• Journal of Fisheries and Marine Sciences Education
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• v.28 no.2
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• pp.596-602
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• 2016

Experiments were carried out examine short-term effects of human chorionic gonadotropin (hCG) and long-term effects of luteinising hormone releasing hormone analogue (LHRHa) on milt production of the tongue sole Cynoglossus semilaevis. In the first experiment, each fish was implanted with a blank cholesterol pellet (control), 100 and $200{\mu}g$ LHRHa per kg body weight. In the second experiment, fish were injected with either 100, 200, 400 and 800 IU hCG per kg body weight or same volume of marine fish Ringer's solution. In the first experiment, milt volume was increased in male implanted with $200{\mu}g$ LHRHa pellet compared with other groups at day 10. Injection of 400 and 800 IU hCG resulted in an increase in the milt volume at hour 96 after the treatment. Although statistical difference is unable to confirm because of small milt volume, compared with the control group, hormone pellet-treated groups had a reduction in the mean spermatocrit (Sct) and sperm concentration (Sc). The results suggest that the increase in milt volume is at least partially gonadotropin (GtH)-dependent and increased milt volume has a relationship with milt hydration.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.6
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• pp.374-379
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• 2007

Two experiments were designed to examine short-term effects of human chorionic gonadotropin (hCG), and long-term effects of gonadotropin-releasing hormone agonist (GnRHa), $17{\alpha}-hydroxyprogesterone$ (17P), and $17{\alpha},20{\beta}-dihydroxy-4-pregnen-3-one\;(17,20{\beta}P)$, alone or in combination, on milt production of the starry flounder Platichthys stellatus. In the first experiment, fish were injected with either 200 IU hCG/kg body weight or the same volume of marine fish Ringer's solution (MFRS). In the second experiment, each fish was implanted with a blank cholesterol pellet (control), $200\;{\mu}g$ GnRHa, $500\;{\mu}g$ 17P, or $100\;{\mu}g\;17,20{\beta}P/kg$ body weight alone or in combination. In the first experiment, hCG injection resulted in an increase in the expressible milt volume and a decrease in the spermatocrit (Sct). After pellet implantation in the second experiment, the milt volume was increased in males treated with GnRHa, GnRHa+17P, or $GnRHa+17,20{\beta}P$. On day 7 after hormone pellet implantation, the milt volume began to increase, and on day 14, the milt volume in the $GnRHa+500\;{\mu}g$ 17P group was significantly higher than that in the control group. Compared with the control group, the hormone pellet-treated groups had a significant reduction in the mean Sct and sperm concentration (Sc) at day 7 after pellet implantation, while there were no differences in total sperm number. The results suggest that increases in milt volume are generally associated with decreases in Sct and SC, suggesting that the main mechanism for the increase in milt volume was milt hydration.

• Fisheries and Aquatic Sciences
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• v.5 no.1
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• pp.64-74
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• 2002

The proper conditions for cold storage of milt in four species of flatfish were investigated. Various diluents were tested for the preservation of marbled sole, brown sole, starry flounder and olive flounder milt at $1\pm0.5^{\circ}C$ for 7 days. The most effective diluent was $1\%$ NaCl for marbled sole and Stein's extender for brown sole, starry flounder and olive flounder. After 7 days of storage in different dilution ratios (milt: diluent), marbled sole milt diluted with 1:3-10 and brown sole, starry flounder and olive flounder milt diluted 1:1-10 maintained good sperm activity index (SAI). SAI was affected by storage volume and presence of antibiotic. SAI was lower after 7 days storage in the volume of 1.5 mL than in 0.5 or 1.0 mL. SAI after 29 days storage was markedly enhanced by addition of antibiotic in marbled sole (400 ppm gentamicin, 400 ppm neomycin, 200-400 ppm streptomycin), brown sole (600 ppm gentamicin), starry flounder (1,000 ppm gentamicin) and olive flounder (200-1,000 ppm gentamicin, 200-400 ppm neomycin, 200-1,000 ppm streptomycin).

• Korean Journal of Ichthyology
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• v.19 no.2
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• pp.168-172
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• 2007

In the present study, attempts were made to find out the physico-chemical properties of milt and the sperm motilities in various osmotic conditions using Panther puffer, Takifugu pardalis. The average concentration of sperm in the milt was $12.1{\pm}3.2{\times}10^9/mL$. pH and osmolality of seminal plasma were $8.2{\pm}0.3$, $385.5{\pm}12.5mOsm/kg$, respectively. Spermatozoa were immotile when the milt was mixed with solutions (electrolyte or non-electrolyte) of lower osmolality than the average seminal plasma osmolality ($385.5{\pm}12.5mOsm/kg$), but became motile after mixing milt with hyperosmotic solutions.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.3
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• pp.353-358
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• 1998

Experiments were performed to find out the physico-chemical properties of milt, and morphological changes of cryopreserved spermatozoa in tiger puffer, Takifugu rubripes. The average number of sperm and spermatocrit in milt stripped were $9.81{\pm}0.34{\times}10^{10}/m{\ell}$ and $97.8{\pm}0.8$, respectively. While total lipid concentration from seminal fluid was higher than that from sperm, total protein concentration from sperm was higher than that from seminal fluid, Na and K concentrations in sperm and those in seminal fluid were similar each other, However, glucose from sperm and seminal fluid were not detectable. Spermatozoon of tiger puffer was consisted of head, middle Piece and tail. Size of head showing horseshoe shape was $0.65{\pm}0.10{\mu}m$ in diameter and $1.35{\pm}0.30{\mu}m$ in length. The head fully containing chromatin did not have acrosome. Mitochondrion in middle piece was $0.2{\mu}m$ in average diameter and flagellum showed 9+2 structure. A few of cryopreserved spermatozoa showed morphologically loose or swollen plasma membranes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.238-241
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• 1999

