Fish hydrolysate supplemented diet improved feed efficiency and growth of coral trout (Plectropomus leopardus)

Abstract

Fish hydrolysate contains hydrolyzed protein which comprised of peptides and free amino acids that are easily digested and absorbed by fish. This study aimed to determine the effectiveness of fish hydrolysate in improving feed efficiency and growth of coral trout. Five experimental diets were formulated to contain 47% protein and 12% lipid with different sources and levels of fish hydrolysate. Diet-1 and diet-2 were added with crustacean hydrolysate at 2% and 4% levels, respectively. Whereas diet-3 and diet-4 were supplemented with 2% and 4% of tuna hydrolysate. Diet-5 was formulated without fish hydrolysate supplementation (control). The diets were prepared as dry pellet with 3 mm diameter. Coral trout juveniles were produced in the hatchery of Institute for Mariculture Research and Fisheries Extension (IMRAFE), Gondol-Bali with the average body weight of 7.6 ± 0.9 g. The juveniles were maintained in 15 fiber tanks, 400L in volume, with a density of 40 fish/tank. The experiment was designed with a completely randomized design (CRD) with 5 treatments (different diets) and 3 replications for each treatment. The fish were fed the experimantal diets three times every day at satiation level for 84 days of feeding experiment. Results of the experiment showed that increased supplementation of fish hydrolysate from 2% to 4% in diet tended to improve fish growth performance. However, the best growth performance, in term of weight gain (WG) and specific growth rate (SGR), was obtained in fish fed diet supplemented with 4% crustacean hydrolysate. This growth performance was significantly higher than of the other treatments (P<0.05). The best feed efficiency (FE) and protein efficiency ratio (PER) were also obtained in fish fed diet supplemented with 4% crustacean hydrolysate. The results of the present study showed that supplementation of 4% crustacean hydrolysate in diet effectively improved the growth and feed efficiency of coral trout.