Inclusion of flax oil in diet supplemented with or without tea polyphenol increased omega-3 fatty acids in blood serum, subcutaneous fat, and longissimus dorsi muscle of fattening pigs

Flax oil (FO) is a major omega-3 source and can be used for increasing the amount of functional fatty acids in body tissues. Tea polyphenol (TP) from green tea can be applied as a natural antioxidant additive. A concurrent study found that inclusion of TP mixed with a sweetener to the diet increased the antioxidative capacity in blood serum and longissimus dorsi muscle of fattening pigs. The current study investigated the effect of including TP and a sweetener, FO, or both in the diet on body fatty acid profiles of fattening pigs. Forty castrated Large White pigs with an average BW of 62 kg were assigned to 4 groups (n = 10 per group) and fed, ad libitum, the following diets for 5 wk: 1) a control (CON), 2) the CON diet + 400 mg/kg TP and 200 mg/kg sweetener; 3) a 2% FO diet, and 4) the 2% FO diet + 400 mg/kg TP and 200 mg/kg sweetener. On the last day of the feeding study, 5 fasting blood samples were taken from each group. At slaughter, subcutaneous fat and longissimus dorsi muscle samples were taken from 4 to 6 pigs of each group for lipids extraction, methylation, and fatty acids analysis. Fatty acids methyl esters were analyzed using gas chromatography. Tt was found that inclusion of FO greatly increased (P < 0.01) weight percent of total n-3 fatty acids and individual 18:3n-3, 20:5n-3, and 22:5n-3 fatty acids, resulting in a reduced (P < 0.01) n-6:n-3 fatty acids ratio in blood serum, subcutaneous fat, and longissimus muscle. Supplementation of TP and sweetener did not (P > 0.05) affect either total and individual n-3 fatty acids or the n-6:n-3 fatty acids ratio, with exceptions: it reduced (P < 0.05) total n-3 fatty acids and increased (P < 0.05) the n-6:n-3 fatty acids ratio in blood serum when was added to the FO diet. In conclusion, inclusion of 2% FO in diets of fattening pigs significantly increased omega-3 fatty acids and reduced the n-6:n-3 fatty acids ratio, whereas inclusion of TP and sweetener did not affect these fatty acids in either subcutaneous fat or longissimus dorsi muscle. Together with results from our concurrent studies on meat quality and antioxidative capacity, these studies indicated that inclusion of FO plus TP mixed with a sweetener to the diet of fattening pigs could improve both meat omega-3 fatty acid levels and antioxidative capacity.