• Korean Journal of Ichthyology
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• v.7 no.2
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• pp.195-202
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• 1995

The seasonal changes in the muscle components of hibernant fish, amphibious mudskipper (Boleopthalmus pectinirostris), caught during the period between June 1993 and April 1994 were studied. The distributional changes of its major components in each muscle tissues was also observed before and after spawning and hibernation. Moisture content was the lowest after spawnig season and the highest just after hibernation, but crude protein was the highest after spawning sea-son. Crude lipid in female was the highest before spawning season, while in male it was the highest after spawning season, but both of female and male the lowest just after hibernation. Carbohydrate content in female and male showed the highest value just before hibernation and tended to decrease thereafter. In case of mudskipper, dyeing distribution was more or less spread in almost all of the tissues after spawning season but showed nearly no difference just after hibernation with the exception of small increase in dyeing degree of muco layer and epidermis layer. Investigation of mudskipper muscle tissue through the method of sudan black B dyeing yielded the results as follows ; lipid component in mudskipper in seasons before and after spawning season was percieved as mainly distributed in muco layer, epidermis and hypodermis layer respectively and also percieved a little between hypodermis subscutoneus cells. In season just before hibernation, it prevailed in almost all of the tissues, contrary to the weakness in its distribution degree just after hibernation.

• Animal cells and systems
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• v.1 no.1
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• pp.99-105
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• 1997

Using three species of Korean frogs (Rana dybowskii, R. rugosa and R. nigromaculata), the annual spermatogenic pattern, the seasonal changes in the steroidogenic competence, and responsiveness of testis to gonadotropins in terms of testosterone secretion in vitro were examined. The spermatogenic pattern of R. dybowskii was classified as a discontinuous type since spermatogenesis stops completely after spawning in late winter (February) until mid-summer (July). In contrast, the pattern of R. nigromaculata and R. rugosa was classified as a potent continuous type since sperm was always present in the seminiferous tubules all year round. In all three species, the levels of testicular testosterone and that of testosterone secreted by testis following in vitro culture were very low in late summer (August), but increased thereafter until winter (hibernation period). Interestingly, responsiveness of testis in vitro to gonadotropins in terms of testosterone secretion increased markedly in November (early hibernation period). Specifically, bullfrog LH was more effective than FSH in stimulating the secretion of testosterone by frog testis in vitro during hibernation period. This fact suggests that testosterone secretion by testis during hibernation is at least regulated by the pituitary gonadotropin rather than environmental factors. Taken together, the data presented here suggest that testicular cycles of three species of Korean frogs are closely linked to their females breeding cycles, and are eventually controlled by various environmental cues.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.14-24
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• 1997

The seasonal variation in lipids, and fatty acid composition of neutral lipid(NL) and phospholipid(PL) contained in the muscles of hibernant fish(loach) were investigated. In the investigation, four groups of wild loaches ere used, those caught May, 1993(before spawning period), August, 1993(after spawning period), November, 1993(just before hibernation) and March, 1994(just after hibernation). The NL was the most abundant in muscle lipid, followed by PL and glycolipid(GL), and also the composition and variation patterns were almost similar between female and male throughout all the periods. NL content began to increase gradually after March and came to the maximum in August(under 90%) ; hereafter got to decrease gradually again and came to the minimum in March of the next year(under 60%). While the variation-pattern of GL and PL was in inverse proportion with that of NL and their content came to the maximum in March of the next year. The NL and PL fractions were mainly consisted of triglyceride and phosphatidyl choline respectively, and both of the contents showed the highest value in August, the lowest in March of the next year. The major fatty acids in NL fraction were 16:0, 16:1, 18:1, 18:2 and 18:3($\omega$3). In particular, the ratio of 16:1 was much higher than that in PL, while those of highly unsaturated fatty acids(HUFAs) such as 20:4($\omega$6), 20:5($\omega$3) and 22:6($\omega$3) were much lower. The ratio of 16:0 in NL was almost constant through the year, however those of 16:1, 18:1, 18:2 and 18:3($\omega$3) showed a tendency to increase after March and were about 2~4% higher in May, compared with that in March, while those of HUFAs were about 2~4% lower. In particular, the ratio of 16:1 in NL continuously decreased after May and markedly decreased in March of the next year, but those of 18:1, 18:2 were almost constant until November. In August, saturates and monoenes were higher levels due to the slight increase of 18:0, 14:1 and 17:1 than in the other periods, while those of HUFAs decreased and the unsaturation(TUFA/TSFA) of NL showed the lowest value in August. On the contrary, saturates and monoenes gradually decreased after November and the most of them including 18:0, 16:1, 18:1 and 18:2 rapidly decreased in March of the next year, while 20:1, 20:4(~6), and 20:5(~3), and 22:6(~3) were in inverse proportion. PL consisted mainly of 16:0, 16:1, 18:1, 18:2, 20:4(~6), and 20:5(~3). Saturates and monoenes-composition showed almost no difference in March and May, while polyene acids ratio showed similar changes with that of NL. In August, the ratio of saturates(16:0, 18:0) were high but that of HUFAs were low, and after November 16:0, 18:0, 18:1, 18:2 and 18:3($\omega$3) began to decrease, while most of HUFAs increased in their composition-ratio until the marking increase of their unsaturation and the big changes of 18:2, 18:3($\omega$3), 20:4($\omega$6), 22:6($\omega$3) in March of the next year.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.3
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• pp.270-277
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• 2017

This study was carried out to investigate seasonal changes in body composition in Boleophthalmus pectinirostris in Korea. B. pectinirostris collected in Gangjin, Jeonnam, consisted of 58.7-75.8% moisture content, 16.1-17.6% protein, 0.8-3.4% crude lipids, and 1.3-3.6% crude ash. Livers consisted of 15-17% moisture content, 14.0-16.8% crude protein, 34.4-71.2% crude lipids, and 0.5-1.2% crude ash. Calcium, iron, potassium, etc., content in B. pectinirostris muscle averaged 267.5-599.8 mg/100 g, 1.98-28.3 mg, 160.7-327.9 mg, 20.6-60.2 mg, 0.4-2.2 mg, 0.23-0.46 mg, 66.5-192.9 mg, and 1.32-3.8 mg, respectively. (Please clarify: the list of measured values must correspond directly with what was measured, not just "etc.") The major amino acids in B. pectinirostris muscle, in proportional order, were glutamic acid, isoleucine, and leucine; whereas the major amino acids in the liver were glutamic acid, lysine, aspartic acid, and leucine. The major saturated fatty acids in the muscle were palmitic acid (15-19%) and stearic acid (8-11%). The major monoenes and polyenes were palmitoleic acid (C16:1) and oleic acid (C18:1), and EPA and DHA, respectively. The major saturated fatty acids and polyenes in the liver were the same as in muscle, but the monoenes were palmitoleic acid (C16:1) and cis-10-hepta-decenoic acid (C17:1). Seasonal changes in B. pectinirostris body composition may be attributable to differential accumulation of fat and nutrients in comparison to the spawning and hibernation period.