湖羊羔羊早期断奶前后瘤胃发酵与微生物区系的变化

本试验旨在研究湖羊羔羊早期断奶前后的瘤胃发酵与微生物区系变化,为幼龄反刍动物瘤胃发育变化理论以及羔羊的早期培育等提供依据。选择初生重接近的湖羊公羔（3.81 kg±0.55 kg）16只,1~7日龄饲喂母乳,8日龄与母羊分离,开始饲喂代乳粉（按8日龄体重的2%,分3次等量饲喂）和开食料（自由采食）,35日龄断奶。分别于断奶前（21日龄）、后（42日龄）各选择5只羔羊进行屠宰,采集瘤胃内容物,测定瘤胃发酵、酶活和微生物区系。结果表明,断奶后羔羊的瘤胃总挥发性脂肪酸、乙酸、丙酸、丁酸及纤维素酶和α-淀粉酶活性均极显著高于断奶前（P<0.01）。断奶后瘤胃菌群多样性和丰富度均低于断奶前（P<0.05）。断奶前后的优势菌门均为拟杆菌门（Bacteroidetes）和厚壁菌门（Firmicutes）,其中,拟杆菌门为第一优势菌门,在断奶前后分别占61.96%和65.36%,厚壁菌门为第二优势菌门,在断奶前后分别占32.08%和24.03%;两菌门之和在断奶前后分别占瘤胃总菌门的94.04%和89.39%。断奶前后的优势菌属均为unidentified_Prevotellaceae,分别占21.85%和38.49%。断奶前后羔羊瘤胃微生物的功能没有显著变化,都主要集中在复制和修复、碳水化合物代谢和翻译等途径。以上结果说明,羔羊早期断奶后的瘤胃发酵和酶活增强,菌群多样性和丰富度有所降低,在早期断奶前后的优势菌群和功能相似。

Variations of Rumen Fermentation and Microflora of Hu Lambs Before and After Early Weaning

This study aimed to evaluate the variation in rumen fermentation and microbiota of pre- and post- early weaning lambs so as to provide theoretical basis for understanding the rumen development and early breeding of lambs.Sixteen male lambs with similar birth weight (BW,3.81 kg±0.55 kg) were selected.Lambs were fed breast milk from 1 to 7 days old.The lambs were separated from their dams at 8 days old and began to be fed milk replacer (MR) (at 2% of BW measured on day 8,three equal amounts) and starter feeds (ad libitum).MR feeding was stopped at 35 days of age.Six lambs were slaughtered pre-weaning (21 days old) and post-weaning (42 days old) respectively and rumen contents were collected to determine rumen fermentation,enzyme activity and microbiota.The results showed that the total volatile fatty acids,acetic acid,propionic acid,butyric acid,activities of cellulase and α-amylase for post-weaning lambs were higher than those for pre-weaning lambs (P<0.01).The diversities and abundances of rumen flora for post-weaning lambs were lower than those for pre-weaning lambs (P<0.05).The dominant phylum for pre- and post-weaning lambs were Bacteroidetes and Firmicutes,in which Bacteroidetes was the first phylum,accounting for 61.96% and 65.36% in pre- and post-weaning periods respectively.And Firmicutes was the second phylum,accounting for 32.08% and 24.03% in pre- and post-weaning periods respectively.The total of the two phylum accounted for 94.04% and 89.39% for pre-weaning and post-weaning lambs.The dominant genus for pre- and post-weaning lambs were unidentified_Prevotellaceae,accounting for 21.85% and 38.49% respectively.There was no significant change in rumen microbial function for pre- and post-weaning lambs,which all mainly focused on replication and repair,carbohydrate metabolism and translation.These results indicated that the rumen fermentation and enzyme activity were increased for post-weaning lambs,whereas the diversity and abundances of flora were decreased,the dominant flora and the function were similar between pre- and post-weaning lambs.