补饲低蛋白开食料对哺乳期牦牛犊牛肠道和胰腺功能的影响OA

This experiment aimed to investigate the effects of supplementary feeding with a low-protein starter diet on the intestinal and pancreatic functions of suckling yak calves.Twenty-seven healthy female yak calves aged 42～45 days were selected and randomly divided into three groups,with nine replicates per group,and one calf per replicate.The group HP was fed with high-protein starter feed(with a protein level of approximately 19.00%),the group LP+RPAA was fed with low-protein starter feed+rumen-protected amino acids(with a protein level of approximately 17.00%,with lysine to methionine ratio of 3∶1),and the group LP was fed with low-protein starter feed(with a protein level of approximately 17.00%).The pre-test period was 21 days,and the formal test period was 100 days.The results showed that duodenal villus height in group LP was significantly greater than that in groups HP and LP+RPAA(P<0.05),and the villus height to crypt depth ratio in group LP was extremely higher than that in groups HP and LP+RPAA(P<0.01).The interleukin-1β(IL-1β)content in the duodenum in groups HP and LP+RPAA was extremely higher than that in group LP(P<0.01).The total area percentage of the pancreatic endocrine portion in groups LP and LP+RPAA was extremely higher than in group HP(P<0.01),and the exocrine-to-endocrine area ratio in group LP was significantly higher than that in groups HP and LP+RPAA(P<0.05).Pancreatic chymotrypsin and carboxypeptidase activities in group HP were extremely lower than in groups LP and LP+RPAA(P<0.01),and pancreatic insulin content in group HP was significantly lower than that in groups LP and LP+RPAA(P<0.05).Pancreatic interleukin-4(IL-4)content in groups HP and LP was extremely higher than that in group LP+RPAA(P<0.01),pancreatic immunoglobulin G(IgG)content in group HP was extremely higher than that in groups LP and LP+RPAA(P<0.01).And pancreatic tumor necrosis factor-α(TNF-α)content in group LP+RPAA was extremely higher than that in groups HP and LP(P<0.01).The study shows that a low-protein starter diet can effectively promote duodenum development,optimize pancreatic function,and maintain immune balance in yak calves.Although additional supplementation with rumen-protected amino acids can enhance the activity of certain digestive enzymes and immune function,it did not demonstrate superior overall benefits.