Effect of coated organic acids on growth performance, Clostridium perfringens colonization, gut integrity and immune response in broilers challenged with subclinical necrotic enteritis.

Necrotic enteritis (NE) is considered a major enteric disease that compromises intestinal health and causes significant economic losses in broiler production. This study aimed to evaluate the effect of dietary coated organic acids (COA) supplementation on growth, Clostridium perfringens colonization, gut integrity, and immune response in broilers challenged with NE. A total of 420 one-day-old broilers were allocated to 30 cages for 28 days. Five treatments included a non-challenged control and four NE-challenged groups with different dietary COA supplementation levels (0, 0.1, 0.2, and 0.4 %). Birds in NE groups were challenged with Eimeria maxima on day 14 and C. perfringens on days 18 and 19. Major measurements included daily feed intake (FI); weekly body weight gain (BWG) and feed conversion ratio (FCR); intestinal C. perfringens load on days 20, 21, and 28; NE lesion score and gut permeability on days 20 and 21; and gene expression of tight junction proteins and cytokines in the jejunum on day 21. Results showed that increasing dietary COA dose-dependently improved FCR from day 0 to 14, with the lowest FCR observed at 0.1 % COA from day 7 to 14 (P < 0.05). Under NE, dietary COA linearly improved BWG and cumulative FI from day 14 to 28 and FCR from day 14 to 21 (P < 0.05). On day 21, dietary COA decreased intestinal C. perfringens loads, NE lesions, and gut permeability in a dose-dependent manner (P < 0.05). Additionally, dietary COA dose-dependently increased the expression of claudin-2 and zonula occludin-2 but decreased the expression of claudin-1, interleukin-1β, interferon-γ, and interleukin-10 (P < 0.05). These results indicate that dietary COA may improve early feed efficiency at a lower dose (0.1 %) and mitigate growth loss in NE-challenged broilers by reducing intestinal C. perfringens colonization and modulating gut integrity and immune responses in a dose-dependent manner. In conclusion, this study suggests that dietary COA could be a potential intervention to alleviate the adverse effects of NE and improve broiler productivity.