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

Abstract

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.

Keywords: Broiler; Coated organic acids; Gut health; Immune response; Necrotic enteritis.

Fig. 1

Effect of dietary coated organic acids supplementation levels on daily feed intake in broilers challenged with necrotic enteritis. Data are presented as a line graph with standard error of the mean (n = 6). NC, non-challenged control group with a basal diet; CC, NE-challenged control group with a basal diet; T1, NE-challenged group with diet containing 0.1 % COA; T2, NE-challenged group with diet containing 0.2 % COA; T3, NE-challenged group with diet containing 0.4 % COA. All birds in the NE-challenged groups (CC, T1, T2, and T3) were challenged with 10,000 sporulated oocysts of E. maxima on d 14 and 1 × 10⁹ CFU per mL of C. perfringens on d 18 and 19. All data were analyzed using one-way ANOVA followed by Tukey’s post hoc test (P < 0.05). Orthogonal polynomial contrast was applied among the NE-challenged groups (CC, T1, T2, and T3) to evaluate the linear and quadratic effects of dietary COA levels. A star (*) above the error bar indicates significant differences from ANOVA, and a star below the error bar indicates significant effects from polynomial contrast (*, P < 0.05; **, P < 0.01; ***, P < 0.001). Different letters (a, b) next to the legend indicate statistical differences (P < 0.05). NE, necrotic enteritis; COA, coated organic acids.

Fig. 2

Effect of dietary coated organic acids supplementation levels on the expression of tight junction-related genes in the jejunal tissue on day 21. (A) The expression of CLDN1. (B) The expression of CLDN2. (C) The expression of OCLN. (D) The expression of ZO1. (E) The expression of ZO2. (F) The expression of JAM2. Data are presented as a bar graph with standard error of the mean (n = 6). NC, non-challenged control group with a basal diet; CC, NE-challenged control group with a basal diet; T1, NE-challenged group with diet containing 0.1 % COA; T2, NE-challenged group with diet containing 0.2 % COA; T3, NE-challenged group with diet containing 0.4 % COA. All birds in the NE-challenged groups (CC, T1, T2, and T3) were challenged with 10,000 sporulated oocysts of E. maxima on d 14, 1 × 10⁹ CFU per mL of C. perfringens on d 18 and 19. All data were analyzed using one-way ANOVA followed by Tukey’s post hoc test (P < 0.05). Orthogonal polynomial contrast was applied among the NE-challenged groups (CC, T1, T2, and T3) to evaluate the linear (L) and quadratic (Q) effects of dietary COA levels (P < 0.05). Different letters (a, b) above the error bar indicate significant (P < 0.05). NE, necrotic enteritis; COA, coated organic acids; CLDN, claudin; OCLN, Occludin; ZO, zonula occludin; JAM, junctional adhesion molecule.

Fig. 3

Effect of dietary coated organic acids supplementation levels on the expression of immune-related genes in the jejunal tissue on day 21. (A) The expression of TNFα. (B) The expression of IL1β. (C) The expression of IL6. (D) The expression of IFNγ. (E) The expression of IL10. Data are presented as a bar graph with standard error of the mean (n = 6). NC, non-challenged control group with a basal diet; CC, NE-challenged control group with a basal diet; T1, NE-challenged group with diet containing 0.1 % COA; T2, NE-challenged group with diet containing 0.2 % COA; T3, NE-challenged group with diet containing 0.4 % COA. All birds in the NE-challenged groups (CC, T1, T2, and T3) were challenged with 10,000 sporulated oocysts of E. maxima on d 14, 1 × 10⁹ CFU per mL of C. perfringens on d 18 and 19. All data were analyzed using one-way ANOVA followed by Tukey’s post hoc test (P < 0.05). Orthogonal polynomial contrast was applied among the NE-challenged groups (CC, T1, T2, and T3) to evaluate the linear (L) and quadratic (Q) effects of dietary COA levels (P < 0.05). Different letters (a, b) above the error bar indicate significant (P < 0.05). NE, necrotic enteritis; COA, coated organic acids; TNF, tumor necrosis factor; IL, interleukin; IFN, interferon.