In the rearing of fish larvae, artificial feed can be given when digestive enzymes have been produced. To improve the ability of fish larvae to utilize artificial feeds can be done with the addition of exogenous enzyme into the artificial feeds. The aim of this study was to determine the dose of papain enzyme and the correct predigest artificial feeding stadium on metamorphosis rate and glycogen content of mangrove larvae (Scylla olivacea). The experimental design used was a factorial pattern with a complete randomized baseline design, the first factor being the dose of papain enzyme (0%, 1.5%, 3.0% and 4.5%), while the second factor was the predigest artificial feeding stage (zoea 2 and 3).  The results showed that the difference of dose of papain enzyme and predigest artificial feeding stages had significant effect (p <0.05) on the metamorphosis rate of  7, 9, 10, 12, 13, 16 and 17 day larvae, but the interaction between them was not significant (p>0,05). The rate of metamorphosis at doses of enzyme papain was 0% and 1.5% longer and significantly different (p <0.05) compared to 3% and 4.5% doses. The rate of metamorphosis at doses of 3.0% and 4.5% was not significantly different (p> 0.05). The content of glycogen larvae in dose of enzyme papain 4,5% not different than dose 1,5% and 3,0% but higher and significantly different than dose 0%. Glycogen content at dose 0%, 1,5% and 3,0%. was not significantly different (p> 0.05). Based on the results of these studies to hydrolyze feed proteins can be used papain enzyme with a dose of 4.5%.Keywords: papain enzyme, metamorphosis rate, mangrove crab larvae (Scylla olivacea), glycogen content

Haryati, Yushinta Fujaya, and Edison Saade. 2018. Effect of Predigested Artificial Diet Using Papain Enzyme on the Degree of Protein Hydrolysis and Protease Enzyme Activity of Mud Crab (Scylla olivacea) Larvae at Zoea 2 and 3 Stages. Aquacultura Indonesiana, 19 (2): 76-82. The ability of mud crab (Scylla olivacea) larvae to digest artificial diet depends on the availability of digestive enzyme. To enhance the larvaes capability to utilize artificial diet can be conducted by adding exogenous enzyme to the diet.The aim of this research was to determine the dose of papain enzyme and stadia of predigest artificial diet that produced the best degree of protein hydrolysis and protease enzyme activity. Completely randomized designwas used to evaluate the effect of papain enzyme dose on the degree of protein, with four treatment and three replications, namely the doses of 0.0%, 1.5%, 3.0%, and 4.5%. Factorial pattern with the completely randomized design was used to evaluate the effect of papain enzyme dose and the proper predigest artificial feeding stage on the activity of protease enzyme. The first factor was the papain enzyme dose (0.0%, 1.5%, 3.0%, and 4.5%), while second factor was the stadia of larvae when it is fed with predigested artificial diet (zoea 2 and zoea 3 stadia). The research showed that the difference of papain enzyme dose provides real effect on degree of protein hydrolysis either on JP 0 or JP 1 diet brands (P<0.05). Degree of protein hydrolysis of the diet predigested with 0.0% papain enzyme was the lowest and has real difference (P<0.05) with the 1.5%, 3.0% and 4.5% doses. Degree of protein hydrolysis on 3% dose of papain enzyme does not provide real difference with the 4.5%, namely 19.753% and 22.890% respectively in JP 0, 18.707 % and 20.430 % in JP 1, but has real difference (P<0.05) with 1.5% doses. The difference papain enzyme dose and stadia of predigest artificial diet as well as the interaction between both of them had significant effect (p<0.05) on the activity of protease enzyme. On the larvae of zoea 2 stadia, the activity of protease enzyme on the larvae fed with predigest artificial diet starting from zoea 2 stadia with 3.0% and 4.5% papain enzyme dose or those still fed with natural diet does not provide real difference, but is higher and provides real difference than 0% and 1.5% doses. On the larvae of zoea 3 stadia, the activity of protease enzyme to the larvae fed with artificial diet starting from zoea 2 with 0% and 1.5% papain enzyme doses, and those fed with artificial diet starting from zoea 3 stadia with 0% papain enzyme dose does not provide real difference (p>0.05) but is lower and provides real difference than other treatments. Protease enzyme activity on the larvae fed with predigest artificial diet using 4.5% papain enzyme starting at zoea 2 stadia , was not significantly different (P <0.05) compared to larvae fed artificial diet which was predigest with 0.0%, 1.5%, 3.0 and 4.5 papain enzyme started at Zoea 3. Based on the degree of protein hydrolysis, papain enzymes ca...

