Effects of different levels of dietary chlorogenic acid supplementation on growth performance, intestinal integrity, and antioxidant status of broiler chickens at an early age

This study was conducted to investigate effects of graded levels of chlorogenic acid (CGA) supplementation on growth performance, serum biochemical parameters, intestinal integrity, and antioxidant capacity of broilers at an early age. Two hundred and forty one-day-old male Arbor Acres broiler chicks were assigned to five groups with six replicates of eight birds each, and were fed a basal diet supplemented with 0 (Control group), 125, 250, 500, and 1000 mg/kg CGA for 14 days, respectively. The CGA administration linearly and quadratically increased body weight and weight gain and quadratically reduced feed conversion ratio (P < 0.05), and these effects were more pronounced when its dosage was 500 mg/kg (P < 0.05). The CGA supplementation especially at a level of 500 mg/kg linearly increased glucose concentration and quadratically lowered serum total cholesterol and triglyceride levels (P < 0.05). Dietary CGA administration linearly and quadratically reduced plasma diamine oxidase activity and D-lactate concentration (P < 0.05), and these effects were more prominent in 500 mg/kg CGA-supplemented group (P < 0.05). The CGA supplementation linearly increased the ratio between duodenal villus height and crypt depth and ileal villus height (P < 0.05). Moreover, supplementing 500 mg/kg CGA elevated the ratio of jejunal villus height and crypt depth when compared with the control group (P < 0.05). The CGA administration linearly and/or quadratically increased total antioxidant capacity (T-AOC), glutathione peroxidase, catalase, and superoxide dismutase activities and glutathione level, and decreased malondialdehyde concentration in serum, duodenum, and jejunum (except T-AOC activity and glutathione level in jejunum) (P < 0.05). Moreover, an addition of CGA linearly or quadratically increased T-AOC activity and glutathione level and reduced malondialdehyde concentration in ileum (P < 0.05). The beneficial effects of CGA on the antioxidant capacity in serum and intestinal mucosa were more apparent when its supplemental level was 500 mg/kg. The results suggested that CGA could improve growth performance, intestinal integrity, and antioxidant status of broilers at an early age, with its recommended dosage being 500 mg/kg.