过瘤胃蛋氨酸对奶山羊产奶性能和血清生化指标的影响

Effects of Rumen Protected Methionine on Milk Performance and Serum Biochemical Indexes of Milk Goat

本试验旨在研究在饲粮中添加不同保护方式的过瘤胃蛋氨酸对奶山羊产奶性能和血清生化指标的影响。采取完全随机试验设计,选取45只平均体重为(52.6±4.9)kg、胎次相近、泌乳日龄[(120±10)d]相近的关中奶山羊,随机分为3组,每组15只。对照组饲粮为不添加过瘤胃蛋氨酸的基础饲粮,试验Ⅰ组在基础饲粮基础上添加4.5 g/d过瘤胃蛋氨酸A(物理包被),试验Ⅱ组在基础饲粮基础上添加4.5 g/d过瘤胃蛋氨酸B(化学保护)。总试验期为39 d,其中预试期9 d,正试期30 d。结果表明:1)试验Ⅰ组、试验Ⅱ组的奶料比极显著高于对照组(P<0.01),2个试验组之间差异不显著(P>0.05);试验Ⅰ组、试验Ⅱ组的产奶收益和毛收益均高于对照组(P>0.05)。2)试验Ⅰ组和试验Ⅱ组羊乳的乳脂率分别比对照组提高了6.75%和13.18%,但差异不显著(P>0.05);试验Ⅱ组羊乳的乳蛋白率和非脂固形物含量均高于对照组,但差异不显著(P>0.05)。3)试验Ⅰ组、试验Ⅱ组的血清总胆固醇和尿素氮含量均低于对照组,但差异不显著(P>0.05);试验Ⅰ组的血清免疫球蛋白G含量显著高于对照组和试验Ⅱ组(P<0.05)。综上所述,饲粮中添加不同保护方式(物理包被和化学保护)的过瘤胃蛋氨酸均能提高奶山羊经济效益,且添加物理包被的过瘤胃蛋氨酸可以提高机体的免疫力,添加化学保护的过瘤胃蛋氨酸可以提升羊乳的乳脂率和乳蛋白率。

This experiment was conducted to the effects of adding different protective modes of rumen protected methionine in diets on milk performance and serum biochemical indexes of milk goat.A completely randomized trial design was adopted to select 45 Guanzhong milk goat with the body weight of(52.6±4.9)kg,similar parities and similar lactation age[(120±10)d],randomly divided into 3 groups,and 15 goats in each group.The diet of control group was a basal diet which did not add rumen methionine,the diet of trial I group was added 4.5 g/d rumen methionine A(physical coating)based on the basal diet,and the diet of trialⅡgroup was added 4.5 g/d rumen methionine B(chemical protection)based on the basal diet.The whole experiment lasted for 39 days including 9 days of pretrial period and 30 days of trial period.The results showed as follows:1)the milk to feed ratio of trialⅠgroup and trialⅡgroup was significantly higher than that of control group(P<0.01),but the difference between experimental groups was not significant(P>0.05);the milk income and gross returns of trialⅠgroup and trialⅡgroup were higher than control group(P>0.05).2)The milk fat percentage in goat milk of trialⅠgroup and trialⅡgroup was 6.75%and 13.18%higher than that of control group,respectively,but the difference was not significant(P>0.05);the milk protein percentage and non-fat solids content in goat milk of trialⅠgroup and trialⅡgroup were higher than that of control group,however,the difference was not significant(P>0.05).3)The contents of serum total cholesterol and urea nitrogen of trialⅠgroup and trialⅡgroup were lower than that of control group(P>0.05),and the serum immunoglobulin G content of trialⅠgroup was significantly higher than that of control group and trialⅡgroup(P<0.05).To sum up,adding different protective modes of rumen protected methionine(physical coating and chemical protection)can both improve the economic benefit of milk goat.Furthermore,adding rumen protected methionine coated by physical method can promote the body immunity of milk goat,and adding rumen protected methionine protected by chemical method can elevate the milk fat percentage and milk protein percentage of goat milk.