• Journal of Aquaculture
• /
• v.11 no.1
• /
• pp.67-75
• /
• 1998

Experiments were performed to obtain cryopreservation techniques of black seabream (Acanthopagrus schlegeli) sperm. For sperm collection, brood stock reared in recirculating seawater system and fed with the commercial feed during experimental period. The results indicated that following cryopreservation method in block seabream sperm could be employed. Post-thaw survival rate of sperm revealed the highest value ($80{\pm}1.4$%) in 3% sodium citrate as a diluent for the cryopreservation. Cryopreserved sperm diluted with 5.4% glucose showed the highest fertilization rate to the ovulated eggs. Glycerol was a better cryoprotectant than dimethyl sulfoxide in sperm cryopreservation : survival rate and fertilizing capacity of cryopreserved sperm were decreased according to increase of glycerol concentration and varied in renges of 0.8~59.3% and 32.5~69.4% with 5~30% glycerol, respectively. A few of cryopreserved spermatozoa showed the enlarged head with granulated chromatin and ruptured plasma membrane by freezing and thawing injuries compared with unfrozen normal spermatozoa.

• Proceedings of the Korean Aquaculture Society Conference
• /
• 2005.05a
• /
• pp.130-130
• /
• 2005

• Journal of Aquaculture
• /
• v.18 no.4
• /
• pp.293-298
• /
• 2005

We examined the effects of GnRHa on expression of the gonadotropin subunit gene in the pituitary and on syn-thesis of the plasma sex steroids (testosterone and 17$\beta$-estradiol) in protandrous black porgy. Fish were injected intraperitoneally with 0.2g GnRHa/g and then both the pituitary and the plasma were sampled 0, 6, 12, 24 and 48 hours after injection. The mRNA level of the FSH subunit increased at 6 hours post-injection, while the LH mRNA levels expressed are same with or without GnRHa treatment. Also, GnRHa stimulation caused a significant increase of the plasma testosterone (T) and 17$\beta$-estradiol ($E_2$) after 24 hours. The homologies of black porgy FSH to red seabream, Pagrus majoy FSH, snakehead fish, Channa maculata FSH and striped bass, Morone saxatilis FSH were $83.3\%,\;79.2\%$ and $76.0\%$ respectively. Amino acid homology analysis using the GenBank and EMBL general searches indicated that black porgy FSH has a high homology with yellowfin seabream, Acanthopagrus latus LH ($97.7\%$ identity) and red seabream LH ($83.3\%$ identity).

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.46 no.6
• /
• pp.923-929
• /
• 2013

Black seabream juveniles Acanthopagrus schlegelii held at $20^{\circ}C$ were exposed to formalin at concentrations of 50 to 400 ppm, and tolerance values were determined by calculating median lethal concentration values (LC50) through probit analysis. The 12-, 24, 48, 72- and 96-h LC50 values for formalin were 297, 233, 171, 162 and 157 ppm, respectively. The histological effects of formalin on gill and liver tissues in this fish were determined. No histological effects were observed in the control group. The intensity of cell damage increased with the concentration of, and duration of exposure to, formalin. Hyperplasia, separation and epithelial necrosis, epithelial lifting, lamellar synechiae and collapsed lamellae were observed in gill tissues exposed to formalin. Hepatic lesions in liver tissues of fishes exposed to formalin were characterized by cloudy swelling of hepatocytes, necrosis, cytoplasmic vacuolization, deposition of pigments, spongiosis hepatis, nuclear hypertrophy, dilation of sinusoids and bile stagnation. The LC50 values and histological results obtained in this study will aid in designing treatment regimens to minimize toxic side effects and increase efficacy.

• Journal of Life Science
• /
• v.25 no.5
• /
• pp.548-556
• /
• 2015

Three groups of black seabream (Acanthopagrus schlegeli) were fed with treatment diets containing certain concentrations of conjugated linoleic acid (CLA) and carotenoids. The control group feed contained 0% CLA and 0% carotenoids, the CP10 group feed contained 1% CLA and 0.1% carotenoids, and the CP25 group feed contained 2.5% CLA and 0.1% carotenoids. The CP10 and CP25 groups demonstrated the enhanced growth and increased feed conversion efficiency of black seabream. The specific growth rates (SGRs) were 0.74, 0.81, and 0.97, while the feed conversion ratios (FCRs) were 2.65, 2.46, and 2.04 for the control, CP10, and CP25 groups, respectively. The total contents of high unsaturated fatty acid (HUFA) for the control, CP10, and CP25 groups were 41.0%, 41.7%, and 43.5%, respectively. CLA was deposited to the extent of 2.8% and 5.6% in the muscle, and 4.0% and 8.3% in the viscera of the CP10 and CP25 groups, respectively. Meanwhile, treatment with the viscera lipid extract (VLE) from CP25 fish evidently lowered 3T3-L1 adipocytes viability. The lipid extract from the muscle and viscera of black seabream contained ample amounts of beneficial substances, such as CLA, carotenoids, EPA, and DHA. CLA, which enriched black seabream muscle, could be categorized as a functional food and serve as a well-being food. Meanwhile, the fish oil from its viscera could serve as a high function supplement.

