Retenção de nitrogênio em ovinos alimentados com concentrações oscilantes de proteína bruta na dieta

Abstract

The objective of this study was to evaluate the intake, digestibility and impact of the daily oscillation of protein protein concentrations in sheep on the plasma content of N-ureic, aminotransferases, and serum sheep proteins, testing the hypothesis that the higher nitrogen retention ruminants submitted to diets with oscillating concentrations of crude protein (CP) may be attributed to increased urea recycling during the period when diets are low in CP. For the experiment, four uncastrated sheep, with a mean of 20 kg of live weight, were distributed in a 4X4 Latin square design. The experimental treatments were: No protein restriction (Control); restriction every 24 hours (T-24); restriction every 48 hours (T-48); and with restriction (TRestri). No significant effect (p> 0.005) was observed between the experimental treatments for the consumption variables: MS, MO, NDT, EE, NDF, CNF. However, for the CP consumption, the Control, T-24 and T-48 treatments did not provide a significant difference in consumption, however, the animals submitted to the T-Restri treatment showed differences in the other treatments, with lower CP consumption. As for the digestibility, the T-48 treatment (75.23) was superior to the Control (74.07) and T-Restri (70.44) diets, while the T-24 diet was intermediate between Control and T -48. The T-Restri treatment had lower digestibility than the others, resulting from the lower CP intake found for this treatment. For Nitrogen consumption, there was no significant difference between Control, T-24 and T48 treatments. However, for Nitrogen in the urine, greater excretion was observed for the animals of the T-48 treatment, whereas the Control was intermediate between T-24 and T-48. There was no significant effect among treatments for nitrogen in the faeces. For the variables of N-ureic, minotransferases and serum proteins , there was no significant effect (p> 0.005) among experimental treatments. It is concluded with this work that the oscillating supply of crude protein does not influence the retention of nitrogen, demonstrating a retention pattern similar to the daily supply that meets the protein requirement in its totality.