Resumen de Designing and evaluation of urea microcapsules in vitro to improve nitrogen slow release availability in rumen

Raymundo Lira-Casas, J. Efrén Ramírez Bribiesca, Hilda A. Zavaleta Mancera, Claudia Hidalgo Moreno, Rosy Gabriela Cruz Monterrosa, María M. Crosby Galván, Miguel A Mendez-Rojas, Ignacio Arturo Domínguez Vara

• There is a growing interest in the development of novel and innovative vehicles for controlled release of urea into the rumen, aiming to provide ammonia-N for the biosynthesis of proteins of bacterial origin and to prevent urea intoxication by direct feeding to livestock. Urea microencapsulation is a system that can control the release of urea to be slow and steady. RESULTS The amount of encapsulated urea was 69% of CSU (calcium silicate + urea + Eudragit RS100? + dichloromethane) and 71% of ACU (activated charcoal + urea + Eudragit RS100? + dichloromethane) groups (p > 0.05) The buoyancy of the microcapsules was over 50% after 12?h of agitation in both groups (CSU and ACU), producing significant differences in the volume of the organic phase factor, which was 20?mL at the lowest value (p = 0.0005). The morphology of the microcapsules produced with CSU and ACU showed no significant differences in microcapsule morphology (p > 0.05). The lower temperature (35 versus 40?°C, p = 0.035) retained better morphology of the microcapsules. Regarding the in vitro ammonia-N release kinetics, unprotected urea reached a maximal peak after 6?h, while CSU and ACU took more than 24?h to reach ammonia-N released concentration. CONCLUSIONS We stabilized the physical factors in the microencapsulation of urea that can allow slow release of rumen fluid. ? 2018 Society of Chemical Industry