Effect of supplemental vitamin E on the performance of growing-finishing pigs fed stored versus freshly harvested barley and on the storage stabilityand eating quality of frozen pork

A 2 x 4 factorial experiment was conducted with 80 growing-finishing pigs t o evaluate effects of barley storage (stored barley harvested the previous year or freshly harvested barley) and supplemental vitamin E (0, 40, 80 or 160 mg/kg as all-rac-alpha-tocopheryl acetate) on pig performance and the s torage stability and eating quality of frozen pork. Pigs were fed isoenerge tic barley-soybean meal diets and vitamin E was rationed on the top of feed , a 2-d dose at a time. Stored and freshly harvested barley contained 33.5 and 31.2 mg/kg of vitamin E in the beginning and 33.0 and 38.7 mg/kg at the end of the study, respectively. Supplemental vitamin E had a quadratic eff ect on pig growth (P < 0.05), the greatest weight grains being observed wit h 40 mg/kg of supplemental vitamin E in both barley diets. Vitamin E supple mentation increased linearly serum (P < 0.001) and quadratically back fat a -tocopherol (P < 0.01). Plasma gluthathione peroxidase activity increased a s pigs grew older (P < 0.001), and at slaughter it decreased linearly with supplemental vitamin E (P < 0.05). Dietary vitamin E supplementation did no t affect the content of thiobarbituric acid reactive substances (TBARS) or the organoleptic quality of pork stored frozen (-18 degrees C) for 16 weeks . The TEARS content of pork increased with time (0 to 8 d) thawed meat was displayed under fluorescent light at 8 degrees C (P < 0.001) which was dete cted as a poorer taste. In conclusion, supplemental dietary vitamin E above 40 mg/kg feed does not improve pig performance nor the storage stability o r eating quality of frozen pork when freshly harvested or stored barley fro m good harvest conditions is fed to growing-finishing pigs.