Subclinical Doses of Combined Fumonisins and Deoxynivalenol Predispose Inoculated Broilers to Necrotic Enteritis.

Fumonisins (FB) and deoxynivalenol (DON) are mycotoxins which may predispose broiler chickens to necrotic enteritis (NE). The objective of this study was to identify the effects of subclinical doses of combined FB and DON on NE. A total of 480 day-old male broiler chicks were divided into four treatment groups; 1) control group (basal diet + ); 2) necrotic enteritis group (basal diet + ); 3) FB + DON group (basal diet + 3 mg/kg FB + 4 mg/kg DON + ); and 4) FB + DON + NE group (basal diet + 3 mg/kg FB + 4 mg/kg DON + ). Birds in NE and FB + DON + NE groups received 2.5 × 10 on day 14. All birds were inoculated with on days 19, 20, and 21. On day 35, birds in the NE, FB + DON, and FB + DON + NE groups had 242, 84, and 339 g lower BWG and a 19-, 2-, and 22-point increase in FCR respectively, than in the control group. Subclinical doses of FB + DON increased ( < 0.05) the NE lesion scores compared to the control group on day 21. On day 21, birds in the NE, FB + DON, and FB + DON + NE groups had increased ( < 0.05) serum FITC-D, lower ( < 0.05) jejunal tight junction protein mRNA, and increased ( < 0.05) cecal tonsil IL-1 mRNA compared to control group. On day 21, birds in the NE group had decreased ( < 0.05) villi height to crypt depth ratio compared to the control group and the presence of FB + DON in NE-induced birds further decreased the villi height to crypt depth ratio. Birds in the NE, FB + DON, and FB + DON + NE groups had increased ( < 0.05) , lower ( < 0.05) loads in the cecal content, and a lower ( < 0.05) CD8: CD4 cell ratio in the cecal tonsils compared to the control group. It can be concluded that subclinical doses of combined FB and DON predispose inoculated birds to NE, and the presence of FB + DON in NE-induced birds exacerbated the severity of NE.