FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

The purpose of this study was to develop Sargassum enzyme hydrolysis extract powders to be added to the diets of Plectropomus leopardus and to assess their effects in terms of antibacterial, antoxidant, and enzyme activity. The results indicated that the Sargassum enzyme hydrolysis extracts had good antibacterial and bacteria-inhibiting effects against Bacillus cereus, Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Vibrio parahaemolyticus, as well as high DPPH and ABTS radical scavenging activity. The growth and proximate analysis results of P. leopardus fed with diets supplemented with Sargassum enzyme hydrolysis extracts were not significantly different from those of fish fed with a control diet. However, P. leopardus fed with diets supplemented with Sargassum enzyme hydrolysis extracts had optimum intestinal microbial flora. According to a blood immune analysis of P. leopardus, the serum protein ratio was better in fish fed with the addition of 1%, 2%, and 4% of the hydrolyzed powder of Sargassum. The antiprotease activity was better at 3% and 2% added, and the lysozyme activity was better with 4% and 2% added. In terms of the proximate composition of muscle of P. leopardus meat after being fed with Sargassum feed formulations for 8 weeks, the level of crude fat was better when the Sargassum composition of the diet was 2% or 4%, while there were no significant differences at other composition levels. According to the above findings, better results were achieved when the hydrolyzed Sargassum powder composition of the diet was 2% or 4%, but a composition of 2% appeared to be best when the cost and benefits were considered. More generally, the results indicate that diets supplemented with seaweed in aquaculture.