发酵底物锰含量对牦牛体外瘤胃发酵的影响

Effects of Manganese Content in Fermentation Substrate on in Vitro Rumen Fermentation of Yaks

为确定牦牛微量元素锰的需要量,本试验以甘氨酸锰为添加形式,研究不同发酵底物锰含量对牦牛体外瘤胃发酵的影响。共设定5个发酵底物锰含量,分别为35.00、40.00、50.00、60.00和70.00 mg/kg,采用体外瘤胃发酵技术进行48 h发酵,结束后测定产气量、瘤胃发酵特性以及消化酶活力。结果表明:1)当锰含量为40.00 mg/kg时,发酵液氨态氮、微生物蛋白质、乙酸、丙酸、异丁酸、丁酸、异戊酸、戊酸和总挥发性脂肪酸含量均达到最大值,分别为10.60 mg/d L、3.90 g/L、47.12 mmol/L、19.45 mmol/L、0.35 mmol/L、5.41 mmol/L、0.96 mmol/L、0.50 mmol/L和72.24 mmol/L;2)当锰含量为50.00 mg/kg时,发酵液脂肪酶活力达最大值,为0.50 U/m L,乙酸/丙酸最低,为2.05。综合可得,对于生长期牦牛,若以甘氨酸锰作为锰元素添加形式,推荐牦牛饲粮锰含量在40.00~50.00 mg/kg,有利于瘤胃发酵和饲草料降解。

In order to find manganese requirement of yaks,manganese bisglycinate was used as additive in this experiment to investigate the effects of different contents of manganese in fermentation substrate on in vitro rumen fermentation of yaks. Five manganese contents in fermentation substrate were designed,which were35.00,40.00,50.00,60.00 and 70.00 mg/kg,respectively. The fermentation lasted for 48 h using in vitro rumen fermentation method. After fermentation,gas production,rumen fermentation characteristics and digestive enzyme activities were measured. The results showed as follows： 1） when the content of manganese was40.0 mg/kg,the contents of ammonia nitrogen,microbial protein,acetic acid,propionic acid,isobutyric acid,butyric acid,isovaloric acid,valeric acid and total volatile fatty acids in fermentation fluid reached the highest,which were 10. 60 mg/dL, 3. 90 g/L, 47. 12 mmol/L, 19. 45 mmol/L, 0. 35 mmol/L,5.41 mmol/L,0.96 mmol/L,0.50 mmol/L and 72.24 mmol/L,respectively; 2） when the content of manganese was 50.00 mg/kg,lipidase activity in fermentation fluid reached the highest as 0.50 U/mL,and acetic acid/propionic acid in fermentation fluid reached the lowest,as 2.05. Therefore,the manganese content recommended in diet for growing yaks is between 40.00 and 50.00 mg/kg,when using manganese bisglycinate as additive,which is help to rumen fermentation and forage degradation.