Submitted to: Research in Veterinary Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/12/2013
Publication Date: 11/23/2013
Citation: Lee, K.W., Hong, Y.H., Lee, S.H., Jang, S.I., Park, M.S., Bautista, D.A., Ritter, D.G., Jeong, W., Jeoung, H.Y., An, D.J., Lillehoj, E.P., Lillehoj, H.S. 2013. Effects of anticoccidial and antibiotic growth promoter programs on broiler performance and immune status. Research in Veterinary Science. 93(2):721-8. doi: 10.1016/j.rvsc.2012.01.001. Interpretive Summary: Coccidiosis is an intestinal disease caused by several distinct species of Eimeria parasites which infect the different areas of gut. Coccidiosis damage gut integrity severely decreasing nutrient absorption. Ability to control coccidiosis will reduce economic losses more than $ 3.2 billion worldwide. In this paper, ARS scientists collaborated with veterinarians from private industries and University of Delaware to investigate the influence of various coccidiosis control programs on growth performance and parameters of immunity in broiler chickens exposed to Eimeria-contaminated litter. The coccidiosis control programs used in this study are commonly applied in the U.S. poultry industry. The results showed that broiler chickens which were vaccinated with live coccidia vaccine showed enhanced body weight growth compared to other treatment groups. The present study also demonstrates that anticoccidial programs in combination with antibiotics growth promoters (AGPs) alter systemic and local parameters of immune status in broiler chickens raised on Eimeria-contaminated litter. The underlying immunomodulatory mechanism(s) seen in this study may be related, in part, to an altered gut microbiota as a consequence of feeding the AGPs or anticoccidials plus AGPs. Determination of whether these altered parameters of immunity correlate with enhanced host susceptibility to subsequent infection by mucosal pathogens in the field will require further investigation. The information gained from this study will enhance the development of logical management scheme for coccidiosis control.
Technical Abstract: This study investigated the effects of various coccidiosis control programs in combination with antibiotic growth promoters (AGPs) on growth performance and host immune responses in broiler chickens. The coccidiosis programs that were investigated include in ovo coccidiosis vaccination (CVAC) with Inovocox or in-feed medication with diclazuril as Clinacox (CLIN) or salinomycin (SAL). The AGPs were virginiamycin or bacitracin methylene disalicylate plus roxarsone. As a negative control, chickens were non-vaccinated and fed with non-supplemented diets (NONE). All animals were exposed to used litter from a commercial broiler farm with confirmed contamination by Eimeria parasites to simulate in-field exposure to avian coccidiosis. Broiler body weights in the CVAC group were greater at 14 and 32 days of age, but not at day 42, compared with the NONE, CLIN, and SAL groups. At day 14, the SAL group showed decreased body weight and reduced ConA-stimulated spleen cell proliferation compared with the CLIN and SAL groups. In contrast, at days 34 and 43, splenocyte proliferation was greater in the CVAC and CLIN groups compared with the NONE and SAL groups. Lymphocyte subpopulations and cytokine mRNA expression levels in the intestine and spleen were also altered by the denoted treatments. Collectively, these results suggest that in ovo coccidiosis vaccination or coccidiostat drug medication programs in combination with AGPs influences chicken growth and immune status in an Eimeria-contaminated environment. Keywords: Coccidiosis control programs; Antibiotic growth promoters; Immunity; Broiler chicken.