Effect of flaxseed oil, poultry fat, and vitamin E supplementation on physical and organoleptic characteristics and fatty acid profile of pork, and expression of genes associated with lipid metabolism

A total of 96 pigs (Yorkshire; 54.3 ± 3.4 kg body weight) were used to investigate the effect of dietary lipid (0 or 1% flaxseed oil + 1, 3, or 5% poultry fat for the diets supplemented with lipids) and vitamin E (11 or 220 IU vitamin E/kg) supplementation in a 4 × 2 factorial arrangement of treatments on the physical and organoleptic characteristics and fatty acid (FA) profile of pork, and the expression of genes associated with lipid metabolism. Forty-eight pens containing 2 gilts or 2 castrated males were randomly assigned to 8 treatments with 3 gilt pens and 3 castrated male pens per treatment. Pigs were harvested when they reached approximately 110 kg. Muscle and adipose tissue samples at the last rib were collected to determine the expression of genes associated with lipid metabolism. Loin muscle samples were collected for the determination of the physical and organoleptic characteristics and FA profile of pork. The percentage of the saturated FA and monounsaturated FA decreased linearly (P < 0.012), while the percentage of ω-6 polyunsaturated FA (PUFA), total PUFA, and C18:2ω6c increased linearly (P < 0.001) as dietary lipids increased. Flaxseed oil supplementation increased C18:3ω3, Cc20:3ω3, and C20:5ω3, and decreased the ω-6 to ω-3 FA and the linoleic acid to α-linolenic acid ratios (P < 0.001). The content of ω-3 PUFA or highly unsaturated ω-3 FA was greatest in pigs fed the diet containing 2% lipids (quadratic, P < 0.001). Serum α-tocopherol content was greater (P < 0.001) in pigs fed the diet containing 220 IU than those fed the diet containing 11 IU vitamin E/kg. Dietary lipid supplementation had no effect on serum α-tocopherol content. Dietary treatments had no effects on Warner-Bratzler shear force, cooking loss, lipid content, and thiobarbituric acid reactive substance content of the loin muscle. Similarly, no major differences were observed on the organoleptic characteristics of pork or the expression of genes associated with lipid metabolism. In conclusion, feeding flaxseed oil and poultry fat to finisher pigs was effective in improving the nutritional value of pork as indicated by ω-6 to ω-3 FA ratio without negatively affecting organoleptic characteristics or oxidative stability of pork.