• Journal of Life Science
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• v.13 no.1
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• pp.34-41
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• 2003

The hatching of fertilized egg and early development of larval black seabream, Acanthopngrus schlegeli by immersion of 3,5,3'-triiodo-L-thyronine ($T_3$) with doses of 0.01~0.5 ppm in tank were examined for early development periods and compared with control fish immersed by 0.1 N NaOH and 99% alcohol. Larvae were fed with rotifers for first 5 days during experimental period. Yolk absorption of larvae from $T_3$ immersion groups were significantly faster than that of control. Although hatching times among each groups were not significant difference. the hatching rates of larvae in higher doses (0.1 ppm and 0.5 ppm $T_3$ groups) were significantly lower than control. The results of $T_3$ immersion experiments to newly hatching larvae indicated that exogenous $T_3$induced significant faster the absorption of yolk and oil globule, faster the development of myotome and digestive duct and higher the growth rate of larvae than larvae of control. These results indicate that $T_3$ immersion supplements appear to confer a distinct advantage to eggs and larvae of black seabream, which is in early fragile developmental stage.

• Journal of Aquaculture
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• v.11 no.3
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• pp.303-310
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• 1998

The growth and survival rate of larvae and juveniles from female rockfish (Sebastes schlegeli) broodstock in vitellogenesis by injection of 3,5,3'-triiodo-L-thyronine $T_3$ with a dose of 20 mg/kg fish wt. were examined for 30 days and compared with sham-control fish injected dime-thyl sulfoxide and control fish. Larvae were fed with rotifers for first 5 days after parturition, rotifers and Artemia nauplii for next 10 days. And then, they were fed with Artemia nauplii and commercial diet. Growth of larvae and juveniles from maternal $T_3$injection was significantly faster than that of two controls, nevertheless, the condition factor was lower than that of controls. The whole body proximate analyses indicated that there were significant effects of $T_3$ injection on protein and lipid, but no significant on moisture and ash contents. Survival rate of the fish from maternal $T_3$injection was significantly higher than that of fish from the two controls. These results indicate that thyroid hormone supplements appear to confer a distinct advantage to larval and juvenile rockfish in early, fragile development stage.

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

• Proceedings of the Korean Society of Developmental Biology Conference
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• 1998.07a
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• pp.66-67
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• 1998

난황형성기의 난소를 가진 암컷 어미에게 갑상선 호르몬인 3,5,3'-triiodo-L-thyronine ($T_{3}$)를 20 mg $T_{3}$/kg체중으로 주사하여 출산된 조피볼락 자어를 대조구 자어와 함께 30일간 사육하면서 성장과 생존율을 비교하였고, 실험종료시인 전어체를 갈아 체성분 조성을 파악하였다. 출산자어의 성장은 대조구에 비해 $T_{3}$구에서 유의하게 빨랐으며, 생존율 역시 $T_{3}$구가 대조구보다 유의하게 높았다. 실험종료시 치어의 비만도는 대조구가 $T_{3}$구에 비해 높게 나타났다. 실험종료시 $T_{3}$구의 어체내 수분과 회분함량은 대조구의 결과와 유의한 차이를 보이지 않았으나, 단백질 함량은 $T_{3}$구에서 대조구 보다 높았으며, 지질은 $T_{3}$에서 오히려 낮았다. 이상의 결과로 조피볼락에 대한 $T_{3}$의 모체주사는 출산자어의 성장과 생존율 향상에 도움을 주는 것으로 평가되었다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.721-726
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• 1998

The changes of thyroid hormone levels in plasma, eggs and yolk-sac larvae in female rockfish (Sebastes schiegeli) were examined after maternal injection of 3,5,3'-triiodo-L-thyronine ($T_3$) with a dose of 20 mg/kg fish wt. There were no differences of L-thyronine ($T_4$) level in maternal plasma and yolk-sac larvae between $T_3$ injection and vehicle-injected control. The significant decrease of $T_4$ level was found in eggs from the $T_3$ injected mother fish compared with that of control. $T_3$ levels in maternal plasma, eggs, and yolk-sac larvae were significantly elevated by $T_3$ injection. Therefore $T_4$ and $T_3$ in maternal circulation may be transferred into oocytes and subsequently into the yolk-sac larvae. These findings suggest that thyroid hormones may play some roles on physiological metabolism during early larval development of rockfish.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1995.06a
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• pp.228-229
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• 1995

