Abstract

This study aimed to investigate the effects of active dry yeast (ADY) on growth performance, rumen microbial composition and carcass performance of beef cattle. Thirty-two finishing beef cattle (yak ♂ × cattle-yaks ♀), with an average body weight of 110 ± 12.85 kg, were randomly assigned to one of four treatments: the low plane of nutrition group (control), low plane of nutrition group + ADY 2 g/head daily (ADY2), low plane of nutrition group + ADY 4 g/head daily (ADY4) and the high plane of nutrition group (HPN). Supplementation of ADY increased average daily gain compared to the control group. The neutral detergent fiber and acid detergent fiber apparent digestibility in HPN group was greater than that in control group. The propionic acid concentration in the rumen in ADY2, ADY4, and HPN groups was greater than that in control group. The Simpson and Shannon indexes in control and HPN groups were higher than that in ADY4 group. At the phylum level, the relative abundance of Firmicutes in the HPN group was higher than that in ADY4 group. The relative abundance of Ruminococcaceae UCG-002 in ADY4 group was higher than that in control and HPN groups. In conclusion, supplementation ADY 4 g/head daily shift the rumen microbial composition of beef cattle fed low plane of nutrition to a more similar composition with cattle fed with HPN diet and produce the similar carcass weight with HPN diet.

• Highlights

• The ADY can improve the utilization of nitrogen and decrease the negative impact on the environment in beef cattle.

• Cattle fed low plane of nutrition diet supplemented with ADY 4 g/head daily increased growth performance.

• Supplementation ADY 4 g/head daily in low plane of nutrition diet might be produced comparable carcass weight to HPN diet.

摘要

本研究旨在探讨活性干酵母（ADY）对肉牛生长性能、瘤胃微生物组成和胴体性能的影响。32 头肥育肉牛（牦牛♂×牛-牦牛♀），平均体重为 110±12.85 千克，随机分配到以下四种治疗之一：低营养组（对照）、低营养组组+ADY 2g/头每日（ADY2），低平面营养组+ADY 4g/头每日（ADY4）和高平面营养组（HPN）。与对照组相比，ADY 的补充增加了平均日增重。HPN组中性洗涤纤维和酸性洗涤纤维表观消化率均大于对照组。ADY2、ADY4、HPN组瘤胃丙酸浓度均高于对照组。对照组和HPN组Simpson指数和Shannon指数高于ADY4组。在门水平上，HPN组厚壁菌门的相对丰度高于ADY4组。ADY4组瘤胃球菌科UCG-002相对丰度高于对照组和HPN组。总之，每天补充 ADY 4 克/头可将饲喂低水平营养的肉牛的瘤胃微生物组成转变为与饲喂 HPN 日粮的牛更相似的组成，并产生与 HPN 日粮相似的胴体重量。ADY4组瘤胃球菌科UCG-002相对丰度高于对照组和HPN组。总之，每天补充 ADY 4 克/头可将饲喂低水平营养的肉牛的瘤胃微生物组成转变为与饲喂 HPN 日粮的牛更相似的组成，并产生与 HPN 日粮相似的胴体重量。ADY4组瘤胃球菌科UCG-002相对丰度高于对照组和HPN组。总之，每天补充 ADY 4 克/头可将饲喂低水平营养的肉牛的瘤胃微生物组成转变为与饲喂 HPN 日粮的牛更相似的组成，并产生与 HPN 日粮相似的胴体重量。

• 强调

• ADY 可以提高氮的利用率，减少肉牛对环境的负面影响。

• 每天补充 ADY 4 克/头的低营养日粮喂养牛可提高生长性能。

• 在低营养饮食中每天补充 ADY 4 克/头可能会产生与 HPN 饮食相当的胴体重量。