Influence of photoperiod and melatonin administration on growth and metamorphosis in Discoglossus pictus larvae

Gutiérrez, Patrícia; Delgado, M.J.; Alonso‐Bedate, M.

doi:10.1016/0300-9629(84)90425-0

Cited by 31 publications

(12 citation statements)

References 19 publications

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“…A menor taxa de metamorfose observada para o tratamento que recebeu o maior período de luz (16L:8D) está de acordo com os relatos de Delgado et al (1984) e Gutierrez et al (1984), que observaram em Discoglossus pictus e Xenopus laevis prejuízo no desenvolvimento dos animais submetidos a longa fase de luz. Entretanto, os resultados deste experimento diferem dos encontrados por Delgado et al (1987), que observaram desenvolvimento mais rápido em girinos do gênero Rana quando submetidos a longa fase de luz.…”

Section: Período Experimental (Dias)unclassified

“…Observações sugerem que a luz representa um papel importante na regulação da taxa de metamorfose, evidenciando uma ação desta pelo caminho do eixo TRH -TSH -TH (Hormônio liberador da tireotropina -hormônio estimulante da tireóide -tiróide) em ambas as espécies, anura e urodela (Gutierrez et al, 1984).…”

Section: Período Experimental (Dias)unclassified

“…Segundo Delgado et al (1984) e Gutierrez et al (1984), a fase longa de luz inibiu o desenvolvimento de Discoglossus pictus e Xenopus laevis, entretanto, em girinos do gênero Rana o desenvolvimento foi mais rápido (Delgado et al, 1987). Filadelfi & Castrucci (1996) verificaram que a escuridão contínua inibiu o crescimento e desenvolvimento de girinos de Rana esculenta e Rana temporaria, enquanto o fotoperíodo curto aumentou o ganho de peso e estimulou a metamorfose em larvas de X. laevis.…”

Section: Introductionunclassified

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Efeito do fotoperíodo sobre o desenvolvimento de girinos de rã-touro (Rana catesbeiana Shaw, 1802)

et al. 2004

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RESUMO -O objetivo deste trabalho foi avaliar o efeito de diferentes fotoperíodos sobre o peso, comprimento e a metamorfose de girinos de rã-touro (Rana catesbeiana Shaw, 1802). Foram utilizados 720 animais de uma mesma desova, no estágio 25, segundo Gosner (1960), distribuídos em 24 caixas de polietileno, com 30 litros de volume d'água, resultando em uma densidade de 1 girino por litro. Os tratamentos consistiram em seis fotoperíodos [0L:24D; 8L:16D; 12L:12D; 14L:10D (natural, como testemunho); 16L:8D e 24L:0D] e quatro repetições, sob temperatura ambiente, sendo observados durante os meses de dezembro de 2000 a abril de 2001. O fotoperíodo foi programado utilizando-se cobertura das caixas com plástico preto, exceto para o fotoperíodo natural (plástico incolor), e três programadores para as lâmpadas fluorescentes de 21watts referentes aos fotoperíodos 8L:16D, 16L:8D e 12L:12D. O delineamento experimental foi inteiramente casualizado em esquema de parcelas subdivididas split-plot (coletas no tempo). O experimento foi analisado, utilizando-se o melhor modelo de regressão. Os girinos apresentaram ganhos de comprimento e de peso com tendência cúbica para maioria dos tratamentos, exceto para o comprimento referente ao fotoperíodo 24L:0D, que apresentou tendência quadrática. Para avaliar a metamorfose, foram realizadas análises estatísticas pela ANOVA (Análise de Variância) e teste de Duncan, em nível de 5%. O melhor tratamento deu-se com os animais submetidos ao fotoperíodo 12L:12D, aos 120 dias, que apresentaram o maior peso (1,80 g) e melhor taxa final de metamorfose, com cerca de 50% da população neste processo. O pior resultado foi obtido com os animais que receberam 24L:0D de fotoperíodo, apresentando aos 135 dias maior peso (2,0 g), com 4% de taxa metamórfica. Este resultado demonstrou que este fotoperíodo inibiu o desenvolvimento do girino. O pior resultado seguinte foi obtido para o tratamento 16L:8D. Os tratamentos 0L:24D, 8L:16D e natural apresentaram resultados intermediários quanto à metamorfose.Palavras-chave: crescimento, fotoperíodo, girino, metamorfose, Rana catesbeiana, rã-touro Effect of the Photoperiod on Bullfrog (Rana catesbeiana Shaw, 1802) Tadpoles DevelopmentABSTRACT -The objective of this work was to evaluate the performance of the bullfrog tadpoles (Rana catesbeiana Shaw, 1802) under different photoperiods. Seven hundred and twenty animals from the same spawn were used, on the stage 25, according to Gosner (1960). The fishes were allotted to 24 polyethylene 30 L boxes, with a density of one tadpole per liter. The treatments consisted of six photoperiods [0L:24D; 8L:16D; 12L:12D; 14L:10D (natural as witnessed); 16L:8D and 24L:0D] and four replicates, using environment temperature. The experiment was developed from December 2000 to April 2001. The photoperiods were programmed using the black plastic covering the boxes, except for natural photoperiod (colorless plastic). Three timers with 21 watts fluorescent lamps, to photoperiods of 8L:16D; 16L:8D and 12L:12D, were also used. The statistical...

