• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.840-846
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• 2014

This study investigated growth and hematological changes in parrotfish Oplegnathus fasciatus (~200 g/fish) reared under different total ammonia nitrogen (TAN) concentrations (0, 4, or 8 mg/L) for 6 weeks. Survival rates of parrotfish in all experimental groups did not significantly differ, as they were all ~100%. Although specific growth rate (SGR), weight gain, and daily feed intake in the high TAN concentration group (TAN8) were significantly lower than in the other two groups, there was no significant difference between the TAN4 group and the control group, (TAN0), indicating that parrotfish have a strong resistance to ammonia toxicity. As for temporal changes of the major blood components, cortisol increased as a result of stress caused by the high ammonia concentration in the TAN8 group. For this reason, the concentrations of energy sources such as glucose and total cholesterol were reduced. However, there was little difference among all experimental groups in concentrations of liver function glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT), and nutrient factors, such as total protein and albumin.

• Journal of Aquaculture
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• v.20 no.2
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• pp.132-139
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• 2007

A four-week feeding trial was conducted to investigate the effects of dietary soybean meal (SBM) and powdered Cheongkukjang (CKJ) on non-specific immune responses of parrotfish Oplegnathus fasciatus. Three isonitrogenous (42% crude protein) and isocaloric (17.1 MJ/kg) diets were formulated to replace fish meal by 0, 25% SBM or 25% CKJ (designated as FM, 25SBM and 25CKJ, respectively). Ninety fish (initial body weight 122 g) were randomly allotted into nine 150 L tanks. One of the three experimental diets was fed to triplicate groups of fish for 4 weeks. After the feeding trial, no differences were observed in growth performances and feed utilization among fish groups. Liver superoxide dismutase activity of the fish fed CKJ containing diet was significantly higher than that of the control groups. DPPH radical scavenging and $Fe^{2+}-chelating$ activities of the experimental diets containing SBM or powdered CKJ were significantly higher than that of the control diet. The results of the present study suggest that dietary inclusion of powdered 25CKJ significantly increased liver superoxide dismutase activity and did not affect the growth performances, feed utilization, morphological parameters, as well as hematological values of parrotfish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.5
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• pp.725-732
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• 2020

The sudden drop of water temperature in winter is very threatening factor that affects the productivity of farmed fish and the management in aquafarm. In this study, we investigated the effect of low temperature on the survival, oxygen consumption and stress responses of parrotfish Oplegnathus fasciatus due to acute drop of water temperature. The survival rate of parrotfish Oplegnathus fasciatus was 5% at 6℃, 95% at 8℃ and 100% at 10℃ on the 4^th day of exposure in each experimental temperature. Low-lethal temperature for 4days of parrotfish Oplegnathus fasciatus (4 day-LT₅₀) was 6.99℃ (confidence limit, 6.55-7.42℃). Oxygen consumption rate was significantly decreased with decreasing water temperature. Temperature coefficient (Q₁₀) was found to be 4.0 between 10℃ and 8℃ and 0.39 between 8℃ and 6℃. As a result of investigating the stress response according to the drop in water temperature, the concentration of SOD (Superoxide dismutase), cortisol, glucose, total Ig, AST (Aspartate) and ALT (Alanine aminotransferase) increased with decreasing of water temperature. This study would be useful for the management of temperature about cultured fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.747-752
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• 2011

The parrotfish Oplegnathus fasciatus is a sub-tropical species that is difficult to culture during the winter in South Korea. As a result, a recirculating aquaculture system (RAS) was developed to rear parrotfish. This study investigated the effects of stocking density and dissolved oxygen (DO) concentration on the growth and hematology of the parrotfish in the RAS. The experimental stocking densities were 5 (SD05), 10 (SD10), 15 (SD15), and 20 kg/m3 (SD20) total body weight to tank water volume. As the stocking density increased, the mean weight gain, feed efficiency, and specific growth rate tended to decrease. However, SD10 and SD15 did not differ statistically from SD05 in feed efficiency (P>0.05). Although better growth was achieved in SD05, SD10 and SD15 appeared to be acceptable, practically and economically, in terms of feed efficiency. The experimental DO concentration ranges were 3-4 (DO3), 5-6 (DO5), and 7-8 mg/L (DO7). The mean weight gain and survival tended to increase with the DO concentration, but there were no differences among treatments (P>0.05). Although the feed efficiency did not differ among the treatments, the specific growth rates and daily feed intake increased with the DO concentration and were the highest in DO7 (P<0.05). The cortisol concentration was the highest in DO3 (P<0.05), while there was no difference between DO5 and DO7 (P>0.05).

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.1
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• pp.62-68
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• 2014

This feeding trial was carried out to evaluate the effects of different dietary cadmium levels on growth and tissue cadmium content in juvenile parrotfish, Oplegnathus fasciatus, using cadmium chloride ($CdCl_2$) as the cadmium source. Fifteen fish averaging $5.5{\pm}0.06$ g (mean${\pm}$SD) were randomly distributed into each of twenty one rectangular fiber tanks of 30 L capacity. Each tank was then randomly assigned to one of three replicates of seven diets containing 0.30 ($C_0$), 21.0 ($C_{21}$), 40.7 ($C_{41}$), 83.5 ($C_{83}$), 162 ($C_{162}$), 1,387 ($C_{1,387}$) and 2,743 ($C_{2,743}$) mg cadmium/kg diet. At the end of sixteen weeks of feeding trial, weight gain (WG), specific growth rate (SGR) and feed efficiency (FE) of fish fed $C_{21}$ were significantly higher than those of fish fed $C_{83}$, $C_{162}$, $C_{1,387}$ and $C_{2,743}$ (p<0.05). Weight gain, SGR and FE of fish fed $C_0$, $C_{21}$ and $C_{41}$ were significantly higher than those of fish fed $C_{162}$, $C_{1,387}$ and $C_{2,743}$. Protein efficiency ratio of fish fed $C_0$, $C_{21}$ and $C_{41}$ were significantly higher than those of fish fed $C_{1,387}$ and $C_{2,743}$. Average survival of fish fed $C_0$, $C_{21}$, $C_{41}$ and $C_{162}$ were significantly higher than that of fish fed $C_{2,743}$. Tissue cadmium concentrations increased with cadmium content of diets. Cadmium accumulated the most in liver, followed by gill and then muscle. Muscle, gill and liver cadmium concentrations of fish fed $C_0$, $C_{21}$, $C_{41}$ and $C_{83}$ were significantly lower than those of fish fed $C_{162}$, $C_{1,387}$ and $C_{2,743}$. Based on the ANOVA results of growth performance and tissue cadmium concentrations the safe dietary cadmium level could be lower than 40.7 mg Cd/kg diet while the toxic level could be higher than 162 mg Cd/kg diet.