There is increasing evidence showing that moderate amounts of insoluble dietary fiber can improve nutrient utilization by positively influencing the physiology of the gastrointestinal tract. The present study was conducted to investigate the effects of wheat bran as a source of insoluble fiber on nutrient digestibility, serum antioxidant status, gastrointestinal development, digestive enzyme activities and intestinal morphology in broiler chickens. A total of 96 one-day-old male Arbor Acre broiler chickens were assigned to two treatments with six replicate cages per treatment and eight birds per replicate for 42 d. Dietary treatments consisted of the control group (CON, control diet) and wheat bran group (WB, 30 g/kg wheat bran). Inclusion of WB increased (p < 0.05) the digestibility of dry matter, organic matter, gross energy and crude protein on Day 42. Birds fed WB had lower (p < 0.05) serum total cholesterol concentration on Day 21, and lower (p < 0.05) serum concentrations of low-density lipoprotein, total cholesterol and total triglyceride on Day 42. Inclusion of WB increased (p < 0.05) serum glutathione peroxidase activity on Day 21 and superoxide dismutase activity on Day 42, but tended (p = 0.07) to decrease serum malondialdehyde concentration on Day 21, and significantly decreased (p < 0.05) serum malondialdehyde concentration on Day 42. Birds fed WB had a greater (p < 0.05) relative weight of gizzard on both Day 21 and 42. Inclusion of WB increased (p < 0.05) activities of amylase and trypsin in pancreas and jejunal mucosa on Day 21, and increased (p < 0.05) amylase activity in pancreas and jejunal mucosa. Birds fed WB had greater (p < 0.05) villus height and villus height to crypt depth ratio in jejunum and ileum on Day 42. In conclusion, supplementation of 30 g/kg WB enhanced nutrient digestibility by improving antioxidant status, gizzard development, intestinal digestive enzyme activities and morphology of broilers.
Keywords: antioxidant status; broilers; digestive enzyme activities; gastrointestinal development; morphology; nutrient digestibility.