Abstract
This experiment evaluated the effects of feeding whole cottonseed (WC) and/or calcium salts of fatty acids (CSFA) on dry matter intake (DMI), performance, and carcass characteristics of Bos indicus animals receiving a high-concentrate diet during the finishing phase. On day 0, 96 Nellore bulls were blocked according to initial shrunk body weight (BW; 302 ± 26.7 kg) into group pens (4 animals/pen) and, within blocks, pens were randomly assigned to receive: 1) 15% of WC and 2% of CSFA [dry matter (DM) basis] of palm, cottonseed, and soybean oil (15WC; n = 6), 2) 10% of WC and 3% of CSFA (DM basis) of palm, cottonseed, and soybean oil (10WC; n = 6), 3) 5% of WC and 4% of CSFA (DM basis) of palm, cottonseed, and soybean oil (5WC; n = 6), and 4) 0% of WC and 5% of CSFA (DM basis) of palm, cottonseed, and soybean oil (0WC; n = 6). Diets were formulated to be isocaloric, isonitrogenous, and isolipidic. Experimental period lasted 108 days, whereas dry matter intake (DMI) was evaluated daily and blood samples and carcass measurements were obtained on days 0, 55, and 108 of the study. Upon slaughter on day 109, steaks were collected for determination of the chemical and fatty acid (FA) profile of the meat. No treatment effects (P ≥ 0.35) were observed on DMI, performance, average daily gain (ADG), carcass ultrasound measurements, and chemical variables of the steak. Nonetheless, including WC into the diets increased C12:0, C16:0, C16:1 trans-9, C17:0, C18:0, C18:1 cis-9, C18:2 cis-9,cis-12, C18:3 cis-9,cis-12,cis-15, saturated, and unsaturated FA intake (P < 0.01). Moreover, adding WC increased DMI fluctuation and feed efficiency (P = 0.03), but decreased marbling (P ≤ 0.03). A treatment × day interaction was observed (P < 0.01) for serum leptin concentration, as 10WC animals had greater leptin concentration on d 103 vs. other treatments (P < 0.01). Regarding steak FA profile, WC addition into the diet increased C18:2 cis-7,trans-9 and C18:3 cis-9,cis-12,cis-15 (P < 0.001), whereas saturated FA was quadratically affected (P = 0.02) and unsaturated FA was reduced for 15WC (P < 0.04). In summary, increasing levels of CSFA into isolipidic finishing diets containing WC did not negatively impact feedlot performance, but reduced feed efficiency and increased marbling scores of Bos indicus bulls, demonstrating its feasibility as a technology to improve carcass traits of low-marbling animals.
Effect of soybean oil availabilities on rumen biohydrogenation and duodenal flow of fatty acids in beef cattle fed a diet with crude glycerine
