Effect of flaxsee d and alpha tocopherol supplementation of pig diets on fatty acid content and lipid oxidation stability of m. Longissimus

The experiment was carried out with 70 fattening hybrid pigs - 45-110 kg divided into 5 groups of 14 - 7 castrated males and 7 females. Pigs were fed compound feed containing 13.24% CP and 12.04 MJ ME/кg. During the last two months of the fattening period 78–120 kg the compound feed of pigs from groups ІІ, ІІІ, ІV and V experimental was supplemented with flaxseed at different levels: group II – 4%, group III – 8%; groups IV and V – 12%. The feed of pigs from group V was also supplemented with vitamin E - alpha tocopherol acetate at 200 mg/kg. Pigs were slaughtered at 120 kg live body weight. The fatty acid contents of triacylglycerols and phospholipids were determined in m. Longissimus samples. Oxidative changes in m. Longissimus meat were assessed in fresh samples and in samples stored at –18°С for 6 months. Linolenic acid content of triacylglycerols increased in experimental groups, being statistically significant higher in group II - Р0.01, III, IV and V Р0.001 vs group I. Linoleic acid concentrations also differed between groups II and III Р0.05, group II and both groups IV and V Р0.001 and groups III and IV Р0.01. Compared to control pigs, eicosapentaenoic acid content in tissue triacylglycerols was higher in group III Р0.05, IV and V Р0.01. Significant differences were also established in groups IV and V vs group II Р0.05. Linoleic acid content decreased in group III vs group I Р0.05 and group II Р0.01, whereas arachidonic acid changed only slightly. The PUFA content was also insignificantly altered. Compared to the non-supplemented group, the PUFA/SFA ratio was substantially higher in groups II, IV and V - Р0.01 and III - Р0.05. The n-6/n-3 ratio in groups III, IV and V was significantly lower than that of groups I and II Р0.001. The difference between groups I and II was also considerable Р0.001. Linolenic acid in tissue phospholipids of group III was significantly more than that in groups I Р0.01 and II Р0.05. In groups IV and V, the content f this fatty acid was higher than that in groups I, II Р0.001 and III Р0.01. The eicosapentaenoic acid in groups IV and V was considerably higher than that in control Р0.05. There were no statistically significant differences between groups with regard to fatty acid groups. The n-6/n-3 ratio was lower in group II vs group I Р0.05 and in groups III, IV and V Р0.001 vs group I. The differences between groups IV and V vs group II were also important Р0.01. The high content of PUFA in tissue lipids resulted in significantly higher thiobarbituric acid number in both fresh and stored meat.