PROCESS FOR IMPROVING WHEAT STRAW DEGRADATION

Abstract

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

Claims

1-18. (canceled)

19. A process for improving ruminal wheat straw degradation in a ruminant comprising the following steps: a) provision of wheat straw, b) chemical pretreatment of said provided straw, c) feeding the ruminant with the wheat straw chemically pretreated in step b), wherein said process further comprises a step d) of direct administration to the ruminant of a ruminal enzyme additive, which means that said enzyme additive is not used in pretreatment on the wheat straw.

20. The process as claimed in claim 19, wherein the chemical pretreatment of step b) is an alkaline pretreatment.

21. The process as claimed in claim 20, wherein the alkaline pretreatment is a pretreatment carried out with a sodium hydroxide, soda, lime, potassium hydroxide, anhydrous ammonia, aqueous ammonia or urea solution or a mixture of these compounds, preferably the alkaline treatment is carried out with a sodium hydroxide solution.

22. The process as claimed in claim 19, wherein the chemical pretreatment is carried out by a wet, semi-wet, dry or semi-dry process, and preferably by a semi-wet process.

23. The process as claimed in claim 19, wherein step d) of direct administration of the ruminal enzyme additive is an oral administration.

24. The process as claimed in claim 19, wherein step d) of administration of the ruminal enzyme additive is carried out before, after or simultaneously with step c) of feeding the ruminant with the pretreated wheat straw, preferably simultaneously with step c).

25. The process as claimed in claim 19, wherein the ruminal enzyme additive is an enzyme mixture comprising at least two enzymes selected from glucanases, xylanases, esterases, or carboxymethylcellulases.

26. The process as claimed in claim 25, wherein the enzyme additive is an enzyme mixture comprising a glucanase and a xylanase, preferably an endo-1,3(4)-β-glucanase and an endo-β-1,4-xylanase.

27. The process as claimed in claim 26, wherein endo-1,3(4)-β-glucanase is present in a dose comprised between 200 units/g straw and 7000 units/g straw, preferably from 4000 units/g straw to 6000 units/g straw, and even more preferentially 4670 units/g straw.

28. The process as claimed in claim 26, wherein endo-β-1,4-xylanase is present in a dose comprised between 200 units/g straw and 7000 units/g straw, preferably from 4000 units/g straw to 6000 units/g straw, and even more preferentially 4670 units/g straw.

29. The process as claimed in claim 26, wherein endo-1,3(4)-β-glucanase and endo-β-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 ratio of 1:1 in the enzyme mixture.

30. The process as claimed in claim 19, wherein the ruminal enzyme additive is in powder or liquid form, preferably in powder form.

31. The process as claimed in claim 19, wherein the ruminant belongs to the family Bovidae.

32. A process for improving ruminal wheat straw degradation in a ruminant, comprising administering to a ruminant a ruminal enzyme additive before, after or simultaneously with the feeding of said ruminant with wheat straw having first undergone an alkaline pretreatment, preferably simultaneously with the feeding of said ruminant, which means that said enzyme additive is not used in pretreatment on the wheat straw.

33. The process as claimed in claim 32, wherein said ruminal enzyme additive is an enzyme mixture comprising at least two enzymes selected from glucanases, xylanases, esterases, or carboxymethylcellulases, preferably a glucanase and a xylanase and even more preferably an endo-1,3(4)-β-glucanase and an endo-β-1,4-xylanase.

34. The process as claimed in claim 33, wherein the endo-1,3(4)-β-glucanase is present in a dose comprised between 200 units/g straw and 7000 units/g straw, preferably from 4000 units/g straw to 6000 units/g straw, and even more preferentially 4670 units/g straw.

35. The process as claimed in claim 33, wherein the endo-β-1,4-xylanase is present in a dose comprised between 200 units/g straw and 7000 units/g straw, preferably from 4000 units/g straw to 6000 units/g straw, and even more preferentially 4670 units/g straw.

