EP3801045A1

EP3801045A1 - Process for improving wheat straw degradation

Info

Publication number: EP3801045A1
Application number: EP19737839.1A
Authority: EP
Inventors: Christine JULIEN; Jean-Philippe MARDEN
Original assignee: Lesaffre et Cie SA
Current assignee: Lesaffre et Cie SA
Priority date: 2018-06-05
Filing date: 2019-06-04
Publication date: 2021-04-14
Also published as: FR3081682B1; CA3101868A1; CN112272521A; AR115483A1; FR3081682A1; US20210307360A1; AU2019281142A1; BR112020024781A2; MX2020013246A; WO2019234347A1

Abstract

The present invention relates to a process for improving wheat straw degradation in a ruminant, comprising the following steps: a) providing the wheat straw, b) chemically pretreating said provided straw, c) feeding the ruminant with the chemically pretreated wheat straw, wherein said process is characterized in that it also comprises a step d) of directly administering an enzymatic rumen additive to the ruminant, i.e. said enzymatic rumen additive is not used as a pretreatment on the wheat straw. The present invention also relates to the direct use of an enzymatic rumen additive in a ruminant before, during or after feeding said ruminant with wheat straw having undergone a chemical pretreatment, i.e. said enzymatic additive is not used as a pretreatment on the wheat straw.

Description

PROCESS FOR IMPROVING THE DEGRADATION OF WHEAT STRAW

FIELD OF THE INVENTION

The present invention relates to the agricultural field of animal nutrition and relates to a method of improving forage degradation.

BACKGROUND

Wheat straw represents an inexpensive resource that could contribute to strengthening the forage and food autonomy of certain farms. In addition, in certain geographical areas, fodder represents a qualitatively very important resource that could advantageously be valued in animal nutrition.

However, the use of wheat straw is limited in ruminants with a high production level, such as cattle. Indeed, despite its high fiber content, wheat straw has a low nutritional value due to poor digestion by ruminants. Indeed, from a chemical point of view, the presence of bonds between the constituents of the plant wall leads to a more or less strong resistance to the attack of the digestive microbiota rumen. This resistance results in a low degradation of the feed in the animal.

Thus, to improve the degradation of forage, including wheat straw, research has been conducted for decades. The use of chemical or enzymatic pretreatments has been shown to improve degradation. It has also been demonstrated that the degradation of wheat straw can be improved by a combined use of chemical and enzymatic pretreatments, said pretreatments even having a synergistic effect.

For example, the publication by Y. Wang et al (J. Animal Sci., 2004) shows the effects of alkaline pretreatment on the efficiency of exogenous enzymes to increase the digestibility of wheat straw. In this publication, the wheat straw is pretreated with an alkaline solution and then with an enzyme solution by spraying. The results thus show that the combination of alkaline chemical pretreatment and enzymatic treatment improves the digestibility of wheat straw. The enzymatic treatment used is applied to the wheat straw upstream of the feed of the animal in order to respect a sufficient incubation time and to allow an effect on the digestibility. The enzymatic treatment can therefore be qualified as pretreatment in that it is a preliminary treatment of the straw. wheat so that the latter, once the incubation time is respected, can be used later in animal feed and that the digestion is improved.

However, the use of pretreatment enzymes is not efficient and has several disadvantages. In fact, in a farm, it is time-consuming for a farmer to spray a whole wheat straw stock. In addition, it is necessary to respect a time of application and that the treatment is applied homogeneously, which implies that the wheat straw is in a relatively free form or in bulk. Finally, since the cost of the enzymes is relatively expensive, this also limits the possibility of pretreatment on a farm scale, especially when the latter is associated with a chemical pretreatment which already represents an additional cost. As a result, the combination of chemical and enzymatic pretreatment, even though it is effective in improving the digestibility of wheat straw, does not allow for large-scale application within farms because of its high cost of application. implemented. This point is also raised by the publication of Y. Wang et al in the part "Implication" which explicitly mentions that the combination between an alkaline and enzymatic treatment is not economically viable.

