Title: Differences in pathogen colonization and mortality of genetically selected Japanese quail lines subjected to heat stress and Escherichia coli challenge Authors
Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 29, 2011
Publication Date: N/A
Technical Abstract: Japanese quail selected for divergent corticosterone response to restraint stress were evaluated for their resistance to heat stress and aerosol challenge with avian pathogenic Escherichia coli (APEC) to determine the impact of stress response on APEC pathogenesis and colonization with food-borne pathogens. These quail lines are designated as the high stress line (HS), low stress line (LS), and the random-bred control line (CS). Heat stress (35oC, 8h/d) was initiated at 24d until the end of the study. Birds were challenged with an aerosol spray containing 2x109 cfu of E. coli at 25d and 32d. At 38d the birds were necropsied and the intestinal tract was screened for both Salmonella and Campylobacter. Body weights of the CS birds were higher than both HS and LS at 17d, 25d, and 32d, but there were no line differences at 38d. At 32d there was no difference in mortality between males and females and the CS line had significantly higher mortality compared to the LS line with the HS line being intermediate. At 38d, females of the CS line that were both heat stressed and challenged had a mortality incidence of 25%, which was significantly higher than male birds of the same line and treatment (5.3%) suggesting a change in susceptibility to heat stress and E. coli challenge in females coming into lay. While Campylobacter was not recovered, we observed an increased incidence in Salmonella enterica serotype Agona isolation in the intestine of quail subjected to heat stress, suggesting that a resident population of Salmonella is present in these quail lines. There was a differential effect of heat stress on Salmonella isolation from male and female quail suggesting that the additional stress of coming into lay may have confounded the female isolation data. Further work using this model will lead to an understanding of the influence of sex and stress hormones on host immunity, APEC pathogenesis, and pathogen colonization. The failure to isolate Campylobacter from these birds suggests that they will be useful for Campylobacter challenge studies.