• 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.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.

• Development and Reproduction
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• v.19 no.4
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• pp.253-258
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• 2015

Spermiation was stimulated in the mature grass puffer, Takifugu niphobles, with an injection of human chorionic gonadotropin (HCG) or carp pituitary extract (CPE). Spermatocrit and sperm density were reduced, but milt production was increased in both the HCG and CPE treatment groups relative to those in the control group (P < 0.05). These results should be useful for increasing the fertilization efficiency in grass puffer breeding programs.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.52-52
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• 2003

For the evaluation of hormonal control of spermiation in fish, a method to quanify the spermiation response or mature Rhynchocypris oxycephalus (Sauvage and Dabry) to hormonal therapy is described. Spermatocrit was determined after 7 min centrifugation at 18,000 $\times$ｇ and sperm density was estimated by a standard hemocytormer method. Sperm density can be predicted from spermatocrit since their relationship is linear as described by the regression equation, Y=3.68X-27,18 ($R^2$=0.82, N=50), where Y is spermatocrit and X is sperm density. Milt production by mature R. oxycephalus was highest at 24 h after injection of 1,000 IU human chorionic gonadotropin (HCG) and 50 $\mu\textrm{g}$ luteinizing hormone-releasing hormone analogue (LHRHa) per kg body weight. Increased milt production coincided with low spermotocrit and sperm density levels. These results demonstrate that spermition in mature R. oxycephalus can be reliably evaluated by a spermatocrit method and that HCG and LHRHa are effecove in stimulating of spermiation in this species.

• Food Science of Animal Resources
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• v.26 no.3
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• pp.368-374
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• 2006

We have studied on characterization and cheese making like mineral contents, protein composition and coagulation pattern on equine milk. At first, for contents of mineral on equine milk, It was lower in equine than bovine milk Contents of Na, Mg, P, Ca and K the major minerals, were indicated as 18.3 mg, 0.4 mg, 33.3 mg, 80.9 mg and 134.9 mg respectively by 100 g. In the distribution of nitrogen, the ratio NPN to Nt was indicated as 9.8% while that of bovine milk was 7%. And In NCN, its percentage was indicated as 45.6% shelving that Equine casein was lower than bovine. From these results, equine milk could not be applicable to cheese production since there are no coagulable nitrogen fraction such as ${\kappa}$-casein, as there aye with bovine milk. Equine milk will be more acceptable if we accept that the phylogenic affinity is near to human. It is the same as equine from the view points that monogastric, which did not contain ruminant's casein. For the rennet coagulation, equine milk was different than bovine milk. Equine milk did not coagulated by rennet after the addition of $Ca^{2+}$. But when bovine ${\kappa}$-casein was added in the presece of rennet, and $Ca^{2+}$ to equine milk, coagulation occurred. Such phenomenon was also observed by the use SEM. Verification of ${\kappa}$-casein by SDS-PACE did not existed in equine milk. The Casein of equine milk(54.4%) is similar to human milk in that casein/whey is about 1. For equine milt this can be explained because distance between casein and Ca is great, casein being lower, which result in reaction of casein with $Ca^{2+}$ because it could not activated which lasting time of coagulation is too long.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.135-139
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• 2002

In order to obtain the basic information for the seedling production of surf clam, Spisula sachalinensis, sperm motility and optimal method for fertilization were investigated. Sperm concentration of S. sachalinensis milt was$ 2.02{\times}10^{10}\;cell/mL$ and approximately $96.0\%$ of sperm showed forward movement after exposure to seawater. When sperm and eggs obtained by incision method were fertilized in 1 hour and 4 hours, respectively, high fertilization and hatching rate were achieved. The optimal sperm concentrations and egg density for fertilization and hatching were 10$\~$100 inds./egg and 100$\~$200 inds./mL sea water, respectively.