Effect of Raw and Fermented Grape Pomace on the Growth Performance, Antioxidant Status, Intestinal Morphology, and Selected Bacterial Species in Broiler Chicks

SIMPLE SUMMARY: Grape pomace (GP) is a by-product of fruit juice and wine production. Owing to its biochemical composition and lower cost, GP has the potential to be a feed additive for poultry nutrition. However, its antinutritional compounds limit its usability in broiler diets. Fermentation is an ancient and useful method for the utilization of agricultural residues. The aim of the study was to investigate the effects of GP and Aspergillus niger-fermented grape pomace (FGP) on the growth performance, antioxidant capacity, intestinal morphology, and selected bacterial species in broilers. Dietary GP improved the antioxidant status and intestinal morphology of broiler chickens. Dietary FGP enhanced the growth performance, antioxidant capacity, and selected intestinal bacterial species of broilers. Dietary GP caused worsened growth performance compared with the synthetic antioxidants, although FGP had similar growth performance. The findings demonstrate that FGP can be an alternative to synthetic antioxidants for broiler diets. ABSTRACT: The effects of raw (GP) and fermented grape pomace (FGP) on the growth performance, some carcass parameters, antioxidant status, intestinal morphology, and selected bacterial species in broiler chicken were investigated in this study. Grape pomace was fermented with Aspergillus niger for 7 d. In total, 140 one-day-old male chicks (Ross 308) were randomly assigned to four treatment groups, with five replicates and seven birds each. Chickens were fed either a basal diet (CON) or the basal diet supplemented with 0.25 g/kg synthetic antioxidants (5% butylated hydroxytoluene, 1% butylated hydroxyanisole, and 11% ethoxyquin) (AO), or 15 g/kg GP (GP), or 15 g/kg FGP (FGP) for 42 d. Dietary GP raised serum glutathione peroxidase (p = 0.031) and superoxide dismutase (p = 0.021) levels, increased ileum lamina muscularis thickness (p = 0.016), and did not affect selected bacterial species in the cecum of broiler chickens. Dietary FGP improved body weight (p = 0.003), increased the serum catalase level (p = 0.032), and decreased the cecal Clostridium perfringens count (p = 0.033) but did not affect the ileal morphology of broiler chickens. The carcass parameters, malondialdehyde level, pH, and color of the breast meat of chickens were not changed by either GP or FGP supplementation. Chickens fed with the synthetic antioxidants had similar growth performance with the chickens fed with FGP but had better body weight (p = 0.003) and feed conversion ratio (p = 0.045) compared with the chickens fed with GP. The obtained results showed that FGP can be used as an alternative to synthetic antioxidants in broiler diets.