Changes on meat fatty acid profile, cholesterol and hepatic metabolism associated with antioxidants and canola oil supplementation for Nellore cattle

Abstract

This study investigated the effect of canola oil supplementation associated with vitamin E and selenium on cholesterol and liver metabolism and meat fatty acid profile of Nellore cattle. Forty-eight Nellore bulls were randomly assessed to were randomly distributed in a 2 × 2 factorial arrangement: two levels of oil in the diet (no inclusion and 3% canola oil, defined as NO and OIL, respectively) and two levels of antioxidants in the diet (no inclusion and 2.5 mg of Se/kg of dry matter (DM) + 500 UI of vitamin E/kg of DM, defined as NA and ANT, respectively). Blood samples were collected at the beginning (day 0) and at days 28, 56 and 84 of the finishing periods for selenium, total cholesterol and its fractions and triglycerides quantification. After slaughter, liver samples were obtained from each animal to analyze the activity of reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione peroxidase (GSH-Px) and TBARS (substances reactive to 2-thiobarbituric acid). Additionally, 5 g of Longissimus thoracis (LT) were collected for evaluation of cholesterol, ethereal extract and fatty acids profile. Serum selenium concentration has a quadratic increase by antioxidant treatments according to the days on feed. Animal fed ANT presented a better liver antioxidant status, improving the activity of GSSG, GSH-Px, decreasing GSH, TBARS values and decreased the cholesterol concentration in the LT. As well as, decreased cholesterol and LDL-cholesterol in blood serum. Addition of 3% canola oil in diets for cattle improved fatty acid profile in meat and associated with antioxidants (selenium and vitamin E) increased antioxidants status and promoted reducing the cholesterol concentration in meat and serum. Supplementation with canola oil increased unsaturated, decreased saturated fat, increased the amount of n-3 and conjugated linoleic acid (CLA) meat content, and improved the n6/n-3 ratio. As consequence, the supplementation with canola oil and antioxidants in Nellore cattle diet can be a potential strategy to provide meat for human consumption with better lipids content in beef meat, with higher n-3 and lower cholesterol, which might impact positively the meat consumers health.