Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 2, 2004
Publication Date: December 1, 2004
Citation: McReynolds, J.L., Byrd II, J.A., Anderson, R.C., Moore, R.W., Edrington, T.S., Genovese, K.J., Poole, T.L., Kubena, L.F., Nisbet, D.J. 2004. Evaluation of immunosuppressants and dietary mechanisms in an experimental disease model for necrotic enteritis. Poultry Science. 83:1948-1952. Interpretive Summary: In the commercial poultry industry, diseases of the gastrointestinal tract can cause serious health and economic effects. One of these diseases is necrotic enteritis. This disease is known to be caused by the bacterium Clostridium perfringens, however the conditions that cause the disease are not understood. The aim of this research was to learn what factors help cause the disease. Results showed that factors such as diet and the presence of other bacteria like E. coli play a major role in allowing the disease condition to develop. Birds were exposed to low levels of these organisms and evaluated for several days, and the disease necrotic enteritis developed. This disease model will help the poultry industry to gain a better understanding of the complexity of necrotic enteritis and help develop strategies to stop it.
Technical Abstract: Clostridium perfringens (CP) is the etiologic agent of Necrotic enteritis (NE). Clinical signs of this disease include depression, decreased appetite, diarrhea, and severe necrosis of the intestinal tract. Understanding the disease progression of NE has been difficult due to its complexity and several suspected predisposing factors (dietary components, immuno-suppression, and mechanical irritation of the gut) that appear to contribute to this syndrome. In the present investigation, day-of-hatch broilers were fed a 55 % wheat diet and randomly assigned to the following groups: control, commercial coccidia vaccine (CCV), commercial bursal disease vaccine (CBDV), or the combination of CCV and CBDV and challenged with 10**7 cfu CP twice daily. Each treatment group had an appropriate non-challenged control. When compared with controls, broilers in each treatment group had a significant increase (P less than or equal to 0.05) in lesion scores, with mean lesion scores of 1.05 and 2.05 in the CP and CBDV + CP treatments, respectively. When compared to controls, the incidence of CP was also increased from (P less than or equal to 0.05) in all treatment groups (73% and 100% in the CCV + CP and CBDV + CP treatment groups, respectively). When compared to controls, percent mortality increased (P less than or equal to 0.05) from 2 to 26% and to, 34%, in the CP and CBDV + CP treatment groups, respectively. Results of this study indicate the methodology employed provides a good model for studying NE.