摘要Grape seed proanthocyanidin(GSP)is a type of plant polyphenol with a wide variety of biological ac-tivities,such as antioxidant properties.This study investigated the effects of GSP supplementation on growth performance and meat quality in growing-finishing pigs.A total of 180 pigs(with an initial average body weight of 30.37±0.66 kg)were randomly assigned to five treatments:a control diet or a control diet supplemented with GSP at 15,30,60,and 120 mg/kg.Each treatment group comprised six replicate pens(6 pigs per pen).Results showed that GSP supplementation linearly increased the average daily gain(P=0.048)and quadratically decreased the feed intake to gain ratio(P=0.049)with the lowest values at 30 and 60 mg/kg GSP.Serum concentrations of immunoglobulins(Ig)(IgA,IgG,IgM),total antioxidative capacity,catalase,and total superoxide dismutase were elevated with the peak levels at 30 mg/kg GSP(P＜0.05).Serum glutathione peroxidase increased and malondialdehyde decreased quadratically(P＜0.05),with peak and trough levels at 120 and 60 mg/kg GSP,respectively.The GSP also improved dressing percentage and muscle redness(a*45 min)with optimal levels at 30 and 60 mg/kg(P＜0.05).Additionally,GSP supplementation quadratically reduced the muscle yellowness(b*24 h)and shear force(P＜0.05),with the lowest values at 120 mg/kg.The expression level of myosin heavy chain I in muscle was quadratically increased with maximum expression at 30 and 60 mg/kg(P=0.015).Furthermore,the expression levels of fatty acid synthase,phosphoenolpyruvate carboxykinase(PEPCK),and glucokinase in the muscle were decreased quadratically(P＜0.05)with the lowest values at 120 mg/kg.Additionally,GSP supplementation at 60 mg/kg upregulated the expression of hepatic hormone-sensitive triglyceride lipase and PEPCK(P＜0.05).These results suggest that GSP enhances carcass characteristics and meat quality in growing-finishing pigs,potentially through improved antioxidative capacity,modified muscle fiber type distribution,and altered glucose-lipid metabolism in muscle and liver.