GB2313287A

GB2313287A - Delayed-action acidifying additive for animal feed

Info

Publication number: GB2313287A
Application number: GB9709799A
Authority: GB
Inventors: Calvez Gilbert Le
Original assignee: GUILDALI SA
Current assignee: GUILDALI SA
Priority date: 1996-05-20
Filing date: 1997-05-14
Publication date: 1997-11-26
Also published as: ITTO970421A1; ES2127139B1; PT102008A; BE1010491A3; IE970360A1; ES2127139A1; DE19720703A1; NL1006014C2; NL1006014A1; ITTO970421A0; FR2748635A1; FR2748635B1; IT1292355B1; GB9709799D0; LU90060B1

Description

2313287 DELAYED-ACTION ACIDIFYING ADDITIVE FOR ANIMAL FEED AND PROCESSES

FOR ITS USE The present invention concerns delayed-action acidifying additives suitable for animal food, that is to say, additives whose acidifying action is progressive and continues over time, and processes for the use of these additives to improve the digestive functions of an animal by lowering the pH of its digestive tract.

It is known that the digestive tract of some animals at the time of weaning is unsuited to the digestion of maternal milk substitute foods and that this deficiency of the digestive tract constitutes a particularly large problem at industrial breeding installations. For example, in the case of the piglet, this deficiency is mainly due to the insufficient production of hydrochloric acid and lactic acid by the stomach; the secretion of these is in fact deficient during the first three weeks of life and only reaches levels compatible with good proteinic digestion and optimum intestinal protection from the third or fourth week after weaning. At the time of weaning, the passage of poorly degraded nutriments into the intestines causes serious digestive disturbances manifested in diarrhoea and hepatic deficiencies. At the microbiological level, weaning can cause an imbalance of the intestinal microbial flora owing to the low level of acidity of the intestinal tract; in the case of the piglet, because gastric pH does not fall below 3 until the sixtieth day of life, before this time has passed the stomach does not play its role as a barrier with regard to undesirable microorganisms such as EscherIchla coll or pathogenic microorganisms which will colonise the small intestine. At the enzymatic level, acidity also affects the functioning and activity of several enzymes of the intestinal tract, such as pepsin, and pancreatic enzymes such as trypsin, chymotrypsin, carboxypeptidase, amylase, lipase, maltase and lactase; the consequence of these dysfunctions manifests itself in the poor digestibility of foods in the diet, which is harmful to nutritive efficiency and to growth.

Much work has been undertaken to remedy this lack of acidity and various methods of acidification have been proposed. Thus, numerous publications have proposed the direct addition of mineral or organic acids or of mixtures of acids and/or salts thereof, to the feed intake of the weaned piglet. For example, JOST and BRACHER-JAKOB (1991, Utilisation d'acides organiques dans 1'alimentation des porcelets d161evage, Revue Suisse Agric. 23 (2), 73-76) have studied the effects of adding citromix (a mixture of acids) at 0.8% or fumaric acid at 1.2% or calcium formate at 1. 2% to food for piglets, on the average daily gain (A.D.G.), on the index of consumption, on digestibility and on the frequency of diarrhoea. In this study, they observed only a slight influence of these acids on the digestibility of the nitrogenous material. This procedure of adding pure acids has the disadvantage of bringing about a fall in the gastric pH to a value below 3.5, thus disturbing the natural secretion of hydrochloric acid by the peripheral cells of the animal's stomach and inhibiting the production of lactic acid by the LactobacIllus spp. Moreover, these "free" acids are too rapidly absorbed to produce beneficial effects and they do not reach the small intestine.

There is therefore a need to use acid in a form that gives it a progressive effect continuing over time so as to avoid a sudden drop in the pH at the time of ingestion of the food by the piglet and to permit the acid to have an effect at the level of the small intestine. In order to obtain an acid which has a progressive action continuing over time, it has been proposed (Feed mix, Vol.2, No. 3, 1994, pages 23-25) to use mineral or organic acids arranged in a layer inside a lipid matrix. The acids protected in this way by a lipid matrix have a delayed action and are therefore more effective than pure acids, but their cost is high.

An aim of the present invention is to propose a delayed-action acidifying additive suitable for addition to animal feed, that is, an additive from which an acid can be released progressively over time. Another aim of the invention is to propose an acidifying additive which can be used in a nutriment for animals in order to lower the pH of the digestive tract. A third aim of the invention is to propose an acidifying additive with a low cost price.

