Effect of rearing temperatures on the sex ratios of Oreochromis niloticus populations

Tessema, Misikire; Müller-Belecke, Andreas; Hörstgen‐Schwark, Gabriele

doi:10.1016/j.aquaculture.2006.04.041

Cited by 95 publications

(75 citation statements)

References 9 publications

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“…High temperatures caused an increase in the male proportion in some progenies from all the wild populations when compared to controls and this is not the result of a differential mortality. Taken together, these studies showed that within the same wild population temperature sensitive and insensitive progenies existed with important differences between populations: 27% of the progenies were sensitive in Lake Rudolph [Tessema et al, 2006] and 94% in Lake Metahara [Bezault et al, 2007;Baroiller et al, 2009]. These results may be due to the proportion of individuals that are thermosensitive or most likely, correspond to different temperature thresholds (duration and intensity) for sex reversal [Baroiller et al, 2009].…”

Section: Effects Of Temperature In Wild Populationsmentioning

confidence: 69%

“…Six wild populations from a variety of temperature regimes comprising constant or alternative conditions were analyzed to see whether temperature affected the sex ratios. Several progenies obtained from tagged breeders were reared at 27 ° C (control) and high temperatures (36 ° C) for either 10-day [Altena and Hörstgen-Schark, 2002;Tessema et al, 2006] or 30-day periods [Baroiller et al, 1995;Bezault et al, 2007]. Balanced sex ratios were observed in fish from Lake Manzala (Egypt), Lake Rudolph (Kenya) and Lake Victoria (Kenya) at 27 ° C [see review of Baroiller et al, 2009].…”

Section: Effects Of Temperature In Wild Populationsmentioning

confidence: 99%

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Environmental Effects on Fish Sex Determination and Differentiation

Baroiller

D'Cotta

Saillant

2009

Sex Dev

270

229

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Environmental factors affect the sex ratio of many gonochoristic fish species. They can either determine sex or influence sex differentiation. Temperature is the most common environmental cue affecting sex but density, pH and hypoxia have also been shown to influence the sex ratio of fish species from very divergent orders. Differential growth or developmental rate is suggested to influence sex differentiation in sea bass. Studies in most fish species used domestic strains reared under controlled conditions. In tilapia and sea bass, domestic stocks and field-collected populations showed similar patterns of thermosensitivity under controlled conditions. Genetic variability of thermosensitivity is seen between populations but also between families within the same population. Furthermore, in the Nile tilapia progeny testing of wild male breeders has strongly suggested the existence of XX males in 2 different natural populations. Tilapia and Atlantic silverside studies have shown that temperature sensitivity is a heritable trait which can respond to directional (tilapia) or frequency dependent selection. In tilapia, transitional forms within a genetic sex determination (GSD) and environmental sex determination (ESD) continuum seem to exist. Temperature regulates the expression of the ovarian-aromatase cyp19a1 which is consistently inhibited in temperature masculinized gonads. Foxl2 issuppressed before cyp19a1. Recent in vitro studies have shown that foxl2 activates cyp19a1, suggesting that temperature acts directly on foxl2 or further upstream. Dmrt1 up-regulation is correlated with temperature-induced male phenotypes. Temperature through apoptosis or germ cell proliferation could be a critical threshold for male or female sex differentiation.

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Section: Effects Of Temperature In Wild Populationsmentioning

confidence: 69%

Section: Effects Of Temperature In Wild Populationsmentioning

confidence: 99%

Environmental Effects on Fish Sex Determination and Differentiation

Baroiller

D'Cotta

Saillant

2009

Sex Dev

270

229

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“…Tessema et al (2006) found that temperature of 36 ºC and 38 ºC increased the proportion of males (78%) when compared to the control (1:1), but in the temperature of 38 ºC the mortality rate was higher. These authors observed also that there are differences in the response to temperature according to the sensitivity of the fish population.…”

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confidence: 95%

Growth and survival of tilapia Oreochromis niloticus (Linnaeus, 1758) submitted to different temperatures during the process of sex reversal

