The effect of various processed seaweed, Kappaphycus alvarezii products as gel diet thickener on the utilization of nutrition in Rabbitfish, Siganus guttatus cultivation in the floating net cage

Seaweed, K. alvarezii as a gel diet thickener. The quality of the thickener is determined by the processing method. The purpose of this study was to determine the type of processed seaweed, K. alvarezii product, which is the best thickener in the gel diet based on fish body nutrient contents, protein efficiency ratio (PER), and protein retention (PR). Experimental fishes used were rabbitfish with an average weight of 55.23±4.46 g/individual, which was cultivated in a small cage (hapa) measuring 100 x 70 x 100 cm and placed in floating net cages (FNC). An experimental diet is a gel diet. The frequency of feeding is done twice a day, 7:00 in the morning, and 16:00 in the afternoon by satiation. The experimental design used was a completely randomized design (CRD) with 4 treatments and 5 replications. The treatment in this study was a gel diet containing some processed seaweed products such as dried seaweed flour (treatment A), fermented seaweed flour (treatment B), carrageenan flour (treatment C), and seaweed soft (treatment D). Analysis of variance (ANOVA) was carried out, and the W Tukey test was continued for the treatment that had a significant effect on determining the effect of various processed seaweed products on the measured parameters. The results showed that processed seaweed products in the gel diet significantly affected changes in fish protein, lipid and carbohydrate contents, protein efficiency ratio, and protein retention in rabbitfish. The best nutritional content of fish, PER, and PR is found in treatment B (fermented seaweed flour). Based on the results of this study, it was concluded that the nutritional body content of fish, REP, and RP was best obtained in rabbitfish, which consumed a gel diet containing fermented seaweed.