Experiments were performed to find out the physico-chemical properties of milt and the sperm motilities in various conditions using the grey mullet, Mugil cephalus. The average concentration of sperm in the milt was $1,11 \pm0.36\times10^{10}/ml$. Spermatocrit was 96.7$\pm$2.6. pH and osmolality of seminal fluid were 7.8$\pm$0.1, 370$\pm$6 mOsm/kg, respectively, Total protein concentration of sperm was higher than that of seminal fluid, but total lipid concentration of seminal fluid was higher than that of sperm. The sperm motility was high in the diluent of milt : artificial seawater (1:10, by volume) and in 822 mOsm/kg and 983 mOsm/kg similar to seawater osmolality, but it decreased after 20 minutes. But activity of sperm was highly maintained in 482 mOsm/kg which was a little higher than osmolality of seminal fluid, and was high in pH 7$\~$9.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.187-188
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• 2003

Conadotropin releasing hormono analogs (GnRHa) have now been tested successfully a range of marine and freshwater species and been shown to be an effective strategy for improving milt quantity and quality (Mylonas and Zohar, 2001; Zohar and Mylonas, 2001; Lim et at, , 2002). Greenback flounder (Rhombosolea tapirina) is currently under consideration as a potential culture species in south-eastern Australia. (omitted)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.243-246
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• 1999

To obtain the basic data for the preservation of river puffer (Takifugu obscurus) sperm, experiments were carried out on the physico-chemical properties and cold storage of milt. The average number of sperm and spermatocrit in milt stripped were $1.13\pm0.34\times10^{10}/ml$ and 64.8$\pm$1.4, respectively. Osmolality of seminal fluid was 266$\pm$2 mOsm/kg, Total protein and total lipid from sperm were higer than that from seminal fluid. $Ca^{2+}$ and $Na^{+}$ concentrations were higher in the seminal fluid than in the sperm, while $Mg^{2+}$ and $K^{+}$ concentrations were lower in the seminal fluid. When sperm of river puffer were preserved in $0\pm0.5^{\circ}C$ with various diluents for 16 days, fertilization rate was $0\~0.7\%$. It suggested that cold storage of river puffer sperm was detrimental to sperm fertility.

• Fisheries and Aquatic Sciences
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• v.24 no.12
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• pp.437-445
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• 2021

Roughscale sole (Clidoderma asperrimum) is only wild caught because basic reproductive research on this species is lacking and gamete production in an artificial setting has not been successful. Exogenous hormone treatment has been used to induce gonadal maturation and final spermiation in wild-caught individuals. In this study, the effects of an exogenous hormone on spermiation in roughscale sole was investigated by implanting different concentrations of a salmon gonadotrophin-releasing hormone analog (sGnRH; 0, 25, 50, and 100 ㎍/kg body weight) into male fishes. The control group did not produce sperm after 21 days post-implantation, and the duration of spermiation was shorter compared to the other groups. The spermiation period and milt amount differed among the hormone-treated groups according to the hormone concentration used. Milt volumes in the groups treated with 25 and 100 ㎍/kg sGnRH increased compared to the control group, whereas exogenous hormone treatment had no effect on the movable sperm ratio. The spermatocrit was high at the beginning of spermiation in all groups and then tended to decrease gradually over time except in the experimental group treated with 100 ㎍/kg sGnRH. Plasma levels of testosterone, 11-ketotestosterone, 17α, 20β-dihydroxy-4-pregnen-3-one were not significantly affected by the sGnRH treatments. Our results demonstrate that it is possible to prolong the spermiation period and increase milt volume by treating male roughscale soles with an exogenous hormone. In addition, the artificial hormone treatment did not affect sperm motility.

• Fisheries and Aquatic Sciences
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• v.5 no.2
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• pp.87-96
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• 2002

The physico-chemical properties of fresh milt of marbled sole, Limanda yokohamae, brown sole, Limanda herzensteini, starry flounder, Platichthys stellatus and olive flounder, Paralichthys olivaceus among flatfishes, and the fine structure of their cryopresserved spermatozoa were investigated. The highest concentration of sperm among these four species was $3.60\pm1.35\times10^{10}/mL$ in marbled sole. Osmolality and pH of seminal plasma in four flatfish species were approximately 330 mOsm/kg and 7.6-8.1, respectively. Seminal plasma compositions showed interspecific differences. The sperm heads of marbled sole, brown sole and starry flounder were ellipsoidal and that of olive flounder was round. The numbers of mitochondria of these four species were eight in marbled sole, seven in brown sole and starry flounder, and six in olive flounder. Cross-sectional view of flagellum showed typical 9+ 2 structure in all species. Most of sperms cryopreserved with a proper method had no visible ultrastructural changes after freeze-thawing, compared with the fresh sperm, but in a few cases, swelling of their heads and midpiece regions were observed.