedom to change the CC content or the ratio between the different fatty acids. Additional formulations were made in which the MCFA was pure nonanoic acid with 30% CC and pure heptanoic acid with 30% CC. In both cases the maximum load was also limited to 60% active ingredients (= sum of MCFA's and choline chloride). Shifting towards more fatty acid; 90 wt.% instead of 70 wt.%, and less choline chloride, 10 wt.% instead of 30 wt.%, did not increase the maximum load of 60%. With these results it can be concluded that choline chloride - MCFA's formulations on silica are very flexible but the maxinnunn load is limited to 60% when use is made of a precipitated silica carrier.

Example 9: Formulation of choline chloride and MCFA salts on silica carrier

Different formulations were made starting from a premix aqueous solution of 53 wt.% active concentration: 30% CC and 70% MCFA sodium salts (50% C7 and 50% C9 sodium salt), the results are described in Table 1 1 .

Table 1 1 : Flowability of the silica carrier loaded with different amounts of an aqueous solution containing a mixture of MCFA salts and choline chloride

In this case, the maximum amount of active material (dry basis) that can added on the pure silica is only 37 wt.%. This is due to the larger amount of water that is introduced by the premix solution into the silica carrier. Drying of the product can increase the maximum amount of active ingredients, but this involves additional costs. An advantage of MCFA salts is however their lower volatility compared to the free MCFA's. Testing of the volatility/stability of the MCFA's on the silica carrier

Example 8.1 was repeated to achieve a 60% load of MCFA's and choline chloride on the silica carrier. The obtained product was placed for 2 hours in an oven at 100°C and the concentration of choline chloride and fatty acids were analysed before and after heating. No fatty acids or choline chloride were lost, more specific the fatty acid concentration was slightly increased from 44.5 to 45.5 % due to the removal of 3% water which was present in the product. The choline chloride content also increased from 16.37 to 17.14 %.

Testing of the flowabilitv of the choline chloride/MCFA's on the silica carrier

The flowability of a 60% active concentration of choline chloride and MCFA's on silica produced as described in Example 8.1 was measured by the powder flow tester. The flow factor index ff was equal to 7.14 so that the product was easy flowing.

Claims

1 . A method for preparing an animal feed supplement composition comprising one or more feed supplement substances including at least one choline feed supplement substance, which method comprises the steps of:

- providing a particulate absorbent carrier consisting of absorbent particles;

- providing a liquid which comprises at least said choline feed supplement substance dissolved in water; and

- allowing the particles of the absorbent carrier to absorb said choline feed supplement substance contained in said liquid,

characterised in that

said absorbent particles are allowed to absorb also at least one medium chain fatty acid feed supplement substance, which medium chain fatty acid feed supplement substance comprises a medium chain fatty acid group having a chain length of 6 to 12 carbon atoms, and which medium chain fatty acid feed supplement substance may be the same as or different from said choline feed supplement substance.

2. A method according to claim 1 , characterised in that the absorbent carrier is dried to produce a dry feed supplement composition having preferably a water content of less than 15 wt.%, more preferably of less than 10 wt.% and most preferably of less than 5 wt.%.

3. A method according to claim 1 or 2, characterised in that both said choline feed supplement substance and said medium chain fatty acid feed supplement substance are contained in said liquid which is absorbed by said absorbent particles.

4. A method according to claim 3, characterised in that said method comprises the step of producing said liquid, in which step an aqueous solution of at least one choline salt is provided and a medium chain fatty acid compound, which comprises the same medium fatty acid group as said medium chain fatty acid feed supplement substance, is added thereto.

5. A method according to claim 4, characterised in that said medium chain fatty acid compound is a free fatty acid in acid form, which free fatty acid is neutralized in the aqueous solution of said choline salt by adding a base thereto, in particular sodium, potassium, calcium and/or magnesium hydroxide or ammonium.

6. A method according to any one of the claims 3 to 5, characterised in that said liquid has a pH higher than 5.0, preferably higher than 6.0, and more preferably higher than 6.8, the pH of said liquid being preferably lower than 12, more preferably lower than 1 1 .

7. A method according to any one of the claims 3 to 6, characterised in that said liquid has a choline feed supplement substance content, expressed in parts by weight of choline cations per 100 parts by weight of liquid, and a medium chain fatty acid feed supplement substance content, expressed in parts by weight of medium chain fatty acid equivalents per 100 parts by weight of liquid, in a ratio which is equal to or larger than 10/90, preferably equal to or larger than 15/85 and which is more preferably equal to or larger than 18/82 parts by weight of choline cations per parts by weight of medium chain fatty acid equivalents but equal to or smaller than 60/40, preferably equal to or smaller than 50/50 and which is more preferably equal to or smaller than 46/54 parts by weight of choline cations per parts by weight of medium chain fatty acid equivalents.

8. A method according to any one of the claims 1 to 7, characterised in that said medium chain fatty acid feed supplement substance is contained in a further liquid, different from said liquid, the absorbent carrier being allowed to absorb both said liquid and said further liquid.

9. A method according to claim 8, characterised in that in the particles of the absorbent carrier are allowed to absorb first said further liquid and subsequently said liquid.

