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Research Article
 

Effect of Xylanase and Phytase Supplementation on Goat’s Performance in Early Lactation



H.H. Azzaz, A.A. Aboamer, Hoda Alzahar, M.M. Abdo and H.A. Murad
 
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ABSTRACT

Background and Objectives: Supplementing diets of dairy animals with phytase and xylanase can enhance phosphorus availability and fiber degradation in the rumen and positively affect animal’s health and productivity. In vitro and in vivo trials have been conducted to define the optimal addition level of xylanase and phytase to lactating Baldi goat’s rations and investigate effects of these enzymes on animal’s nutrients digestibility, blood chemistry, milk production and milk composition. Materials and Methods: In vitro batch culture technique was used to evaluate the effect of phytase and xylanase supplementation at different levels (0, 1, 2 and 3 g kg1 DM) on rumen fermentation characteristics. Eighteen early lactating Baldi goats were randomly assigned into three groups and fed 4% dry matter according to their body weight. The first group was fed control ration (35% yellow corn, 20% corn stalks, 20% berseem hay, 12.5% soybean meal and 12.5% wheat bran), the second group fed control ration+Penizyme at 2 g kg1 DM (R1), while the third group fed control ration+Phtase-Plus® at 1 g kg1 DM (R2). Results: Xylanase and phytase supplementation increased the in vitro DM and OM degradability and ruminal NH3-N and total volatile fatty acids (TVFA) concentrations, with no effect on total gas production (TGP) volume. All nutrients digestibility (except CP), blood serum glucose concentration, milk production and milk components yields were increased for enzymes supplemented goats than control. Conclusion: Inclusion of xylanase and phytase in lactating goat’s rations improved their productive performance with no deleterious effects on their health.

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H.H. Azzaz, A.A. Aboamer, Hoda Alzahar, M.M. Abdo and H.A. Murad, 2019. Effect of Xylanase and Phytase Supplementation on Goat’s Performance in Early Lactation. Pakistan Journal of Biological Sciences, 22: 265-272.

DOI: 10.3923/pjbs.2019.265.272

URL: https://scialert.net/abstract/?doi=pjbs.2019.265.272
 
Copyright: © 2019. This is an open access article distributed under the terms of the creative commons attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.

INTRODUCTION

At the present time, cereal grains and grains by products represent at least 50% of dairy animal’s rations in Egypt. In view of the high xylan and phytate phosphorus content of these feedstuffs, limitations in fibers and phosphorus utilization can occur in the rumen1,2. It is worth to mention that, xylan is a fiber polysaccharide composed of more than 10000 xylose units linked by 1,4-β-linkages3. While, phytate is an organic complex (myo-inositol hexakisphosphate) generally regarded as the primary storage form of phosphorus (P) in plants4. Also, phytate has anti nutritive properties as it has the ability to reduce mineral's (i.e., P, Ca, Mg, Zn and Fe) availability and bind with proteins and digestive enzymes (i.e., amylase, pepsin and trypsin) to make them less soluble5,6.

It was reported that dairy cows are able to utilize 98% of phytate- P present in their diets7, but, in another report it was pointed out that only 67% of phytate- P has been hydrolysed1. Also, it was stated that around 80% of grain’s phytate were hydrolysed to inorganic P by dairy cows8. However, slow or incomplete digestion of dietary fibers and the deficiency of phosphorus (P) bioavailability can significantly influence animal performance and increase the cost of production4,9. Therefore, the search for tools able to increase nutrients bioavailability for farm animals is very important approach.

The use of enzymatic preparations as a feed supplements have attracted a lot of interest at last decade10,11. Phytate P can be hydrolysed to inorganic P and myo-inositol phosphate esters by using phytase. Phytase belongs to a class of enzymes that enables dephosphorylation of phytate in the feed before ingestion or in the digestive tract of the treated animals12,13. Similarly, xylanase is the main enzyme of cell wall degrading enzymes that can hydrolyses xylan into soluble sugars14. Supplementing diets of ruminants with phytase and fiber degrading enzymes can improve feed utilization and animal performance by enhancing P availability and fiber degradation in vitro14-18, in situ19,20 and in vivo4,21-25. The proposed mode of action of xylanase and phytase in ruminants including partial hydrolysis of dietary phytate and xylan before ingestion, increase ruminal total xylanase and phytase hydrolytic activity by synergism with endogenous enzymes and improve ability of ruminal micro-organisms to attachment and access of the feed particles8,9.

