Effects of duration of cooking of full-fat soya beans on proximate analysis, levels of antinutritional factors, and digestibility by weanling pigs

Chemical analyses and a digestibility trial were carried out to determine the effect of cooking full-fat soya beans on their proximate analysis, level of antinutritional factors and apparent nutrient digestibility by weanling pigs. Samples of soya bean meal and of raw soya beans subjected to four different periods of cooking were assayed for nutrient analysis and level of antinutritional factors. The digestibility trial was conducted with five pairs of two littermate (Large White X Hampshire) castrates of an average initial weight of 9.28 kg to evaluate the effect of cooking soya beans at 100 degrees C for 15, 20, 25 or 30 min on apparent nutrient digestibility. The results showed that duration of cooking had no effect on the proximate analysis of soya beans, However, trypsin inhibitor activity level and percentage tannin decreased linearly (P < 0.01), while percentage phytic acid decreased non-significantly (P > 0.05) with increase in duration of cooking. Apparent digestibility and retention of dietary dry matter, nitrogen and ether extract increased linearly with increase in duration of cooking (P < 0.05).