10. A method according to claim 8 or 9, characterised in that said further liquid comprising said medium chain fatty acid feed supplement in the form of an undissociated free fatty acid, said first liquid consisting preferably for at least 50 % by weight, more preferably for at least 70 % by weight and most preferably for at least 90 % by weight of undissociated free medium chain fatty acid.

1 1 . A method according to any one of the claims 8 to 10, characterised in that the particles of said carrier are allowed to absorb such an amount of said liquid and of said further liquid that the animal feed supplement composition has a choline feed supplement substance content, expressed in parts by weight of choline cations per 100 parts by weight of the animal feed supplement composition, and a medium chain fatty acid feed supplement substance content, expressed in parts by weight of medium chain fatty acid equivalents per 100 parts by weight of the animal feed supplement composition, in a ratio which is equal to or larger than 10/90, preferably equal to or larger than 15/85 and which is more preferably equal to or larger than 18/82 parts by weight of choline cations per parts by weight of medium chain fatty acid equivalents but equal to or smaller than 60/40, preferably equal to or smaller than 50/50 and which is more preferably equal to or smaller than 46/54 parts by weight of choline cations per parts by weight of medium chain fatty acid equivalents.

12. A method according to any one of the claims 1 to 1 1 , in particular according to any one of the claims 3 to 7, characterised in that said particulate absorbent carrier is an organic carrier and comprises preferably a ground vegetable or animal material, in particular ground corn cob, wheat bran and/or rice hulls.

13. A method according to any one of the claims 1 to 1 1 , in particular according to any one of the claims 8 to 1 1 , characterised in that said particulate absorbent carrier is an inorganic carrier and comprises preferably a silica material, in particular a precipitated silica material.

14. A method according to any one of the claims 1 to 13, characterised in that said carrier is allowed to absorb such an amount of said medium chain fatty acid feed supplement substance and of said choline feed supplement substance that said feed supplement composition comprises at least 30 wt.%, preferably at least 35 wt.% and more preferably at least 40 wt.%, but less than 80 wt.% and preferably less than 70 wt.% of said medium chain fatty acid and choline feed supplement substances on the total dry weight of said feed supplement composition.

15. An animal feed supplement composition obtainable by a method according to any one of the claims 1 to 14, which feed supplement composition comprises a particulate carrier consisting of particles having absorbed one or more feed supplement substances including at least one choline feed supplement substance and at least one medium chain fatty acid feed supplement substance which comprises a medium chain fatty acid group having a chain length of 6 to 12 carbon atoms and which may be the same as or different from said choline feed supplement substance.

16. An animal feed supplement composition according to claim 15, characterised in that said choline feed supplement substance and said medium chain fatty acid feed supplement substance are substantially uniformly distributed over said particles.

17. An animal feed supplement composition according to claim 15 or 16, characterised in that at least 70 wt.%, preferably at least 80 wt.% and more preferably at least 90 wt.% of said medium chain fatty acid and choline feed supplement substances are a salt.

18. An animal feed supplement composition according to any one of the claims 15 to 17, characterised in that it has a medium chain fatty acid feed supplement substance content, expressed in parts by weight of medium chain fatty acid equivalents per 100 parts by weight of the feed supplement composition, and it is free of free medium chain fatty acids in acid form or it has a free medium chain fatty acid content in acid form which is less than 30%, preferably less than 20% and more preferably less than 10% of said medium chain fatty acid feed supplement substance content.

19. An animal feed supplement composition according to any one of the claims 15 to 18, characterised in that it has a medium chain fatty acid feed supplement substance content, expressed in parts by weight of medium chain fatty acid equivalents per 100 parts by weight of the feed supplement composition and a content of medium chain fatty acid feed supplement substances having a MCFA group with a chain length of less than nine, preferably of less than eight carbon atoms, expressed in parts by weight of medium chain fatty acid equivalents per 100 parts by dry weight of the feed supplement composition, which comprises between 20 and 90 wt.%, preferably between 30 and 80 wt.% of said medium chain fatty acid feed supplement substance content.

20. An animal feed supplement composition according to any one of the claims 15 to 19, characterised in that it has a choline feed supplement substance content, expressed in parts by weight of choline feed supplement substances per 100 parts by weight of the feed supplement composition, and it is free of choline carboxylates or has a choline carboxylate content which is less than 30%, preferably less than 20% and more preferably less than 10% of its choline feed supplement substance content.

21 . An animal feed supplement composition according to any one of the claims 15 to 20, characterised in that it has a choline feed supplement substance content, expressed in parts by weight of choline cations per 100 parts by weight of the feed supplement composition, and a medium chain fatty acid feed supplement substance content, expressed in parts by weight of medium chain fatty acid equivalents per 100 parts by weight of the feed supplement composition, in a ratio which is equal to or larger than 10/90, preferably equal to or larger than 15/85 and which is more preferably equal to or larger than 18/82 parts by weight of choline cations per parts by weight of medium chain fatty acid equivalents but equal to or smaller than 60/40, preferably equal to or smaller than 50/50 and which is more preferably equal to or smaller than 46/54 parts by weight of choline cations per parts by weight of medium chain fatty acid equivalents.