RESUMEN
Urea is a common non-protein supplement used in ruminant feed; however, excessive consumption may lead to poisoning by NH3. Although the slow release of urea into the rumen has shown to be an essential aspect for ruminant feed, to date only a few studies have addressed this matter. In this study we examined the influence of five different NH3-N slow release systems based on clay-urea nanocomposites on the fiber digestibility of low-quality forage (sugarcane straw) in vitro. Physical properties of nanocomposites were evaluated and their effects on digestibility were tested in vitro using pristine urea as a positive control (level of 1 % of DM of sugarcane straw sample) and sugarcane (with no additives) as a negative control. Ammonia release and digestibility were evaluated at 12, 24, 36, 48, 72 and 96-h. Generally, all nanocomposites increased (p < 0.05) digestibility of fiber over control under all the conditions stipulated, but the samples with hydrogel content were more expressive. We concluded that an ideal release rate and optimum environment for microbial synthesis are necessary to maximize the digestion of sugarcane.
RESUMEN
Urea is a common non-protein supplement used in ruminant feed; however, excessive consumption may lead to poisoning by NH3. Although the slow release of urea into the rumen has shown to be an essential aspect for ruminant feed, to date only a few studies have addressed this matter. In this study we examined the influence of five different NH3-N slow release systems based on clay-urea nanocomposites on the fiber digestibility of low-quality forage (sugarcane straw) in vitro. Physical properties of nanocomposites were evaluated and their effects on digestibility were tested in vitro using pristine urea as a positive control (level of 1 % of DM of sugarcane straw sample) and sugarcane (with no additives) as a negative control. Ammonia release and digestibility were evaluated at 12, 24, 36, 48, 72 and 96-h. Generally, all nanocomposites increased (p < 0.05) digestibility of fiber over control under all the conditions stipulated, but the samples with hydrogel content were more expressive. We concluded that an ideal release rate and optimum environment for microbial synthesis are necessary to maximize the digestion of sugarcane.(AU)
RESUMEN
Neste trabalho, apresenta-se um novo material adsorvente, obtido a partir da pirólise de resíduos da erva-mate. O carvão resultante demonstrou elevada área superficial específica quando comparado com outros materiais pirolisados e elevada capacidade de remoção de contaminantes orgânicos de soluções aquosas. Os valores de área específica apresentados pelos materiais foram de 344, 191 e ~0,5 m² g-1, para o carvão Mate 1, Mate 2 e Mate 3, respectivamente. As isotermas de adsorção mostraram que os carvões apresentam potencial para utilização como adsorvente para compostos orgânicos, tais como: o corante têxtil vermelho reativo, o corante azul de metileno e para o herbicida atrazina, sendo que os máximos de adsorção utilizando o carvão Mate 1 foram de 16, 230 e 30 mg g-1, respectivamente.
In this work we present a new adsorbent material, obtained by maté waste pyrolisis. The resulting charcoal presented high specific area when compared with other pyrolized materials and also high capacity to remove organic contaminants from aqueous solution. The charcoal showed specific area of 344, 191 and ~0.3 m² g-1 for sample Mate 1, Mate 2 and Mate 3, respectively. According to the corresponding adsorption isotherm these materials present good adsorption capacity for reactive textile and methylene blue dyes and the herbicide atrazine. Adsorption maxima were respectively 16, 230 and 35 mg g-1 for such substances, when sample Mate 1 was used.