There is thus a need for methods to improve the degradation of wheat straw, said methods being inexpensive and allowing implementation at the scale of a farm. The valorization of the wheat straw thus makes it possible to improve the fodder autonomy and overall of the exploitation.

It is therefore the merit of the inventors to have developed a method for responding to all or part of the problems of the prior art. The inventors have surprisingly discovered that when the enzyme additive is no longer used in pretreatment on wheat straw, but is administered directly to the ruminant (especially by the oral route), before, during or after the administration of wheat straw pretreated chemically, then the effective improvement on the degradation of wheat straw is maintained, or even a synergistic effect appears with the chemical treatment and enzymatic treatment.

This direct administration, especially by the oral route, is quite advantageous because it suffices to simply pretreat the wheat straw chemically, and the enzymatic additive can be administered before, during or after ingestion of the chemically pre-treated wheat straw. .

There was no evidence to suggest that the direct administration of the enzyme additive would allow a positive action on the rumen degradation of chemically pretreated wheat straw as effective as when the enzyme additive was previously sprayed on the chemically pre-treated wheat straw. Such an administration is very interesting because it allows, in addition to saving time and simplicity of the process, to use less enzymatic additive than when the latter is sprayed on the wheat straw.

SUMMARY OF THE INVENTION

A first subject of the invention relates to a method for improving the ruminal degradation of wheat straw in a ruminant comprising the following steps:

a) supply of wheat straw,

b) chemical pretreatment of said straw provided,

c) feeding the ruminant with the wheat straw pretreated chemically in step b),

said method being characterized in that it further comprises a step d) of direct administration to the ruminant of an enzymatic rumen additive, which means that said enzymatic additive is not used in pretreatment on the straw.

A second subject of the invention relates to the direct use in a ruminant of an enzymatic rumen additive, before, during or after feeding said ruminant with wheat straw having undergone chemical pretreatment.

The "direct" use in a ruminant means that the enzymatic additive is administered directly to the ruminant, in particular by the oral route, without going through a pretreatment of the wheat straw with the enzymatic additive.

DETAILED DESCRIPTION

a) supply of wheat straw,

b) chemical pretreatment of said straw provided,

c) feeding the ruminant with the wheat straw pretreated chemically in step b),

said method being characterized in that it further comprises a step d) of direct administration to the ruminant of an enzymatic rumen additive, which means that said enzymatic additive is not used in pretreatment on wheat straw.

Degradation is defined as the degradation of food by the action of reticulo-rumen microorganisms. For the purposes of the present invention, the term "pretreatment" denotes a treatment carried out on wheat straw upstream of the administration to the animal, said treatment being carried out by placing a chemical solution in contact with the wheat straw.

The process according to the invention thus makes it possible to improve the degradation of wheat straw when it is used to feed a ruminant.

Indeed, the process developed makes it possible to make the parietal constituents of wheat straw more accessible to the degradation enzymes of the rumen microorganisms and to improve their degradation.

The extent of this degradation affects digestibility throughout the digestive tract and, consequently, the energy value of the ruminant diet.

Digestibility is a criterion that defines the degree to which an organic matter is digested by an animal. The higher the digestibility, the better the digestion.

In addition, by improving the degradation of wheat straw, the process according to the invention also makes it more suitable for animal feed because at present it is underutilized because of the difficulties animals have in digesting it. compared to other foods.

The first step of the process according to the invention therefore consists of providing wheat straw.

Wheat straw is the agricultural product represented by the part of the stalk or stubble of wheat. The wheat straw provided is that conventionally used by those skilled in the animal feed industry and can be in various forms, both in the form of straw bales and in bulk form.

According to a particular embodiment, the straw may first undergo a mechanical treatment step whose objective is to reduce the size of the strands and to allow both a better accessibility of the fibers to subsequent treatments and better degradation. According to this particular embodiment, the wheat straw may previously be minced, lacerated or defibrated, or a grinding.

