单宁对绵羊瘤胃原虫数量和种群多样性的影响

Effects of Tannin on Rumen Protozoa Number and Population Diversity in Sheep

本试验旨在研究饲粮中不同水平单宁对绵羊瘤胃原虫数量和种群多样性的影响。试验选取45 kg左右、体况良好的杜蒙杂交羯羊15只,根据饲粮单宁水平随机分为3组,分别为Ⅰ组(对照组,不含单宁)、Ⅱ组(含2%单宁)和Ⅲ组(含4%单宁),每组5只。预试期14 d,正试期20 d。于正试期的第18天和第19天晨饲前和晨饲后6 h使用瘤胃液口腔采样器采集瘤胃液,应用显微镜计数方法检测绵羊瘤胃液样品中原虫的数量,采用高通量测序技术检测晨饲后6 h瘤胃原虫的种群多样性。结果表明:1)在晨饲前和晨饲后6 h,Ⅲ组原虫数量显著低于对照组(P<0.05),Ⅱ组有低于对照组的趋势,但差异不显著(P>0.05)。2)饲粮含2%和4%的单宁显著降低绵羊瘤胃原虫Chao 1指数(P<0.05),Shannon指数、Simpson指数和Ace指数有降低的趋势(P>0.05)。3)在属水平上,Ⅲ组绵羊瘤胃原虫均毛虫属相对丰度显著高于对照组和Ⅱ组(P<0.05);Ⅱ组和Ⅲ组的内毛虫属相对丰度有低于对照组的趋势(P=0.06),Ⅱ组和Ⅲ组的前毛虫属相对丰度有低于对照组的趋势(P=0.07);瘤胃中其他原虫属相对丰度与对照组相比无显著差异(P>0.05)。由此可见,饲粮中单宁含量为2%和4%可显著降低绵羊瘤胃液中原虫数量,对原虫种群多样性无显著影响。

The purpose of this experiment was to investigate the effects of different levels of tannin in the diet on the number and population diversity of protozoa in the rumen of sheep.A total of 15 healthy sheep with weight about 45 kg were selected and randomly divided into 3 groups:groupⅠ(control group,without tannin),groupⅡ(2%tannin)and groupⅢ(4%tannin),with 5 sheep in each group.The pre-trial period was 14 days and the formal trial period was 20 days.The rumen fluid was collected at days 18 and 19 during the trial period before morning feeding and after morning feeding for 6 h using rumen fluid oral sampler.Microscope counting method was used to detect the number of protozoa in sheep rumen fluid samples.High-throughput sequencing technology was used to detect the population diversity.The results showed as follows:1)before morning feeding and after morning feeding for 6 h,the number of protozoa in the groupⅢwas significantly lower than that in the control group(P<0.05),and the groupⅡhad a tendency to be lower than the control group,but the statistical analysis was not significant(P>0.05).2)Diets containing 2%and 4%tannins significantly reduced the Chao 1 index of sheep rumen protozoa(P<0.05),Shannon index,Simpson index and Ace index had a decreasing trend(P>0.05).3)At the genus level,the relative abundance of Entodinium of rumen protozoa in groupⅢwas significantly higher than that in control group and groupⅡ(P<0.05);the relative abundance of Epidinium of groupⅡand groupⅢtended to be lower than control group(P=0.06).The relative abundance of Isotricha in groupⅡand groupⅢtended to be lower than control group(P=0.07);the relative abundance of other protozoa in the rumen had no significant difference compared with control group(P>0.05).It can be seen that when the tannin content in the diet is 2%and 4%,the number of protozoa in the rumen fluid of sheep is significantly reduce;it has no significant effect on the diversity of protozoan population.