Caracterização, uso e limitações da glicerina na alimentação de suínos: revisão

Glycerin is a sweet, hygroscopic, odorless, viscous, energetic liquid containing variable glycerol levels being used as glycogen or lipogenic nutrient, depending on the energy condition of the animal. Glycerol, or 1,2,3-propanetriol, belongs to the alcohol group, with three hydroxyls, and the molecular formula of C3 H8 O3 . In pigs, the inclusion of high levels of glycerin can provide low energy content, since the enzyme system in glycerol kinase becomes saturated in the conversion of glycerol to glycerol-3-phosphate, with the excess being excreted in the urine. The feedstock is one of the factors that most influence the composition of glycerin, which may be produced from soybean oil, beef tallow, yellow grease, and poultry fat. The components with the highest involvement in the composition are glycerol, water and lipids, however, the limitations of use in animal feed are connected to residual levels of sodium, potassium, methanol and humidity. Crude glycerin levels better suited to the technical and economic viability are at approximately 10%, while compromising the performance and economic viability if above 15%. Since it has favorable characteristics and energy levels around 3.579 kcal/kg of metabolizable energy, glycerin can be used as an energy ingredient in pig feed.