Destoxificação da torta de mamona por produtos químicos alternativos

• Ano de defesa: 2015
• Autor(a) principal: Andrade, Igo Renan Albuquerque de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Ricina; Ricinus aglutinina; Ricinus communis; Subproduto; Valor nutritivo; Viabilidade econômica; Ricin; Ricinus agglutinin; Nutritional value
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/20061

The objectives of the present study were to evaluate the use of alternative chemical sources in the degradation and inactivation of ricin and Ricinus communis agglutinin from castor cake; the use of an easily applicable methodology able to precisely identify the biological activity of the lectins present in the castor cake; and the influence of the detoxification process on the nutritional values of the castor cake and estimate the maximum sale price of detoxified cakes so that their use in the concentrate feed replacing soybean meal can be viable. The use efficiency of ten chemical compounds (calcitic limestone, magnesian limestone, sodium chloride, potassium chloride, dicalcium phosphate, monodicalcium phosphate, calcium hydroxide, sodium hydroxide, calcium oxide, and urea) in the inactivation of lectins from castor cake was evaluated, using four different volumes of water. Detoxification analyses were performed by visual observation and densitometry of electrophoresis gels, in addition to hemagglutination assays. After satisfactory results were obtained with the treatments using calcium oxide and sodium hydroxide, analyses of chemical composition; crude protein fractionation; rumen degradation of dry matter, crude protein, and neutral detergent fiber; and intestinal digestibility of crude protein were performed. Next, aiming to analyze the viability of using detoxified castor cake in concentrate diets completely replacing soybean meal, different diets were formulated to estimate its maximum sale costs. Alkaline treatments calcium oxide and sodium hydroxide provided complete inactivation of the lectins from castor cakes. Reagent concentration and water volume were decisive to the inactivation efficiency, with detoxification being effective when 60 or 90 g sodium hydroxide were used with water volumes equal to or greater than 1500 mL/kg castor cake or calcium oxide at the concentration of 90 g with 2500 or 3000 mL water/kg of cake. Chemical detoxification treatments directly influenced the profile of the different nitrogen fractions that compose the dietary crude protein; the rumen degradation parameters of dry matter, crude protein, and neutral detergent fiber; as well as the intestinal digestibility of the rumen-undegradable protein. Chemical detoxification treatments changed the nutritional value and the use of the dietary protein by the ruminant, reducing the nutritional value of the cakes and providing feedstuffs with different nutritional characteristics. Castor cakes treated with calcium oxide allowed a higher level of replacement of soybean meal as compared with the cakes treated with sodium hydroxide. In economic terms, the cakes treated with calcium oxide allowed a higher sale price of the product in relation to those treated with sodium hydroxide.