The objective of this experiment was to test the effect of supplementation of analogues of methionine 2‐hydroxy‐4‐methylthio butanoic acid isopropyl ester (HMBi) on growth, digestibility, antioxidant index, abundance and composition of rumen bacterial community in Xiangdong Black Goats. Thirty‐six growing Xiangdong Black Goats were divided into four groups in such a way that each group had three replicate and each replicate had three animals. Experimental groups were assigned four levels of HMBi in basal diet: 0% HMBi (on dietary DM basis); 0.05% HMBi; 0.10% HMBi and 0.20% HMBi. Goats fed 0.10% HMBi in basal diet had higher average daily weight gain (p  < .05). Goats fed 0.05% HMBi had higher apparent digestibility of gross energy (p  < .01). The group 0% HMBi supplementation had a higher level of superoxide dismutase and malondialdehyde (p  < .01). The goats fed 0.20% HMBi in basal diet had a higher level of insulin and leptin (p  < .01) than 0% HMBi supplementation goats. 16S rRNA high‐throughput sequencing analysis revealed similarities in the community composition, species diversity and relative abundance of dominant bacteria at the phylum and genus levels among the four groups. In conclusion, HMBi supplementation has no negative effect on apparent digestibility, antioxidant index and the ruminal bacteria composition. Therefore, 0.10% supplementation of HMBi is recommended in the diet of goats to improve the growth performance.

中文翻译：

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山羊日粮中添加HMBi对采食量，养分消化率，瘤胃细菌群落和血清参数的影响。

本实验的目的是测试补充蛋氨酸2-羟基-4-甲硫基丁酸异丙酯（HMBi）对湘东黑山羊生长，消化率，抗氧化指数，瘤胃细菌群落组成和组成的影响。将三十六只正在生长的湘东黑山羊分成四组，每组三只，每只三只。实验组在基础饮食中分配了四个水平的HMBi：0％HMBi（基于饮食DM）；0.05％HMBi；0.10％HMBi和0.20％HMBi。基础饮食中饲喂0.10％HMBi的山羊平均日增重较高（p  <.05）。饲喂0.05％HMBi的山羊具有较高的表观总能量消化率（p <.01）。补充0％HMBi的组具有较高水平的超氧化物歧化酶和丙二醛（p  <.01）。基础饮食中饲喂0.20％HMBi的山羊 比补充0％HMBi的山羊具有更高的胰岛素和瘦素水平（p <.01）。16S rRNA高通量测序分析揭示了四组在门和属水平上的群落组成，物种多样性和优势细菌的相对丰度相似。总之，补充HMBi对表观消化率，抗氧化指数和瘤胃细菌组成没有负面影响。因此，建议在山羊饲料中添加0.10％的HMBi以改善生长性能。