Submitted to: FEMS Immunology and Medical Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/17/2004
Publication Date: 1/25/2005
Citation: Swaggerty, C.L., Ferro, P.J., Pevzner, I.Y., Kogut, M.H. 2005. Heterophils are associated with resistance to systemic Salmonella enteritidis infections in genetically distinct chicken lines. FEMS Immunology and Medical Microbiology. 43:149-154. Interpretive Summary: During the first week of life, baby chickens are very susceptible to bacterial infections. Salmonella is a bacterium that infects baby chickens and people. Baby chicks have blood cells that can help them prevent these infections. These cells are called heterophils. The objective of this research was (1) to compare different lines of baby chicks (A, B, C, and D) to see which line was best able to resist a Salmonella infection and (2) to count the number of heterophils in the abdomen of chicks. We found that chicks from lines A and D were more resistant to Salmonella than chicks from lines B and C. We also found that chicks from lines A and D had more heterophils than chicks from lines B and C. These experiments are important to the commercial poultry breeders because we have shown that chickens can be selected for an increased resistance to Salmonella infections. A resistant chicken is likely going to be stronger and will fight off infections better; therefore, people are less likely to get an infection from eating contaminated poultry.
Technical Abstract: We reported differences in in vitro heterophil functional efficiency between parental lines (A>B) of broilers and the F1 reciprocal crosses (D>C). Heterophils modulate acute protection against Salmonella in young poultry. Therefore, we are interested in evaluating susceptibility of the four lines to a systemic Salmonella enteritidis (SE) infection. In this study, SE was administered intraperitoneally to day-old chicks. Line A chicks were more resistant to SE than line B chicks and line D chicks were more resistant than line C chicks (p less than or equal to 0.002). Heterophil and macrophage influx into the peritoneum were also evaluated. More heterophils migrated to the peritoneal cavity of lines A and D compared to lines B and C (p less than or equal to 0.002). No differences in the number of macrophages were found. These data indicate increased heterophil influx into the peritoneal cavity contributes to increased resistance. Taken together with previous studies our results show that chicks with increased heterophil functional efficiency are less susceptible to a systemic SE infection.