Effect of whole wheat feeding on selected immune parameters in growing male turkeys.

The objective of this study was to determine the effect of whole wheat feeding on selected parameters of humoral and cell-mediated immunity in growing turkeys. A total of 210 one-day-old heavy-type Hybrid Converter male turkeys were randomly divided into three different dietary treatment groups, each consisting of 7 replicate pens of 10 birds per pen. Until 4 wk of age, all birds were fed a commercial diet formulated to meet nutrient requirements. From 5 to 12 wk of age, diets were composed of wheat (ground-pelleted or whole grain) and protein-fat-mineral-vitamin concentrate. The total wheat concentration in diets was 500 or 600 g/kg in the feeding periods of 5-8 and 9-12 wk of birds' age, respectively. Whole grain wheat had a 0, 50 or 100% share of the total wheat amount in the daily ration in treatment groups W0, W50 or W100, respectively. Commercial vaccines against ND (Newcastle disease) and TRT (Turkey rhinotracheitis) were administered to turkeys via the drinking water on days 20 and 30, respectively. Over the entire experiment, a significant linear decrease was observed in body weight gains (BWG) with increasing dietary levels of whole grain wheat. As a result the BWG of control turkeys (W0) were significantly higher than the BWG of group W100 birds (P = 0.002). A significant linear increase in feed conversion ratio (FCR) was observed with increasing dietary levels of whole grain wheat (P < 0.001). The levels of antibodies against TRT and ND viruses after immunization were significantly higher in both the W50 and W100 group, in comparison to group W0 (P = 0.006 and P = 0.001, respectively). Turkeys from group W50, in comparison to those from groups W0 and W100, had a significantly higher percentage of CD4+ T cell subpopulation within the lymphocytes isolated from blood and ileal mucosa, as well as CD4+ CD8+ and CD8+ T cell subpopulations within the blood immunocompetent cells (P = 0.022, P = 0.029, P = 0.009 and P = 0.011, respectively). In the cecal tonsils, the percentage of CD8+ T cell subpopulation was significantly lower in group W50 than in groups W0 and W100 (P = 0.014). The results of our study indicate that diluting diets with whole grain wheat stimulates the non-specific cell-mediated defense mechanisms of the gastrointestinal immune system in turkeys, thus positively affecting humoral response after vaccination.