The second step of the process according to the invention consists in carrying out a chemical pretreatment of the wheat straw.

Chemical pretreatment allows a significant reduction in the rigidity of plant structures, swelling of the walls and their penetration by electrolytes and cellulolytic enzymes of rumen microorganisms. The microorganisms can thus colonize more quickly the vegetable particles which are then degraded more quickly and in a more intense way, thus improving the degradation. The chemical pretreatment used in the process of the invention is a pretreatment carried out by an alkaline solution as conventionally used by those skilled in the art. Thus, the chemical pretreatment can be carried out with a solution of sodium hydroxide (NaOH), sodium hydroxide, lime, potassium hydroxide (KOH), anhydrous ammonia (NH ₃ ), aqueous ammonia (NH ₄ OH), urea or a mixture of these compounds. Preferably, the chemical pretreatment carried out in step b) is carried out with a solution of sodium hydroxide (NaOH).

In addition, the chemical pretreatment can be carried out in different ways according to the techniques known to those skilled in the art, whether industrial or not. Thus, the chemical pretreatment can be carried out wet, semi-wet, semi-dry, or dry. According to a particular embodiment, when the pretreatment is carried out wet or semi-wet, it can be applied by spraying or by dipping.

Depending on the manner in which the treatment is carried out, those skilled in the art will adapt the concentration of the alkaline solution, as well as the post-treatment incubation times (see Chenost and Kayouli) 2.3 Chemical treatments In: Use roughage in hot regions, Rome, 1997. FAO Animal Production and Health Study - 135. ISBN 92-5-203981-3).

For pretreatment with a semi-wet soda solution, said solution can be concentrated from 1.6 to 5% and then mixed at a rate of 1 to 3 L / kg of wheat straw. The wheat straw can then be distributed to the animals 24 to 48 hours after mixing.

For pretreatment with a semi-dry soda solution, the development of a machine coupled to the PTO of a tractor for chopping and kneading the straw is necessary. The sodium hydroxide solution is concentrated between the semi-wet and dry channels at 12% and then mixed in the machine with the straw at a rate of 0.4 L / kg of straw. The action time of soda is about 8 days. The straw can be dried in the open air.

For pretreatment in the dry process, which is an industrial process of treatment, the soda solution is more concentrated (16%). The solution is then mixed with the chopped straw at a rate of about 0.3 L / kg of wheat straw. The latter is then passed through a die press. The improving action of the soda is very fast (from 20 seconds to about one minute) thanks to the high temperature and pressure prevailing in the die.

Preferably, the chemical pretreatment is carried out semi-wet way. Once the pretreatment step has been performed, the method according to the invention comprises a step of feeding an animal with the straw which has been pretreated chemically.

This feeding step is a conventional step well known to those skilled in the breeding industry. The animals are then fed with the pretreated wheat straw. In a preferred manner, the animals are ruminants, such as, for example, cows or cattle. The administration step consists in administering the ruminant enzymatic additive to the ruminant so that the ruminant is found in the reticulo-rumen of said ruminant.

An example of administration of the enzymatic additive is the oral route.

This administration step can be performed before, simultaneously with, or after the feeding step of the ruminant with the chemically pre-treated wheat straw.

"Before" the feeding step means a maximum of 24 hours before. Thus the enzyme additive will never be administered more than 24 hours before the administration of the chemically pre-treated wheat straw. Preferably the enzymatic rumen additive will be administered from 2 hours to 8 hours prior to administration of the chemically pretreated wheat straw.

Similarly, "after" the feeding step means at most 24 hours later. Thus the enzyme additive will never be administered more than 24 hours after the administration of the chemically pre-treated wheat straw. Preferably the enzymatic rumen additive will be administered from 2 hours to 8 hours after administration of the chemically pre-treated wheat straw.

