Impact of in ovo administered pioneer colonizers on intestinal proteome on day of hatch

Abstract

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 ∼10 2 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.

Oral Treatment With Ileal Spores Triggers Immunometabolic Shifts in Chicken Gut

“…Additionally, Feng et al found that higher levels of Akt phosphorylation and PI3K activation enhance gut barrier integrity ( 65 ), suggesting SPORE-induced changes of the PI3K/Akt signaling pathway may also contribute to this reduction in gut permeability. Although we did not look at changes in tight junction protein formation and gene expression in this study, ileal spore treatment may have affected these parameters, as in ovo exposure to bacteria induced changes in tight junction signaling ( 47 ). Future studies will evaluate expression of tight junction proteins to allow better-interpretation of gut permeability data.…”

“…This study showed a consistent trend in which phosphorylation shifts in immunometabolic pathways, mainly innate immunity, were reduced from 3 to 7 dpi. Similarly, single-dose in ovo delivery of Citrobacter species or LAB also altered early inflammatory responses in the chicken gut ( 47 , 48 ). These findings suggest that innate immune responses are highly responsive to microbial “pioneers” in the chicken intestine.…”

Research Note: Application of an Escherichia coli spray challenge model for neonatal broiler chickens

“…Results were consistent in both exp 1 and 2, indicating that spraying the inoculum on seeder chicks horizontally transmitted the pathogen during hatch ( Table 1 ). Significant differences ( P < 0.0001) in LAB were also observed between the challenged groups and negative control ( Table 1 ), indicating that gram-negative bacteria may contribute to colonization by LAB ( Wilson et al., 2020 ). LAB are naturally found in the GIT of animals ( Reuben et al., 2019 ).…”

Enteric permeability and inflammation associated with day of hatch Enterobacteriaceae inoculation

“…While the 2 Enterobacteriaceae used were both Citrobacter sp. , the proteomic analysis predicted increased inflammation alongside suppression of the ability to respond to inflammation ( Rodrigues et al, 2020 ; Wilson et al, 2020 ). This uncontrolled inflammation can result in a nonbeneficial intestinal environment, suppression of the immune system, and in turn, increased risk of opportunistic infection ( Meirow and Baniyash, 2017 ).…”