Nutrient analysis, apparent metabolisable energy and ileal amino acid digestibility of full fat soybean for broilers

Nutrient composition, ileal amino acid digestibility and apparent metabolisable energy (AME) of four full-fat soybean (FFSB) samples, collected from commercial feed mills in Southeast Asia, were evaluated using laboratory analyses and animal studies. The AME assay was conducted with broilers using the classical total excreta collection between days 21 and 29 posthatch. A maize-soy basal diet was formulated and test diets, each containing different FFSB samples, were developed by replacing (w/w) 300 g/kg of the basal diet with FFSB. The AME of FFSB was calculated based on the difference between AME values of the basal and test diets. The ileal amino acid digestibility assay was conducted with 29-day-old broilers using assay diets containing FFSB as the only source of protein. Digesta from lower ileum was collected on day 34. The ratios between the titanium and amino acids in the diet and digesta were used to calculate the digestibility. The crude protein and fat contents of the four FFSB samples ranged from 351 to 399 g/kg and from 177 to 192 g/kg, respectively. The AME contents varied widely between the four samples, ranging from 12.62 to 15.46 MJ/kg. The standardised ileal digestibility coefficient of protein ranged from 0.763 to 0.821. Variations in the digestibility of amino acids and digestible amino acid contents generally followed that observed for protein digestibility. In conclusion, FFSB contained more fat and AME than soybean meal, but less digestible contents of protein and amino acids due to the diluting effect of fat. Overall, these data show that properly processed FFSB is a valuable feedstuff and offers an attractive method of adding fat to poultry diets.