Comparison of intestinal microbial composition of Hainan black goat and hybrid of Hainan black goat × Nubian goat

【Objective】 To reveal the internal mechanism of hybrid goats with good growth traits, which could provide reference basis for breed selection of Hainan black goat and feeding management of hybrid of Hainan black goat × Nubian goat. 【Method】 Six Hainan black goats（HN group） and six hybrids of Hainan black goat × Nubian goat（HY group） born within 4 d were selected and raised under uniform feeding management standards until about 120 days old. Fecal samples were collected for 16S rRNA sequencing to analyze the differences in composition of the intestinal microbial community between the 2 groups of goats, and Pearson correlation analysis was performed to assess relationships between intestinal microbe community and body weight and daily weight gain.【Result】There was no significant difference in the Alpha diversity index of the intestinal microbe between the 2 groups of goats（P＞0.05）.However,principal coordinate analysis（PCoA） based on Bray-Curtis distances revealed distinct microbial community structures between the 2 groups of goats.At phylum level,Hainan black goat and hybrid of Hainan black goat×Nubian goat exhibited dominant phyla including Firmicutes,Bacteroidota,Verrucomicrobiota,Campylobacterota,Spirochaetota and Proteobacteria.At the genus level,the intestinal microbial composition was similar in the 2 groups,with a variety of fiber-fermenting genera.Metastats analysis identified significantly higher relative abundance of Monoglobus in hybrid of Hainan black goat×Nubian goat compared to Hainan black goat（P＜0.05,the same below）.The biomarkers of intestinal microbes in Hainan black goat in‐cluded Enterococcaceae,Enterococcus,Family_XIII_UCG_001,etc.The biomarkers of intestinal microbes in hybrid of Hainan black goat×Nubian goat were Levilactobacillus and unclassified_Oscillospiraceae.The relative abundance of Fir‐micutes among the intestinal microbes of hybrid of Hainan black goat×Nubian goat was significantly and positively corre‐lated with body weight and daily weight gain.In the intestinal microbes of Hainan black goat,there was extremely signifi‐cant positive correlation（P＜0.01） between the relative abundance of Alistipes and body weight,as well as a significant positive correlation with daily weight average gain.Combining 2 groups of goats into a population for analysis,it was found that the relative abundance of Firmicutes was significantly and positively correlated with average daily weight gain of goats,and the relative abundance of Monolobus was significantly and positively correlated with body weight of goats.【Conclusion】 There are certain differences in the intestinal microbial composition between Hainan black goat and hybrid of Hainan black goat and Nubian goat,among which Monolobus has significantly higher relative abundance in Hainan black goat compared to hybrid of Hainan black goat×Nubian goat.In addition,Firmicutes,Alistipes and Monolobus in intestinal microbes might be key microbial communities that may regulate goat growth performance,which provides new directions for selection of targeted feed additives for goat fattening.