Wheat levels have minor effects on the progression of coccidiosis in turkey poults

Coccidiosis, a major poultry disease caused by Eimeria species, compromises intestinal health and challenges nutrient utilization. Wheat is widely used in poultry diets worldwide and can serve as an effective alternative energy source. While several studies have highlighted the beneficial effects of wheat in poultry, evidence of its role under the Eimeria challenge remains limited. Therefore, this study was performed to better understand the effect of two dietary wheat levels on Eimeria-challenged turkey poults. A total of 240 one-day-old male turkey poults were divided into four treatments for 22 days. NC, non-challenged negative control receiving a diet with 0% wheat; T1, challenged and fed a diet with 0% wheat; T2, challenged and fed a diet with 15% wheat; T3, a group challenged and fed a diet with 30% wheat. The Eimeria challenge was accomplished on day 16. One-way ANOVA was performed, and the Tukey post hoc test was applied to determine significant differences among treatments. On d 22, the NC group had a higher body weight (682 g), and T1 had the lowest (562 g); Among the challenged groups, T2 showed the highest body weight (P < 0.0001). Ileal digesta viscosity increased linearly with wheat inclusion, whereas duodenum and cecal lesions were reduced with inclusion of wheat, and gut leakage was significantly lower in T2 compared to the other challenged treatments. Histological parameters differed among the treatments at d 22 in almost all parts of the intestine except the ileum, where birds fed wheat-containing diets showed greater ileal villus height than the 0% wheat challenged group. Eimeria infection markedly elevated proinflammatory cytokine expression in the jejunum and altered microbial communities in the ceca. Among the challenged groups, birds fed 30% wheat showed lower cecal lesion scores and differences in cecal microbial composition, including higher relative abundance of Bacteroidota and Bacteroidaceae and lower Bacillota at d 22. In conclusion, moderate wheat inclusion (15%) improved performance before Eimeria challenge. However, because body weight differences were already present before challenge and histology, gene expression, and microbiota were assessed only at d 22, post-challenge differences should be interpreted cautiously and cannot be attributed solely to dietary wheat effects on the response to Eimeria.