Metabolismo dos compostos nitrogenados em ovinos alimentados com dietas contendo farelo de mamona destoxificado

Abstract

The study evaluated the effect of levels 0, 33, 67 and 100% of detoxified castor bean meal (DCBM) to replace soybean meal on nitrogen metabolism in diets for finishing sheep. The experimental design was randomized blocks in a split plot design (plot = levels of DCBM, and subplot = four collection times of ruminal liquid or blood: 0, 2.5, 5 and 7.5h), with five animals per treatment. No effect (p > 0.05) was verified on nitrogen metabolism parameters: N intake, Nfaeces, Nurinary, Nabsorbed and Nretained (g day-1) Nfaeces/N intake, Nurinary (%) and Nfecal/N urinary(g g-1) ratio and nitrogen balance (%), with means 26.70 ± 5.50, 8.73 ± 1.79, 2.17 ± 0.71, 17.96 ± 3.98, 15.78 ± 3.17, 32.90 ± 2.82, 7.89 ± 2.55, 5.08 ± 1.61 and 59.19 ± 4.68, respectively. The diets influenced (p < 0.05) pH and N-NH3 in ruminal fluid (RF) and blood urea concentrations, with interaction (p < 0.05) levels of inclusion of castor bean meal x collection times of RF and blood only for N-NH3 and urea concentrations. Detoxified castor bean meal can be used to replace soybean meal in diets for finishing sheep, as it has no influence on nitrogen metabolism, with stable rumen pH, concentration of N-NH3 in ruminal fluid and urea in blood serum in relation to normal physiological values for sheep. In this case, the level of inclusion of this co-product in diets of sheep should be done according to the economic feasibility of substitution.