Use of glycerine in poultry diets

Continuous advances in the poultry industry have stimulated the use of alternative feeds in poultry diets, and in particular glycerine, given its availability via the increase in world production of biodiesel. Glycerol is the principal component of glycerine, and can be used as an energy source to replace e.g. corn. However, other residual compounds, such as methanol and high levels of sodium, limit its use in animal feeds in large quantities. Several studies have found that the nitrogen-corrected apparent metabolisable energy of glycerine (AMEn) varies significantly between broilers, laying hens and quail, due to different processing/extraction methods (via biodiesel production). However, an energetic availability of at least 85% has been verified. Knowledge of the main metabolic pathways of glycerol and other components of glycerine is important for future studies on this feed material and to determine its main limitations. Understanding the relationship between the quality of the glycerine and its role as a source of dietary energy will allow more precise inclusion of glycerine in the formulation of balanced diets, without negatively affecting the performance of poultry.