The objective of the present study was the fractionation and the degradation kinetics of the nitrogenous compounds and of the carbohydrates of the sugar cane, poultry litter and cottonseed meal. The non-protein nitrogenous compounds, soluble and insoluble nitrogen in borate-phosphate buffer, neutral detergent and in acid detergent insoluble protein nitrogen were analyzed for the determination of the nitrogen fractions. The degradation rates of the protein fractions were obtained by the In vitro incubation of the feeds with proteases isolated from ruminal ambient. The total carbohydrates, and its fractions C, B2 and the soluble neutral detergent components were calculated for the determination of the carbohydrates using the Cornell system. The potentially degradable (B2) and undegradable (C) fractions of the neutral detergent fiber, corrected for ashes and protein, and the lag dynamic rates, of degradation and of specific microbial growth, from the fraction B2, were determined. Besides, the coefficient of degradabilities and of the NDF ruminal repletion effect of the feeds, were also determined. The values of 71.01; 45.80 and 71.66% of the fraction B2 of the nitrogenous compounds were observed for sugar cane, poultry litter and cottonseed meal, respectively. The poultry litter stood out for the highest B3 and C fraction (23.57 and 10.11%). The B3 fraction degradation rates were of 0.03; 0.031 and 0.09 h-1 for sugarcane, poultry litter and cottonseed meal, respectively. The fraction C of the carbohydrates varied of 22.74, 28.00 and 32.64% for the three feeds, respectively. The sugar cane presented high soluble components fraction (35,99%), however it presented low digestion of the potentially degradable fiber (3.41% h-1) and a significant repletion effect (6,6 h-1). The feeds, sugarcane and poultry litter present low nutritional value to meet the ruminal microorganisms and of the hostess requirements.
carbohydrate degradation; protein; rumen
