Nutritional evaluation of lectin-free soybeans for poultry

This study evaluated the nutritional value of raw lectin-free soybeans in c omparison with raw Kunitz trypsin inhibitor-free soybeans, raw conventional soybeans, and commercial heat processed soybean meal (SBM). Analyzed lecti n values (milligrams per kilogram) were 7.2, 7.1, and < 0.00015 for the Kun itz-free, conventional, and lectin-free soybeans, respectively. Three exper iments were conducted using New Hampshire x Columbian male chicks fed 23% C P dextrose-soybean diets from 8 to 17 d of age. Growth performance of chick s fed lectin-free soybeans was greater (P < 0.05) than that of chicks fed r aw conventional soybeans in all three experiments. However, performance of chicks fed lectin-free soybeans was lower than that of chicks fed Kunitz-fr ee soybeans or SBM. The SBM yielded weight gains and feed efficiencies that were much higher than those observed from any of the soybeans. True amino acid digestibility and TMEn of the value of raw lectin-free soybeans in com parison with lectin-free and conventional soybeans were determined using th e precision-fed cecectomized rooster assay. value of raw lectin-free soybea ns in comparison with Seven roosters were crop-intubated with 30 g of soybe ans and excreta were collected for 48 h. Digestibility coefficients of most amino acids for lectin-fi ee soybeans were 5 to 8 percentage units higher than those for conventional soybeans, but the differences were not signific ant (P > 0.05). Likewise, the TMEn for lectin-free soybeans was 11% higher than that for raw conventional soybeans (3.577 vs 3.227 kcal/g DM) but the difference was not significant (P > 0.05). The results of this study indica te that the nutritional value of raw lectin-free soybeans is greater than r aw conventional soybeans but is less than raw Kunitz-free soybeans and SBM, suggesting that trypsin inhibitor is a greater antinutritional factor than lectins.