Effects of Grape Seed Proanthocyanidin Extract (Vinox) on Growth Performance, Immune Indices, Antioxidant Status, and Oxidative Stress in Broiler Chickens

Abstract

Natural polyphenolic antioxidants are increasingly investigated as alternatives to synthetic antioxidants and antibiotic growth promoters in poultry nutrition. Objective: This study evaluated the effects of dietary grape seed proanthocyanidin extract (GSPE; Vinox) on growth performance, antioxidant status, oxidative stress, and selected immune-related indices in Ross 308 broiler chickens.  Birds were allocated to four dietary treatments: basal diet, basal diet plus 0.05% Vinox, basal diet plus 0.10% Vinox, and basal diet plus 0.15% Vinox. The experimental allocation was four treatments with three replicate pens and 10 birds per pen. Growth performance was recorded through 42 days. Serum superoxide dismutase (SOD), glutathione peroxidase (GPx), ferric reducing antioxidant power (FRAP), and malondialdehyde (MDA) were assessed on days 28 and 42, together with relative bursa and spleen weights and peripheral lymphocyte percentage. Data were analyzed using a general linear model and Duncan's multiple-range test. Dietary 0.10% and 0.15% Vinox were associated with greater average daily gain and lower feed conversion ratio than the basal diet (p < .05), whereas feed intake did not differ significantly. Vinox supplementation increased SOD, GPx, and FRAP and decreased MDA. Relative bursa and spleen weights and lymphocyte percentage were also higher in supplemented groups. Under the reported experimental conditions, dietary GSPE was associated with improved growth efficiency, antioxidant status, and selected immune-related indices. These findings should be interpreted cautiously because the experimental protocol did not permit complete separation of dietary effects from the IBD vaccination procedure.