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dc.contributor.authorGallardo, Wenresti G.
dc.contributor.authorHagiwara, Atsushi
dc.contributor.authorTomita, Yuichi
dc.contributor.authorSnell, Terry W.
dc.identifier.citationGallardo, W. G., Hagiwara, A., Tomita, Y., & Snell, T. W. (1999). Effect of growth hormone and γ-aminobutyric acid on Brachionus plicatilis (Rotifera) reproduction at low food or high ammonia levels. Journal of Experimental Marine Biology and Ecology, 240(2), 179-191.en
dc.description.abstractGrowth hormone (GH, 0.0025 and 0.025 I.U. ml−1) and γ-aminobutyric acid (GABA, 50 μg ml−1) enhance rotifer population growth in batch cultures. In order to further understand the mechanism of their actions, we conducted experiments culturing isolated females at low food and high free ammonia levels. At an optimum food level of 7×106Nannochloropsis oculata cells ml−1 or at low free ammonia level of 2.4 μg ml−1, the F1 offspring of rotifers treated with GH at 0.0025 I.U. ml−1 had significantly higher population growth rate (r) and net reproduction rate (Ro), and shorter generation time than untreated rotifers. At a lower food level of 7×105 cells ml−1 or at high free ammonia level of 3.1 μg ml−1, rotifers treated with GABA at 50 μg ml−1 had significantly higher r and Ro, and shorter generation time. These results indicate that GABA is effective in enhancing rotifer reproduction when rotifers are cultured under stress whereas GH enhances rotifer reproduction when culture conditions are optimal. Significant effects were also observed in F1 and F2 generations which were not treated with hormones. These data may be useful for treating rotifer mass cultures to mitigate the effects of stress caused by high population densities.en
dc.description.sponsorshipThis work was partly supported by the Sasakawa Scientific Research Grant (No. 9-383M) from The Japan Science Society to W.G. Gallardo. The Japanese Government is also gratefully acknowledged for the Monbusho scholarship to W.G. Gallardo for his Ph.D. studies.en
dc.subjectNannochloropsis oculataen
dc.subjectBrachionus plicatilisen
dc.subjectFood limitationen
dc.subjectFree ammoniaen
dc.subjectGrowth hormoneen
dc.subjectγ-Aminobutyric aciden
dc.subjectWheel animalculesen
dc.subjectgamma-amino butyric aciden
dc.titleEffect of growth hormone and γ-aminobutyric acid on Brachionus plicatilis (Rotifera) reproduction at low food or high ammonia levelsen
dc.citation.journalTitleJournal of Experimental Marine Biology and Ecologyen
seafdecaqd.library.callnumberVF SJ 0606
dc.subject.asfaBatch cultureen
dc.subject.asfaBiological stressen
dc.subject.asfaFood availabilityen
dc.subject.asfaGrowth regulatorsen
dc.subject.asfaPopulation dynamicsen
dc.subject.asfaSexual reproductionen

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