代乳品中不同蛋白质源组合对哺乳期犊牛生长性能和能氮代谢的影响

Effects of Different Protein Source Combinations in Milk Replacer on Growth Performance,Energy and Nitrogen Metabolism of Sucking Calves

本试验旨在研究代乳品中不同蛋白质源组合对哺乳期犊牛生长性能和能氮代谢的影响。选取64头初生荷斯坦公犊牛,随机分成4组(每组16头),分别饲喂4种代乳品,代乳品中的总蛋白质由乳源蛋白(MP)和植物蛋白按照3∶7的比例提供,植物蛋白分别为大豆分离蛋白(SP)、小麦水解蛋白(WP)和大米分离蛋白(RP)。各组代乳品中蛋白质源组成如下:A组,30%MP+70%SP;B组,30%MP+40%SP+10%WP+20%RP;C组,30%MP+10%SP+40%WP+20%RP;D组,30%MP+10%SP+20%WP+40%RP。试验期63 d。结果显示:1)14~63日龄,B组犊牛体重、平均日增重显著高于A组(P<0.05),各组之间开食料采食量、干物质采食量及饲料转化率没有显著差异(P>0.05)。2)14~63日龄,各组犊牛的腰角宽、胸围和体斜长差异不显著(P>0.05),但B组犊牛的体高、十字部高显著高于A组(P<0.05)。3)28日龄时,C组犊牛的总能消化率、总能代谢率和消化能代谢率显著低于A组和B组(P<0.05);各组之间粪氮和氮消化率差异显著(P<0.05),但是氮沉积率差异不显著(P>0.05)。56日龄时,各组之间在能氮代谢方面差异不显著(P>0.05)。4)28~56日龄,B组、C组和D组犊牛血清中生长激素(GH)水平均高于A组,其中D组与A组的差异达到显著水平(P<0.05);B组、C组和D组犊牛血清中胰岛素样生长因子-1(IGF-1)水平均显著高于A组(P<0.05)。综上所述,饲喂复合植物蛋白代乳品能够影响哺乳期犊牛的生长性能及能氮代谢,且综合来看B组饲喂效果最佳。

The objective of this study was to investigate the effects of different protein source combinations in milk replacer on growth performance,energy and nitrogen metabolism of sucking calves.In this experiment,sixty-four newborn Holstein calves were randomly assigned to one of four groups with 16 calves per group,which were fed with milk replacer whose proteins contained 30% milk protein(MP)and 70% vegetable protein.Vegetable proteins were soybean protein isolate(SP),wheat hydrolyzed protein(WP)and rice protein isolate(RP),respectively.Calves in different groups were fed four replacers,which were as follows:group A,30%MP+70%SP;group B,30%MP+40%SP+10%WP+20%RP;group C,30%MP+10%SP+40%WP+20%RP;group D,30%MP+10%SP+20%WP+40%RP.The trial lasted for 63 days.The results showed as follows:1)at 14 to 63 days of age,calves’body weight and average daily gain of group B were significantly higher than those of group A(P<0.05).However,there were no significant effects on starter intake,dry matter intake and feed conversion ratio among all groups(P>0.05).2)At 14 to 63 days of age,calves’hip width,heart girth and body length were not significant difference among all groups(P>0.05),but calves’wither height and hip height of group B were significantly higher than those of group A(P<0.05).3)At 28 days of age,calves’gross energy digestibility,gross energy metabolic rate and digestible energy metabolic rate of group C were significantly lower than those of groups A and B(P<0.05).The differences in fecal nitrogen and nitrogen digestibility among all groups were significant(P<0.05),but the difference in nitrogen retained rate was not significant(P>0.05).At 56 days of age,the differences of energy and nitrogen metabolism among all groups were not significant(P>0.05).4)At 28 to 56 days of age,the growth hormone(GH)level in serum of groups B,C and D was higher than that of group A,and the difference was significant between groups D and A(P<0.05);the insulin-like growth factor-1(IGF-1)level in serum of groups B,C and D was significantly higher than that of group A(P<0.05).In summary,feeding the compound vegetable protein milk replacer can affect the growth performance and nitrogen metabolism of the sucking calves,and the B group has the best feeding effect.