Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/2017
Publication Date: 10/5/2017
Citation: Adhikari, P., Cosby, D.E., Cox Jr, N.A., Kim, W.K. 2017. Effect of dietary supplementation of nitrocompounds on salmonella colonization and ileal immune gene expression in laying hens challenged with salmonella enteritidis. Poultry Science. 96(12):4280-4286.
Interpretive Summary: Foodborne illness caused by Salmonella is of both public health and economic concerns. Alternative feed amendments and interventions have received increased interests of late with the push to eliminate the use of antimicrobials in animal production. This research looked at the inclusion of two nitrocompounds to influence the gut microflora of laying hens in order to reduce Salmonella contamination. Our results indicated a reduction of Salmonella with both nitroethane and nitropropane and a significant immune response in the ileum. This makes the use of nitrocompounds as an intervention strategy to reduce Salmonella infections in laying hens a viable alternative to antimicrobial compounds.
Technical Abstract: Foodborne disease caused by Salmonella Enteritidis (SE) is one of the important public health and economic concerns. A study was conducted to determine the effect of supplementation with 2-nitroethanol (NE) and 2-nitropropanol (NP) on Salmonella recovery of internal organs as well as on the immune gene expression in the ileum of laying hens. Thirty-six White Leghorns were orally gavaged with nalidixic acid resistant Salmonella Enteritidis (SENR). Hens were housed individually in wire-laying cages and randomly assigned to six dietary treatments: T1= SENR unchallenged (negative control), T2 = SENR challenged (positive control), T3 = SENR challenged + 100 ppm NE, T4 = SENR challenged + 200 ppm NE, T5 = SENR challenged + 100 ppm NP and T6 = SENR challenged + 200 ppm NP. Hens were sampled at 7 days post inoculation (dpi). Ceca, liver with gall bladder (L/GB), and ovary samples were collected for bacteriology, and ileum samples were collected for analysis of immune gene expression. T3 and T6 significantly reduced (P < 0.05) cecal SENR count, whereas T4 and T5 were not different from T2, the SENR challenged control. There was no significant difference in SENR reduction in the L/GB or ovary after supplementation of either nitrocompounds. Pro- and anti-inflammatory cytokines such as interferon (IFN)-', interleukin (IL)-1B, IL-6, toll-like receptors (TLR)-4 and IL-10 all were significantly upregulated (P < 0.05) after SENR challenge. Supplementation at both levels of NE and NP showed a significant immune gene expression response in the ileum with reduction of IFN-', IL-6, TLR-4 and IL-10 mRNA expression. Overall, nitrocompounds such as NE and NP can be used in the intervention strategy to reduce Salmonella infection in hens.