饲喂含秸秆发酵饲料对育成牛瘤胃微生物组成和功能的影响

Effect of feeding straw-containing fermented feed on the composition and function of the rumen microbiota in heifers

本研究旨在探究饲喂含秸秆发酵饲料对育成牛瘤胃微生物组成与功能以及代谢生理等方面的影响。选取36头8~11月龄、体重相近且健康的荷斯坦育成牛,随机分成2组,即在基础饲粮的基础上分别饲喂0 kg/d(对照组)、4 kg/d含秸秆发酵饲料(按干物质计,秸秆约占日粮16.0%;处理组),持续8周,每2周测定一次育成牛日增重情况,并在第8周时采集尾静脉血及瘤胃内容物,分析2组育成牛在表型以及瘤胃微生物区系上的差异。结果发现:饲喂含秸秆发酵饲料组育成牛日增重(0.991 kg/d)与对照组(1.080 kg/d)相比明显下降(p=0.042)。与对照组相比,饲喂含秸秆发酵饲料组瘤胃总挥发性脂肪酸浓度、血清中β-羟丁酸和甘油三酯浓度均显著升高(p<0.05),葡萄糖浓度显著降低(p<0.05);瘤胃细菌α多样性指数中,饲喂含秸秆发酵饲料组Sobs指数和香农(Shannon)指数显著升高(p<0.05),β多样性无显著差异(p>0.05)。饲喂含秸秆发酵饲料组中,与表型相关的核心菌种主要为厌氧支原体属;在微生物功能上,2组主要在碳水化合物代谢和氨基酸生物合成途径上存在显著差异。综上所述,饲喂含秸秆发酵饲料促进了育成牛瘤胃发酵,并在一定程度上影响其脂质代谢。本研究在瘤胃微生物组成与功能差异以及高效利用秸秆饲料的关键微生物挖掘上均有一定突破,为育成牛饲粮中非常规饲料的有效利用提供了实践依据。

This study aimed to investigate the effect of feeding straw-containing fermented feed on the composition and function of the rumen microbiota and metabolic physiology in heifers.A total of 36 healthy heifers aged 8-11 months were randomly divided into two groups,and fed 0 kg/d(control)and 4 kg/d of straw-containing fermented feed(the straw accounted for 16.0%of diet dry matter;treatment group)for eight weeks.The daily gain was measured every two weeks;the samples of rumen contents and coccygeal vein blood were collected at week eight to analyze the differences in phenotype and rumen microbiota between the two groups in heifers.The daily gain was significantly lower in the heifers in the straw-containing fermented feed group than in the control group(0.091 kg/d vs 1.080 kg/d,p=0.042).The total volatile fatty acid,serumβ-hydroxybutyrate and triacylglycerol concentrations were significantly higher in the straw-containing fermented feed group than in the control group(p<0.05),but with a lower glucose concentration(p<0.05).Theαdiversity index of the rumen bacteria,such as the Sobs index and the Shannon index in the straw-containing fermented feed group were significantly higher than those in the control group(p<0.05).Theβdiversity showed no significant differences(p>0.05)between the two groups.The core species associated with the phenotype in the staw-containing fermented feed group was Anaeroplasma.In the microbial function,significant differences existed between the two groups mainly in carbohydrate metabolism and amino acid biosynthesis pathways.In summary,the straw-containing fermented feed promoted rumen fermentation and affected the blood lipid metabolism of heifers to some extents.This study made some breakthroughs in rumen microbial composition and functional differences as well as key microbiota excavation for the efficient utilization of straw feeds,which provides a practical basis for the effective utilization of non-conventional feeds in heifers.