Selection for pro-inflammatory mediators produces chickens more resistant to Clostridium perfringens-induced necrotic enteritis

Authors: Swaggerty, Christina - Christi; MCREYNOLDS, J - Elanco Animal Health, Inc; Byrd Ii, James - Allen; PEVZNER, I - Cobb-Vantress, Inc; Duke, Sara; Genovese, Kenneth - Ken; He, Louis; Kogut, Michael - Mike

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/26/2015
Publication Date: 2/25/2016
Publication URL: https://handle.nal.usda.gov/10113/62050
Citation: Swaggerty, C.L., McReynolds, J.L., Byrd, J.A., Pevzner, I.Y., Duke, S.E., Genovese, K.J., He, H., Kogut, M.H. 2016. Selection for pro-inflammatory mediators produces chickens more resistant to Clostridium perfringens-induced necrotic enteritis. Poultry Science. 95:370-374.

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 that are more resistant to Salmonella and coccidiosis, among the most important foodborne causing bacteria and poultry pathogens, respectively. We produced a more resistant line of chickens referred to as the "high" line, and also a "low" line that is more susceptible. Clostridium is the fourth leading cause of bacterial-induced foodborne illnesses with an estimated economic burden of $342M USD per year. In addition to being a foodborne pathogen, Clostridium is an economically important poultry pathogen and is one of the known causes of necrotic enteritis (NE) which costs the poultry industry approximately $2B USD per year. In the current study we wanted to know if our high line chickens were also more resistant to Clostridium compared to the low line chickens. In two separate experiments, chickens from the high and low lines were challenged with Clostridium. Birds were sacrificed at 21-days-of-age, the gut was removed and scored for lesions and the number of bacteria were counted. High line birds were more resistant as shown by lower lesion scores in the gut compared to the low line. The results from this study showed that in addition to improved resistance against foodborne bacterial and parasitic infections, high line chickens are also more resistant to Clostridium and NE compared to low line birds. 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, and Clostridium. Use of more naturally resistant birds by the poultry industry would significantly improve the safety of poultry products reaching the consumer.

Technical Abstract: Clostridium perfringens is the fourth leading cause of bacterial-induced foodborne illnesses with an estimated economic burden of $342M USD per year. In addition to being a foodborne pathogen, C. perfringens is also an economically important poultry pathogen and is one of the known etiologic agents of necrotic enteritis (NE). NE is categorized into clinical and subclinical infections with an estimated annual cost of $2B USD. We recently developed a novel selection method 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 the resultant high line chickens are more resistant to the foodborne pathogen Salmonella enterica serovar Enteritidis and the poultry pathogen Eimeria tenella 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 in an experimental NE model following challenge with C. perfringens. Birds were administered a commercial bursal disease vaccine at 10 times the recommended dose via the ocular route at 14-d-of-age, challenged once daily for 3 d beginning at 16-d-of-age by oral gavage (3 mL) with a stock culture of 10^7 colony forming units (cfu) of C. perfringens/mL. To determine if the high and low line chickens differed in susceptibility to pathological intestinal damage caused by NE, sections of the intestine were evaluated and lesions were scored. Chickens from the high line were more resistant to C. perfringens-induced NE pathology compared to the low line as indicated by reduced NE-associated lesion scores. Ninety percent (45/50) of the high line birds had lesions of zero or one while the remaining 10% (5/50) had lesion scores of two to four. Sixty-seven percent (35/52) of the low line birds had lesions of zero or one and 32.7% (17/52) had a score of two or greater. The average lesion score in the high line was 0.50 ± 0.13 compared to 1.08 ± 0.12 in the low line (P = 0.002). In addition to lesion scores, the amount of C. perfringens recovered from the intestines of infected birds was quantified; however no differences were observed (P = 0.83). Since the high line birds were also more resistant to C. perfringens, both a foodborne and poultry pathogen, it provides additional validation of selection based on pro-inflammatory mediators and therefore should be more appealing and valuable to the poultry industry.