The objective of this research was to investigate antibiotic alternatives to controlling Eimeria and necrotic enteritis in chickens. Eimeria are apicomplexan intestinal parasites ubiquitous to commercial poultry production. Because of their ubiquitous nature, control of coccidia is required in essentially every commercial poultry facility. Coccidia replicate intracellularly in the host intestinal epithelium, which not only causes nutrient malabsorption, but predisposes the birds for necrotic enteritis. Necrotic enteritis and coccidiosis cost the poultry industry a combine US $9 Billion annually. With consumer preference shifting towards antibiotic-free animal production, developing and implementing viable alternatives will continue to be crucial to sustainable agriculture. Antibiotic-free poultry production is continuing to grow in market share and in order to maintain the low-cost of the world's most popular protein, viable antibtioic alternatives need to be elucidated. My first aim was to evaluate the potential of functional feed ingredients as interventions to mitigate necrotic enteritis in broiler chickens experimentally co-infected with Eimeria spp. and C. perfringens. Because of their antimicrobial activities, functional feed ingredients, including dietary prebiotics and botanical extracts, are widely seen as potential alternatives to antibiotics in the prevention and management of gastrointestinal disease in poultry. We administered a dietary prebiotic or a botanical extract blend to broilers under experimental coinfection with Eimeria spp. and C. perfringens and evaluated growth performance, gross intestinal lesions, and gastrointestinal counts of C. perfringens. My second aim was to profile the longitudinal response of commercial broiler operations to bioshuttle administration. Referred to as a bioshuttle, ionophores can be administered postvaccination to mitigate Eimeria vaccine-related performance losses. Although vaccine administration has been demonstrated to restore drug-sensitive Eimeria populations, it is unknown whether similar population shifts occur as a result of commercial bioshuttle use. In order to address this unmet need we took field data to profile the response of bird performance and coccidia presence before, during, and after bioshuttle application using aggregate production data (e.g., live weights, adjusted FCR, etc.) over 12-months from a large commercial broiler integrator as indicators of anticoccidial drug sensitivity. My last aim was to investigate the potential of Acetyl CoA-Carboxylase (ACC) as a novel target for the development of anticoccidial drugs in vivo. Acetyl-CoA Carboxylase (ACCase), responsible for conversion of Acetyl-CoA to Malonyl-CoA, is an essential metabolic reaction. Because of low conservation in structure between apicomplexans and vertebrates, inhibitors of apicomplexan ACCase are predicted to have low toxicity in chickens. We administered ACCase inhibitors to broilers chicken experimentally infected with Eimeria spp. and evaluated growth performance. From the studies, we determined administration of phenoxy carboxylic acid inhibitors of apicomplexan ACCase inhibit coccidia in vivo and mitigated coccidiosis in experimentally infected broiler chickens.
