In conclusion, the dietary PL requirement, if any, of juvenile channel catfish (5.8g, initially) for growth and survival is less than or equal to 4.3% (1.5% PC) of the diet. Feed conversion is improved in channel catfish fed diets supplemented with 4% soy lecithin (7.2% PL; 5.1% PC), but it is not known if improvement in FCR will offset the added costs of dietary soy lecithin inclusion. Lecithin supplementation of practical diet formulations had limited effects on whole-body composition and the innate immune system in channel catfish. Dietary soy lecithin inclusion altered plasma and liver lipid composition, but it is unknown whether these effects can alter the ability of catfish to survive and grow under various conditions.