ABSTRACT The effects of diets containing oilseeds were measured to evaluate the productive and economic parameters in the finishing of young, feedlot Nellore bulls. Twenty-four young Nellore bulls were used, with an initial body weight (BW) of 311.46±0.37 kg and 24 months of age, distributed into individual stalls ( 4 × 20 m) in a completely randomized design, totaling four treatments with six repetitions per treatment. Four diets (control, based on corn and soybean meal, and three diets containing cottonseed, soybean, and sunflower) were evaluated. Feed and orts were measured daily to calculate intake and costs. The dry matter intake of the control group was higher than soybean (10.64 kg/day), cotton (9.88 kg/day), and sunflower (9.30 kg/day) treatments, respectively. The cottonseed treatment showed the highest average neutral detergent fiber intake. There was a dietary effect of diets on average daily gain, total weight gain, and final weight. The soybean treatment showed the highest performance, total gain (232.55 kg), and final weight (544.38 kg). Oilseed intake can modify the fatty acids profile in the meat, decreasing its saturated fatty acid content. Whole soybean seed favors performance, improves feed efficiency, fatty acid profile, and fat distribution in the carcass, and can reduce production costs.

Abstract We hypothesize that lambs fed diets with different lipids sources from oilseeds would similar performance but fatty acids profile of meat superior to those fed with conventional diets. We evaluated the effects of inclusion of oilseeds on the ingestive behaviour, performance, carcass trait and meat quality in feedlot lambs. Three isonitrogenous (18.31% crude protein) diets were evaluated, where one diet was the standard (control), and the others two diets contained soybean and cottonseed. Fifteen Texel lambs, weighting 28.5 ± 1.65 kg were distributed in a completely randomized design by 56 days. Animals fed soybean diet demonstrated greater final body weight when compared to animals fed cottonseed diet and standard diet. The inclusion of cottonseed provided lower average daily gain and total weight gain. Ingestive behaviour of the animals fed diets with grains resulted in greater rumination time. Lambs fed cottonseed diet spent greater time during rumination and presented greater number of chews/day. The hot carcass and cold carcass weight presented lower values in animals fed cottonseeds diet. There was no significant difference in meat for marbling, maturity, fat texture and shear force. Meat from animals fed soybean diet had highest fat content. There was a diet effect for fatty acids composition in the meat. Meat of lambs treated with soybean have greater amounts for fatty acids mostly the unsaturated ones, related to the decrease in cholesterol levels, and lower risk of cardiovascular diseases, thus, lambs fed soybean enrich meat produced with fatty acids that benefit human health.