Preferably the administration step is performed simultaneously with the feeding step.

In a completely surprising manner, the inventors have indeed found that a step of direct administration in the ruminant, in particular orally, of an enzymatic ruminate additive made it possible to significantly improve the degradation, or even , to create a synergy on the degradation with the chemical pretreatment of wheat straw.

In a very advantageous manner, and unlike what was known until now, the method according to the invention can be applied on a large scale on the whole of a farm and inexpensive way since the enzyme is not used in pretreatment on straw but is administered directly to the animal as an enzyme additive. This allows substantial savings in time and cost. In fact, the ruminant enzymatic additive is directly administered to the ruminant before, during feeding or after feeding with chemically pre-treated wheat straw, and it is no longer necessary to spray it on the whole stock of straw. wheat or wheat straw to eat soon. In this way, the process according to the invention makes it possible to dispense with the incubation times normally required to allow the enzyme to act when it is used in pretreatment of wheat straw. The enzymatic rumen additive is a mixture comprising at least two enzymes. Enzymes used in the enzymatic rumen additive may be glucanases, xylanases, esterases, or carboxymethylcellulases.

According to one particular embodiment, the enzymatic rumen additive is a mixture of glucanase and xylanase, and in particular endo-1,3 (4) -beta-glucanase and endo-beta-1,4-xylanase. .

The endo-1, 3 (4) -3-glucanase enzyme is a highly concentrated preparation of β-glucanase, obtained by submerged fermentation of a selected strain of Trichoderma reesei.

The endo-b-1, 4-xylanase enzyme is a highly concentrated xylanase preparation obtained by submerged fermentation of a selected strain of Trichoderma reesei. According to the EC nomenclature of Enzymes Commission number:

the endo-1, 3 (4) - glucanase enzyme has the EC code 3.2.1.6,

the endo-1,4-xylanase enzyme has the EC code 3.2.1.8.

According to this embodiment, the dose of glucanase can be between 200 units / g of straw and 7000 units / g of straw, preferably 4000 units / g of straw at 6000 units / g of straw, for example about 4670 units / g of straw.

The xylanase dose may be from 200 units / g of straw to 7000 units / g of straw, preferably from 4000 units / g of straw to 6000 units / g of straw, for example about 4670 units / g of straw.

The enzymatic units correspond to the amount of enzyme necessary for:

releasing 1 pmole glucose per minute at pH 4.8 and 50 ° C from a barley glucan substrate for glucanase;

release 1 pmol of xylose per minute at pH 5.3 and 50 ° C from a Birchwood xylan substrate for xylanase.

Still according to this embodiment, the glucanase may be an endo-1,3 (4) -glucanase and the xylanase may be an endo-1, 4-xylanase. In this case, and advantageously, the glucanase / xylanase ratio is at least 0.5, preferably at least 0.75, and most preferably about 1.

The enzymatic rumen additive is in a form suitable for animal administration. Thus, the enzymatic rumen additive can be in the form of capsules, bolus, powder, granules or liquid, such as in ampoules. Preferably, the enzymatic rumen additive is in powder or liquid form, preferably in the form of a powder. A capsule or capsule is a solid preparation, consisting of a hard or soft envelope of varying shape and capacity.

A tablet or bolus is a solid preparation containing a unit for taking one or more active ingredients (or preparation). They are obtained by compression of a constant volume of particles. Destined for cattle, they become bigger and they are called boluses.

According to a particular embodiment of the invention, when the enzymatic rumen additive is administered simultaneously with the chemically pretreated wheat straw, said enzymatic ruminate additive may be in the form of a powder which will be mixed with the pretreated wheat straw. chemically. The mixture is then used to feed the ruminant.

According to another embodiment of the invention, the ruminant belongs to the family Bovidae. The family Bovidae (Bovidae) includes several sub-families, including cattle (including cattle) and goats (including sheep and goats).