Sargassum sp. meal is a plant ingredient that has not been used properly, and its potential has not fully realized as an herbivorous fish diet. This experiment aims to determine the potential use of sargassum meal in the grow-out of the rabbitfish diet. Rabbitfish (initial weight of 51.76 ± 0.11 g ind−1) those were cultivated in fifteen floating net cages sized 1×1×1.5 m3 at 20 fish cage−1 stocking density lasted for 90 days. This experiment was designed as Completely Randomized Design with five treatments of sargassum meal dosages in diets, which were 0.0, 7.5, 15.0, 22.5, and 30.0%, with three replications each. The results showed that no significant effect (P>0.05) of different sargassum meal dosages on the specific growth rate and survival rate of rabbitfish. However, feed intake increased with increasing sargassum meal, where the highest was obtained at 22.5% (275.6±9.2 g fish−1) and 30.0% (270.8±8.4 g fish−1) dosages which were significantly higher (P<0.05) than the other dosages. At the same time, sargassum meal dosages were significantly different (P<0.05) on feed efficiency and protein efficiency ratio, where they both seem to decrease with the increase of sargassum meal. The highest feed efficiency was obtained at the dosage of 0.0% (68.6±3.6%) that had no significant effect (P>0.05) with 7.5% (63.7±2.2%) and for protein efficiency ratio was obtained at 0.0% (2.29±0.12) that had no significant effect (P>0.05) with 7.5% (2.20±0.08) and 15.0% (2.12±0.05) dosages. The use of sargassum meal as much as 30.0% caused a lower crude lipid and higher crude protein contents in the nutritional body composition of rabbitfish, and was significantly different (P<0.05) compared to 0.0% dosage. Based on the growth rate of fish, the optimum dosage of sargassum meal in rabbitfish grow-out diet was estimated at 19.46%, but only 7.5% of sargassum meal could be used in the diet based on feed efficiency.

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.

Gel diet is one of the aquaculture diets that use seaweed, K. alvarezii, as a thickener made with cooking with water contents of between 50-70%. One effort to increase the nutritional content of seaweed is fermentation. However, fermentation affects the attractiveness, palatability, and gel strength of aquaculture artificial diet. This study aims to compare various fermenter combinations that are most effective in fermenting seaweed, K. alvarezii meal in terms of attractiveness, palatability, and gel strength. This research was carried out at the Laboratory of Nutrition and Feed Technology, Faculty of Marine Sciences and Fisheries, Hasanuddin University, Makassar, Indonesia. Experimental fishes used were tilapia size 7, 15, and 28 g. Various combinations of fermenters as treatment were seaweed meal without fermenter (treatment A), + 1.5g Bacillus sp. (treatment B), + 1.5g Bacillus sp. + 1.5 g of Rhizopus sp. (treatment C), + 1.5 g Bacillus sp. + 1.5g Saccharomyces sp. (treatment D), and + 1.5g Bacillus sp. + 1.5g Aspergillus sp. (treatment E). Fermentation is carried out on an an-aerobic basis. The parameters measured were attractiveness, palatability, and gel strength. The experimental design used was a completely randomized design with 5 treatments and 5 replications. Data were analyzed by ANOVA and W-Tukey test. The results of this study indicate that the attractiveness and gel strength of the experimental diet were the same in all treatments (p>0.05), while the highest palatability of the experimental diet was obtained in the experimental fish that consumed D diet, namely seaweed meal fermented with 1.5g Bacillus sp. + 1.5g Saccharomyces sp. Based on the results of this study, it was concluded that tilapia, which consumed the gel diet, contained seaweed fermented with 1.5g Bacillus sp. + 1.5g Saccharomyces sp. has the best palatability.