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KMID : 0900919920160040353
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Korean journal of Animal Reproduction
1992 Volume.16 No. 4 p.353 ~ p.361
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Physiological Studies on Adaptation of Tilapia(Oreochromis miloticus) in the Various Salinities I. Endocrine Changes
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Yoon Jong-Man
Park Hong-Yang
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Abstract
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This study was taken to examine external changes, behavioral changes, and endocrine changes such as estradiol-17beta, progesterone, T4 and T3 of female Oreochromis niloticus living in 0textperthousand, 10textperthousand, 20textperthousand, and 30textperthousand salt concentrations, respectively. The results obtained in these experiments were summarized as follows. In seawater obtained in these experiments were summarized as follows. In seawater challenge test, any fish didn’t die in each group such as 10textperthousand, 20textperthousand and 30textperthousand. When fish were adapted from 0textperthousand to 10textperthousand$, 20textperthousand and 30textperthousand, external body color of fish changed from dark-striped to light-grey color. At the same time, thyroxine and triiodothyronine concentrations significantly(P<0.05) increased, and then were at the highest level in 30 salinity. When fish were adapted from 0textperthousand to 10textperthousand, feed intake of fish started from the fourth day. From 0textperthousand to 10textperthousand, 20textperthousand and 30textperthousand, estradiol-17beta levels were increased gradually. When fish was adapted from 0textperthousand to 10textperthousand, 20textperthousand$ and 30textperthousand, the levels of each progesterone didn’t show significant change, and especially showed the lowest peak in 20textperthousand. The greatest thyroxine activity(T4) was observed in 30textperthousand. The levels of and triiodothyronine(T3) significantly changed in all salinities, and its level was at the highest peak in 30textperthousand salinity. Correlation coefficients between serum progesterone and triiodothyronine in 10textperthousand and 30textperthousand were ＋0.677 and ＋0.843, respectively. Correlation coefficient of serum thyroxine(T4) and triiodothyronine(T3) individuals in 10textperthousand was ＋0.768, and ＋0.843, respectively.
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KEYWORD
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Tilapia(Oreochromis niloticus), external changes, behavioural changes, endocrine changes, correlation coefficients
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