2009

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The objective of this research was to evaluate the sex reversal technique using 17 --methyltestosterone (MT) hormone, submitted to temperature modification of fry Nilo tilapia storage, aiming to get the data of sex reversal combined with growth performance and fry survival. The experiment was performed at UFLA Fish Culture Station, using tilapia fry (0,008 ± 0.002 g e 0,9 ± 0.1 cm) obeying a totally randomized experimental delineation in a factorial scheme 4x4, in 4 temperatures (26º, 28º, 30º, 32ºC) and 4 hormonal doses (0, 20, 40, 60mg of MT/kg of ration) during 28 days, with 5 repetitions. As temperature raised, weight gain rate, size and survival increased (p<0.01); however, this temperature raise was not effective in modifying males ratio (p>0.01), which occurred only due to the used hormone treatment. The dose of 40 mg of MT/kg of ration provided similar results to those of 60mg of MT/kg of ration. Hence, the temperature band from 26º to 32ºC does not affect sex reversal rate, but temperatures around 30ºC improves the performance of tilapias related to the growth and survival, and the dose of 40 mg of MT/kg of ration is enough to achieve monosex populations.Index terms: Tilapia, 17 -methyltestosterone, temperature. RESUMOObjetivou-se, neste trabalho, avaliar a técnica de inversão sexual utilizando hormônio 17 -metiltestosterona (MT), submetidas à modificação da temperatura de estocagem das pós-larvas de tilápia, visando obter os melhores dados de inversão sexual aliado à performance de crescimento e sobrevivência das pós-larvas. O experimento foi conduzido na Estação de Piscicultura da UFLA, utilizando pós-larvas (0,008 ± 0,002 g e 0,9 ± 0,1 cm) de tilápia em delineamento experimental inteiramente casualizado em esquema fatorial 4x4, com 4 temperaturas (26º, 28º, 30º e 32ºC) e 4 doses hormonais (0, 20, 40 e 60mg de MT/kg de ração) durante 28 dias, com 5 repetições. À medida que se elevou a temperatura, a taxa de ganho de peso, o tamanho e a sobrevivência foram maiores (p<0,01); entretanto, esse aumento na temperatura não foi suficiente para alterar a proporção de machos (p>0,01), que ocorreu apenas em função do hormônio utilizado. A dose de 40 mg de MT/kg de ração proporcionou resultados semelhantes aos da dose de 60 mg de MT/ kg de ração. Portanto, a faixa de temperatura entre 26º e 32ºC não influencia na taxa de inversão sexual, mas temperaturas em torno de 30ºC melhoram o desempenho das tilápias quanto ao crescimento e à sobrevivência, e a dose de 40 mg de MT/kg de ração é suficiente para a obtenção de populações monossexo.Termos para indexação: Tilápia, 17 -metiltestosterona, temperatura.

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“…The most important techniques are the production of a monosex population through hormonal sex reversal, interspecific hybridization and the production of genetically improved male tilapia (GMT) through breeding of YY "super-males" (Mair et al 1991, Mair et al 1997, Beardmore et al 2001. Moreover, more recent studies provided evidence that water temperature also governed the phenotypic sex of genus Oreochromis (Tessema et al 2006;Wessels & Hörstgen-Schwark 2007). It was found that high-temperature treatments (around 36°C) during early developmental stage (labile period) cause a significant deviation of sex ratio in favor of males in Oreochromis niloticus (Baroiller et al 1996a, b;Baras et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Effect of Replacement of Fish Meal by Soybean Meal on Growth of Oreochromis niloticus (Linné, 1758) Juvenile under High Temperature Treatment for Masculinization

Boussou

Aliko

Yoboué

et al. 2017

Int J Appl Sci Biotechnol

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Two experiments were conducted consecutively in triplicates to evaluate and compare the impact of different feeds on survival rate and growth performances of Oreochromis niloticus larvae during both the heat treatment for thermal masculinization and the subsequent juvenile stage. A commercial feed containing fishmeal with 32.38% crude protein (CFA) and an experimental feed with 25.48% crude protein (EFB) where fishmeal was entirely replaced by soybean meal were tested. In the first experiment, larvae of about 4 days post-hatch were reared for 21 days at a temperature of 36°C and the second has consisted in testing at ambient temperature the performances of these feeds on the previous fry for 70-72 days. Fish were fed four times a day ad libitum.Results showed that there were no significant differences between growth performances (survival rate, final body weight, daily weight gain and specific growth rate) of larvae bred in hot water and nourished with feed containing fishmeal (CFA) or feed containing soybean (EFB) as protein source. However, better results were obtained with control batches bred at ambient temperature and fed with feed CFA or EFB. Postlarval rearing of previously heated fry showed that feed containing fishmeal has similar growth performances as feed containing soybean. Then, soybean meal can replace successfully fish-meal in diet of larvae during heating treatment for masculinization and also for the postlarval rearing of fry.

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Effect of rearing temperatures on the sex ratios of Oreochromis niloticus populations

Cited by 95 publications

References 9 publications

Environmental Effects on Fish Sex Determination and Differentiation

Environmental Effects on Fish Sex Determination and Differentiation

Growth and survival of tilapia Oreochromis niloticus (Linnaeus, 1758) submitted to different temperatures during the process of sex reversal

Effect of Replacement of Fish Meal by Soybean Meal on Growth of Oreochromis niloticus (Linné, 1758) Juvenile under High Temperature Treatment for Masculinization

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