• Journal of Aquaculture
• /
• v.21 no.4
• /
• pp.304-308
• /
• 2008

Strength of juvenile black seabream (Acanthopagrus schlegeli) produced in the different types of hatchery for wild stock enhancement was evaluated in terms of resistances against anesthetizing agent, tricaine methane sulfonate (MS-222), and dry exposure. The working dosages of MS-222 varied significantly with two different water temperature and hatchery populations. Namely, water temperature $22^{\circ}C$ populations were less resistant against the chemical over water temperature $12^{\circ}C$ ones. MS-222 effects also differed with the fish with different growth histories. The fish seeds in collected from wild showed stronger resistances, earlier recoveries, and lower mortalities, compared to those cultured in land-based tank. Similar results were achieved in the juveniles challenged to dry exposure. These results suggest that wild population of black seabream are more resistant against anesthetic stress, expressed as anesthesia, recovery, and mortality, and further that the population are "healthier" than others.

• Journal of Aquaculture
• /
• v.9 no.3
• /
• pp.215-222
• /
• 1996

An experiment was conducted to assess the effects of dietary 3,5,3'-triiodo-L-thyronine ($T_3$) at 0, 10, 20, 50, 100 ppm on growth and survival rate in juvenile black seabream held at $27.9{\pm}1.1^{\circ}C$ for 50 days. Fish were fed the $T_{3}$ experimental diet for 4() days by hand to satiation in $2{\~}4$ times per day. After 50 days period, food intake rate (${\%}$), feed efficiency (${\%}$), survival rate (${\%}$), growth of weight and length (specific growth rates), and condition factor were measured. Food intake rate was inversely related to the dietary $T_{3}$ level. But feed efficiency was not changed by $T_{3}$ level. $T_{3}$ slightly improved survival rate of larvae. Survival rate of larvae from 100 ppm was significantly higher than that of fish from control. Dietary $T_{3}$ influenced growth in length and weight. Growth of black seabream fed a diet containing 10 ppm of $T_{3}$ was significantly higher than that of fish fed control. However 100 ppm of $T_{3}$ induced the inhibition for length and weight growth. The condition factor was inversely related to the dietary $T_{3}$ content.

• Korean Journal of Ichthyology
• /
• v.33 no.1
• /
• pp.37-42
• /
• 2021

This study sought to reveal spawning period and sex inversion of black seabream, Acanthopagrus schlegelii collected off the coast of Tongyeong, Korea. The monthly gonodosomatic index (GSI) showed the same pattern of between both sexes, and it was estimated that black seabream spawned once a year (between April and May). Histological examination revealed the transition from male to female sex, size of fork length bisexual gonad with ovarian (primary hermaphrodite; progress from male to female, MF) was seen at 20.5 to 39.6 cm and bisexual gonad with testicular (post hermaphrodite; female development and Male degeneration, FM) was seen at 26.4 to 50.2 cm. The egg diameters was in the range of 0.02 to 0.60 mm, with the smallest average egg diameter of 0.09 mm in February, the highest average egg diameters of 0.43 mm in August, and the range of fecundity was number of eggs 277,148 (33.9 cm) to 2,772,421 (34.1 cm).

• Journal of Aquaculture
• /
• v.19 no.4
• /
• pp.315-322
• /
• 2006

The objective of the present study was to investigate the expression of heat shock protein 90 (HSP90) and 70 (HSP70) mRNA as cellular stress responses, the levels of plasma cortisol with glucose as neuro-endocrine stress responses during water temperature rising in freshwater adapted black porgy, Acanthopagrus schlegeli. A cDNA fragment of 891 (HSP90) and 465 (HSP70) bp was cloned from black porgy testis by Reverse transcription-polymerase chain reaction (RT-PCR) with primers designed from the conserved regions of other teleost. The PCR product of HSP90 showed very high homology to red seabream (99%), rainbow trout (95%), Atlantic salmon (94%), zebrafish (94%) HSP90, HSP70 of black porgy was also highly similar to those of rainbow trout (96%), silver seabream (95%), zebrafish (95%) HSP70. Water temperature rising ($20{\sim}30^{\circ}C$) induced elevation of HSP90 mRNA in black porgy gonad, liver, brain, intestine and kidney, whereas it resulted in an induction of the HSP70 mRNA expression in gonad only. Plasma cortisol levels increased significantly at $30^{\circ}C$ in the fish compared to those at $20^{\circ}C$. Glucose levels of the fish showed a tendency of co-increase with cortisol during water temperature rising. These results suggest that increased HSP90 mRNA in liver with plasma cortisol following heat shock may be related to increasing glucose for homeostasis in this species.

• Journal of Life Science
• /
• v.25 no.1
• /
• pp.16-20
• /
• 2015

During the storage of these two species in a large conservation tank, fertilized eggs were collected and the offspring were raised. During culturing of the offspring, individuals with mixed characteristics of these two species were observed, and 96 individuals were randomly tested using microsatellite markers applicable to both species. Among the 96 individuals, 15 individuals with mixed morphological characteristics were confirmed to be hybrids showing both of genotypes red seabream and blackhead seabream. Additionally, based on sequence analysis of mitochondrial cytochrome oxidase subunit 1 (mtDNA CO1), 81 showed 99% nucleotide sequence identity to that of black sea bream, and the remaining 15 individuals showed over 99% sequence identity to that of red seabream. So, hybrids were produced by female red seabream and male blackhead seabream. These results suggest that hybrids may form in nature between these two species if their habitats overlap due to the influence of humans or global climate change.