Herkelman K L, Cromwell G L, Stahly T S
University of Kentucky, Lexington 40546.
J Anim Sci. 1991 Nov;69(11):4477-86. doi: 10.2527/1991.69114477x.
Two 21-d trials were conducted to evaluate the effect of heating time and sodium metabisulfite (SMBS) on the nutritional value of full-fat soybeans for chicks. In Trial 1, four pen-replicates of eight chicks each were fed corn-based diets (19% CP; 3,167 kcal of ME/kg) containing either 44% CP soybean meal or full-fat soybeans. The soybeans either were unheated or were autoclaved at 121 degrees C for 10, 20, 30, 40, 60, or 90 min. Soybean oil was added to the soybean meal diet to make it isoenergetic with the soybean diets. Trypsin inhibitor, urease activity, and the solubility of protein in the soybeans decreased as heating time increased. Weight gain increased and feed:gain and pancreas weights decreased quadratically (P less than .01) with heating time. Rate and efficiency of gain were maximized when the soybeans were heated for 40 min; further heating for 60 or 90 min reduced performance. In Trial 2, SMBS was added at levels of 0, 1, or 2% to full-fat, unheated soybeans or to soybeans before autoclaving at 121 degrees C for 10, 20, or 40 min. Four pen-replicates of seven chicks each were fed corn-soybean diets (19% CP; 3,144 kcal of ME/kg) with 12 treatments in a factorial arrangement of heating times and SMBS levels. The rate and efficiency of chick weight gain improved linearly (P less than .01) and pancreas weights decreased linearly (P less than .01) as heating time increased. Less heating time was required to maximize performance and minimize pancreas weights when SMBS was added, resulting in a heating time x SMBS interaction (P less than .05). Under the conditions of this research, chicks fed full-fat soybeans achieved maximum performance when the soybeans were heated at 121 degrees C for 40 min, and SMBS decreased by one-half the heating time required to inactivate the trypsin inhibitors. Trypsin inhibitor activity in soybeans was more closely related to their nutritional value than was urease activity.
进行了两项为期21天的试验，以评估加热时间和焦亚硫酸钠（SMBS）对雏鸡全脂大豆营养价值的影响。在试验1中，四个重复栏，每个栏有八只雏鸡，分别饲喂以玉米为基础的日粮（粗蛋白含量19%；每千克代谢能3167千卡），日粮中含有44%粗蛋白的豆粕或全脂大豆。大豆要么未加热，要么在121℃下高压灭菌10、20、30、40、60或90分钟。向豆粕日粮中添加大豆油，使其与大豆日粮能量相等。随着加热时间的增加，大豆中的胰蛋白酶抑制剂、脲酶活性和蛋白质溶解度降低。随着加热时间的增加，体重增加呈二次曲线上升，料重比和胰腺重量呈二次曲线下降（P<0.01）。当大豆加热40分钟时，增重速度和效率达到最大值；进一步加热60或90分钟则会降低生产性能。在试验2中，向全脂未加热大豆或在121℃下高压灭菌10、20或40分钟前的大豆中添加0、1或2%的SMBS。四个重复栏，每个栏有七只雏鸡，饲喂玉米-大豆日粮（粗蛋白含量19%；每千克代谢能3144千卡），采用加热时间和SMBS水平的析因设计，共12种处理。随着加热时间的增加，雏鸡体重增加的速度和效率呈线性提高（P<0.01），胰腺重量呈线性下降（P<0.01）。添加SMBS时，达到最佳生产性能和最小化胰腺重量所需的加热时间减少，从而产生加热时间×SMBS的交互作用（P<0.05）。在本研究条件下，雏鸡饲喂全脂大豆时，大豆在121℃下加热40分钟可达到最佳生产性能，SMBS可将使胰蛋白酶抑制剂失活所需的加热时间减少一半。大豆中的胰蛋白酶抑制剂活性与其营养价值的关系比脲酶活性更为密切。
