Strategies for utilizing Over-processed Soybean Meal: II. Lysine Supplementation

Four experiments were conducted to determine the amount of lysine needed to overcome the negative effects of feeding over-processed soybean meal (SBM) to broiler chicks. Over-processed SBM reduced 15-day body weight and increased feed:gain ratio. The addition of graded levels of lysine significantly (P < .05) increased body weight to a level similar to that of controls, thus overcoming the effects of over-processing. In Experiment 1, feeding moderately over-processed SBM (55% protein solubility [PS]) required the addition of 0.082% lysine to overcome the effect of over-processing. In Experiments 2, 3, and 4, when feeding slightly over-processed SBM (68, 66, and 66% PS), the addition of 0.072, 0.032, and 0.054% lysine, respectively, was required to achieve the same body weight as control groups. On the basis of these studies, it is suggested that over-processed SBM can be included in practical diets if the PS is known and adequate supplemental lysine is incorporated in the ration.