Heat stress reduces Eimeria spp. infection and interferes with C. perfringens infection via activation of the hypothalamic-pituitary-adrenal axis

Heat stress has a relevant effect on animal health and productivity. Stress and environmental changes can contribute to disease development, such as avian necrotic enteritis (NE). The goal of this study was to analyze the effects of heat stress applied to broiler chickens in an experimental model of co-infection with Clostridium perfringens and Eimeria spp. Therefore, the current study was designed to analyze the effect of heat stress to broiler chickens in an experimental model of infection or co-infection with Clostridium perfringens and Eimeria spp. C. perfringens was given in the poultry feed and the Eimeria infection was induced by gavage with a live oocysts vaccine dose 30 times higher than the manufacturer recommendation. We observed a reduction in the secretory IgA concentration in the jejunum and ileum in heat-stressed chickens compared to non-stressed chickens. Decreased maximum scores of intestinal necrosis, crypt abscesses and transmural lesions were observed in the heat-stressed chickens co-infected and infected with Eimeria compared to the respective unstressed groups. Heat stress caused an increase the intestinal lesion scores in chickens infected with C. perfringens only. The crypt depth was greater in chickens from the heat-stressed groups compared to the non-stressed groups. We also demonstrated that HS decreased infection and/or Eimeria development in the intestinal epithelium, reducing the harmful potential of C. perfringens. •Heat-stressed animals presented a reduction in the secretory IgA concentration in the jejunum and ileum.•Heat stress reduce the pathogenesis of Eimeria spp. infection in broiler chickens.•Eimeria infected and heat-stressed birds presented intestinal crypt lesions while non-stressed birds present villus lesions.•The reduction in the pathogenesis of Eimeria infection prevent C. perfringens to induce tissue damage.