Energy Utilization of By-Products from the Soybean Oil Industry by Broiler Chickens: Acidulated Soapstock, Lecithin, Glycerol and Their Mixture

Acidulated soy soapstock (ASS) and lecithin (LEC) are by-products from processing soy oil (SO) for human consumption, whereas glycerol (GLY) can be obtained through the transesterification of vegetable oils during the production of biodiesel. These are valuable by-products for poultry feeds that have been underutilized in many parts of the world. One study was conducted to estimate the AME(n) of ASS, LEC, GLY as well as of their mixture (MIX: 85% ASS, 5% LEC and 10% GLY). Two hundred and sixty Cobb 500 female broilers of 20 days of age were housed in steel wire battery cages in a controlled temperature room for broilers. A completely randomized (energy sources x fat inclusion level) factorial design was applied, with 4 replicates of three birds per treatment. Birds were fed a corn-soybean meal control diet without supplemental fat or with the addition of 2, 4, or 6% of the four energy sources. Total excreta collection was performed from 26 to 28 days. The AME(n) values of by-products were calculated using regression analysis as well as by the difference method. The average AME(n) values calculated by regression analysis were: 9,232, 7,502, 5,447 and 8,404, whereas results with the difference method were: 7,951, 6,579, 3,979 and 8,101 kcal/kg for, in both cases for ASS, LEC, GLY and MIX, respectively. It is concluded that these energy sources can be for broilers and that there are significant differences between the methods used to estimate AME(n) of fats.