Ureia de liberação lenta microencapsulada com cera de abelha na dieta de ruminantes.

Abstract

This study aimed at evaluating the slow release of a non-protein nitrogen source in ruminants diet by the microencapsulation of urea with and also without a sulfur source, using beeswax as encapsulant and lyophilization as drying method, as well as the intake of nutrients, digestibility coefficients, and nitrogen balance in sheep fed diets with increasing concentrations of microencapsulated urea. Two microencapsulated formulations were obtained by lyophilization [2:1 (wax:urea) and 2:1S (wax:urea with addition of source of sulfur)]. The products were evaluated regarding microencapsulation yield and efficiency, as well as characterized by Termogravimetry, Differential Scanning Calorimetry, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, moisture content, water activity, and finally an in vivo digestibility test. The formulation 2:1 exhibited the highest microencapsulation yield and efficiency values, besides greater thermal stability, demonstrating the negative influence of the incorporation of the sulfur source to the system. The in vivo digestibility study showed that the replacement of true soybean protein with micrencapsulated NPN until 4.5% did not present any negative effect on the dry matter, nutrients intake or nitrogen balance, but there was an increase in neutral and acid detergent fiber digestibility. The slow-release microencapsulated system development allowed the insertion of up to 1.5% of urea to the total diet without any prior adaptation, under the conditions of this study. The microencapsulated urea obtained by using the beeswax as encapsulant highlighted the great potential of this raw material to such use.