利用体外产气法研究不同瘤胃降解蛋白平衡对瘤胃代谢的影响

旨在探讨利用体外产气法研究不同瘤胃降解蛋白平衡日粮(RDPB,g·kg-1 DM)对瘤胃发酵、总产气量和甲烷产量的影响.试验选用美国Ankom产气系统,采用随机区组试验设计,配置6种不同瘤胃降解蛋白平衡日粮,分别为日粮1(-20 g· kg-1 DM),日粮2(-10 g· kg-1 DM),日粮3(0 g· kg-1 DM),日粮4(10g·kg-1DM),日粮5(20 g·kg-1 DM)和日粮6(30 g· kg-1 DM),每组2个重复,培养期为24 h.结果表明:(1)本研究中6种类型日粮发酵液的pH、乙酸/丙酸、产气量和CH4产生量表现为日粮3(P＜0.01)或日粮4(P＜0.01)值最低.(2)挥发性脂防酸乙酸、丙酸、丁酸以及氨氮的浓度随着瘤冒降解平衡值的增加而增加,表明改变日粮瘤胃降解蛋白平衡可以影响瘤胃发酵.而瘤胃降解蛋白平衡对总挥发性脂肪酸以及原虫数量无显著影响.(3)日粮瘤胃降解蛋白平衡值影响不同时间点甲烷的浓度和24 h甲烷产量.其中以日稂4(P＜0.05)甲烷总产量最低.由此可见,在体外培养条件下,改变日粮RDPB影响了瘤胃发酵液pH、氨态氮(NH3-N)及挥发性脂肪酸(VFA)浓度、总产气量、CH4产生量,综合考虑其对瘤胃发酵和甲烷产量等指标的影响,体外产气条件下适宜的RDPB水平为0～10g·kg-1 DM.

Effects of Different Rumen Degradable Protein Balance (RDPB) on Rumen Fermentation,Total Gas and Methane Production in vitro

This experiment was conducted to study the effects of RDPB(RDPB,g·kg-1 DM) on rumen fermentation,total gas and methane production in vitro.AnkomRFgas production system was used by random block design,with 6 different rumen degradable protein balance(RDPB) diets,namely diet 1(-20 g·kg-1 DM),diet 2(-10 g·kg-1 DM),diet 3(0 g·kg-1 DM),diet 4(10 g·kg-1 DM),diet 5(20 g·kg-1 DM) and diet 6(30 g·kg-1 DM),with 2 replicates,respectively,culturing for 24 h.The results showed that:(1) The fermentation broth pH,acetic acid / propionic acid,amount of gas production and CH4 production of and diet 3(P<0.01) or diet 4(P<0.01) showed the lowest level.(2) Volatile fatty acids,acetic acid,propionic acid,butyric acid and rumen ammonia concentration increased with the increase of the balance value of the degradation,therefore,changing the balance of dietary rumen degradable protein could affect the rumen fermentation.The balance of rumen degradable protein had no significant effect on the total amount of volatile fatty acids and protozoa.(3) Concentration of methane at different time points and 24 h methane production were affected by dietary rumen degradable protein balance.Methane production of diet 4(P<0.05) was lower than that of other diets.Thus,in vitro culture conditions,dietary RDPB affected rumen pH,ammonia nitrogen(NH3-N),volatile fatty acids(VFA) concentration,gas and CH4 production.The results indicated that appropriate RDPB was 0-10 g·kg-1 DM,considering its effect on rumen fermentation and methane production.