Supplementation of grape pomace (Vitis vinifera) in broiler diets and its effect on growth performance, apparent total tract digestibility of nutrients, blood profile, and meat quality

This experiment was conducted to explore the efficacy of grape pomace (Vitis vinifera) on growth performance, apparent total tract digestibility of nutrients, blood profile, and meat quality in commercial broilers. Four hundred broiler chicks (3-d-old) were randomly allotted to 4 dietary treatments for 28 d. Each treatment had 5 replicates with 20 birds per replicate. The dietary treatments were 1) control, 2) 5 g/kg grape pomace (GP), 3) 7.5 g/kg GP, and 4) 10 g/kg GP supplemented in diets after drying. Supplementation of GP did not show linear effects (P > 0.05) on body weight (BW) gain, however, quadratic effects (P < 0.05) on BW gain were observed during d 0 to 7 and d 8 to 14. Body weight gain, feed intake, and feed conversion ratio remained unaffected during d 22 to 28 and overall period. The nutrient digestibility studies conducted at the end of the feeding trial did not show (P > 0.05) any effect due to GP supplementation, except a quadratic trend (P = 0.07) for digestibility of ash was observed. Serum levels of glucose, triglyceride, and high-density lipoprotein cholesterol were not affected (P > 0.05), however, total cholesterol and serum immunoglobulin G levels showed quadratic effects (P < 0.05) due to GP supplementation. The thio-barbituric acid reactive substances values in breast meat linearly decreased (P < 0.01) in supplemented groups at 0, 5, and 10 d of storage showing linear effects due to GP supplementation, and quadratic effects were also observed at 5 and 10 d of storage. The meat color value such as redness was also decreased (P < 0.05) in supplemented groups showing both linear and quadratic effects. Overall, it could be concluded that GP supplementation showed quadratic effects on BW gain during early growth stages and was effective in reducing serum cholesterol level and improving meat quality parameters in broilers. Keywords: Broiler, Digestibility, Growth, Immunity, Meat quality, Grape pomace