Subject matter of the invention, therefore, is a delayed-action acidifying additive suitable for animal feed, the said additive containing at least a strong acid that is compatible with the digestive functions of animals, characterised in that the strong acid is formic acid and in that it is bonded at least with an organic or mineral, particulate, hydrophilic support that is compatible with the digestive functioning of animals.

Formic acid is in fact a much stronger acid than its superior homologues; it has an excellent acidification capacity owing to the high value of its dissociation constant (pKs - 3.75). Moreover, tests have shown that, in piglet rearing, it is a source of better results than other acids, not only for digestibility of nutriments but also for the reduction of diarrhoea and the stimulation of growth.

In the matter of chemistry, pure formic acid is unstable and a certain water content is necessary for stabilising it; at ambient temperature, formic acid decomposes as soon as it is totally dehydrated. According to the invention, by associating formic acid with a hydrophilic, pulverulent support which has a high water retention capacity and which is compatible in nutritive terms with the digestive physiology of animals, its molecular stability is increased and it can be incorporated into an animal feed intake in pulverulent form.

According to the invention, the hydrophilic support serves to provide an active, stable acidifying additive having a particulate structure. This support can therefore have great affinity for water provided that it adsorbs and/or absorbs the water without any important variation in its structure or properties, in order to be capable of transforming the acid or acid solution bonded with the support into sufficiently fluid powder. As used within the context of the present invention, the terms "bonded" or "bond" cover forms of bonding of the acid with the support, which are variable according to the support. The bonds can be hydrogen bonds by electrovalency, for example in the case of silicas and alginates, or else an adsorption possibly combined with a chemical bond, for example in the case of clays.

The bonding of formic acid with the support enables its acidifying power to be maintained for longer, since it is released only progressively from the additive. It enables the release of formic acid into the whole of the digestive tract, including the small intestine part and, furthermore, at a given point, this release is more progressive and thus more effective owing to the less rapid absorption of the mucous membranes.

The particulate or pulverulent form of the acidifying additive enables the contact surface to be increased with a view to the release of formic acid. The support must therefore be resistant to settling and not have a tendency to form agglomerates.

Suitable supports according to the invention are 5 advantageously chosen from the group formed by:

hydrophilic mineral products of natural and/or synthetic origin chosen from silica, in particular pyrogenous or precipitated silica, alumina; alkaline-earth silicates, in particular talcum; aluminium silicates, in particular clays such as kaolinite, montmorillonite, bentonite, vermiculite; and alkaline or alkaline-earth silicoaluminates, in particular zeolites such as natrolite phonolite; biodegradable organic products, in particular biopolymers such as alginic acids and salts thereof, in particular ammonium, sodium, potassium, magnesium or calcium salts; pulverised biodegradable natural products such as algal powders, in particular micronized algal powders obtained from Fucus spp, Lamd-narla spp or Ascophyllum spp.

Preferably, the support has a size grading between 10 nm and 10 mm.

The quantity of support(s) advantageously represents from 30% to 75% by weight of the total weight of the acidifying additive according to the invention. In addition to formic acid and the support, the acidifying additive can contain at least one active constituent, other than formic acid, bonded with the support(s) and/or formulation adjuvants. A vegetable or animal oil added in small quantities, preferably at the rate of 1% to 8 by weight so as not to destroy the pulverulent aspect of the additive, can be mentioned as the other active constituent. An anti-clotting agent such as magnesium stearate can be mentioned as the adjuvant.

Further subject matter of the present invention is a process for improving the digestive functions of an animal by lowering the pH of the digestive tract, in which process an acidifying additive according to the invention is added to the nutritive intake of the animal. The quantity of acidifying additive that is added is preferably between 0.2% and 10% by weight in relation to the weight of the nutritive intake; this quantity is preferably in the region of 1% by weight. The nutritive intake is preferably a nutritive intake for a young animal, in particular a piglet; in a particularly advantageous way, the nutritive intake is a nutritive intake for a piglet in the first phase after weaning, that is to say, for the 14 days following weaning.

The examples given below by way of illustration and in a non-restrictive manner, will permit a better understanding of the invention.

EXAMPLE 1

In the powdered sodium alginate there is incorporated 35% by weight formic acid at 85% by dropping the formic acid drop by drop into the alginate while mixing carefully to avoid clotting. The acidifying additive that is obtained can be preserved without degradation of the formic acid for six months in a flask that is impervious to ultra-violet rays.

EXAMPLE 2

There is incorporated 60% by weight of formic acid at 85% of a mixture constituted by 62.5% by weight of hydrophilic silica, 25% of kaolinite and 12.5% of algal proteinic concentrate. 5% by weight of soya oil is then introduced to this mixture.

