Selection for pro-inflammatory mediators produces chickens more resistant to Campylobacter jejuni

Authors: Swaggerty, Christina - Christi; PEVZNER, IGAL - Cobb-Vantress, Inc; He, Louis; Genovese, Kenneth - Ken; Kogut, Michael - Mike

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/5/2016
Publication Date: 2/22/2017
Publication URL: https://handle.nal.usda.gov/10113/5801893
Citation: Swaggerty, C.L., Pevzner, I.Y., He, L.H., Genovese, K.J., Kogut, M.H. 2017. Selection for pro-inflammatory mediators produces chickens more resistant to Campylobacter jejuni. Poultry Science. 96(6):1623-1627.

Interpretive Summary: We recently worked with one of the largest chicken companies in the world and were able to develop a new method to identify and produce chickens with higher levels of chemical mediators. Chickens expressing these mediators are more resistant to Salmonella, coccidiosis, and necrotic enteritis caused by Clostridium, all of which are very important foodborne bacteria and/or poultry pathogens. We produced a more resistant line of chickens referred to as the "high" line, and a "low" line that is more susceptible. Campylobacter is the second leading cause of bacterial-induced foodborne illnesses with an estimated economic burden of $2 billion per year. In the current study, we wanted to know if our high line chickens were also more resistant to Campylobacter compared to the low line chickens. In two separate experiments, 2-day-old chicks from the high and low lines were challenged with Campylobacter. Birds were sacrificed 4 days later and the gut contents of each bird was removed and the number of bacteria was counted. Fewer high line birds had countable numbers of Campylobacter compared to the low line, indicating they were more resistant and could kill the Campylobacter before it could establish an infection in the chicken. These findings show that our selection method is a new way to produce chickens that are naturally more resistant to both foodborne and poultry pathogens including Salmonella, coccidia, Clostridium, and Campylobacter. Therefore, we could potentially reduce the number of foodborne pathogens entering the food chain and reduce the number of food poisoning cases that are caused by chicken consumption of poultry products. Use of more naturally resistant birds by the poultry industry would significantly improve the safety of poultry products reaching the consumer.

Technical Abstract: Campylobacter spp. are the second leading cause of bacterial-induced foodborne illnesses with an estimated economic burden of nearly $2 billion per year. Most human illness associated with campylobacteriosis is due to infection by C. jejuni and chickens are recognized as a reservoir, which could lead to foodborne illness in humans resulting from handling or consuming raw or undercooked chicken. We recently developed a novel breeding strategy based on identification and selection of chickens with an inherently high and low phenotype of pro-inflammatory mediators including IL-6, CXCLi2, and CCLi2. We have shown that the high line chickens are more resistant to the foodborne and poultry pathogens Salmonella enterica serovar Enteritidis, Eimeria tenella, and Clostridium perfringens-induced necrotic enteritis compared to the low line. The objective of this study was to determine whether the same trend of enhanced resistance in the high line birds was observed for C. jejuni. Birds were challenged at 2-days-of-age by oral gavage (0.5 mL) with 5 × 10^6 colony forming units (cfu) of C. jejuni/mL, necropsied four days post-challenge and cecal content collected to determine if there was a difference in C. jejuni resistance between the high and low line chickens. There were fewer (P = 0.01) chickens from the high line (28/40 = 71.8%) that were colonized by C. jejuni compared to the low line (37/39 = 94.9%). The amount of C. jejuni recovered from the ceca of infected birds was quantified; however, no differences were observed (P = 0.10). Since the high line birds were also more resistant to C. jejuni, it provided additional validation that selection based on pro-inflammatory mediators produces a line of chickens with increased natural resistance against diverse foodborne and poultry pathogens. The poultry industry is moving towards reduced therapeutics, and as such our breeding strategy would be a viable method to incorporate into traditional poultry breeding programs.