Studies in mammals, including chickens, have shown that the development of the immune system is affected by interactions with intestinal microbiota. Early life microbial colonization may affect the development of innate and adaptive immunity and may contribute to lasting effects on health and resilience of broiler chickens. We inoculated broiler chickens with adult-derived-microbiota (AM) to investigate their effects on intestinal microbiota composition and natural killer (NK) cells, amongst other immune cells. We hypothesized that AM inoculation directly upon hatch (day 0) would induce an alteration in microbiota composition shortly after hatch, and subsequently affect (subsets of) intestinal NK cells and their activation. Microbiota composition of caecal and ileal content of chickens of 1, 3, 7, 14, 21, and 35 days of age was assessed by sequencing of 16S ribosomal RNA gene amplicons. In parallel, subsets and activation of intestinal NK cells were analyzed by flow cytometry. In caecal content of 1- and 3-day-old AM chickens, a higher alpha-diversity (Faith's phylogenetic diversity) was observed compared to control chickens, whereas ileal microbiota were unaffected. Regarding beta-diversity, caecal microbiota profiles could be clustered into three distinct community types. Cluster A represented caecal microbiota of 1-day-old AM chickens and 1- and 3-day-old control chickens. Cluster B included microbiota of seven of eight 3- and 7-day-old AM and 7-day-old control chickens, and cluster C comprised microbiota of all chickens of 14-days and older, independent of inoculation. In 3-day-old AM chickens an increase in the percentages of intestinal IL-2Rα⁺NK cells and activated NK cells was observed compared to control chickens of the same age. In addition, an increase in relative numbers of intestinal cytotoxic CD8αα⁺T cells was observed in 14- and 21-day-old AM chickens. Taken together, these results indicate that early exposure to AM shapes and accelerates the maturation of caecal microbiota, which is paralleled by an increase in IL-2Rα⁺NK cells and enhanced NK cell activation. The observed association between early life development of intestinal microbiota and immune system indicates possibilities to apply microbiota-targeted strategies that can accelerate maturation of intestinal microbiota and strengthen the immune system, thereby improving the health and resilience of broiler chickens.

对包括鸡在内的哺乳动物的研究表明，免疫系统的发育受到与肠道菌群相互作用的影响。生命早期的微生物定植可能会影响先天免疫和适应性免疫的发展，并可能对肉鸡的健康和复原力产生持久影响。我们用成年微生物菌群（AM）接种肉鸡，以研究它们对肠道菌群组成和自然杀伤（NK）细胞以及其他免疫细胞的影响。我们假设在孵化后（第0天）直接接种AM疫苗会在孵化后不久引起微生物群组成的变化，并随后影响肠道NK细胞（的亚群）及其激活。1,2,3,7,14,21鸡的盲肠和回肠含量的微生物群组成 通过对16S核糖体RNA基因扩增子进行测序，评估了35天的年龄。并行地，通过流式细胞术分析肠NK细胞的亚群和活化。在1日龄和3日龄AM鸡的盲肠含量中，与对照鸡相比，观察到了更高的α多样性（Faith的系统发育多样性），而回肠微生物群未受影响。关于β-多样性，盲肠微生物群谱可分为三种不同的群落类型。群集A代表1日龄AM鸡和1日龄和3日龄对照鸡的盲肠菌群。B组包括八只3日龄和7日龄AM和7日龄对照鸡中的七只的微生物群，C组包括14天及更大龄的所有鸡的微生物群，与接种无关。与相同年龄的对照鸡相比，观察到⁺ NK细胞和活化的NK细胞。此外，在14天和21天的AM鸡中观察到肠道细胞毒性CD8αα ⁺ T细胞的相对数量增加。两者合计，这些结果表明早期暴露于AM形状并加速了盲肠菌群的成熟，这与IL-2Rα ⁺ NK细胞的增加和NK细胞活化的增强相平行。观察到的肠道菌群早期发育与免疫系统之间的联系表明，有可能应用针对微生物菌群的策略，这些策略可以加速肠道菌群的成熟并增强免疫系统，从而改善肉鸡的健康和适应力。