Understanding Urea Encapsulation in Different Clay Minerals as a Possible System for Ruminant Nutrition

Considering the challenges of urea administration due to the high ureolytic activity of the rumen and the importance of its use, as well as taking into account the relevance of sustainably exploiting the technological potential of biodiversity, this research studies the encapsulation of urea in different clay minerals (palygorskite (Pal), sepiolite (Sep), and Veegum(®) (V)) as an alternative for use as nonprotein nitrogen (NNP) sources. A method of incorporation was developed in which the encapsulation of urea was proven by X-ray diffraction; fibrous materials, Pal and Sep had similar characteristics due to the decrease in the relative plane intensity (011), suggesting a decrease in the order of their stacking due to the presence of urea on the surface or inside channels. By contrast, V showed a 7.74° reflection shift, suggesting an increase in basal spacing from 11.45 Å in V to 14.88 Å in the sample after urea encapsulation. By thermogravimetry, it was observed that the presence of urea did not change the mass-loss profiles but only increased the percentage of loss in respective events, indicating urea incorporation in the clay minerals. These results provide a promising alternative for administering NNP sources in the ruminant diet.