The first goal for dairy herd’s breeders is to provide their animals with adequate amount of nutrients to optimize their animal’s performance at an economic cost. Feeding excessive amounts of phosphorus should be avoided because it is costly and environmental pollutant and it may affect milk production adversely26. In contrast, insufficient intake of P can negatively affect fiber digestion, protein degradation and microbial protein synthesis in the rumen4. Therefore; the optimal level for enzymes addition to dairy animal’s diets is very important issue.

In this study, the focus has been on: (1) Defined the optimal level of xylanase and phytase enzymes addition to ruminant’s rations through (in vitro) trial. (2) Investigated the impact of these enzymes addition to Baldi goat’s rations on animal’s nutrients digestibility, blood chemistry, milk production and milk composition.

MATERIALS AND METHODS

This study was carried out at a private farm (Alsttar farm for animal production), Khatatba, Menofia governorate, Egypt. The entire experimental period was extended from January 2-March 3, 2018. This experimental research has been conducted according to the experimental and ethical rules of the National Research Centre of Egypt.

Xylanase and phytase sources
Penizyme: A laboratory produced xylanase (22.88 IU g1) from Penicillium chrysogenumin dry form by using insoluble-starch as a carrier material. The produced enzyme activity was determined according to method of Bailey et al.27. One unit of xylanase activity was defined as the amount of enzyme that liberates 1 μmol of reducing sugars equivalent to xylose per minute under the assay conditions27.

Phytase-Plus®: A commercial dry form of phytase enzyme source (500 IU g1) produced by Baytara for pharmaceuticals technology, Sadat Industrial city under license of VTR© Guangdong VTR Bio-Tech Co., Ltd.,-China. A mixture of wheat bran and calcium carbonate were used as carrier materials for the enzyme activity. One unit of phytase is defined as the amount of enzyme that liberates 1 μmol of phosphate per minute from sodium phosphate under the assay conditions15.

In vitro study: A 400 mg of total mixed ration (TMR) consisted of 35% yellow corn, 20% corn stalks, 20% berseem hay, 12.5% soybean meal and 12.5% wheat bran was accurately weighed into125 mL incubation vessels and separately supplemented with solution of Penizyme and Phtase-Plus® at different levels (0, 1, 2 and 3 g kg1 DM). Each vessel was filled with 40 mL of mixture of 1:3 (v/v) rumen fluids: buffer solution28. After 24 h of incubation, all vessels were filtered in fiber filter bags 25 micron porosity (ANKOM-USA). The residues in the bags were dried at 70°C in oven for 48 h to analyse dry matter (DM) and organic matter (OM) digestibility. Rumen fluid pH was measured using pH-meter. Overall volume of the produced gases was determined using Hohenheim Syringes (100 mL)29. Quantitative analysis of ammonia concentration was carried out by a modified Nessler’s method30. The total volatile fatty acids (VFA) were determined28.

Digestibility and lactating trails: Eighteen early lactating baladi goats weighed on average (26±0.5 kg) were used in the present study. Goats were randomly divided after a week of parturition into three groups. The first group was fed the control ration (35% yellow corn, 20% corn stalks, 20% berseem hay, 12.5% soybean meal and 12.5% wheat bran). The second group was fed control ration+Penizyme at 2 g kg1 DM (R1), while the third group was fed control ration+Phtase-Plus® at 1 g kg1 DM (R2). The goats were fed dry matter according to 4% of their body weight and the entire experimental period was 63 days. The feed ingredients and the chemical composition of the experimental control ration are shown in Table 1.

Determination of digestion coefficients: During the last 7 days of each month of the experimental period, fecal grab samples were collected in cloth bag connected to the animal back at 1 pm from 3 animals of each group. The dried feces from each animal were mixed and ground to pass a 1 mm sieve in a feed mill for chemical analysis. The digestibility coefficient of nutrient was calculated according to the following equation31:

Feed and fecal analysis: Feed stuffs and fecal samples were analyzed according to the AOAC32 methods to determine dry matter (DM), crude protein (CP), ether extract (EE) and ash contents. Organic matter (OM) contents were calculated by difference. The neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) contents were determined33.

Blood sampling and analysis: Blood samples were taken from jugular vein of 3 animals each group through the last 3 days of each month of the experimental period. At about 4 h after morning feeding the blood samples were collected in glass tubes and left to coagulate at room temperature. Serum was separated by centrifugation at 4000×g/20 min and kept frozen at -20°C for later analysis. The measured blood parameters (urea, AST, ALT, etc...) were determined34.

