Effect of Dietary Chlorogenic Acid on Growth Performance, Antioxidant Function, and Immune Response of Broiler Breeders under Immune Stress and Stocking Density Stress

Abstract

The study was conducted to evaluate the effects of dietary chlorogenic acid supplementation on the growth performance, antioxidant function, and immune response of broiler breeders exposed to immune stress or high stocking density stress. The test was divided into two stress models. For the immune stress test, 198 birds were distributed into three experimental treatments with six replicates per treatment. The treatments were: (1) saline control (birds injected with saline and fed basal diet), (2) LPS group (birds injected with 0.5 mg LPS/kg body weight and fed basal diet), and (3) CGA + LPS group (birds injected with LPS and fed basal diet supplemented with 1 g/kg CGA. LPS was intraperitoneally injected from day 14, and then daily for 10 days. For the high stocking density stress model, 174 birds were distributed into three experimental treatments with six replicates per treatment. The treatments were: (1) controls (birds fed basal diet and raised at a stocking density of 14 broilers per m²), (2) high-density group (birds fed with basal diet and raised at a stocking density of 22 broilers per m²), and (3) high density + CGA group (birds fed with 1 g/kg CGA and raised at a stocking density of 22 broilers per m²). Results showed that LPS injection and high stocking density significantly decreased the body weight and feed intake of broiler breeders, while CGA supplementation increased feed intake of broiler breeders under LPS injection and high stocking density stress. Moreover, LPS injection and high stocking density increased the concentration of corticosterone in serum, and CGA addition remarkably downregulated serum corticosterone levels. The GSH level decreased with LPS injection and CGA increased the GSH concentration in the intestines of immune-stressed broiler breeders. LPS injection promoted the production of circulating proinflammatory cytokines (serum IL-1β and TNF-α) by 72 h after LPS injection. Dietary supplementation with CGA prevented the increase in serum TNF-α caused by LPS. These results suggest that dietary inclusion of 1 g/kg CGA could increase the feed intake of broiler breeders and alleviate the effects of inflammatory mediator stress and exposure to high stocking density.

Keywords: anti-inflammatory; antioxidant; chlorogenic acid; growth performance; stress.

Figure 1

Effects of chlorogenic acid on broiler performance challenged with immune stress and high density stress. (A) Body weight of broilers challenged with immune stress. (B) Body weight gain of broilers challenged with immune stress. (C) Feed intake of broilers challenged with immune stress. (D) Feed conversion ratio of broilers challenged with immune stress. (E) Body weight of broilers challenged with high density stress. (F) Body weight gain of broilers challenged with high density stress. (G) Feed intake of broilers challenged with high density stress. (H) Feed conversion ratio of broilers challenged with high density stress. a means significant difference between Saline and LPS groups, b means significant difference between LPS and CGA + LPS groups, c means significant difference between Saline and CGA + LPS groups, and * means significant difference between groups.

Figure 2

Effects of chlorogenic acid on serum corticosterone concentrations of broilers challenged with immune stress and high density stress. (A) Serum corticosterone concentrations after immune stress. (B) Serum corticosterone concentrations after high density stress. * means significant difference between groups.

Figure 3

Effects of chlorogenic acid on serum glutathione and malondialdehyde levels of broilers challenged with immune stress and high density stress. (A) GSH levels of broilers challenged with immune stress. (B) MDA levels of broilers challenged with immune stress. (C) GSH levels of broilers challenged with high density stress. (D) MDA levels of broilers challenged with high density stress. GSH = glutathione, MDA = malondialdehyde, * means significant difference between groups.

Figure 4

Effects of chlorogenic acid on intestinal glutathione levels of broilers challenged with immune stress and high density stress. (A) GSH levels of duodenum after immune stress. (B) GSH levels of jejunum after immune stress. (C) GSH levels of ileum after immune stress. (D) GSH levels of duodenum after high density stress. (E) GSH levels of jejunum after high density stress. (F) GSH levels of ileum challenged after high density stress. GSH = glutathione, * means significant difference between groups.

Figure 5

Effects of chlorogenic acid on serum cytokine levels of broilers challenged with immune stress and high density stress. (A) IL-1β levels of broilers challenged with immune stress. (B) TNF-α levels of broilers challenged with immune stress. (C) IL-1β levels of broilers challenged with high density stress. (D) TNF-α levels of broilers challenged with high density stress. IL = Interleukin, TNF-α = tumor necrosis factor-α, * means significant difference between groups.