Efeito do tipo de processamento da amostra sobre o desaparecimento ruminal e as digestibilidades intestinal e total da proteína de duas gramíneas

The objective of this work was to evaluate the effect of the processing type (dried at 55°C for 48 hours, dried at 105°C for 12 hours, and fresh) of the pearl millet (Pennisetum americanum Leeke) and elephantgrass (Pennisetum purpureum Schum., cv. merckeron pinda) samples, upon ruminal protein disappearance and intestinal and total digestibilities of the grasses crude protein. The ruminal disappearance and the intestinal and total digestibilities of the grasses crude protein were determined by using the in situ incubation and the mobile nylon bag technique. The samples were incubated for 0, 8, 12, 24, 48 and 72 hours. At the end of each ruminal incubation time, six bags (two grasses x three sample processing types) were inserted into the intestine via a "T" type duodenal cannulae. To estimate the crude protein cumulative disappearance curve, the values obtained were subjected to the fitting of the first order assimptotic growth model corrected for a discrete lag. The intestinal disappearance of the rumen undegraded protein was not constant, decreasing for dried samples (55 e 105°C), and reducing dramatically after 10-20 hours of ruminal incubation for fresh samples. The drying temperature of the samples prior to ruminal incubation affected the ruminal and intestinal disappearance of crude protein. The grasses crude protein degradation kinetics should be evaluated with fresh samples.