Soy lecithin (SOL) is extracted from crude soybean oil during the degumming process and is a rich source of phospholipids. This ingredient has been used as an aquafeed supplement to improve metabolic and physiological responses of farmed fish. Two separate feeding trials were conducted to evaluate SOL supplementation in channel catfish fingerling feeds. The first feeding trial determined the optimal SOL inclusion level through a dose-response feeding trial, followed by assessment of fish physiological responses after a stress challenge, and cumulative survival following Edwardsiella ictaluri challenge. This trial used experimental feeds formulated with plant-based ingredients, and SOL was included at 0, 0.5, 1.0, 1.5, and 2% at the expense of soybean oil. The second feeding trial compared production performance, stress response, and survival upon bacterial challenge in fish offered a diet containing SOL at the optimal level as determined in Trial 1 (1%) or diets containing soybean or catfish oil. In both feeding trials channel catfish juveniles (~4.5g) were stocked in a recirculating aquaculture system with 30 fish/tank and fed for 70 days. At the end of the first feeding trial, production performance and condition indices were assessed and blood and digesta were sampled. Fish offered the diet containing 1.5% SOL had higher weight gain and better feed efficiency when compared to the control group. No statistical differences were observed in whole-body proximate composition, however, the catfish fed diets supplemented with 0.5% SOL had a higher protein conversion efficiency than the unsupplemented group. The intestinal microbiota did not present differences, except for a mild effect on alpha diversity (Pielou’s evenness index). Blood samples were collected 0, 0.5, 1, 2, and 6 hours after a 2-minute acute air emersion stressor. Post-stressor changes were observed in plasma cortisol, glucose, lactate, and osmolality over time, with an interaction observed between experimental diet and time for cortisol. Upon termination of the second study, blood and tissue samples were collected to assess production performance and welfare. The impacts of these diets on the innate immune response was assessed by qPCR targeting select genes associated with innate immunity. Catfish fed diets supplemented with SOL presented higher weight gain and feed efficiency when compared to catfish fed the soybean oil only diet. However, no differences were observed between SOL and catfish oil for the same parameters. No differences were observed for condition indices, survival, or blood parameters. Results of blood chemistry, gene expression, histology, and bacterial challenge for the second feeding trial are currently being evaluated. Collectively, these data suggest dietary SOL supplementation can enhance growth performance of channel catfish juveniles, and possibly affect physiological responses associated with acute stress and disease resistance.