Selection for pro-inflammatory mediators produces chickens more resistant to Eimeria tenella

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 interleukin (IL)-6, CXCLi2, and CCLi2. The resultant high line of chickens is more resistant to Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) compared to the low line. In the current study, we sought to determine if the high line birds were also more resistant to the protozoan parasite Eimeria tenella. In three separate experiments, 14-day-old chickens from the high and low lines were challenged orally with 10×10(3) to 45×10(3) E. tenella oocysts. Birds were sacrificed 6 d postchallenge and the caeca was removed and scored for lesions and body weight gain compared to mock-infected controls. The high line birds were more resistant to intestinal pathology as demonstrated by lower lesion scores (P≤0.04) compared to the low line. There were no differences in body weight gain between the lines. The results from this study showed that in addition to enhanced resistance against Salmonella Enteritidis, high line chickens are also more resistant to the pathology associated with coccidial infections compared to the low line birds. Taken together with our initial study utilizing the high and low lines, selection based on increased pro-inflammatory mediator expression produces chickens that are more resistant to both foodborne and poultry pathogens, including cecal pathology associated with costly coccidial infections.