精料中直链与支链淀粉比对羔羊瘤胃细菌菌群的影响

本文旨在研究精料中直链与支链淀粉比对不同日龄羔羊瘤胃细菌菌群的影响。选取48只体重无显著差异(P0.05)的初生公羔,随机分成4组(每组3个重复,每个重复4只),各组精料中直链与支链淀粉比分别为0.12(木薯淀粉组)、0.23(玉米淀粉组)、0.24(小麦淀粉组)和0.48(豌豆淀粉组)。试验全期共77 d。于羔羊21、35、56和77日龄时,每个重复随机选择1只羔羊屠宰,采集瘤胃液样品。通过PCR-变性梯度凝胶电泳(DGGE)技术测定分析羔羊瘤胃细菌菌群的多样性。结果表明,不同直链与支链淀粉比精料组的羔羊于21、35、56和77日龄时,瘤胃细菌多样性指数、均匀度和丰富度均无显著性差异(P0.05)。21日龄羔羊瘤胃细菌多样性指数显著高于35日龄(P0.05),56和77日龄羔羊瘤胃细菌多样性指数有所升高,但在数值上仍低于21日龄羔羊。DGGE回收的条带多属厚壁菌门及拟杆菌门。56日龄的小麦淀粉组羔羊瘤胃内牛单胞月形菌含量较高。由此可见,不同直链与支链淀粉比精料未影响羔羊瘤胃优势细菌的结构,但饲喂小麦淀粉饲粮可促进56日龄羔羊瘤胃内牛单胞月形菌的生长。

Effects of Amylose to Amylopectin Ratio in Concentrate on Rumen Bacterial Community in Lambs

The objective of this study was to determine the effects of amylose to amylopectin ratio in concen-trate on rumen bacterial community in lambs at different days of age. Forty-eight male lambs with no significant difference in body weight (P>0.05) were randomly divided into 4 groups, there were 3 replicates per group with 4 lambs per replicate. The concentrate amylose to amylopectin ratio of different groups was 0.12 ( tapioca starch), 0.23 (corn starch), 0.24 (wheat starch) and 0.48 (pea starch), respectively. The whole experiment period was 77 days. One lamb from each replicate were randomly selected and slaughtered at 21, 35, 56 and 77 days of age to collect rumen fluid sample. The diversity of rumen bacterial community in lambs was deter-mined by PCR-denaturing gradient gel electrophoresis ( DGGE) . The results showed that there was no effect on diversity index, evenness and richness of lambs at 21, 35, 56 and 77 days of age( P>0.05) . Diversity index in lambs at 21 days of age was significant higher than that at 35 days of age ( P<0.05) ,and it was increased at 56 and 77 days of age, but the numerical values were still lower than that at 21 days of age. Bands recovered from DGGE were almost belonged to Bacteroidetes and Firmicutes. Selenomonas bovis content in rumen in lambs at 56 days of age in wheat starch group was higher. Therefore, different amylose to amylopectin ratio in concen-trate do not affect the structure of lamb rumen dominant bacteria, but feed wheat starch diet can promote the growth of Selenomonas bovis in rumen in lambs at 56 days of age.