• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.1
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• pp.20-24
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• 2000

A 7-week growth trial was conducted to investigate the effects of yeasts (Kluyveromyces fragilis and Candida utilis) with or without cell wall chemical treatment (protoplasted) in formulated diets on growth and body composition of larval ayu (Plecoglossus altivelis). Three replicate groups of ap average weighing 100 mg were fed diets containing each level ($5{\%}$) of K. fragilis, protoplasted K. fragilis, C. utilis, protoplasted C. utilis or brewer's yeast as an additive. Survival rate of fish fed the diet containing protoplasted K. fragilis, C. utilis or protoplasted C. utilis was higher than that of fish tea the control diet (P<0.05). Body weight .gain of fish fed the diet containing protoplasted K. fragilis was higher than that of fish fed the control diet (P<0.05). Crude protein and ash contents of Ssh were not significantly affected by the different dietary yeasts (P>0.05), On the other hand, crude lipid content of fish fed the diet containing K. fragilis, protoplasted K. fragilis or brewer's yeast was higher than that of fish fed the control diet (P<0.05). Amino acids composition of fish was not significantly affected by the different dietary yeasts (P>0.05), except aspartic acid. The results suggest that protoplasted K. fragilis as an additive in micro-formulated diet can improve weight gain and body quality of larval ayu.

• Korean Journal of Ichthyology
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• v.22 no.1
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• pp.9-16
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• 2010

Osmoregulatory capabilities of a euryhaline medaka, Oryzias dancena (Beloniformes; Teleostei), was examined with a particular emphasis on adult and larval viability during direct salinity changes. O. dancena adults were highly capable for hyper-osmoregulation as well as hypo-osmoregulation, as evidenced by no adverse effect on their viability during the direct transfer either from complete freshwater ($0^{\circ}/_{\circ\circ}$) to $40^{\circ}/_{\circ\circ}$ salinity, or from $70^{\circ}/_{\circ\circ}$ to $0^{\circ}/_{\circ\circ}$. Furthermore, the phased increase of external salinity with acclimation periods allowed them to survive at a salinity as high as $75^{\circ}/_{\circ\circ}$. However, tolerant capability to acute salinity increase in early larval stage was much less than in adult stage, based on the finding that the tolerance range of salinity increase was only $15^{\circ}/_{\circ\circ}$ from freshwater, indicating that the hyper-osmoregulation system might not be fully developed in the early larval stage. On the contrary, the hypoosmoregulation system could be more solidified in O. dancena larvae, as evidenced by their good survival even after direct transfer from $45^{\circ}/_{\circ\circ}$ to $0^{\circ}/_{\circ\circ}$. Knowledge achieved in this study could form the basis for a wide scope of researches including ecotoxicogenomics and geneexpression assay using this model species.

• International Journal of Industrial Entomology and Biomaterials
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• v.22 no.1
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• pp.1-4
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• 2011

This study was conducted to test the use of colored cocoon silkworm, Golden Silk, as a host for the fruiting body production of Cordyceps mushroom. Golden Silk variety had a shorter larval period than Yangwonjam at $25.3^{\circ}C$ and 78.5% RH: The average larval period of the Golden Silk was 24 days and 7 hr, and that of the Yangwonjam was 24 days and 15 hr. In the infection test of I. tenuipes on silkworm, the larval period of normal silkworms was longer than the silkworms inoculated with I. tenuipes in both Golden Silk and Yangwonjam. The pupae survival percentage of Golden Silk was 94.4%, whereas it was 91.9% in Yangwonjam. Golden Silk had a higher pupation rate than Yangwonjam. The pupation rate of normal silkworms was about 5% higher than that of silkworms inoculated with I. tenuipes. Infection rate of I. tenuipes into larvae of 5th instar newly exuviated silkworm was 93.8% in Golden Silk, and 96.9% in Yangwonjam. Synnemata production of I. tenuipes was better in Yangwonjam with an incidence rate of 99.8% than Golden Silk with 98.6%. The average synnemata weight of Golden Silk was 1.12 g and that of Yangwonjam 1.29 g. Golden Silk had a lower synnemata weight than Yangwonjam. But no significant difference was observed in synnemata weight varieties. The synnemata of I. tenuipes produced on pupae were white or milky-white in color, and similar in shape and color to wild synnemata collected in Korea.

• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.232-240
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• 2018

This study was performed to investigate the effects of water temperature and salinity on the egg development and larval attachment of Ascidiella aspersa. The egg development and larval attachment were examined in 12 different water temperatures (6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26 and $28^{\circ}C$) and two salinity conditions(30 and 34 psu). The hatching and developmental rates of A. aspersa showed a tendency to increase with increasing water temperature regardless of salinity and to decrease after the optimal water temperature range. The optimal water temperatures for the hatching and development of egg of A. aspersa were in the range of $20-22^{\circ}C$. The low threshold water temperature was not different between 1.5 and $1.8^{\circ}C$ at 30 and 34 psu, respectively. The attachment rate showed the optimal water temperature range of $16-22^{\circ}C$ irrespective of the salinity and the attachment time increased continuously with increasing water temperature. Experimental results showed that optimum development and survival temperature of the egg and larvae of A. aspersa were in the range of $20-22^{\circ}C$ regardless of the salinity conditions. The results can be used to predict the distribution and occurrence of A. aspersa, and to prevent economic damages caused by its spread.

• International Journal of Industrial Entomology and Biomaterials
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• v.18 no.1
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• pp.8-12
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• 2009

A study has been made to know the effect of a phytoecdysteroid 'Sampoorna' on uniform maturation of silkworms during spinning and its effect on diseased silkworms infected by major silkworm disease viruses, Bombyx mori nuclear polyhedrosis virus (BmNPV) and Bombyx mori infectious flacherie virus (BmIFV). In the present investigation, the effect of the phytoecdysteroid "Sampoorna" on Grasserie disease caused by BmNPV have shown an average cocoon melting of 11.91% with a disease incidence of 5.83%. The values of 't' test for different treatments of BmNPV indicated low survival rate and cocoon traits were drastically reduced. Another major disease Flacherie caused by BmIFV has shown considerable levels of larval disease incidence (22-32%) and cocoon melting (3-7.67%) with an average melting of 12.95% and 20.24% disease incidence. There is a drastic reduction in survival rate, cocoon yield and other economic traits. The control batches were indicated negligible values for disease incidence and cocoon melting with Sapoorna application and without the inoculation of the two disease-causing viruses. The application of Sampoorna on already infected batches with major pathogens triggered high mortality and disease incidence and melting percentage was also significantly increased with reduced economic traits. Hence, it is suggested that application of Sampoorna in infected batches should be done only in the extreme conditions of rearing. Application of Sampoorna on healthy batches led to uniform maturation and improvement in productivity with the added advantage of better quality cocoons and labour saving.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.1
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• pp.7-12
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• 2004

This study investigated the possibility of salinity acclimation of freshwater rotifers (Brachionus calyciflorus) as live food for sweetfish (Plecoglossus altivelis) larvae, and also examined the optimal salinity for the growth of sweetfish. Freshwater rotifers cultured in 0 and 4 PSU and seawater rotifers (B. rotundiformis) cultured in 33 PSU were supplied to the larvae with four kinds of enrichment material (condensed freshwater Chlorella, $\omega-yeast,$ baker's yeast, Super Selco) and larval growth at 4 PSU was examined. Growth of the freshwater rotifers positively increased from 0 PSU to 6 PSU, but decreased when over 8 PSU was reached. Growth and survival of the sweet fish larvae reared in 0 PSU were significantly lower than those reared in either 4 PSU or 33 PSU. This indicated that the freshwater rotifers (B. calyciflorus) could be used as live food for sweetfish larvae reared in 4 PSU. The body weight of sweetfish larvae fed on freshwater rotifers enriched with Super Selco was the highest at 0.163 mg, but there was no significant difference in survival and body length of the fish fed with the other enrichment materials. The content of n-3 HUFA of the sweetfish larvae fed on the freshwater rotifers enriched with Super Selco and the condensed freshwater Chlorella was higher than that enriched with $\omega-yeast$ and baker's yeast. These results indicated that B. calyciflorus cultured with the condensed freshwater Chlorella could be used for the sweetfish larvae without enrichment, and the most efficient enrichment material for B. calyciflorus is Super Selco.

• Journal of Aquaculture
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• v.12 no.1
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• pp.39-45
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• 1999

In order to obtain the basic biological data for artificial seedling production of sea cucumber, Stichopus japonicus, the influence of water temperature and air dry for spawning induction, egg development and larvae rearing was investigated during the period from April, 1995 through September, 1995. Spawning induction rate by the water temperature was 6.0~17.5% and air dry was responsed 1.4~4.0%. Number of eggs spawned of Stichopus japonicus were $50~500\times10^4$ individuals, the fertilization and hatching rate were ranged 84.0~96.0%, 71.4~84.6% respectively. The fertilized egg of Stichopus japonicus appeared mean diameter of $154{\mu}m$. At a constant water temperature of $23^{circ)C$, it become 4 tell stage from fertilization after 2 hours 10 minutes, hatching larvae after 14 hours half, auricularia larvae after 3 days, doliolaria larvare after 11 days and pentactula larvae after 15 days ready for settlement. The suitable food in the larvae reared for 17 days after fertilization were shown the best growth and survival in the larvae food of Chaetoceros calcitrans. Optimum density for larvae rearing were maintained of the larval density lower than 2 individuals/ml.