The improvement in the degradation of wheat straw can be determined by the techniques known to those skilled in the art, for example by measuring the loss of dry matter by incubation in ruminal liquid. The details of the measurements are presented in the example section below.

The process according to the invention is particularly advantageous because it surprisingly allows a synergistic action between the enzymatic rumen additive and the chemical pretreatment of the wheat straw on the degradation of the wheat straw.

Indeed, the effect on ruminal degradation is greater than the sum of the combined effects of chemical pretreatment and enzymatic ruminate additive alone.

No method known hitherto improved the degradation of wheat straw to a level equivalent to the improvement provided by the process according to the invention.

It is known to use a chemical pretreatment, and in particular an alkaline pretreatment for the treatment of wheat straw in order to improve digestibility. It is also known to use an enzymatic pretreatment to improve this same digestibility.

So far, treatments performed on straw, whether chemical or enzymatic were pretreatments in the sense that they were carried out before ingestion by the animal, by pretreatment of the wheat straw itself. Enzymatic pretreatment is known to improve the digestibility of straw in animals, but this type of pretreatment is rarely used because it is too expensive to spray or pretreat batches of whole straw for later feeding. animal. The purpose of these pre-treatments is to better potentiate a food source that has not been valued so far. However, the use of enzymatic pretreatments, even if they have proved to be of interest for the improvement of digestibility, has not been developed in the agricultural environment because the necessary cost of an enzymatic pretreatment is not compensated by the gain in terms of food for the animals.

It has already been proved in the prior art that the combination of a chemical and enzymatic pretreatment of the straw could improve the digestibility of the straw and even present a synergy. However, considering the costs of in situ or ex vivo enzymatic pretreatment of wheat straw, the combination of the two pretreatments has never been implemented at the farm level and has so far been considered inappropriate by the industry. skilled person.

It is therefore of the merit of the present invention to have been able to develop a method for improving the degradation of straw, said method being able to be implemented at the scale of a farm without presenting additional work or additional costs. damaging. On the contrary, the process according to the invention makes it possible to potentiate the wheat straw and thus enables the animals to present a better digestion with respect to this food, which sometimes constitutes one of the main resources.

Thanks to the process according to the invention, the wheat straw is better valued and it is simpler for the farms to tend towards food self-sufficiency without generating significant additional cost.

A second subject of the invention relates to the direct use in a ruminant of an enzymatic rumen additive before, after or simultaneously with feeding said ruminant with wheat straw having previously undergone alkaline pretreatment, and preferably simultaneously with feeding said ruminant, which means that said enzymatic additive is not used in pretreatment on wheat straw.

The enzymatic rumen additive is an enzyme mixture comprising at least two enzymes. Enzymes used in the enzymatic rumen additive may be glucanases, xylanases, esterases, or carboxymethylcellulases.

According to a particular embodiment, the enzymatic rumen additive is a mixture of glucanase and xylanase and in particular endo-1,3 (4) -beta-glucanase and endo-beta-1,4-xylanase. According to this embodiment, the dose of endo-1, 3 (4) -3-glucanase can be between 200 units / g of straw and 7000 units / g of straw, preferably of 4000 units / g of straw at 6000 units / g of straw, for example about 4670 units / g of straw.

Similarly, the dose of endo-3-1, 4-xylanase can be between 200 units / g of straw and 7000 units / g of straw, preferably of 4000 units / g of straw to 6000 units / g of straw as for example about 4670 units / g of straw.

Advantageously, the ratio endo-1, 3 (4) -3-glucanase / endo-3-1, 4-xylanase is at least 0.5, preferably at least 0.75, and especially about 1.

The enzymatic rumen additive is in a form suitable for animal administration. Thus, the enzymatic rumen additive can be in the form of capsules, bolus, powder, granules or liquid, such as in ampoules. Preferably, the enzymatic rumen additive is in the form of powder or liquid, preferably in powder form.

