Nutritive value of marine oils. II. Effects ofin vivo antioxidants in feeding menhaden oil to swine

Five pair-groups of swine were fed diets composed of crude feed materials to which 10% of clay-bleached, light cold-pressed menhaden oil was added. The oil was allowed to oxidize under controlled conditions and aliquots of fresh and oxidized oil were removed at peroxide values (PV) of 2.6, 15.5, and 61—each of which was fed to one group of animals. Two additional animal groups received diets containing the highly oxidized oil (PV=61) plus either alpha-tocopherol acetate or ethoxyquin. All oils were stored frozen and were mixed with the diets daily. Lard was fed at a similar 10% level to a control group of pigs. Both feed intakes and weight gains were progressively reduced as the diet oil was more highly oxidized. As oxidation of the oil increased, intensity of “yellow fat” increased and hemoglobin and hematocrit levels were progressively decreased. Both alpha-tocopherol acetate and ethoxyquin actedin vivo to improve feed intake, rate of gain, and blood condition, and eliminated the incidence of steatitis. Paper I in this series appeared in the Journal of Nutrition79, 323–332 (1963). Carried out under Contract No. 14-17-0001-352, U.S.D.I. Bureau of Commercial Fisheries. Technical Paper 1615, Oregon Agricultural Experiment Station.