36. The process as claimed in claim 33, wherein the endo-1,3(4)-β-glucanase and endo-β-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 ratio of 1:1 in the enzyme mixture.

Description

FIGURES

[0084] FIG. 1: Comparison of the effect of an aqueous (H.sub.2O) or alkaline (NaOH 5%) pretreatment alone, of the use of a ruminal enzyme additive alone (represented hereinafter by (GP+XP)×10) or the combination of an alkaline pretreatment and a ruminal enzyme additive (represented hereinafter by (NaOH 5%+(GP+XP)×10)) on wheat straw dry matter degradation (in percentage % disappearance/degradation of the wheat straw dry matter).

[0085] The two dotted lines represent respectively the value of the disappearance/degradation of the dry matter of wheat straw pretreated with soda (NaOH 5%) (upper line) and not pretreated (control (C)) (bottom line).

EXAMPLES

Materials and Methods

[0086] 1. Preparation of Fermentation Modules

[0087] Wheat straw is crushed on a 2 cm mesh (Electra) and then the fine particles are removed using a 1.18 mm sieve (Penn State Separator).

[0088] Fractions (3 g) are then weighed in triplicate and placed in bottles equipped with a pressure measurement module (Ankom Technology).

[0089] 2. Pretreatment

[0090] A pretreatment is applied by a semi-wet process for 24 hours on the straw before incubation with rumen fluid. Two types of pretreatment are applied. A water pretreatment (control) and a chemical pretreatment.

[0091] The water pretreatment is a negative control. Indeed, the pretreatment is done by a solution of soda in water. Both (i) a negative control pretreated with water only and (ii) a negative control without pretreatment are therefore needed to then dissociate the effect of water pretreatment and that of soda, and thus to be able to conclude specifically about the effect of soda as pretreatment.

[0092] The chemical pretreatment is applied by bringing the wheat straw into contact with a 5% sodium hydroxide (NaOH) solution. 9 mL of solution is used for 3 g of wheat straw.

[0093] 3. Additive

[0094] In order to recreate the in vivo conditions of co-administration of wheat straw and the enzyme additive according to the process of the invention, the additive is added to the modules at the time of incubation with ruminal fluid.

[0095] The ruminal enzyme additive is a mixture of two enzymes in a 1:1 ratio: [0096] an endo-1,3(4)-beta-glucanase, hereinafter GP, having an activity of 70000 units/g and [0097] an endo beta 1-4 xylanase, hereinafter XP, having an activity of 70000 units/g.

[0098] Enzyme units correspond to the amount of enzyme needed to: [0099] release 1 μmole of glucose per minute at pH 4.8 and 50° C. from a barley glucan substrate for glucanase; [0100] release 1 μmole of xylose per minute at pH 5.3 and 50° C. from a birchwood xylan substrate for xylanase.

[0101] Ten doses of the enzyme mixture ((GP+XP)×10) corresponds to 0.4 g of the enzyme mixture for 3 g of straw, i.e. 0.2 g of GP and 0.2 g of XP for 3 g of straw, i.e. 4670 units (rounded to the nearest ten) of GP and XP for 1 g of straw.

[0102] 4. Obtaining Ruminal Fluid for Fermentation

[0103] Ruminal contents are collected about 2 hours after feeding from dry dairy cows, carrying a ruminal cannula and fed a ration based on wheat straw, corn silage and a mineral and vitamin supplement.

[0104] After collection, the ruminal contents are filtered through a metal sieve with a 1.6 mm mesh size in order to obtain the ruminal fluid.

[0105] The ruminal fluid is then mixed with a pH=7 buffer solution (ratio 1:1) to form the incubation medium. The incubation medium is bubbled with oxygen-free CO.sub.2

[0106] 5. Preparation of the Fermentation Modules

[0107] Several modules are prepared and distributed within 4 tests. The composition of the different modules and their distribution within the tests are presented below.