• Advances in environmental research
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• v.4 no.1
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• pp.39-48
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• 2015

Bisphenol A is widely used in plastic and other industrial consumer products. Release of bisphenol A and its analogues into the aquatic environment during manufacture, use and disposal has been a great scientific and public concern due to their toxicity and endocrine disrupting effects on aquatic wildlife and even human beings. More recent studies have shown that these alkylphenols may affect the molting processes and survival of crustacean species such as American lobster, crab and shrimp. In this study, we have developed gas chromatography with flame ionization detection (GC-FID) and gas chromatography-mass spectrometric (GC-MS) methods for the determination of bisphenol A and its analogues in shrimp Macrobrachium rosenbergii, blue crab Callinectes sapidus and American lobster Homarus americanus samples. Bisphenol A, 2,4-bis-(dimethylbenzyl)phenol and 4-cumylphenol were found in shrimp in the concentration ranges of 0.67-5.51, 0.36-1.61, and < LOD (the limit of detection)-1.96 ng/g (wet weight), and in crab of 0.10-0.44, 0.13-0.62, and 0.26-0.58 ng/g (wet weight), respectively. In lobster tissue samples, bisphenol A, 2-t-butyl-4-(dimethylbenzyl)phenol, 2,6-bis-(t-butyl)-4-(dimethylbenzyl)phenol, 2,4-bis-(dimethybenzyl)phenol, 2,4-bis-(dimethylbenzyl)-6-t-butylphenol and 4-cumylphenol were determined at the concentration ranges of 4.48-7.01, 1.23-2.63, 2.71-9.10, 0.35-0.91, 0.64-3.25, and 0.44-1.00 ng/g (wet weight), respectively. At these concentration levels, BPA and its analogs may interfere the reproduction and development of crustaceans, such as larval survival, molting, metamorphosis and shell hardening.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.2
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• pp.127-133
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• 2001

With an objective of evolving quantitatively and qualitatively superior bivoltine breeds/hybrids of silkworm Bombyx mori L. for tropical conditions, breeding work was initiated in Central Sericultural Research and Training Institute, Mysore during 1992 by utilizing two Japanese hybrids namely BNl8$\times$BCS25 and Shunrei$\times$Shogetsu along with Indian evolved breed, KA. The breed CSR12 which is characterized with sex-limited larval marking and white oval cocoons was evolved from the Japanese hybrid BNl8 ${\times}$ BCS25 by crossing with KA, while the breed CSR6 which is characterized with normal marking (marked larvae) and white dumbbell cocoons was extracted from the Japanese commercial hybrid Shunrei${\times}$Shogetsu through continuous inbreeding coupled with selection. After fixation, these breeds along with other newly evolved breeds were subjected to hybrid study under optimum environmental conditions in the laboratory for expression of full potential of the genotypes. These hybrids were evaluated by Multiple Trait Evaluation Index (Mano et al., 1993). The hybrid CSR12${\times}$CSR6 was selected based multiple trait evaluation index value. The hybrid CSR12$\times$CSR6 recorded survival of 96.0%, shell weight of 50.0 cg, shell ratio of 24.3%, raw silk percentage of 19.6, filament length of 1,216 m, boil off loss of 22.4% and renditta of 5.1. On the other hand, the control hybrid (KA ${\times}$ NB4D2) has recorded survival of 90.6%, shell weight of 42.1 cg, shell ratio of 20.4%, raw silk percentage of 15.9, filament length of 999 m, boil off loss of 24.8% and renditta of 6.3. The hybrid CSR12$\times$CSR6 was authorized during 1997 by Central Silk Board, Government of India for commercial exploitation during favourable months based on national level race authorization test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.682-687
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• 2018

This study investigated the food value of Paracyclopina nana for flounder Paralichthys olivaceus larvae in two feeding stages, rotifer (for 12 days) and Artemia (for 16 days). In the rotifer feeding stage, survival and growth of flounder larvae in the only P. nana (nauplii) feeding experiment were higher than in the only rotifer feeding experiment on 12 DAH (days after hatching). In the Artemia feeding stage, the growth of flounder larvae in the only P. nana (C4-adult) feeding experiment and mixture feeding experiment (P. nana+Artemia) were higher than in other experiments on 30 DAH, but the survival of flounder larvae did not differ significantly among experiments. The n-3 HUFA contents of nauplius and C4-adult were 4.0% and 5.4%, respectively. Overall the results of this study indicate that the brackish water cyclopoid copepod, P. nana, is an effective live food organism for larval seedling production of marine fish.