The use according to the invention is particularly advantageous because it makes it possible to improve the degradation of wheat straw by animals. In addition, the simultaneous use makes it possible to create a synergistic effect on the degradation of wheat straw.

The invention will be better understood with the aid of the following examples, which are intended to be purely illustrative and do not in any way imply a limitation.

FIGURES

FIG. 1: Comparison of the effect of an aqueous pretreatment alone (H ₂ 0) or alkaline alone (NaOH 5%), of the use of an enzymatic ruminate additive alone (represented hereinafter by (GP + XP) x10) or the combination of an alkaline pretreatment and an enzymatic ruminate additive (hereinafter represented by (5% + NaOH + (GP + XP) x10)) on the degradation of the dry matter of wheat straw ( percentage of disappearance / degradation of the dry matter of wheat straw).

The two dashed lines respectively represent the value of the disappearance / degradation of the dry matter of wheat straw pretreated with soda (5% NaOH) (upper line) and not pretreated (control (C)) (lower line).

EXAMPLES Materials and methods

1. Preparation of fermentation modules

Wheat straw is milled on a 2 cm mesh (Electra) and then the fine particles are removed through a sieve of 1. 18 mm (Penn State Separator).

Fractions of 3 g are then weighed into triplicates and placed in vials equipped with a pressure measuring module (Ankom Technology).

2. Pretreatment

Pretreatment is applied semi-wet for 24 hours on straw before incubation with rumen juice. Two types of pretreatment are applied. Pretreatment with water (control) and chemical pretreatment.

Pretreatment with water is a negative control. Indeed, the pre-treatment is made by a soda solution in water. On the one hand, (i) a negative control pre-treated with water only, and (ii) a negative control without pre-treatment, and then dissociating the water pre-treatment effect and soda, and therefore to be able to conclude specifically about the effect of soda as a pre-treatment.

The chemical pretreatment is applied by contacting the wheat straw with a 5% sodium hydroxide (NaOH) solution. 9 ml of solution are used for 3 g of wheat straw.

3. Additive

In order to recreate the in vivo conditions of the co-administration of the wheat straw and the enzyme additive according to the process of the invention, the additive is added in the modules at the time of incubation with the ruminal liquid.

Enzyme ruminate additive is a mixture of two enzymes in a 1: 1 ratio:

an endo-1,3 (4) -beta-glucanase, hereinafter GP, having an activity of 70000 units / g and an endo beta 1-4 xylanase, hereinafter XP, having an activity of 70000 units / g.

The enzymatic units correspond to the amount of enzyme necessary for:

Ten doses of the enzymatic mixture ((GP + XP) × 10) corresponds to 0.4 g of the enzyme mixture for 3 g of straw, ie 0.2 g of GP and 0.2 g of XP for 3 g of straw, or 4670 units (rounded to the tens) of GP and XP for 1 g of straw. 4. Obtaining rumen fluid for fermentation

Ruminai content is collected approximately 2 hours post-meal in dry dairy cows, carrying a ruminal cannula and fed with a ration based on wheat straw, corn silage and a mineral and vitamin supplement.

After collection, the ruminai content is filtered through a 1.6 mm mesh metal screen to obtain rumen fluid.

The rumen fluid is then mixed with a pH = 7 buffer solution (1: 1 ratio) to form the incubation medium. The latter is bubbled with C0 ₂ oxygen-free.

5. Preparation of fermentation modules

Several modules are prepared and distributed within four trials. The composition of the different modules and their distribution within the tests are presented below.

Trial 1: Wheat straw only pretreated

6 modules containing straw chemically pretreated with an alkaline solution according to the protocol of point 2. above;

3 modules containing pretreated straw according to the same protocol as point 2. but replacing the alkaline solution with water;

3 control modules containing only straw, hereinafter C.

Test 2: Unpretreated wheat straw and enzymatic rumen additive (see point 3. above).