Sampling and analysis of milk: Goats were milked by hand twice a day at 8:00 am and 8:00 pm by milking one teat while, the other one was left to the kid for suckling. Samples of milk were collected immediately from each animal after morning and evening milking and milk yield was recorded. Milk samples were analyzed for total solids, fat, true protein and lactose by infrared spectrophotometry (Foss 120 Milko-Scan, Foss Q3 183 Electric, Hillerød, Denmark) according to AOAC32, procedures. Solids-not-fat (SNF) was calculated. Fat corrected milk (4% fat) was calculated by using the following equation35:

FCM = 0.4 M+15 F

where, M is the milk yield (g) and F is the fat yield (g).

Table 1:Chemical composition of feed ingredients and the calculated total mixed ration (on DM basis)
DM: Dry matter, OM: Organic matter, CP: Crude protein, EE: Ether extract, NDF: Neutral detergent fiber, ADF: Acid detergent fiber, ADL: Acid detergent lignin, NFC: Non fiber carbohydrate and TMR: Total mixed ration (Corn grain 35%, Soybean meal 12.5%, Wheat bran 12.5%, Corn stalks 20% and Clover hay 20%)

Table 2:Effect of xylanase and phytase supplemented rations on in vitro rumen fermentation characteristics
DMD (%): Dry matter degradability, OMD (%): Organic matter degradability, TGP: Total gas production (mL/24 h), NH3-N: Ammonia-Nitrogen (μmol L1), TVFA: Total volatile fatty acids (mEq dL1) and MSE±: Mean of standard error. *Means with different letter (a, b, c) in the same column are significantly different at p<0.05. 1, 2 and 3 refers to amount of enzymes by grams which added to each kilogram of animal's rations on dry matter basis

Table 3:Effect of xylanase and phytase supplementation on nutrient digestibility and nutritive values of the experimental rations
Control group: Goats fed control ration (35% yellow corn, 20% corn stalks, 20% berseem (clover) hay, 12.5% soybean meal and 12.5% wheat bran). R1: Goats group fed control ration+xylanase (Penizyme) at 2 g kg1 DM. Group was fed control R2: Goats group fed control ration+phytase (Phtase-Plus®) at 1 g kg1 DM. *Means with different letter in the same row are significantly different at p<0.05

Statistical analysis: Data obtained from this study were statistically analyzed by IBM SPSS Statistics for Windows36 using the following general model procedure:

Yij = μ+Ti+eij

where, Yij is the parameter under analysis of the ij vessel of in vitro trial or goats of digestibility and lactation trials, μ is the overall mean, Ti is the effect due to treatment on the parameter under analysis, eij is the experimental error for ij on the observation, the Duncan's multiple range tests was used to test the significance among mean s using probability level less than 0.05 (p<0.05) for significance expression37.

RESULTS

In vitro trial: Data of Table 2 showed that xylanase and phytase supplementation increased the in vitro dry matter (DMD %) and organic matter (OMD %) degradability for the treated rations than that of the control. Also, ruminal ammonia-nitrogen (NH3-N) and total volatile fatty acids (TVFA) concentrations take the same trend of the ration’s degradability. Penizyme (2 g kg1 DM) and Phytase-Plus® (1 g kg1 DM) supplementation levels gave the highest (p<0.05) values of DMD (%), OMD (%), NH3-N and TVFA for rations treated with xylanase and phytase, respectively. Ruminal pH recorded the highest (p<0.05) value by the control ration, while no significant differences were detected between all of the tested rations in the ruminal total gas production (TGP) volume.

Apparent nutrients digestibility: The goats fed enzymes supplemented rations (R1 and R2) showed significant increase (p<0.05) for most of nutrients digestibility coefficients and total digestible nutrients (TDN) than those fed the control ration (Table 3), but, no significant differences were found between all goatʹs groups in CP digestibility and digestible crude protein (DCP) values.

Blood serum parameters: Xylanase and phytase supplemented goats (R1 and R2) had higher (p<0.05) serum glucose concentration than those of the control (Table 4). While no significant change were detected between all goatʹs groups in creatinine, urea, cholesterol, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values.

