抑制不同种类瘤胃微生物活性对水牛瘤胃发酵和脂肪酸代谢的影响

试验旨在采用体外产气法研究抑制瘤胃细菌、真菌、原虫对添加亚油酸和亚麻酸后水牛瘤胃体外发酵参数和脂肪酸代谢的影响。体外培养底物0.5 g，精粗比为3：7，分别添加底物干物质量3%的亚油酸和3%的亚麻酸，每组设置5个重复，同时再设立4个组：对照组及抑制原虫、细菌、真菌组。体外模拟瘤胃发酵培养24 h，测定24 h产气量和气体中的甲烷（CH₄）含量、瘤胃发酵液的pH、挥发性脂肪酸（VFA）、氨态氮（NH₃-N）、微生物蛋白（MCP）浓度以及长链脂肪酸（LFA）组成。结果表明：①在添加亚麻酸情况下，与对照组相比，抑制细菌和原虫生长后产气量显著降低，抑制细菌和真菌生长后CH₄产量显著升高，而抑制原虫生长后CH₄产量显著降低（P<0.05）；在添加亚油酸情况下，与对照组相比，抑制细菌、真菌或原虫生长后产气量均显著降低，且抑制原虫后CH₄产量显著低于其他组（P<0.05）。②抑制细菌、真菌或原虫生长后，添加亚油酸和亚麻酸显著影响了体外瘤胃发酵液pH和MCP浓度（P<0.05），添加亚油酸对NH₃-N浓度影响不显著（P>0.05）。③与对照组相比，抑制细菌、真菌或原虫生长后显著降低了乙酸、丙酸含量（P<0.05）；在添加亚麻酸情况下，抑制细菌生长显著降低了丁酸含量（P<0.05）；在添加亚油酸情况下，抑制细菌、真菌或原虫生长后丁酸含量显著降低（P<0.05）。④与对照组相比，在添加亚麻酸情况下，抑制细菌生长显著降低了C11：0、C12：0、C13：0、C14：0、C14：1n5、C15：1n5、C16：1n7、C16：0、C18：3n3、C18：2n6c、C18：0、C20：2n6、C20：3n6、C20：1、C20：3n3、C20：0、C21：0、C22：6n3、C22：2n6、C22：0浓度（P<0.05）；在添加亚油酸情况下，抑制细菌生长显著降低了C12：0、C13：0、C14：0、C15：0、C16：1n7、C16：0、C17：0、C18：3n6、C18：3n3、C18：2n6c、C18：1n9t、C18：0、C18：2（cis-9，trans-11）、C18：2（trans-10，cis-12）、C20：2n6、C20：1、C20：0、C21：0、C22：6n3、C22：0、C23：0、C24：1n9、C24：0浓度（P<0.05）。由此可见，抑制细菌、真菌或原虫生长后，添加亚油酸和亚麻酸对体外瘤胃发酵参数、CH₄产量和脂肪酸组成均能产生影响，原虫对产气量和CH₄产量贡献最大，细菌对瘤胃液脂肪酸代谢影响最大。

Effects of Inhibition of Different Rumen Microbial Activity on Rumen Fermentation and Fatty Acid Metabolism in Buffaloes

This study was aimed to evaluate the effects of inhibiting rumen bacteria,fungi and protozoa with adding linoleic acid and linolenic acid on in vitro rumen fermentation and fatty acid metabolism in buffaloes.Both fatty acids were supplemented with substrate and roughage (3:7) at the rate of 3% on dry matter (DM) basis in an in vitro batch culture system,there were 5 repetitions for each group.At the same time,four groups were set up:Control group and inhibition groups of protozoa,bacteria and fungi.After 24 h of incubation,total gas production,CH₄,pH,VFA,NH₃-N,MCP and LFA concentrations were measured.The results showed that:①With the addition of linolenic acid,compared with control group,the gas production decreased significantly after inhibition the growth of bacteria and protozoa,CH₄ production increased significantly after inhibition of the growth bacteria and fungi,and CH₄ production decreased significantly after inhibition of the growth protozoa (P<0.05).With the addition of linoleic acid,compared with control group,the gas production decreased significantly after inhibiting the growth of bacteria,fungi or protozoa,and CH₄ production was significantly lower than other groups after inhibition of protozoa (P<0.05).② After inhibiting the growth of bacteria,fungi or protozoa,the pH and MCP concentration were affected significantly with the addition of linolenic acid (P<0.05),there was no significant effect on NH₃-N concentration with the addition of linoleic acid (P>0.05).③ Compared with control group,the content of acetic acid and propionic acid was reduced significantly after inhibiting the growth of bacteria,fungi or protozoa (P<0.05).The butyric acid was reduced significantly after inhibiting the growth of bacteria with the addition of linolenic acid (P<0.05).The butyric acid was reduced significantly after inhibiting the growth of bacteria,fungi or protozoa with the addition of linoleic acid (P<0.05).④ Compared with control group, the concentrations of C11:0, C12:0, C13:0, C14:0, C14:1n5, C15:1n5, C16:1n7, C16:0, C18:3n3, C18:2n6c, C18:0, C20:2n6, C20:3n6, C20:1, C20:3n3, C20:0, C21:0, C22:6n3, C22:2n6, C22:0 was reduced significantly after inhibiting the growth of bacteria with the addition of linolenic acid, the concentrations of C12:0, C13:0, C14:0, C15:0, C16:1n7, C16:0, C17:0, C18:3n6, C18:3n3, C18:2n6c, C18:1n9t, C18:0, C18:2(cis-9,trans-11), C18:2(trans-10,cis-12), C20:2n6, C20:1, C20:0, C21:0, C22:6n3, C22:0, C23:0, C24:1n9, C24:0 was reduced significantly after inhibiting the growth of bacteria with the addition of linoleic acid (P<0.05).The results revealed that the addition of linoleic acid and linolenic acid could significantly manipulate in vitro rumen fermentation parameters,CH₄ yield and fatty acid composition after inhibiting the growth of bacteria,fungi or protozoa.Protozoa greatly contributed to total gas and CH₄ production while bacteria significantly affected rumen fatty acid metabolism.