Potential effects of Sargassum kjellmanianum as a dietary supplement on the growth performance, immunity response, antioxidant status, and ammonia resistance of yellow catfish (Pelteobagrus fulvidraco)

Abstract

This study aimed to investigate the potential effects of seaweed Sargassum kjellmanianum (SK) as a dietary supplement on the growth performance, blood biochemistry, immunology, antioxidants, and ammonia stress resistance of yellow catfish, Pelteobagrus fulvidraco. Four diets containing 0 % SK (control), 2.5 % SK, 5 % SK, and 10 % SK were fed to fish for 8 weeks. After the feeding trial, the fish were exposed to ammonia for 72 h and their mortality was recorded. Compared with the control group, the growth performance was significantly increased in the 2.5 % and 5 % SK groups (P < 0.05). Serum albumin levels were significantly increased (P < 0.05), meanwhile serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels were significantly decreased in fish fed with 2.5 % and 5 % SK (P < 0.05). Interestingly, the serum AST and ALT activities were significantly increased in the 10 % SK group (P < 0.05). Additionally, serum lysozyme, acid phosphatase, and complement 4 levels were all significantly increased in all SK groups than those of the control group (P < 0.05). In addition, serum malondialdehyde levels were significantly decreased (P < 0.05). Meanwhile, the total antioxidant capacity, superoxide dismutase, and catalase levels were significantly increased in the 2.5 % and 5 % SK groups with relative to the control group (P < 0.05). Notably, the cumulative mortality rate was significantly higher (46.67 %) in the control fish than those fed the SK diets (35–38.33 %) (P < 0.05). Taken together, the results indicated that adding SK to the diet of yellow catfish can enhance growth performance, stimulate immune responses, improve antioxidant status, and increase resistance to ammonia stress. It is recommended to use concentrations between 2.5 % and 5.0 % in present study.