低精料日粮和高精料日粮对牦牛生长性能和瘤胃菌群结构的影响

Effects of low-concentrate and high-concentrate diets on yak growth performance and rumen microbiota structure

本研究旨在探究低精料日粮和高精料日粮对牦牛瘤胃微生物菌群的影响。本试验选取3周岁,体重相近的12头牦牛,平均分为两组。分别用低精料[精粗比30∶70(C30组)]的日粮和高精料[精粗比70∶30(C70组)]的日粮,饲喂2个月。结果表明:1)C70组平均日增重极显著高于C30组(P<0.01)。2)C30组Chao1指数、Shannon指数和谱系多样性指数都极显著高于C70组(P<0.01)。3)在门水平上,髌骨细菌门、脱硫杆菌门、疣微菌门、蓝藻菌门相对丰富度C30组显著高于C70组(P<0.05)。厚壁菌门相对丰富度C30组极显著高于C70组(P<0.01)。拟杆菌门相对丰富度C70组极显著高于C30组(P<0.01),变形菌门C70组显著高于C30组(P<0.05)。在属水平上C30组牦牛的瘤胃微生物克里斯滕森菌科_R-7、未分类瘤胃细菌、NK4A214属、未培养菌(uncultured bacterium)和不确定的菌属(unidentified)的相对丰富度极显著高于C70组牦牛瘤胃微生物丰富度(P<0.01)。理研菌属丰富度C30组显著高于C70组(P<0.05)。普雷沃氏菌属、毛螺菌科-NK3A20、瘤胃球菌属C70组相对丰富度显著高于C30组(P<0.05)。4)在KEGG2水平上,所有的牦牛瘤胃样本中有31个基因家族。C70组运输和分解代谢(transport and catabolism)、辅因子和维生素代谢以及能量代谢显著高于C30组(P<0.05)。C70组的碳水化合物代谢(carbohydrate metabolism)极显著高于C30组(P<0.01)。C30组的免疫疾病(immune disease)极显著高于C70组,C70组的次级代谢产物的生物合成(biosynthesis of other secondary metabolites)极显著高于C30组(P<0.01)。综上所述,与低精料组相比饲喂高精料日粮降低了牦牛瘤胃微生物菌群的多样性,并减少了不利于瘤胃菌群健康的菌群丰富度,同时提高了优势菌群的丰富度。在代谢功能上,高精料日粮增加了碳水化合物代谢和其他营养因子代谢,降低了免疫疾病代谢。

The objective of this study was to determine the effects of low-and high-concentrate diets on the rumen microbiota in yaks.Twelve 3-year-old yaks with similar body weight were selected and divided into two groups of six.One group was fed with a low-concentrate diet[30∶70 fine-to-rough ratio(C30 group)]and the other was fed with a high-concentrate diet[70∶30(C70 group)]for 2 months.It was found that:1)The average daily weight gain of the C70 group was significantly higher than that of the C30 group(P<0.01).2)The Chao1 index,Shannon index,and phylogenetic diversity index were significantly higher for the C30 group than for the C70 group(P<0.01).3)At the phylum level,the relative richness of Patescibacteria,Desulfobacterota,Verrucomicrobia,and Cyanobacteria in the rumen was significantly higher in the C30 group than in the C70 group(P<0.05).The relative richness of Firmicutes in the rumen was significantly higher in the C30 group than in the C70 group(P<0.01).The relative richness of Bacteroides in the rumen was significantly higher in the C70 group than in the C30 group(P<0.01),and that of Proteobacteria was significantly higher in the C70 group than in the C30 group(P<0.05).At the genus level,the relative richness of Christensenellaceae_R-7,unclassified_rumen_bacterium,NK4A214_group,uncultured bacteria,and unidentified bacteria in the rumen was significantly higher in the C30 group than in the C70 group(P<0.01).The Rikenellaceae_RC9_gut_group in the C30 group was significantly higher than that in the C70 group(P<0.05).The relative richness of Prevotella,Lachnospiraceae_NK3A20_group and Ruminococcus in the C70 group was significantly higher than that in the C30 group(P<0.05).4)There were 31 gene families identified across all yak rumen samples.At KEGG level 2,pathways of transport and catabolism,cofactor and vitamin metabolism,and energy metabolism were significantly enriched in the C70 group compared with the C30 group(P<0.05).The carbohydrate metabolism pathway was highly significantly enriched in the C70 group compared with the C30 group(P<0.01).The immune disease pathway was enriched in the C30 group compared with the C70 group,and the biosynthesis of other secondary metabolites pathway was also very highly enriched in the C70 group compared with the C30 group(P<0.01).In summary,high concentrate was fed compared to the low concentrate group the diet reduced the diversity of rumen microbiota in yak and reduced the richness of microflora that was not conducive to rumen microbiota health,while increasing the abundance of dominant microflora Richness.In terms of metabolic function,the high-concentrate diet increased the metabolism of carbohydrates and other nutrients,and decreased the metabolism of immune diseases.