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Section: Período Experimental (Dias)unclassified

Section: Introductionunclassified

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Efeito do fotoperíodo sobre o desenvolvimento de girinos de rã-touro (Rana catesbeiana Shaw, 1802)

et al. 2004

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“…On the other hand, short photophases accelerated growth and development of Discoglossus pictus (5,14) and Xenopus laevis (6) tadpoles. Despite these differences, the most common effect of melatonin treatment of tadpoles in spontaneous metamorphosis was retardation of development or growth (2, 5, 6, 10, 14), regardless of the LD cycle, even in species where short photophases were stimulatory.…”

Section: Rana Temporaria (15) Rana Ridibunda (5) Andmentioning

confidence: 99%

“…The influence of the pineal or melatonin on metamorphosis has been studied in a number of anurans and found to vary with the species, LD cycle, and melatonin concentration, although retardation of development or growth was a common finding (1,2,5,6,14). However, none of the studies were on Rana pipiens, and all used tadpoles in spontaneous metamorphosis in vivo, where neuroendocrine or peripheral influence of melatonin on metamorphic rate could not be dis-tinguished.…”

Section: Introductionmentioning

confidence: 99%

Influence of Melatonin on the Rate of Rana pipiens Tadpole Metamorphosis In Vivo and Regression of Thyroxine‐Treated Tail Tips In Vitro

Wright¹,

Cykowski²,

Mayrand³

et al. 1991

Dev Growth Differ

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Metamorphosis of Rana pipiens tadpoles may be retarded when the light phase of the light/dark (LD) cycle is shortened or when thyroxine (T4) is given in the dark because melatonin peaks during the dark. Injection of premetamorphic tadpoles in spontaneous metamorphosis with melatonin (1 5 pg) retarded tail growth and hindlimb development on 18L:6D but had no significant effect on 6L: 18D. During induced metamorphosis (30 pg/liter T4), melatonin injections retarded tail resorption on 18L : 6D and accelerated it on 6L : 18D, but did not affect the hindlimb. When melatonin was injected during T4 immersion at different times in the photophase on 18L : 6D (L onset 0800 hr), tail regression was retarded by melatonin at 1430 or 2030 hr. At 0830 hr, shrinkage of tail length was accelerated whereas tail height was not affected. Tail tips in vifro induced to resorb by 0.2 pg/ml T4 in Niu-Twitty solution regressed more slowly in the presence of melatonin (10 or 15pg/ml) than with T4 alone on both 6L: 18D and 18L:6D. The findings implicate melatonin in LD cycle effects on tadpole metamorphic rate in vivo, show the importance of the time of melatonin injections, and indicate that melatonin antagonizes the metamorphic action of T4 at the tissue level.

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Direct influence of melatonin on the thyroid and comparison with prolactin

et al. 2000

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Melatonin administered in vivo had previously been shown to inhibit thyroid cell proliferation and subsequent in vitro thyroxine (T4) secretion in anuran tadpoles. Melatonin in vitro also directly reduced the sensitivity of the thyroid to thyrotropin (TSH). The present work sought to determine whether melatonin directly affected baseline, unstimulated T4 secretion, and to compare its effect with that of prolactin (PRL). Thyroids from larval Rana catesbeiana or adult Rana pipiens were incubated in control or melatonin (0.01 to 100 μg/ml) media. Melatonin directly inhibited T4 secretion by thyroids from both tadpoles and frogs at all concentrations of melatonin used and at both prometamorphic and climax tadpole stages. PRL, used in vitro at 10 μg/ml, did not influence the response of the thyroid to TSH (0.2 μg/ml) in young tadpoles, or the baseline secretion of T4 by thyroids at any stage of larval life except climax, when T4 secretion was significantly decreased by the third day of culture. Thus although both melatonin and PRL have been shown to antagonize the action of T4 in vitro, and to decrease metamorphic rate, melatonin is a much more effective thyroid gland inhibitor than PRL. J. Exp. Zool. 286:625–631, 2000. © 2000 Wiley‐Liss, Inc.

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Influence of photoperiod and melatonin administration on growth and metamorphosis in Discoglossus pictus larvae

Cited by 31 publications

References 19 publications

Efeito do fotoperíodo sobre o desenvolvimento de girinos de rã-touro (Rana catesbeiana Shaw, 1802)

Efeito do fotoperíodo sobre o desenvolvimento de girinos de rã-touro (Rana catesbeiana Shaw, 1802)

Influence of Melatonin on the Rate of Rana pipiens Tadpole Metamorphosis In Vivo and Regression of Thyroxine‐Treated Tail Tips In Vitro

Direct influence of melatonin on the thyroid and comparison with prolactin

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