Análises químicas e instrumentais de carcaças de bovinos suplementados com torta de mamona

Abstract

The aim of this study was to evaluate the substitution levels of soybean meal for castor bean cake in the supplementation of cattle grazing Brachiaria decumbens, regarding the carcass characteristics and the fatty acids profile of the Longissiumus dorsi muscle. Therefore, it was used 32 half-breed cattle in the termination phase, the initial body weight was 330 ± 52,30 kg and age mean of 36 months, maintained in a total area of 28 hectares, divided in 4 paddocks of 7 hectares each, grazing Brachiaria decumbens, in an 84 days period. The diets were calculated to supply the requirements for maintenance weight gain of 0,8 kg/day according to BR – Corte (2010). All the diets were calculated to obtain an isonitrogenous diet, with 15,00% of crude protein. The supplement was provided in even quantities to 0,5% of the body weight for all the sizes, daily feed was at 11 am, in a collective trough. The experimental design adopted was entirely randomized with four treatments and eight replications composed of substitution levels of the soybean meal for castor bean cake in the concentrate in the following way: 0 – Concentrate with 0% of substitution of the soybean meal for the castor bean cake; 33 – Concentrate with 33% of substitution of the soybean meal for the castor bean cake; 67 – Concentrate with 67% of substitution of the soybean meal for the castor bean cake; 10 – Concentrate with 100,0% of substitution of the soybean meal for the castor bean cake. There was no difference (P>0,10) on the morphometric parameters between the treatments. In the chemical composition of the carcass of the Longissimus dorsi the concentration means of dry matter, humidity, organic matter, crude protein, and ether extract did not presented effect in the diet. There was no effect in the diet on the saturated fatty acids composition, with exception of the arachidonic acid that revealed a crescent linear effect, increasing from 0,38% in the control diet to 0,46% in the diet with 100% protein substitution of the soybean meal for protein from the castor bean cake. Only a percentage of the muscle presented quadratic effect on the experimental diets, not being observed effect on the other characteristics of the carcass analyzed. The substitution of the soybean meal for the castor bean cake in levels up to 100% of substitution in the beef cattle supplementation finished on pasture, do not promote significant effect on the quantitative and qualitative parameters related to the carcass characteristics of carcass or the fatty acids profile in the Longissimus dorsi muscle.