Growth performance, serum biochemical parameters, immune parameters and hepatic antioxidant status of yellow catfish Pelteobagrus fulvidraco supplemented with Sargassum horneri hot-water extract

The yellow catfish, Pelteobagrus fulvidraco, an important aquatic species of high economic value and excellent meat quality, has suffered great losses due to disease in intensive farming. The aim of this study was to investigate the effects of Sargassum horneri extract (SHE) as a dietary supplement on growth performance, blood biochemical parameters, immune parameters and the liver antioxidant status of juvenile yellow catfish. A basal diet was supplemented with increasing amounts of SHE to formulate five groups of experimental diets (0 (control), 0.1%, 0.2%, 0.3%, and 0.4% SHE). Four-hundred and fifty fingerlings with approximate mean initial body weight of 3 g were fed the experimental diets for 8 weeks. The results of our present study revealed that the SHE-fed groups showed significantly higher final body weight, weight gain rate and specific growth rate than those in control group. Meanwhile, SHE diets increased significantly the levels of serum total protein and decreased significantly the contents of serum total cholesterol and triglyceride. The application of SHE in fish diet increased significantly the activities of serum lysozyme, alkaline phosphatase and acid phosphatase, and complement 3 contents. Furthermore, SHE supplementation increased antioxidant capacity and reduced lipid peroxidation in the liver of yellow catfish. In conclusion, dietary supplementation with SHE could promote growth performance, stimulate immune parameters, and improve hepatic antioxidant status in yellow catfish. Based on the final body weight, the secondary curve equation analysis suggested that SHE at 0.24% is recommended as the optimum level of supplementation.