Effect of the inclusion of natural additives on animal performance and meat quality of crossbred bulls (Angus × Nellore) finished in feedlot

The objective of this study was to evaluate the influence a finishing diet containing natural additives fed for 94 days on animal performance, carcass, and meat quality characteristics of crossbred bulls (1/2 Angus x 1/2 Nellore). Forty-eight bulls (initial BW 318 +/- 4.7 kg and initial age 22 months) were used in a completely randomised design. Bulls were fed one of four diets: (1) CON - Control; (2) CCO - addition of 4 g/animal.day of a mix of essential oils from castor bean and cashew; (3) MIX - addition of 4 g/animal.day of a mix of essential oils (oregano oils, castor bean, cashew); (4) YST - addition of 4 g/animal.day of yeast. Bulls were finished in feedlot (in individual pens) and slaughtered at an average weight of 469 +/- 6.7 kg. Final BW, hot carcass weight and average daily gain were greater (P < 0.05) in MIX diet than in the three other diets. However, DM intake, G : F, fat thickness, longissimus muscle area, marbling, and meat colour were similar (P > 0.05) among the four diets. The carcass conformation score was higher (P < 0.05) for bulls that were fed with the YST diet and similar for the three other diets. Meat from CCO had a reduced (P < 0.05) cooking loss when compared with CON diet. Shear force from MIX diet had lesser values (P < 0.05) than meat from YST diet, and it was similar among CON and CCO diets. There was no diet effect (P > 0.05) on lipid oxidation, moisture, ash, and total lipids contents. C14:0, C14:1 n-9, C16:0, C18:1 n-9, C18:1 n-7 and C18:3 n-6 fatty acids in intramuscular fat from the longissimus muscle were affected by the inclusion of additives in the diets. SFA, MUFA, PUFA, n-3 and n-6 fatty acid percentages, and the ratios PUFA : SFA and n-6 : n-3 were similar (P > 0.05) among diets. In conclusion, adding a mix of oregano, castor bean, and cashew oils in the diet improved the performance of the bulls, but meat characteristics did not significantly change.