The effects of adding vitamin B1 and calcium propionate to the high-concentrate diet on the growth performance,rumen fermentation,and serum hormone levels of yaks
The aim of this experiment is to investigate the effects of adding vitamin B1 and calcium propionate to the high-concentrate diet on the growth performance,rumen fermentation,and serum hormone levels of yaks.A total of 120 healthy male yaks(189.46±13.31 kg)were randomly divide into 6 groups with 5 replicates per group and 4 yaks per replicate.The basic feed has a concentrate to coarse ratio of 65∶35.On this basis,50,150,and 300 mg/kg of vitamin B1 and 2%and 4%calcium propionate were added in gradients as feed for experimental groups 1-6.The experiment lasted for a total of 52 days,including a 7-day pre test and a 45 day trial.The results showed that compared with experimental group 1,the ADG of yaks in experimental groups 5 and 6 significantly increased by 3.37%and 2.94%,respectively(P＜0.05);ADFI significantly increased by 2.46%and 2.15%,respectively(P＜0.05);In addition,there was no significant difference in the final weight and feed weight ratio of yaks among the experimental groups(P＞0.05).The rumen pH of yaks in experimental groups 5 and 6 was significantly higher than other groups(P＜0.05);The MCP content in experimental groups 5 and 6 was significantly increased compared to other groups(P＜0.05);The content of T-VFA and propionic acid significantly decreased(P＜0.05);Different combinations of vitamin B1 and calcium propionate gradients had no significant effect on the content of NH3-N,acetic acid,isobutyric acid,butyric acid,isovaleric acid,and valeric acid in the rumen of yaks(P＞0.05).The serum IGF-1 levels of yaks in experimental groups 4,5,and 6 were significantly higher than those in other groups(P＜0.05);The serum INS content of yaks in experimental groups 5 and 6 was significantly increased compared to other groups(P＜0.05);The serum GH levels of yaks in experimental groups 4,5,and 6 were significantly increased compared to other groups(P＜0.05);The combination of different vitamin B1 and calcium propionate gradients had no significant effect on the serum Cort and GN content of yaks(P＞0.05).Conclusion:The combination of 150 or 300 mg/kg vitamin B1 and 4%calcium propionate has the best feeding effect on high-precision yaks.
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