The additive that is thus obtained is then incorporated in a "first-age" piglet food commercially produced by the company "GUILDALV', at the rate of 2 to 20 kg in weight of additive for 1 tonne in weight of food. The buffer capacity of the food has passed from 920 meq/kg to 700 meq/kg. There has thus been achieved a buffer capacity of less than 750 meq/kg, which is consequently unfavourable to the development of EscherIchla Coll in the case of the piglet.

EXAMPLE 3

AS in Example 4, an acidifying additive was prepared and mixed with the piglet food in an industrial mixer at the rate of 10 kg/tonne.

Three categories of tests were carried out at a birth and fattening farm of 300 "Large White x Landrace" sows, on a total of 450 piglets.

Tests 1 and 2 were carried out during the period of use of a first-age nutriment, that is to say, from weaning to the 14th day after weaning. Test 3 was carried out over a period covering both the first-age phase and the second-age phase. The following parameters were measured:

Consumption of nutriments (g/day), Average daily gain (g) (ADG), Index of conversion.

A reference batch of piglets consuming the same nutriment but without acidifying additive, was studied by way of a comparison.

TABLE 1

Reference batch Batch with additive Number 72 71 Weight at 7.7 7.5 weaning (kg) Weight at end of 11.25 12 test (kg) Duration of test 14 14 (in days) Consumption 265 327 g/day Average daily 253 321 gain (g) LIndex f 1.05 1.02 convIerosion co v TABLE 2

Reference batch Batch with additive Number 70 70 Weight at 8.37 8.71 weaning (kg) Weight at end of 11.27 12.47 test (kg) Duration of test 14 14 (in days) -g- Consumption 306 382 g/day Average daily 207 268 gain (g) Index of 1.47 1.42 conversion TABLE 3 10

Reference batch Batch with additive Number 67 68 Weight at 8.74 8.97 weaning (kg) Weight at day 14 11.77 12.83 (kg) Average daily 216 276 gain at day 14 (g) Weight at day 54 35.11 36.41 (kg) Average daily 583 589 gain day 14 to day 54 (g) Average daily 488 508 gain day 0 to day 54 (g) Index of 1.67 1.62 conversion Tables 1 and 2 show that the presence of the acidifying additive in a first-age nutriment enables the consumption and the average daily gain (ADG) to be improved. The improvement in consumption is 23% in Table 1 and 24% in Table 2 and the improvement in ADG is 26% in Table 1 and 29% in Table 2.

Table 3 confirms the improvement in ADG in the first period. With the second-age nutriment, the effect of the addition of the acidifying additive on the ADG is less significant. However, a sanitary effect is observed: the reduction of diarrhoea.

0

Claims

1. A delayed-action acidifying additive suitable for animal feed, the additive comprising at least a strong acid, the strong acid is formic acid and wherein it is bonded to at least an organic or mineral, particulate, hydrophilic support that is compatible with the digestive functioning of animals.

2. An additive according to claim 1, wherein the support is silica, alumina, an alkali metal silicate, an alkaline earth metal silicate, an aluminium silicate, an alkali metal silicoaluminate, an alkaline earth metal silicoaluminate, a biopolymer, or an algal powder, or a mixture thereof.

3. An additive according to claim 2, wherein the is biopolymer is alginic acid or an ammonium, alkali metal or alkaline earth salt thereof.

4. An additive according to claim 3, wherein the support is talcum, kaolinite, montmorillonite, bentonite, vermiculite or a zeolite, or a mixture thereof.

5. An additive according to any of claims 1 to 4, wherein the support or supports has or have a size of from 10 = to 10 mm.

6. An additive according to any of claims 1 to 5, wherein the quantity of support or supports is from 30% to 75% by weight of the total weight of the acidifying additive.

7. An additive according to any of claims 1 to 6, further comprising (a) at least one active constituent, other than the strong acid or acids, bonded to the support or supports, and/or (b) at least one formulation adjuvant.

8. An additive according to claim 7, comprising from 1% to 89,; by weight of a vegetable or animal oil.

9. A process for the improvement of the digestive functions of an animal by lowering the pH of its digestive tract, which comprises adding an acidifying additive according to any of claims 1 to 8 to the nutritive intake of the animal.

ILO. A process according to claim 9, wherein the quantity of acidifying additive that is added is from 0.2% to 10% by weight relative to the weight of the nutritive intake.

11. A process according to claim 9 or 10, wherein the nutritive intake is an intake for a piglet in the first phase after weaning.

12. An additive according to claim 1, substantially as described herein.

13. An animal feed containing an additive according to any of claims 1 to 8 and 12.