• Fisheries and Aquatic Sciences
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• v.26 no.9
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• pp.525-534
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• 2023

Vitamin C plays an important role for fish survival, growth and disease resistance. However, the optimal vitamin C for rearing red drum Sciaenops ocellatus juveniles in Vietnam is not known. To address this issue, a 70-day feeding trial was conducted to evaluate the optimal dietary vitamin C requirements for red drum juveniles. Seven isonitrogenous (55.35% protein) and isolipidic (9.07% lipid) diets were formulated to include graded vitamin C concentrations of 23.2, 124.5, 235.2, 423.8, 626.7, 824.6, and 1,027.3 mg/kg, respectively. The results showed that fish fed on 423.8 mg/kg vitamin C diet had the highest growth rate, which can be linked to the increased feed utilization. Broken-line analysis indicated that the optimal dietary vitamin C requirements of red drum juveniles were 342.92 and 405.80 mg/kg for growth parameters, feed utilization, body composition and biochemical parameters of serum. Based on these parameters the optimal vitamin C supplementation level for red drum juveniles was estimated in the range of 342.92-405.80 mg/kg vitamin C in the diets with direct applications in producing artificial feed for rearing juveniles of this species in Vietnam.

• Proceedings of the Korean Aquaculture Society Conference
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• 2005.05a
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• pp.85-85
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• 2005

• Korean Journal of Ichthyology
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• v.12 no.2
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• pp.118-123
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• 2000

Heritabilities of growth traits, and phenotypic and genetic correlations for rearing masu salmon Oncorhynchus masou in adult stage were described. Genetic parameters were estimated for total length, body weight, and head length of masu salmon at 19 and 23 months of age. The heritabilities of growth traits estimated for sire component at 19 months of age was 0.22 in each trait in 1995, and ranged from 0.19 to 0.36 at 23 months of age in 1996. Phenotypic and genetic correlations were high among growth traits(0.85~0.98, 0.67~1.26, respectively). Family selection or that combined with individual selection is proposed to improve growth of masu salmon.

• Journal of Marine Bioscience and Biotechnology
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• v.8 no.1
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• pp.24-29
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• 2016

Microalgae are considered as superior biodiesel producers, because they could effectively produce high amount of lipid with fast growth rate. In this study, Chlorella vulgaris was exposed to various light wavelengths (${\lambda}_{max}$ 470 nm, ${\lambda}_{max}$ 525 nm, and ${\lambda}_{max}$ 660 nm) using light emitting diodes (LEDs) to examine effect of light quality on their growth and fatty acid production in 0.4-L bubble column photobioreactors. Fluorescent lamps were also used as polychromatic light sources (control). From the results, biomass productivity was varied by light wavelength from 0.05 g/L/day to 0.30 g/L/day. Maximum biomass productivity was obtained from red LED among tested ones. We also observed that contents of oleic acid and linolenic acid, which affect biodiesel properties, were significantly changed depending on supplied wavelength. These results indicated that production of algal biomass, and fatty acid content and productivity could be improved or controlled by supplying specific light wavelength.

• Journal of Marine Bioscience and Biotechnology
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• v.8 no.2
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• pp.54-66
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• 2016

Productivity of Saccharina japonica was evaluated by water layers in Gijang and Wando sea area to find the suitable farming areas for mass production of biomass. For this, S. japonica was cultivated at various depths (0.5, 1, 2, 3 m), respectively. As the result, the growths in Gijang were 225.1-261.5 cm in length, 18.5-21.3 cm in widths, 396.0-537.7 g in weights, 14.3-17.8 kg/cluster in biomass, and those in Wando were 332.0-435.7 cm in lengths, 24.6-32.5 cm in widths, 766.0-1,232.9 g in weights, 16.4-24.3 kg/cluster in biomass. It showed that the growths of blades in Wando were faster than those in Gijang. The growth rates of blades by the depths were faster at 0.5-1 m depth from January to June. After June, however, as the growth rates of blades were lower than the shedding rates of blades, it showed that the growth of S. japonica decreased at all depth conditions except 2 m depth. Productivity of S. japonica was better in Wando which is lower in the water temperature and nutrients than Gijang.

• Journal of Marine Life Science
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• v.7 no.2
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• pp.154-162
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• 2022

In this study, data on the types and density of abalone attached organisms were provided in marine net cage of the southern coast. In addition, the effect of the removal of attached organisms was evaluated. In marine net cage, oysters, bryozoa, and barnacles were dominated among the attached organisms, and their average area ratio was about 57.5%. The growth rate and hepatopancreas condition were better in removal group of attached organisms than control group. Therefore, it is judged that the removal of attached organisms from abalone is necessary for the growth of individuals and improvement of value.

