Effect of dietary vitamin E supplementation on carcass and meat quality and oxidation stability of pork

The effect of addition of vitamin E to pig diet (200 mg per kilogram diet) on carcass and meat quality and susceptibility to oxidative deterioration was investigated on crossbreeds White meaty and Pietrain genetically defined on occurrence of mutation in RYR-1 gene connected with malignant hyperthermia. Control and experimental group (supplemented with vitamin E) consisted of equal number of sex and genotype Nn. Experiment started at live weight 30 kg and lasted to live weight 100 kg. Both groups were fed with complete feed mixture with nutritional values 18.1% nitrogen, 0.89% lysine and 12.6 MJ metabolizable energy. Experimental pigs were supplemented with 200 mg vitamin E (fi. Slovakofarma, Hlohovec, Slovak Republic) per kilogram of feed mixture daily during two months to final live weight. After slaughter of pigs (live weight 100 kg) values such as percentage of valuable lean meat cuts, percentage of belly and fat cuts, dressing and lean meat content were estimated in carcass side. Following meat quality traits were estimated: - 45 min after slaughter pH values in m. longissimus dorsi (between 13th-14th rib), m. semimembranosus and m. semitendinosus (in the middle); - 2 hours after slaughter electrical conductivity in m. longissimus dorsi and m. semimembranosus; - after 24 hours of chilling in samples of m. longissimus dorsi free water, drip loss, shear force, total water and proteins, intramuscular fat. Thiobarbituric acid reactive substances were estimated in m. longissimus dorsi after one and five days. Statistical analyses were calculated as mean values, standard error and differences were evaluated by t-test. Content of vitamin E assessed in musculus longissimus dorsi is significantly higher in the experimental group (2.73 mg vs. 1.71 mg per kilogram of muscle in the control group). Differences between the groups in carcass data were not significant, but higher percentage level of shoulder in experimental pigs was significant. Results showed that the pH-values of meat and electrical conductivity were not significantly influenced after the application of higher amount of vitamin E additive into the feed mixture. Marked differences between groups were not found in physical and chemical parameters of the meat quality (total water, water holding capacity, total proteins, intramuscular fat). Measured values of shear force and drip losses can point out the positive effect of vitamin E on stability on cell membranes after 24-hours and after five days storage in a cool place. The lower value of differences of remission (630-580 nm) after five days storage in a cool place suggest the improving oxidation - reduction state of myoglobine. Content of thiobarbituric acid reactant substances are in the experimental group more favourable after five days, which suggests the increased oxidation stability in pork