Microesferas lipídicas de ceras abelha e carnaúba contendo ureia enriquecidas com fonte de enxofre para liberação gradual na dieta de ruminantes.

Abstract

Urea is one of the alternatives in cost reduction and because of its applicability in food. The objective was to obtain microencapsulated systems with natural lipid encapsulants containing urea with and without sulfur by the emulsification/lyophilization technique, including four systems at a fixed ratio of 2:1 (Wax:Urea), namely: CAUS (Beeswax: urea: sulfur), CCUS (Wax of carnauba: urea: sulfur), CCA (Beeswax: urea), CCU (Carnauba wax: urea). For systems enriched with sulfur (magnesium sulfate heptahydrate), whose nitrogen and sulfur source ratio was 10:1, respectively. All microencapsulated systems were characterized regarding microencapsulation yield (RM), retained urea content (loading capacity), microencapsulation efficiency (EM) and thermogravimetry (TG), differential scanning calorimetry (DSC) techniques and water activity (Aw). The microparticles in situ were also histories against the ruminal and blood parameters, using two rumen fistulated sheep, male Santa Inês breed with an average weight of 48.9 ± 5.2 kg and aged 2 years. The formulations CAUS, CCUS, CAU, and CCU microencapsulation dissipation 97.15±9.28, 75.65±2.44, 98.29±2.15, 94.46%±1.8 respectively. The DSC and TG curves showed that the presence of the S source decreases the effectiveness of urea protection, the beeswax lipid microparticles as an encapsulant have greater thermal stability, which is related to a better protection of the core in relation to temperature, enabling the intended gradual release. The of the microparticles for the last incubation time (48 h) was investigated by scanning electron microscopy (SEM) in which the presence of the sulfur source decreased, even if slightly, the thermal stability of the microparticles for both cerids studied. The CCU system established the highest mean with pH among the neutrality reference values of 6.45, this system favored the significant increase in the population density of rumen protozoa expressing its significance of the highest mean of 14.97 protozoa (106/mL). The CAUS formulation promoted greater protozoan density and motility among the categories, presenting the respective values of 6.0, 6.88 and 7.5 min. The microstructure for the last incubation time (48 h) was investigated by scanning electron microscopy (SEM), suggesting the occurrence of biodegradation, which increases with the inclusion of the sulfur source for both cerids studied.