Enteric permeability and inflammation associated with day of hatch Enterobacteriaceae inoculation

Early exposure to Enterobacteriaceae may result in inappropriate microbial colonization of the gastrointestinal (GI) tract, induce mild GI inflamma-tion, alter immune system development, and predispose poultry to opportunistic infection. Four experiments were conducted to test Enterobacteriaceae isolates Escherichia coli LG strain (LG), E. coli Huff strain (Huff), Salmonella Enteritidis LB (SE) and Salmonella Typhimurium (ST) on ability to induce GI inflamma-tion. All 4 experiments included a noninoculated con-trol, and day of hatch (DOH) oral inoculation of LG, Huff, SE and ST in experiment 1, LG and SE in experi-ment 2, and LG, Huff, SE, and ST in experiment 3. Experiment 4 included LG, Huff, a noninoculated con-trol (NIC), and Clostridium perfringens only (NCP) wherein birds received oral C. perfringens challenge on d15-16 to induce necrotic enteritis. Body weight was measured, yolk sacs and spleens were collected, and blood was obtained for serum fluorescein isothiocyanate dextran (FITC-d) recovery and alpha-1-acid glycopro-tein (A1GP) concentrations. Samples were taken weekly through 2 wk of age in experiments 1 and 2, or 4 wk of age in experiments 3 and 4. Increased FITC-d recovery was observed for LG and SE on d13 in experi-ment 2 (P < 0.05), and C. perfringens only birds on d27 in experiment 4 (P < 0.05) as compared to noninocu-lated controls. Each experiment resulted in notable dif-ferences in A1GP serum concentrations over time, with fluctuations in A1GP patterns through d14 based on DOH inoculation (P < 0.05). Over time, A1GP was increased for DOH inoculated birds from d 22 to 29, the fourth wk of life, and d 2-29, the entire experiment, vs. noninoculated controls in experiment 3 (P < 0.05). Simi-larly, NCP and LGCP showed increased A1GP from d 20 to 27 and d 6 to 27, vs. NIC in experiment 4 (P < 0.05). In experiment 4, C. perfringens challenge resulted in earlier A1GP response in DOH inoculated birds, d 17-20, as compared to NCP birds, d 20-27 (P < 0.05). These results suggest early Enterobacteriaceae exposure may influence early inflammatory state in the GI tract and may also alter patterns of inflammation and responsive-ness to pathogens.

Automated summary

The study indicates that early exposure to Enterobacteriaceae may have an impact on the microbial colonization of the gastrointestinal tract, immune system development, and susceptibility to infection in poultry, potentially leading to gastrointestinal inflammation.