Understanding the Effectiveness of Blended Fats and Oils in Poultry Diets

Fats and oils are chemically diverse group of compounds, which have the highest energy density among all macro nutrients. Besides having high caloric values, they are major sources of essential fatty acids (Ω-3 and Ω-6), fat soluble vitamins (A, D, E and K) and lecithin. Moreover, supplementation of fats and oils to poultry rations increases the metabolizable energy of the total ration, the calculated energy of the diet. This “extra-caloric” effect of the fat comes from the increased utilization of other dietary components. The main factor affecting the metabolizable energy of fats is their digestibility, which is dependent on the length of carbon chain and the degree of saturation of the fatty acids. Fats of vegetable origin have high metabolizable energy as they contain high amounts of unsaturated fatty acids (U) unlike fats of animal origin, which contain high amounts of saturated fatty acids (S). Fats and oils from animal and vegetable sources are often blended to attain a specific U/S ratio, which increases the digestibility of animal fats, and thus produces a product with superior metabolizable energy. Also the quality of the fat is an important consideration as fats with high moisture, impurities and unsaponifiables (MIU) decrease digestibility, and thus metabolizable energy. Hence it is vital to account for the fatty acid profile, MIU and extra caloric effect, when calculating the metabolizable energy contribution of supplemental fats and oils in poultry diets.