3 modules containing untreated straw and a 10-fold concentrated ruminal additive ((GP + XP) x10);

3 control modules containing only straw, hereinafter C.

Trial 3: duplicate of Trial 2 to validate and confirm the results.

Test 4: Pretreated wheat straw (see point 2.) and enzymatic rumen additive (see point 3.)

6 modules containing straw chemically pretreated with an alkaline solution according to the protocol of point 2. and a 10-fold concentrated enzymatic ruminal additive ((GP + XP) x10);

3 control modules containing only straw, hereinafter C.

For each of the tests, the untreated straw corresponds to pretreated straw according to the same protocol as point 2. but replacing the alkaline solution with water.

For each test, 3 white modules are made. They contain only incubation medium as described in point 4 of this example. The incubation flasks receive 200 ml of incubation medium each and then are saturated with oxygen-free CO ₂ . The quantity of straw, pretreated or not, within each module is 3 grams.

6. Measurement of degraded dry matter.

The flasks are incubated at 39 ° C for 96 hours to allow fermentation.

After 96 hours of incubation, the modules are placed in the ice to stop the fermentation. The amount of non-degraded dry matter is then measured by filtering and drying the incubation residue at 60 ° C for 4 days (hereinafter referred to as residue).

The incubated substrate corresponds to pretreated or unpretreated wheat straw.

The disappearance of the dry matter (in percentage%) is calculated according to the formula below:

[incubated substrate - (incubated substrate residue - control module residue)] / incubated substrate x 100

Whether for the incubated substrate, the residues of the incubated substrate or the control module, this is the average of the results obtained for the modules of the same treatment.

7. Statistical analysis

The dry matter degradation results (percentages%) were subjected to an analysis of variance using the linear general univariate model of the statistical data processing software SPSS® (IBM®, SPSS®, version 22). The model integrates the effects of the covariate and the products, the covariate being the degradation of the control dry matter (in percentage%). An Iog10 transformation of the percent values was performed for the analysis.

The results are considered insignificant when P> 0.05.

The different letters a, b, c, d used in the figure indicate whether values are significantly different or not. Thus, the results are not significantly different when the same letter is reported (P> 0.05).

Results

Effect of use of alkaline pretreatment and enzymatic ruminate additive

FIG. 1 shows a significant effect on the ruminal degradation of the dry matter by the use of an enzymatic rumen additive on wheat straw pretreated with sodium hydroxide (5% NaOH + (GP + XP) x10 ). The results show that pretreatment with sodium hydroxide (5%) improves the ruminal degradation of straw with respect to (i) no pre-treatment and (ii) pre-treatment with water. These results thus confirm the direct effect of the soda used in pre-treatment on ruminal degradability of the straw.

Pretreatment with sodium hydroxide makes it possible to improve rumen degradation of the dry matter by 22.3 points compared with untreated wheat straw (control).

However, no significant increase in dry matter consumption is observed on untreated straw in the presence of the addition of enzymatic rumen additive ((GP + XP) x10) compared with untreated wheat straw. (control).

By cons, quite surprisingly, the addition of an enzymatic rumen additive on straw chemically pretreated with sodium reveals a synergistic effect on the ruminal degradation of the dry matter.

The synergistic effect is understood to mean that ruminal degradation in animals of chemically pretreated wheat straw and in the presence of enzymatic rumen additive is greater than the ruminal degradation achieved by chemical pretreatment alone, by the administration. of the enzymatic additive alone or by the two combined but working independently.

Indeed, the addition of the enzymatic rumen additive ((GP + XP) x10) on sodium-pretreated wheat straw increases the consumption by 13.2 points respectively.

The process according to the invention is therefore particularly advantageous in that it makes it possible to significantly improve the ruminal degradation of wheat straw when the latter is chemically pretreated.

Claims

A method of improving rumen degradation of wheat straw in a ruminant comprising the steps of:

a) supply of wheat straw,

b) chemical pretreatment of said straw provided,

c) feeding the ruminant with the wheat straw pretreated chemically in step b),

The process of claim 1 wherein the chemical pretreatment of step b) is an alkaline pretreatment.