Table 4:Effect of xylanase and phytase supplementation on goat’s blood parameters
Control group: Goats fed control ration (35% yellow corn, 20% corn stalks, 20% berseem (clover) hay, 12.5% soybean meal and 12.5% wheat bran). R1: Goats group fed control ration+xylanase (Penizyme) at 2 g kg1 DM. Group was fed control R2: Goats group fed control ration+phytase (Phtase-Plus®) at 1 g kg1 DM. *Means with different letter in the same row are significantly different at p<0.05

Table 5:Effect of xylanase and phytase supplementation on goat’s milk yield and milk composition
Control group: Goats fed control ration (35% yellow corn, 20% corn stalks, 20% berseem (clover) hay, 12.5% soybean meal and 12.5% wheat bran). R1: Goats group fed control ration+xylanase (Penizyme) at 2 g kg1 DM. Group was fed control R2: Goats group fed control ration+phytase (Phtase-Plus®) at 1 g kg1 DM. *Means with different letter in the same row are significantly different at p<0.05

Milk yield and its composition: Milk composition of supplemented goats with xylanase and phytase were not affected significantly compared with goats of the control (Table 5), but goats fed xylanase supplemented ration (R1) had higher (p<0.05) milk, 4% fat corrected milk (FCM) and all milk components yields than those fed the control. The goats fed ration supplemented with phytase (R2) showed numerical (but not significant) increase in milk and its components yields compared with those of the control. Also, there were no significant differences between goats fed enzymes supplemented rations (R1 and R2) in milk and its component's yields.

DISCUSSION

The resulting improvement in the in vitro ruminal parameters after enzymes supplementation may be due to highly hydrolytic effect of xylanase on the ration’s hemicellulose and positive impact of phytase on ration’s phosphorus bioavailability. The availability of P and simple carbohydrates may lead to increase in microbial colonization of feed particles and consequently more DM and OM digestion and increase TVFA's and microbial protein production. In this concern, it has been reported that phytase addition to ruminant’s rations can positively affect the P-utilization (in vitro)38. Also, it was found that total bacterial count were higher in rumen liquor of goats and steers treated with xylanase than untreated18. The reduction of ruminal pH values after enzymes supplementation maybe due to higher TVFA's production in response to enzymes treatment. In this context, it has been reported that in vitro ruminal pH decreased and TVFA's and NH3-N concentrations increased with xylanase addition14. While, maize stover treated with fibrolytic enzymes had no effects on final ruminal pH values, but increase significantly TVFA's production in vitro39. Generally, ruminal gas production seems to be related to the ration's chemical composition especially fiber contents40. This may give an explanation for non-significant change of TGP after xylanase or phytase supplementation. Similarly, positive effects of phytase and xylanase supplementation on in vitro DM and OM digestion have been noticed15,18. Increase DM, OM, EE, NFC, NDF and TDN digestibility for goats fed enzymes treated rations (R1 and R2) was may be due to break down of ration’s anti-nutritional factors (phytate and compacted cell wall fibers), beside liberation of more phosphorus and soluble carbohydrate for the action of rumen microflora. Absence of the enzymes effect on the CP digestibility is may be due to low degradability of corn protein (zein) in the rumen35. The current positive nutrients digestibility results are supported by findings of many researchers4,9,10,23. The elevation of blood glucose concentrations due to enzymes supplementation was may be attributed to higher nutrients digestibility (Table 3) which may let for more blood glucose circulation in goat’s body. In this concern, many studies stated increase animal’s blood glucose concentration after their feeding on fiber degrading enzymes9,40. However, it was also reported that no marked effect of phytase addition to diets on sheep’s blood parameters4. The marked increase in milk and its component’s yields by enzymes treated goats is probably due to higher production of TVFA’s especially propionate and NH3-N in their rumen, higher nutrients digestion and higher blood glucose concentration, which may lead for more glucogenic precursor’s delivery to the mammary gland11. It was stated that fibrolytic enzymes addition to goat’s rations have been associated with improved of microbial protein synthesis and increase efficiency of diet’s energy utilization11. This may gave an explanation for higher milk fat and protein yields in goats of R1. The positive impact of fiber degrading enzymes on milk and its components production has been recorded9,11,22,23. While, many researchers demonstrated that addition of phytase to lactating animals rations has no significant impact on the milk production or milk components yields21,41,42. It was obvious from the results of this study that phytase and xylanase addition to lactating goat’s diets can improve animal's performance; so more studies are recommended in this topic for find out the relation (synergism or antagonism) between action of xylanase and phytase as feed additives.

CONCLUSION

It could be concluded that inclusion of xylanase and phytase in lactating goat’s rations positively affect all rumen fermentation characteristics (in vitro) and improved most of nutrients digestibility coefficients and milk production by treated goats than those of control with no deleterious effects on goat’s health.

SIGNIFICANCE STATEMENT

This study discovered the effectiveness of the xylanase enzyme produced by aerobic fungi in the degradation of feed fibers in anaerobic media like rumen. This can be beneficial for the researchers and industry men as well and gives a greater opportunity to expand production of these enzymes on a commercial scale to be used in several areas including animal nutrition.

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