Test 1: Pretreated Wheat Straw Only

[0108] 6 modules containing straw chemically pretreated with an alkaline solution according to the protocol of point 2. above; [0109] 3 modules containing straw pretreated according to the same protocol as point 2. but replacing the alkaline solution with water; [0110] 3 control modules containing only straw, hereinafter C.

Test 2: Non-Pretreated Wheat Straw and Ruminal Enzyme Additive (See Point 3. Above).

[0111] 3 modules containing non-pretreated straw and a 10× concentrated ruminal additive ((GP+XP)×10); [0112] 3 control modules containing only straw, hereinafter C.

Test 3: Duplicate of Test 2 to Validate and Confirm the Results.

Test 4: Pretreated Wheat Straw (See Point 2.) and Ruminal Enzyme Additive (See Point 3.)

[0113] 6 modules containing straw chemically pretreated with an alkaline solution according to the protocol of point 2. and a 10× concentrated ruminal enzyme additive ((GP+XP)×10); [0114] 3 control modules containing only straw, hereinafter C.

[0115] For each of the tests, the non-pretreated straw corresponds to straw pretreated according to the same protocol as in point 2. but replacing the alkaline solution with water.

[0116] For each test, 3 blank modules are made. They contain only the incubation medium as described in point 4. of the present example.

[0117] The incubation bottles receive 200 mL of incubation medium each and are then saturated with oxygen-free CO.sub.2 The amount of pretreated or non-pretreated straw within each module is 3 grams.

[0118] 6. Measurement of the Degraded Dry Matter.

[0119] The bottles are incubated at 39° C. for 96 hours to allow fermentation.

[0120] After 96 h of incubation, the modules are placed in ice to stop fermentation. The amount of undegraded dry matter is then measured by filtering and drying the incubation residue at 60° C. for 4 days (hereinafter called residue).

[0121] The incubated substrate corresponds to the pretreated or non-pretreated wheat straw.

[0122] The disappearance of dry matter (in percentage %) is calculated according to the following formula:

[incubated substrate−(incubated substrate residue−control module residue)]/incubated substrate×100

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

[0123] 7. Statistical Analysis

[0124] The dry matter degradation results (in 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 incorporates the effects of the covariate and the products, the covariate being the dry matter degradation of the controls (in percentage %). A log 10 transformation of the values expressed in percentage was performed for the analysis.

[0125] Results are considered insignificant when p>0.05.

[0126] 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 the Use of an Alkaline Pretreatment and a Ruminal Enzyme Additive

[0127] FIG. 1 highlights a significant effect on ruminal dry matter degradation of the use of a ruminal enzyme additive on wheat straw pretreated with soda (NaOH 5%+(GP+XP)×10).

[0128] The results show that a pretreatment with soda (5%) improves ruminal straw degradation compared with (i) no pretreatment and (ii) a pretreatment with water. These results thus confirm the direct effect of the soda used in pretreatment on the ruminal straw degradability.

[0129] The pretreatment with soda improves ruminal dry matter degradation by 22.3 points compared with non-pretreated wheat straw (control).

[0130] No significant increase in dry matter consumption is however observed on the non-pretreated straw in the presence of an addition of the ruminal enzyme additive ((GP+XP)×10) compared with non-pretreated wheat straw (control).

[0131] In contrast, quite surprisingly, the addition of a ruminal enzyme additive on straw chemically pretreated with soda makes it possible to highlight a synergistic effect on ruminal dry matter degradation.

[0132] The synergistic effect is understood as the fact that the ruminal degradation in the animal of chemically pretreated wheat straw in the presence of a ruminal enzyme additive is higher than the ruminal degradation obtained by a chemical pretreatment alone, by the administration of the enzyme additive alone or by the two combined but working independently.

[0133] Indeed, the addition of the ruminal enzyme additive ((GP+XP)×10) on wheat straw pretreated with soda increases said consumption by 13.2 points respectively.

[0134] The process according to the invention is therefore particularly advantageous in that it significantly improves ruminal wheat straw degradation when the wheat straw is chemically pretreated.