Microesferas de cera de carnaúba contendo ureia na dieta de ovinos: obtenção, caracterização, consumo, digestibilidade e perfil metabólico.

Abstract

Urea is widely used in the diet of ruminants as a source of non-protein nitrogen (NNP) in partial substitution to true protein sources, due to its low cost per unit of nutrient and high capacity to provide ammonia as a source of nitrogen for the production of microbial protein. However, there is a concern about its use at high levels to the animal diet, due to the low utilization of ammoniacal nitrogen, and mainly due to the possibility of intoxication of the herd. The present study aimed obtaining and characterizing urea-containing carnauba wax microspheres. The microencapsulated systems were investigated in terms of microencapsulation efficiency and yield, and also characterized by techniques of Thermogravimetry, Differential scanning calorimetry, Fourier transform infrared Spectroscopy, Scanning electron microscopy, moisture content, and water activity. The formulations presented high urea retention rates, as well as good yields, attesting the adequacy of carnauba wax and also the lyophilization technique to obtain the microencapsulated systems. Carnauba wax provided the inhibition of the hygroscopicity of urea, preventing its petrification during storage, facilitating its homogenization with other ingredients of the diet. Carnauba wax is a promising encapsulant for the production of urea microparticles for possible slow release, in which, according to the present study, between the two formulations developed, it is recommended the formulation UM2 (2:1), since it presented better yield and is the system with higher content of urea, providing a higher supply of slow release non-protein nitrogen (NNP) to the animal.