The animal gut is a major site affecting productivity via its role in mediating functions like food conversion and pathogen colonization. Live microorganisms like probiotics are widely used to improve poultry productivity. However, given that chicks receive their microbiota from the environment at-hatch, a bacterial treatment that can stimulate gut immune maturation in early life can benefit animal health. Thus, our lab has begun investigating alternative means to improve poultry health via single inoculation with microbial spores. In this study, we orally-inoculated day-old chicks with ileal scrapings (ISs) enriched for spores via chloroform treatment (SPORE) or non-treated (CON). At 3, 7, and 14 days post-inoculation (dpi), gut permeability was measured via FITC-dextran assay in serum. Additionally, small intestinal scrapings (SISs) were tested for in vitro Salmonella killing and total IgA. Lastly, distal ileum was either fixed or flash-frozen for microscopy or kinome peptide array, respectively. Using bacterial 16S rRNA gene sequencing, SPORE and CON inocula were highly-similar in bacterial composition. However, spores were detected in SPORE but not in CON inoculum. Segmented filamentous bacteria (SFB) filaments were observed in the distal ileum in SPORE birds as early as 3 dpi and all birds at 7 and 14 dpi. Additionally, SFB were detected via PCR in the ceca, colonizing all SPORE birds at 3 dpi. At 3 dpi, SPORE birds exhibited lower gut permeability vs. CON. In SPORE birds, SISs induced greater Salmonella growth in vitro at 3 dpi yet significantly-reduced Salmonella load at 7 and 14 dpi compared to CON in an IgA-independent manner. SPORE distal ileal tissue exhibited unique upregulation of several immunometabolic processes vs. CON birds, including innate (Toll-like receptor, JAK-STAT) and adaptive (T/B cell receptor, T_H17 differentiation) immune pathways, PI3K/Akt signaling, mTOR signaling, and insulin-related pathways. Collectively, these data suggest oral inoculation with ileal spores generally-improved gut health.

Importance: We report that ileal, spore-forming commensal microbes have potent effects on ileum immunometabolism. Additionally, we identify a functional ileal phenotype in spore-treated chickens, which matched several of the observed immunometabolic changes and was associated with SFB colonization in the ileum.

动物肠道是通过影响食物转化和病原菌定殖等功能来影响生产力的主要场所。诸如益生菌之类的活微生物被广泛用于提高家禽的生产率。但是，考虑到小鸡在孵化场时会从环境中获得微生物，因此可以在幼年时期刺激肠道免疫成熟的细菌治疗可以有益于动物健康。因此，我们的实验室已开始研究通过单次接种微生物孢子来改善家禽健康的替代方法。在这项研究中，我们给日龄雏鸡口服回肠刮片（ISs），通过氯仿处理（SPORE）或未处理（CON）富集孢子。在接种后3、7和14天（dpi），通过FITC-葡聚糖测定法测定血清中的肠通透性。另外，体外沙门氏菌杀死总IgA。最后，将远端回肠固定或快速冷冻，分别用于显微镜检查或kinome肽阵列检查。使用细菌16S rRNA基因测序，SPORE和CON接种物的细菌组成高度相似。但是，在SPORE中检出了孢子，但在CON接种物中未检出。在SPORE鸟类的回肠末端观察到分段的丝状细菌（SFB）细丝，最早出现在3 dpi时，而所有鸟类则分别在7 dpi和14 dpi时。另外，通过盲肠中的PCR检测到SFB，以3 dpi定居所有SPORE禽类。在3 dpi时，SPORE禽类的肠通透性低于CON。在SPORE鸟类中，SIS导致更大沙门氏菌 成长 体外 3 dpi时却显着降低 沙门氏菌与CON相比，以IgA独立的方式在7 dpi和14 dpi时加载。SPORE远端回肠组织表现出几个immunometabolic过程与CON鸟类，包括先天的独特上调（Toll样受体，JAK-STAT）和自适应（T / B细胞受体，T _ħ 17分化的）免疫途径，PI3K / Akt信号， mTOR信号传导和胰岛素相关途径。总的来说，这些数据表明口服回肠孢子通常可以改善肠道健康。

重要性：我们报告回肠，形成孢子的共生微生物对回肠免疫代谢有有效的影响。此外，我们在经孢子处理的鸡中鉴定出一种功能性回肠表型，该表型与几种观察到的免疫代谢变化相匹配，并且与回肠中的SFB定植有关。