3. Method according to claim 2, characterized in that the alkaline pretreatment is a pretreatment carried out with a solution of sodium hydroxide, sodium hydroxide, lime, potassium hydroxide, anhydrous ammonia, aqueous ammonia, of urea or a mixture of these compounds, preferably the alkaline treatment is carried out with a solution of sodium hydroxide.

4. Method according to any one of claims 1 to 3, characterized in that the chemical pretreatment is carried out wet, semi-wet, dry or semi-dry, and preferably semi-wet.

5. Method according to any one of claims 1 to 4, characterized in that step d) direct administration of the enzymatic rumen additive is an oral administration.

6. Method according to any one of claims 1 to 5, characterized in that the step d) of administering the enzymatic rumen additive is carried out before, after or simultaneously in step c) feeding the ruminant with the pretreated wheat straw, preferably simultaneously with step c).

7. Method according to any one of claims 1 to 6, characterized in that the enzymatic rumen additive is an enzyme mixture comprising at least two enzymes selected from glucanases, xylanases, esterases, or carboxymethylcellulases.

8. Process according to claim 7, characterized in that the enzymatic additive is an enzymatic mixture comprising a glucanase and a xylanase, preferably an endo- 1, 3 (4) -3-glucanase and an endo-b-1, 4-xylanase.

9. Process according to claim 8, characterized in that the endo-1,3 (4) -3-glucanase is present in a dose of between 200 units / g of straw and 7000 units / g of straw, of preferably from 4000 units / g of straw to 6000 units / g of straw, and even more preferentially 4670 units / g of straw.

10. Method according to claim 8, characterized in that the endo-b-1, 4-xylanase is present in a dose of between 200 units / g of straw and 7000 units / g of straw, preferably 4000 units / straw at 6000 units / g of straw, and even more preferentially 4670 units / g of straw.

A process according to claim 8, characterized in that endo-1,3 (4) -3-glucanase and endo-b-1,4-xylanase are present in a ratio of at least 0, 5, preferably in a ratio of at least 0.75 and even more preferably in a 1: 1 ratio within the enzyme mixture.

12. Method according to one of claims 1 to 1 1, characterized in that the enzymatic rumen additive is in the form of powder or liquid, preferably in the form of powder.

13. Method according to one of claims 1 to 12, characterized in that the ruminant belongs to the family Bovidae.

14. Direct use in a ruminant of an enzymatic rumen additive before, after or simultaneously feeding said ruminant with wheat straw having previously undergone alkaline pretreatment, preferably simultaneously with feeding said ruminant, which means that said enzymatic additive is not used in pretreatment on wheat straw.

15. Use of an enzymatic rumen additive according to claim 14, characterized in that said enzymatic ruminate additive is an enzymatic mixture comprising at least two enzymes selected from glucanases, xylanases, esterases, or carboxymethylcellulases, preferably a glucanase. and xylanase and more preferably endo-1,3 (4) -glucanase and endo-b-1,4-xylanase.

16. Use according to claim 15, characterized in that the endo-1,3 (4) -b-glucanase is present in a dose of between 200 units / g of straw and 7000 units / g of straw, preferably of 4000 units / g of straw at 6000 units / g of straw, and even more preferentially 4670 units / g of straw.

17. Use according to claim 15, characterized in that the endo-b-1, 4-xylanase is present in a dose of between 200 units / g of straw and 7000 units / g of straw, preferably 4000 units / straw at 6000 units / g of straw, and even more preferentially 4670 units / g of straw.

18. Use according to claim 15, characterized in that the endo-1,3 (4) -b-glucanase and the endo-b-1,4-xylanase are present in a ratio of at least 0.5 preferably in a ratio of at least 0.75 and even more preferably in a 1: 1 ratio within the enzyme mixture.