Differences in rectal fecal microbes among Hu sheep, Tibetan sheep and their hybrid breeds, and their relationship with growth traits

Variety diversity serves as the foundation for animal husbandry development. Nowadays, heterosis is often used to improve animal performance and thus increase economic benefits. The intestine is an important organ for nutrient absorption and also the largest immune organ in the body. Intestinal microorganisms can be influenced by various factors such as animal growth and development stages, gender, health status, feed nutrition level, host genetic background, among others. In this study, three strains of male sheep, with no significant differences in initial weight at 6 months old, were raised under the same conditions until they reached 9 months old. We collected the rectal feces of these nine-month-old sheep and compared the differences in rectal fecal microorganisms among the three strains using 16S rDNA sequencing technology. The PERMANOVA test revealed significant differences in microorganisms among different strains. Additionally, we identified six biomarkers in Tibetan sheep and Hu sheep, respectively. Functional enrichment analysis showed that microorganisms may affect the growth traits of sheep through lipid metabolism, and the functional differences among different strains were obvious. Therefore, we believe that crossbreeding can result in the offspring obtaining intestinal microorganisms from their parents to varying degrees, and host heredity is the primary cause of the intestinal microorganism differences.

品种多样性是畜牧业发展的根基。当前，杂种优势（heterosis）常被用于提升动物生产性能，进而提高经济效益。肠道是动物体内重要的营养吸收器官，同时也是体内最大的免疫器官。肠道微生物可受多种因素影响，包括动物生长发育阶段、性别、健康状况、饲料营养水平以及宿主遗传背景等。本研究选取3个品系的6月龄公绵羊，其初始体重无显著差异，在相同饲养条件下培育至9月龄。我们采集了这批9月龄绵羊的直肠粪便，采用16S rDNA测序技术比较3个品系绵羊直肠粪便微生物的差异。置换多元方差分析（PERMANOVA）结果显示，不同品系间的肠道微生物存在显著差异。此外，我们分别在藏绵羊与湖羊中鉴定出6个生物标志物（biomarker）。功能富集分析结果表明，肠道微生物可通过脂质代谢途径影响绵羊的生长性状，且不同品系间的微生物功能差异显著。综上，我们认为杂交育种可使后代不同程度地继承亲本的肠道微生物，而宿主遗传是造成肠道微生物差异的主要原因。