Efficacy of Curcumin as an Immunostimulatory Dietary Supplement for Channel Catfish

Natural agents such as curcumin may have the potential to enhance disease resistance in aquaculture. In this study, 30 catfish (Ictalurus punctatus), 2 years of age, were allotted to one of 3 treatment groups (n = 10) to receive diets supplemented with 0.0, 0.5, or 1.0% curcumin. Body weights and lengths of fish were taken at 0, 20, 40 and 60 days after starting the fish on experimental diets. At 60 days, blood samples were collected from 9 fish of each group and then were challenged with Aeromonas hydrophila (0.1 mL of 9×10⁶ CFU/mL) intra-peritoneally. Morbidity and mortality was observed daily for 7 days following challenge. Serum separated from blood samples was analyzed for the cytokines, interleukin-4 (IL-4) and interleukin-12 (IL-12). Results indicated significantly higher body weights and lengths but lower levels of both IL-4 and IL-12 with curcumin at 0.5 and 1.0% than the control group. At 24 h following challenge with A. hydrophila, mortality was100 (9/9), 33 (3/9) and 22% (2/9) in the fish supplemented with 0.0, 0.5 and 1.0% curcumin, respectively. At 48 h following challenge, two more fish in the 0.5% group died but the fish remaining in 1.0% group survived even after 7 days. Results of this study suggest that curcumin has the potential to enhance performance of catfish and increase their disease resistance which may help in reducing use of antimicrobials in fish farming.