Effects of Fermented Grape Seed in Breeding-Pigeon Diets on Growth Performance, Immune Responses, and Oxidative...

This study evaluated the effects of graded fermented grape seed (FGS) supplementation in breeding-pigeon diets on the growth performance, immune responses, and redox status of squabs. Forty-eight healthy pairs of Gray King breeding pigeons were randomly assigned to four treatments, with 12 cages per treatment. Breeding pigeons received the experimental diets beginning 7 d before the expected hatch date. The basal diet was supplemented with 0, 10, 20, or 30 kg FGS per 1000 kg of diet (CON, FGS10, FGS20, and FGS30, respectively), and each pair reared three squabs until 28 d of age. Growth performance, carcass traits, meat quality, serum biochemical parameters, immunoglobulins, inflammatory cytokines, and serum and hepatic redox indices were evaluated. FGS supplementation affected body weight at 14 d of age and average daily gain (ADG) from 14 to 21 d and from 14 to 28 d of age (p < 0.05), but did not affect body weight at 28 d of age. FGS30 reduced ADG from 14 to 21 and 14 to 28 d and increased relative carcass yields, immunoglobulin A, G, and M levels, interleukin-10, tumor necrosis factor-α, aspartate aminotransferase, low-density lipoprotein cholesterol, and serum and hepatic malondialdehyde levels, while decreasing hepatic superoxide dismutase and glutathione peroxidase activities. FGS20 and FGS30 increased breast muscle L* values and press loss. FGS20 showed numerical advantages in several production traits, but increased breast muscle press loss and did not improve hepatic redox status. Overall, FGS supplementation in breeding-pigeon diets resulted in stage-specific and dose-related responses. FGS30 may exceed the appropriate inclusion range. Based on the present data, none of the tested supplementation levels can be considered optimal, and the range of 10-20 kg FGS per 1000 kg basal diet requires further validation.