Influence of fish oil in finishing diets on growth performance, carcass characteristics, and sensory evaluation of cattle1

Abstract

Inclusion of fish oil, a source of n-3 fatty acids, in ruminant diets may fortify the fatty acid composition of meats and alter consumer perceptions of taste. Therefore, a 70-d study of 16 crossbred steers (441 +/- 31.7 kg of initial BW; 4 steers/pen; 2 pens/dietary treatment) consuming a high concentrate diet was conducted. Dietary treatments consisted of 1) control (75% corn, 11% soybean meal, and 10% cottonseed hull-based diet) and 2) the control diet with 3% fish oil replacing a portion of the corn. Steers were weighed on consecutive days at d 0 and 70 (i.e., the beginning and end of the trial), and interim weights were taken on d 28 and 56. On d 63, all steers were bled by jugular venipuncture to determine plasma fatty acid profiles. Steers were stratified by treatment and slaughtered on d 71 and 72. Fish oil supplementation decreased ADFI (13.97 vs. 11.49 kg; P < 0.01); however, it had no effect on ADG (P = 0.20) or G:F (P = 0.27). Fish oil supplementation increased (P < 0.01) the concentrations of MUFA, as well as linolenic and eicosapentaenoic acid in the plasma. Fish oil supplementation did not alter (P > 0.24) the color of the LM, LM area, yield grade, dressing percent, marbling, quality grade, or fat thickness. However, after extended (15 mo) storage at -20 degrees C, a professional descriptor panel discerned steaks from steers that had been supplemented with fish oil from a commercially available product or steaks from control steers. In summary, supplementation with fish oil decreased feed intake and subsequent HCW (P = 0.06) and had varying effects on sensory traits. Nevertheless, fish oil supplementation increased the proportions of n-3 fatty acids in the plasma, which may increase acceptability of the meat to the beef consumer.