Porcine RFI-associated intestinal microbiota

Our aim was therefore to characterize the intestinal microbiota of pigs ranked as low, medium and high residual feed intake (RFI; a metric for FE), where genetic, nutritional and management effects were minimized, in order to explore a possible link between the intestinal microbiota and FE. A total of 81 pigs were ranked on RFI between weaning and day 126 post-weaning, and 32 were selected as the extremes in RFI (12 low, 10 medium, 10 high). Intestinal microbiota diversity, composition and predicted functionality were assessed by sequencing the V3-V4 region of the 16S rRNA gene from faeces and intestinal digesta. No differences in microbial diversity were found between the three RFI ranks. However, some RFI-associated compositional differences were found, mainly among members of Firmicutes and predominantly in faeces collected at the end of the finishing period. In particular, microbes previously associated with a leaner and healthier host (e.g. Christensenellaceae, Oscillibacter, Cellulosilyticum) were enriched in highly feed efficient pigs. Differences were also observed in the ileum of low RFI (more feed efficient) pigs, the most notable being that Nocardicaceae (Rhodococcus) were considerably less abundant. Predictive functional analysis suggests improved metabolic capabilities in these animals, especially in the ileal microbiota, which were corroborated by higher ileal isobutyric acid concentrations. Taken together, these data indicate differences, albeit relatively subtle, within the intestinal microbiota of low RFI pigs compared to their high RFI counterparts, demonstrating a potential link between the intestinal microbiota and FE in pigs.

本研究旨在对按剩余采食量（Residual Feed Intake, RFI，饲料利用效率（Feed Efficiency, FE）的核心衡量指标）划分为低、中、高三组的猪只肠道菌群进行表征，同时尽可能控制遗传、营养及饲养管理因素的干扰，以探究肠道菌群与饲料利用效率之间的潜在关联。本研究共纳入81头猪，在断奶至断奶后126天期间对其剩余采食量进行排序，并从中选取32头极端值个体（低RFI组12头、中RFI组10头、高RFI组10头）。通过对粪便及肠道食糜样本的16S rRNA基因V3-V4可变区进行测序，分析肠道菌群的多样性、组成及预测功能。结果显示，三组RFI分组的猪只在菌群多样性层面未观察到显著差异。但研究发现了与RFI相关的菌群组成差异，这类差异主要集中在厚壁菌门（Firmicutes）类群，且多出现于育肥期末采集的粪便样本中。具体而言，此前被报道与宿主瘦肉率更高、健康状态更佳相关的菌群（如克里斯滕森菌科（Christensenellaceae）、颤杆菌属（Oscillibacter）、溶纤维素杆菌属（Cellulosilyticum））在高饲料利用效率的猪只体内富集。低RFI（即饲料利用效率更高）猪只的回肠菌群也存在类似组成差异，其中最显著的是诺卡氏菌科（Nocardicaceae，红球菌属（Rhodococcus））的丰度显著降低。预测性功能分析结果显示，这类猪只的代谢功能有所提升，尤其是回肠菌群，这一结论得到了回肠内异丁酸浓度更高的实验结果佐证。综合来看，尽管差异相对细微，但低RFI组猪只与高RFI组猪只的肠道菌群仍存在显著区别，这表明猪只肠道菌群与饲料利用效率之间存在潜在关联。