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1998.06a
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• pp.145.1-146
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• 1998

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.588-593
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• 2001

Rockfish (Sebastes schlegeli) juveniles were fed with the diets containing 0 (control and sham), 5, 10 and 15 ppm of 3,5,3'-triiodo-L-thyronine ($T_3$) for 50 days to assess the effect of the hormone on the change of physiological condition, growth and survival rate, fish were fed the commercial diet by hand to satiation 2 times per day. After 50 days, food intake, feed efficiency, thyroid cell height (TCH), abnormality, proximate body composition, growth, condition factor and survival rate were also examined. The food intake and the feed efficiency of S. schlegeli fed with diet containing 10 ppm of $T_3$ was significantly higher than those of fishes fed with the other diets. On the final day of experiment, atrophy of thyroid gland was observed in fish administered with 10 and 15 ppm of $T_3$. $T_3$increased slightly the abnormality according to the increase of $T_3$dose. The whole body proximate analyses indicated that the fishes administrated with 15 ppm of $T_3$ were the highest in protein content and were the lowest in lipid, but in ash content were there a significant effects of $T_3$. The growth of S. schlegeli fed with a diet containing 10 ppm of $T_3$ was significantly higher than that of control. The condition factor was not related to administered $T_3$ content. $T_3$ slightly improved the survival rate of juvenile S. schlegeli, and the survival rate of fish administered with 10 ppm was significantly higher than that of sham-control but was lower than that of control.

• Development and Reproduction
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• v.9 no.1
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• pp.15-22
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• 2005

The objective of the present study was to investigate changes of sex steroid(testosterone: T and $estradiol-17{\beta}:\;E_2$), cortisol levels and gonadal development following $T_3$ treatment to protandrous black porgy, Acanthopagrus schlegeli. Exogenous $T_3$ was found to significantly stimulate the increase of T levels in plasma of black porgy after 60 days of treatment. However no effects of $T_3$ on $E_2$ levels and oocyte size were found. $T_3$ treatment resulted in stimulated spermatogenesis and testicular development in gonad and prolonged spermiation. Also, the levels of cortisol were significantly increased in the fish treated with $T_3$ as compared to control fish at 60 days. The results showed that exogenous $T_3$ had direct effect on the release of T and cortisol, thus $T_3$ seems to play, either directly or indirectly, an important role in the testis development of functional male black porgy.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.101-101
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• 2002

GH-transgenic coho salmon (Oncorhynchus kitsutch) juveniles in tGH＊T$_3$and tGH*PTU were fed with the diets containing 1 ug/g fish of 3,5,3'-triiodo-L-thyronine (T$_3$) and 30 ug/g fish of 6-n-propyl-2- thiouracil (PTU), respectively, to assess the effect of these drugs on the change of physiological activity, growth and survival rate in comparison with normal transgenic (tGH＊C) and nontransgenic coho salmon (Wild) for 90 days. Although the daily food intakes of all transgenic (tGH)-groups were higher than Wild, the amount was reduced by exogenous PTU supply. The fred efficiencies of tGH-groups were lower than Wild, but the efficiency was reduced both by T$_3$and PTU. The survival rate of tGH-group was significantly higher than that of Wild, but there was no significant difference among tGH-groups. Although the growth of tGH-coho salmon was faster than Wild. the growth rate of transgenic salmon was increased by exogenous T$_3$, but was reduced by PTU Plasma TT$_4$levels of tGH-groups was approximately 2-fold higher relative to Wild, but there were no difference of plasma TT$_4$levels among tGH-groups. plasma TT$_3$level or tGH-coho salmon was increased by exogenous T$_3$administration, but was reduced by exogenous PTU. In addition, although plasma GH levels of all tGH-groups were higher than that of Wild, the GH level in plasma of transgenic coho salmon was increased by exogenous T$_3$and reduced by exogenous PTU. In the meantime, the transgenic fishes also displayed head, jaw and opercular abnormalities typical of the offsets of this gene construct in coho salmon, indicating that some imbalance in growth processes has been induced. However, the abnormalities of transgenic coho salmon was reduced following exogenous PTU administration.