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dc.contributor.authorTan-Fermin, Josefa D.
dc.contributor.authorMarte, Clarissa L.
dc.contributor.authorUeda, Hiroshi
dc.contributor.authorAdachi, Shinji
dc.contributor.authorYamauchi, Kohei
dc.identifier.citationTan-Fermin, J. D., Marte, C. L., Ueda, H., Adachi, S., & Yamauchi, K. (1999). Effect of season on oocyte development and serum steroid hormones in LHRHa and pimozide-injected catfish Clarias macrocephalus (Günther). Fisheries Science, 65(6), 865–870.en
dc.description.abstractOocyte and blood samples were taken from gravid female catfish Clarias macrocephalus at 4-h intervals to monitor the stage of oocyte development and serum steroid hormone profiles after injection of luteinizing hormone-releasing hormone analogue (LHRHa) and pimozide (PIM) during the off-season (February) and the peak of the natural breeding period (August). Results showed that the onset of final oocyte maturation (12h) and ovulation (16h), and levels of serum estradiol-17β (E2) did not vary with season in LHRHa+PIM-injected fish. In February, ovulated eggs were stripped from three and two hormone-treated fish at 16h and 20h post-injection, respectively. In August, ovulation was observed in all hormone-treated females (n=5) at 16h post-injection but stripping of the eggs was possible only 4h thereafter. Serum E2 levels were significantly different only with varying time post-injection; a marked increase occurred at 12h, but the elevation was higher in fish induced to ovulate during the peak (16.8ng/ml) than off-season (7.7ng/ml). Hormone-treated fish showed higher serum testosterone (T) levels during the peak season (17-23ng/ml) than those injected during the off-season (10-20ng/ml) at 4-12h post-injection. Serum 17α, 20β-dihydroxy-4-pregnene-3-one (DHP) levels of hormone-treated fish during the off-season were only about half the level (0.29 and 0.52 ng/ml) of those treated with the same hormones during the peak season (0.54 and 0.9ng/ml) at 8 and 12h postinjection, respectively. Development of oocytes and serum steroid hormone profiles after LHRHa+PIM-induced ovulation provide basic understanding of the processes that mediate final oocyte maturation and ovulation in captive C. macrocephalus.en
dc.publisherJapanese Society of Fisheries Scienceen
dc.subjectClarias macrocephalusen
dc.subjectsteroid hormonesen
dc.subjectfreshwater catfishen
dc.titleEffect of season on oocyte development and serum steroid hormones in LHRHa and pimozide-injected catfish Clarias macrocephalus (Günther)en
dc.citation.journalTitleFisheries Scienceen
dc.subject.asfafish cultureen
dc.subject.asfafreshwater aquacultureen
dc.subject.asfainduced ovulationen
dc.subject.asfasex hormonesen
dc.subject.asfaspawning seasonsen

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