Effect of 125% and 135% arginine on the growth performance, intestinal health, and immune responses of broilers during necrotic enteritis challenge

The objective of this study was to evaluate the effects of 25% and 35% arginine supplementation in partially alleviating the effects of necrotic enteritis (NE) challenge on the production performance, intestinal integrity, and relative gene expression of tight junction proteins and inflammatory cytokines in broilers. Four hundred and eighty one-day-old chicks were randomly allocated to the 4 treatments- Uninfected + Basal, NE + Basal, NE + Arg 125%, and NE + Arg 135%. NE was induced by inoculating 1 × 104 Eimeria maxima sporulated oocysts on day 14 and 1 × 108 CFU/bird C. perfringens on days 19, 20, and 21 of age by oral gavage. The NE challenge significantly decreased body weight gain (BWG) (p < 0.05) and increased the feed conversion ratio (FCR) (p < 0.05). On day 21, the NE challenge also increased the jejunal lesion score (p < 0.05) and relative gene expression of IL-10 and decreased the expression of the tight junction proteins occludin (p < 0.05) and claudin-4 (p < 0.05). The 125% arginine diet significantly increased intestinal permeability (p < 0.05) and the relative gene expression of iNOS (p < 0.05) and IFN-γ (p < 0.05) on day 21 and the bile anti-C. perfringens IgA concentration by 39.74% (p < 0.05) on day 28. The 135% arginine diet significantly increased the feed intake during days 0 – 28 (p < 0.05) and 0 - 35 (p < 0.05) and increased the FCR on days 0 - 35 (p < 0.05). The 135% and 125% arginine diet increased the spleen CD8+: CD4+ T-cell ratio on days 28 (p < 0.05) and 35 (p < 0.05), respectively. The 135% arginine diet increased the CT CD8+:CD4+ T-cell ratio on day 35 (p < 0.05). In conclusion, the 125% and 135% arginine diets did not reverse the effect of the NE challenge on the growth performance. However, the 125% arginine diet significantly increased the cellular and humoral immune response to the challenge. Hence, the 125% arginine diet could be used with other feed additives to improve the immune response of the broilers during the NE challenge.