Improving the predication efficiency of porcine production performance at early stage will contribute to reducing the breeding and production costs. The intestinal microbiota had received plenty of attention in recent years due to their influence on host health and performance. The purpose of this study was to investigate the relationship between the fecal microbiota at early growth period and porcine feed efficiency (FE) under a commercial feeding environment. Ninety-one pigs were reordered according to the residual feed intake (RFI) values between day 90 on test and day 160 off test, 9 lowest RFI pigs and 9 highest RFI pigs were selected as the LRFI group and the HRFI group, respectively. Fecal samples from pigs in the early grower phase (day 80) were performed for microbial diversity, composition, and predicted functionality by using 16S rRNA sequencing. The results showed that no significant differences in microbial alpha diversity were observed between two RFI groups, whereas, some RFI-associated compositional differences were revealed. In particular, the microbiota of the LRFI group (more feed-efficient) had significantly higher levels of some members of Clostridiales and Bacteroidales (e.g., g_1_68 and g_norank_f_p_2534_18B5), which may promoted FE through protecting gut barrier function, compared with those of the HRFI pigs. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis found that the LRFI pigs were likely have microbiota with higher levels of amino acid metabolism. Moreover, redundancy analysis (RDA) showed that litter size, parity, and date of birth had significant effects on the bacterial community structure. These results improved our knowledge of the porcine early-life fecal microbiota and its potential link underlying RFI, which would be useful for future development of microbial biomarkers for predicting and improving porcine FE as well as investigation of targets for dietary strategies.

早期提高猪生产性能的预测效率将有助于降低育种和生产成本。近年来，肠道菌群由于对宿主健康和性能的影响而受到了广泛关注。这项研究的目的是调查在商业饲养环境下，粪便菌群在早期生长阶段与猪饲料效率（FE）之间的关系。根据第90天测试和第160天关闭测试之间的剩余饲料摄入量（RFI）值对91头猪进行了重新排序，分别将LRFI组和HRFI组选为9头最低RFI猪和9头最高RFI猪。在生长期初期（第80天）对猪的粪便样本进行了微生物多样性，组成，通过使用16S rRNA测序来预测功能。结果表明，在两个RFI组之间未观察到微生物α多样性的显着差异，而揭示了一些与RFI相关的组成差异。尤其是LRFI组的微生物群（饲料效率更高），其中某些成员的水平明显更高。梭状芽胞杆菌和拟杆菌属（例如g_1_68和g_norank_f_p_2534_18B5），与HRFI猪相比，可通过保护肠屏障功能促进FE。京都基因与基因组百科全书（KEGG）途径分析发现，LRFI猪可能具有微生物群，其中氨基酸代谢水平更高。此外，冗余分析（RDA）显示，产仔数，胎次和出生日期对细菌群落结构有重要影响。这些结果提高了我们对猪早期粪便微生物群及其潜在的RFI的了解，这对于将来开发预测和改善猪FE的微生物标志物以及研究饮食策略目标很有用。