Palma forrageira em substituição à cana-de-açúcar para ovinos em terminação

Abstract

The effects of replacement of sugarcane by spineless cactus (0; 33; 66 and 100% on dry matter (DM) basis) were evaluated on intake, digestibility of nutrients, ingestive behavior, performance, leg tissue composition, carcass characteristics, weight and yield of meat cuts, physicochemical characteristics and fatty acid profile of lamb meat. Thirty-six non-castrated Santa Ines lambs at four months of age and an initial body weight of 22 ± 2.3 kg were assigned in a randomized block design. A quadratic effect was found for intake of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), and digestible organic matter (DOM), with maximum values of 1.31, 1.19, 0.219, 0.358, and 0.845 g/day estimated with 42.5, 38.5, 38.8, 21.3, and 44.9% replacement level, respectively. The digestibility of DM, OM, CP, and EE increased linearly; however, there was a quadratic effect on NDF digestibility with maximum value estimated of 500 g/kg with 64.2% replacement level. Rumination time, total chewing, and rumination efficiency decreased linearly with the replacement levels; however, idle time increased linearly. A quadratic effect was found for final weight, body weight gain, and total weight gain with maximum values estimated of 38.6 kg, 0.232 kg/day, and 16.2 kg with 39.1, 38.2 and 40.4% replacing levels. It was observed a quadratic behavior to body weight at slaughter, empty body weight, hot and cold carcass weight with maximum values of 38.60; 32.76; 18.60; and 18.11 kg obtained with replacement levels of 38.60; 45.73; 44.42; and 43.14%, respectively. Hot and cold carcass yields presented an increasing linear behavior and the biological yield presented a quadratic behavior. The compactness index of carcass and leg presented a quadratic effect with estimated maximal values of 0.28 and 0.57 kg/cm with replacement levels of pectively. The weights of commercial cuts of leg, loin, shoulder, and saw showed a quadratic behavior with maximum values of 2.79; 0.852; 1.46; and 1.30 kg obtained with replacement levels of 49.5; 45.32; 39.0; and 40.7. For tissue composition, it was verified a quadratic behavior for leg weight, subcutaneous fat and total fat. Replacing sugar cane by spineless cactus had no effect on the physicochemical characteristics and chemical composition of meat. Total saturated fatty acids were not affected by the replacement levels, except to stearic acid that linearly increased. Except to vaccenic acid that linearly increased, there was a linear reduction in the palmitoleic and oleic acids and the total concentration of monounsaturated fatty acids. Among the polyunsaturated fatty acids, linolelaidic acid showed a quadratic effect with minimum estimated value of 6.09% with 36.5% replacement level. There were no effect of the saturated fatty acids, monounsaturated and polyunsaturated ratios. However, the cholesterol content of the meat linearly increased as the spineless cactus levels. The replacement of sugarcane by spineless cactus at levels ranging from 44 to 50% is recommended for finishing lambs.