Metabolizable and bioavailable energy of soybean gums and soap stocks determined in precision-fed roosters, restrict-fed broiler chickens, and ad libitum-fed broiler chickens

The objective was to determine metabolizable and bioavailable energy content of soybean gums and soap stocks using precision-fed roosters and both restrict-fed and ad libitum-fed broiler chickens. In Experiment 1, nitrogen-corrected true metabolizable energy (TME_n) of gums and soap stocks relative to refined soybean oil was determined using precision-fed adult Single Comb White Leghorn roosters. Diet 1 was 85% corn and 15% Solka Floc. Diets 2 through 7 were the same as diet 1, except 7.5 or 15% soybean oil, gums, or soap stocks were added in place of Solka Floc. In Experiment 2, TME_n of soybean meal (SBM) with 4% inclusion of gums and soap stocks was measured in precision-fed roosters. In Experiments 1 and 2, roosters were fasted for 26 h, precision-fed 25 g of diets, and excreta were quantitatively collected for 48 h. In Experiment 3, relative bioavailable energy (RBV) of gums and soap stocks was determined in restrict-fed broilers. Energy-deficient diets containing 0, 5, or 10% soybean oil, gums, or soap stocks were fed from 10 to 21 d-of-age. In Experiment 4, nitrogen-corrected apparent metabolizable energy (AME_n) was determined in SBM with 4% inclusion of gums and soap stocks using ad libitum-fed broilers from 19 to 22 d-of-age. In Experiment 1, TME_n increased with lipid inclusion (P < 0.05). The TME_n of gums and soap stocks relative to soybean oil was 53 and 45% (as-fed basis) and 79 and 81% (DM basis), respectively. In Experiment 2, the addition of 4% gums and soap stocks increased TME_n of SBM (P < 0.05). In Experiment 3, RBV of gums and soap stocks ranged from 40 to 51% (as-fed basis) and 73 to 77% (DM basis) relative to soybean oil in broilers. In Experiment 4, the addition of 4% gums and soap stocks increased AME_n of SBM (P < 0.05) in broilers. In conclusion, soybean gums and soap stocks are viable lipid energy sources in poultry diets, particularly when moisture content is reduced.