Re-evaluation of the lysine requirement and lysine utilization by fingerling channel catfish.

Studies were conducted to reassess the lysine requirement for fingerling channel catfish and to evaluate the effects of feeding lysine-supplemented diets. Based on growth studies, utilizing casein and gelatin diets supplemented with crystalline L-amino acids to correspond to the pattern of 30% whole egg protein, the lysine requirement for fingerling channel catfish is approximately 1.5% of the dry diet or 5.0% of the dietary protein which confirms the previously reported lysine requirement. Contrary to prior reports, growth and feed efficiency data from studies using peanut meal diets (formulated to be first limiting in lysine) supplemented with feed grade lysine, demonstrate that fingerling channel catfish are able to utilize free amino acids effectively.