Effects of dietary flaxseed oil with or without products with antioxidant properties on pig performance, carcass characteristics, meat quality and oxidative stability

Context. The inclusion of natural products with antioxidant properties in animal diets as well as the use of different lipid sources has been tested to improve the nutritional quality of meat. Aim. The aim of this work was to compare natural products with antioxidant properties and vitamin E in swine diets containing flaxseed oil. Methods. Ninety-six animals were allocated to six treatments: control diet (C), diet with 3% flaxseed oil (F), diet with 3% flaxseed oil + 10% grape pomace (FGP), diet with 3% flaxseed oil + 0.0022% grape seed extract (FGE), diet with 3% flaxseed oil + 5% Nile tilapia carcass hydrolysate (FH), and diet with 3% flaxseed oil + 200 ppm vitamin E supplement (FVitE). Key results. The treatments had no effect on growth performance or serum total antioxidant status, while low-magnitude effects on carcass traits were observed. The addition of flaxseed oil to the diet increased the omega-3 and total polyunsaturated fatty acid concentrations and decreased saturated fatty acid and monounsaturated fatty acid concentrations in meat; high concentrations of total tocopherol were observed in the treatments FVitE, FGE, and FH, while a higher oxidative stability (Rancimat (R)) of backfat was observed for the treatment FVitE. The thiobarbituric acid-reactive substances assay and the sensory evaluation of mini-burgers revealed that vitamin E was the most efficient antioxidant throughout the storage, although the treatments FH and FGE have presented a mild effect. Conclusions. Problems of oxidative stability of pork resulting from including flaxseed oil in the diet of pigs due to increases in omega-3 fatty acids were better overcome by dietary vitamin E than by the use of the other natural antioxidants assessed here. However, this study also demonstrated that both the tilapia hydrolysate and grape seed extract have potential to be used as natural antioxidants, although further studies are required.