4. Discussion
Selective breeding programs of broiler chickens by poultry industry over 50 years have preferentially selected for economic traits such as growth rate, feed conversion and breast yields. Nonetheless, genetic selection will be complicated by their instability according to chicken line, age and environment. These efforts often led to increase disease susceptibility and less than optimal immune response to pathogens. Indeed, blunted humoral and cellular immune
responses have been described in modern broiler breeds selected for high economic performance related, in part, to diminished baseline functional parameters of their mononuclear phagocytes. Given that innate immunity mediated by macrophages plays a protective role in the development and progression of avian necrotic enteritis (NE), it is not unreasonable to predict that poultry genetics also plays a major role in dictating the type of host response to NE. Until now, however, limited information has been available on the effect of commercial chicken breeds on NE susceptibility, which is an emerging and devastating poultry disease caused by C. perfringens infection,typically following Eimeria-induced intestinal damage.