• Fisheries and Aquatic Sciences
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• v.26 no.1
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• pp.58-68
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• 2023

This study was conducted to determine dietary threonine (Thr) requirement for juvenile olive flounder (Paralichthys olivaceus). A total of 450 juvenile fish (23.2 ± 0.4 g) were randomly distributed to 18 tanks (215 L) with 25 fish per tank. Experimental diets included with graded levels of Thr at 0.0%, 0.4%, 0.8%, 1.2%, 1.6%, and 2.0% were assigned for triplicate groups of fish and fed two times daily to apparent satiation for 12 weeks. Weight gain, specific growth rate, feed intake, feed utilization and survival were significantly (p < 0.05) increased in fish fed with dietary Thr levels over 0.8%, and no significant differences were observed between 0.8% to 2.3% levels. Non-specific immune parameters of serum lysozyme, myeloperoxidase activity, antiprotease activity, and total immunoglobulin were significantly increased by dietary Thr over 0.8%. Based on the broken-line regression analysis, the Thr requirement for the optimum growth and immune response in olive flounder is likely to be 1.03% in the diet.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.37-37
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• 2003

Intraspecific hybrids have been proven to be a useful tool for increase growth rate in some freshwater fish species. However the effects of intraspecific hybrids in seawater fish species is little known. To assess whether intraspecific hybrids in red sea bream was associated with growth enhancement, growth performances of offspring from two inbred lines, selected Korean line (KORDI-F4) and cultured Japanese line (IPN) and two intraspecific hybrids lines (KORDI-F4♀×JPN♂ and JPN♀×KORDI-F4♂) of red sea bream were compared. There's no significant difference in body weight between offspring groups during seed production period (until 4 months old). At seven months old (after three months rearing trials on sea cages communally), the offspring from KORDI-F4 (41.0±11.1g) and JPN♀×KORDI-F4♂ (39.3±8.1g) showed significantly better performance in body weight than that of the offspring from KORDI-F4♀×JPN♂ (37.0±8.1g) and IPN (35.7±9.7g). At 15 months old, the offspring from JPN♀×KORDI-F4♂ showed best growth performances in body weight, weight gain, specific growth rate among four offspring groups. As the results, the intraspecific hybrids between cultured Japanese line and selected Korean line showed superior growth performances than their paternal and maternal inbred lines.

• Ocean and Polar Research
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• v.34 no.4
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• pp.385-394
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• 2012

In this study, crude extracts of the marine eelgrass Zostera japonica and their solvent-partitioned fractions were evaluated for their inhibitory effect against AGS, HT-1080 and MCF-7 human cancer cells using MTT assay. Each of the crude extracts (acetone/methylene, chloride, and methanol) of Z. japonica showed a significant inhibitory effect on the growth of human cancer cells. The combined crude extracts were partitioned between $CH_2Cl_2$ and water. The organic layer was further partitioned between 85% aq. MeOH and n-hexane, and the aqueous layer was then fractionated into n-BuOH and $H_2O$, successively. Growth inhibition effects of solvent-partitioned fractions from Z. japonica on human cancer cells increased in a dose-dependent manner. Among these tested samples, the 85% aq. MeOH fraction revealed good inhibitory effects on the growth of AGS and HT-1080 human cancer cells, while the n-hexane fraction exhibited good inhibitory effects on the growth of AGS and MCF-7 human cancer cells. In addition, 85% aq. MeOH and n-hexane fractions enhanced mRNA expression of p53 gene. These results suggest that there is further scope for the isolation of active compounds from Z. japonica, which should show much stronger anticancer activity.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.2
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• pp.272-277
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• 2012

Compensatory growth of grower olive flounder (Paralichthys olivaceus) was determined at suboptimal temperature ($13.0{\pm}1.9^{\circ}C$). Fifteen fish averaging 201.1 g per tank were distributed into 18 of 300 L flow-through tanks. Six treatments were prepared in triplicate: fish were hand-fed with an extruded pellet to apparent satiation once a day for 16 weeks (16 WF); and the other five groups of fish were hand-fed for 15, 14, 13, 12 and 10 weeks after 1-, 2-, 3-, 4- and 6-week feed deprivation, referred to as 15 WF, 14 WF, 13 WF, 12 WF and 10 WF, respectively. A linear relationship between body weight of fish and feed deprivation was observed: Y (Body weight of fish) = -1.81X (Weeks of feed deprivation)+201.07, $R^2$ = 0.83. Weight gain of grower olive flounder in 15 WF, 14 WF, 13 WF and 12 WF treatments was comparable to that of fish in 16 WF treatment, but lower than that of fish in 10 WF treatment. Specific growth rate of fish in 15 WF treatment was higher than that of fish in 16 WF, 14 WF and 10 WF treatments. Feed consumption of fish was not affected by feeding regime. Feed and protein efficiency ratios of fish in 15 WF treatment were higher than those of fish in 13 WF, 12 WF and 10 WF treatments. Grower olive flounder could achieve full compensatory growth when fish were daily fed for 12 weeks after 4-week feed deprivation at suboptimal temperature.