Pioneer colonization of the gastrointestinal tract (GIT) by bacteria is thought to have major influence on neonatal tissue development. Previous studies have shown in ovo inoculation of embryos with saline (S), species of Citrobacter (C, C2), or lactic acid bacteria (L) resulted in an altered microbiome on day of the hatch (DOH). The present study investigated GIT proteomic changes at DOH in relation to different inoculations. Embryos were inoculated in ovo with S or ∼102 cfu of C, C2, or L at 18 embryonic days. On DOH, the GIT was collected, and tissue proteins were extracted for analysis via tandem mass spectrometry. A total of 493 proteins were identified for differential comparison with S at P ≤ 0.10. Different levels were noted in 107, 39, and 78 proteins in C, C2, and L groups, respectively, which were uploaded to Ingenuity Pathway Analysis to determine canonical pathways and biological functions related to these changes. Three members of the cytokine family (interleukin [IL]-1β, IL6, and Oncostatin M) were predicted to be activated in C2, indicated with Z-score ≥ 1.50, which suggested an overall proinflammatory GIT condition. This was consistent with the activation of the acute-phase response signaling pathway seen exclusively in C2 (Z-score = 2.00, P < 0.01). However, activation (Z-score = 2.00) of IL-13, upregulation of peroxiredoxin-1 and superoxide dismutase 1, in addition to activation of nitric oxide signaling in the cardiovascular system of the L treatment may predict a state of increased antioxidant capacity and decreased inflammatory status. The nuclear factor erythroid 2-related factor 2 (NRF2)-mediated oxidative stress response (Z-score = 2.00, P < 0.01) was predicted to be upregulated in C which suggested that chicks were in an inflammatory state and associated oxidative stress, but the impact of these pathways differed from that of C2. These changes in the proteome suggest that pioneer colonizing microbiota may have a strong impact on pathways associated with GIT immune and cellular development.

中文翻译：

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孵化当天，卵内施用的先锋定居者对肠道蛋白质组的影响。

细菌在胃肠道（GIT）的先驱定植对新生儿组织的发展有重要影响。先前的研究表明，在卵内用生理盐水（S），柠檬酸杆菌属（C，C2）或乳酸菌（L）进行卵内接种会导致孵化当天（DOH）的微生物组发生变化。本研究调查了DOH与不同接种相关的GIT蛋白质组学变化。在胚胎18天时，用S或约102 cfu的C，C2或L在卵内接种胚胎。在DOH上，收集GIT，并提取组织蛋白以通过串联质谱分析。鉴定出总共493种蛋白质用于与P≤0.10的S进行差异比较。在C，C2和L组中，分别在107、39和78种蛋白质中发现了不同的水平，并将其上载到Ingenuity Pathway Analysis，以确定与这些变化相关的规范途径和生物学功能。预测细胞因子家族的三个成员（白介素[IL]-1β，IL6和制瘤素M）在C2中被激活，Z分数≥1.50表示这提示了整体促炎性GIT状态。这与仅在C2中看到的急性期反应信号通路的激活是一致的（Z评分= 2.00，P <0.01）。然而，除了L治疗的心血管系统中一氧化氮信号的激活外，IL-13的激活（Z分数= 2.00），过氧化物酶1和超氧化物歧化酶1的上调也可能预示着抗氧化能力增强的状态和炎症状态降低。预测核因子红系2相关因子2（NRF2）介导的氧化应激反应（Z分数= 2.00，P <0.01）在C中上调，这表明小鸡处于炎症状态并伴有氧化应激，但这些途径的影响不同于C2。蛋白质组学的这些变化表明，先驱者定居微生物群可能会对与GIT免疫和细胞发育相关的途径产生强烈影响。