Selection experiments to increase the proportion of males in Nile tilapia (Oreochromis niloticus) by means of temperature treatment

Wessels, Stephan; Hörstgen‐Schwark, Gabriele

doi:10.1016/j.aquaculture.2007.08.009

Cited by 72 publications

(44 citation statements)

References 14 publications

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“…The genetic variability of temperature sensitivity was exploited as a quantitative trait in a selection experiment based on the male sex ratios. The high thermosensitive line presented after 2 generations a mean of 1 90% males whereas the low-or non-thermosensitive line had ϳ 54% males [Wessels and Hörstgen-Schwark, 2007]. Taken together these studies indicate that sex in tilapia is governed by strong genetic !…”

Section: Genetic Variability Of Temperature Sensitivitysupporting

confidence: 49%

“…Diallel matings (5 ! 5) revealed that there was a genetic component to the temperature sensitivity dependent on both the dam and sire [Baroiller et al, 2001[Baroiller et al, , 2009 following an additive mode [Wessels and Hörstgen-Schwark, 2007]. This inter-population genetic variation was also revealed in several wild populations [Tessema et al, 2006;Bezault et al, 2007].…”

Section: Genetic Variability Of Temperature Sensitivitymentioning

confidence: 91%

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Environmental Effects on Fish Sex Determination and Differentiation

Baroiller

D'Cotta

Saillant

2009

Sex Dev

264

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: Genetic Variability Of Temperature Sensitivitysupporting

confidence: 49%

Section: Genetic Variability Of Temperature Sensitivitymentioning

confidence: 91%

Environmental Effects on Fish Sex Determination and Differentiation

Baroiller

D'Cotta

Saillant

2009

Sex Dev

264

229

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“…Os resultados obtidos com a tilápia do Nilo variedade Supreme demonstram haver um comportamento quadrático (P < 0,05) entre o maior número de indivíduos machos e o aumento da temperatura, com nível para melhor desempenho em temperatura de 32 e 34 o C, confirmando os resultados já obtidos por diversos autores em estudos prévios com tilápias do Nilo (BAROILLER et al, 1995;LIKONGWE et al, 1996;ABUCAY et al, 1999;JACOBS;MÉLARD, 2001;KARAYÜCEL et al, 2003;BORGES et al, 2005;BEZAULT et al, 2007;HÖRSTGEN-SCHWARK, 2007;AZAZA;DHRAÏEF;KRAÏEM, 2008;ROUGEOT et al, 2008; ANGIENDA; AKETCH; WAINDI, 2010; WESSELS; SAMAVATI; HÖRSTGEN-SCHWARK, 2011), bem como para outras espécies de tilápias (DESPREZ; MÉLARD, 1998;BARAS et al, 2000;WANG;TSAI, 2000;BARAS et al, 2002). Figura 3.…”

Section: Resultsunclassified

Inversão sexual de alevinos de tilápias do Nilo (Oreochromis niloticus) variedade Supreme, submetidos a diferentes temperaturas durante fase de diferenciação sexual

et al. 2013

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ResumoEste experimento avaliou os efeitos da temperatura na inversão sexual, sobrevivência e presença de deformidades em larvas de tilapia submetidas aos seguintes tratamentos controle (28ºC + ração 60 mg kg -1 de 17 α-metiltestosterona), 28, 30, 32 e 34ºC. Os resultados demonstraram diferença estatística entre a proporção de machos, sendo que as temperaturas controle, 32 e 34ºC (98; 91; 96 %, respectivamente) apresentaram resultados superiores aos obtidos para os tratamentos 28 e 30ºC (71 e 82 %). A sobrevivência observada nos diferentes tratamentos foram 90,74; 90,49; 88,20; 85,43 e 82,16 para o controle, 28, 30, 32 e 34ºC, respectivamente, sendo que houve diferença estatística entre os tratamentos 32 e 34 o C, somente quando estes foram comparados com o controle. Na análise das radiografias não foi possível observar presença de alterações morfológicas nos peixes submetidos aos diferentes tratamentos. Com este experimento, concluiu-se que as temperaturas de 32 e 34ºC foram capazes de masculinizar larvas geneticamente fêmeas, e que não houve incremento na mortalidade e na presença de deformidades que possam ser atribuídas aos tratamentos. Essa técnica é uma alternativa para a utilização de hormônios esteroides. Palavras-chave: Inversão sexual, sobrevivência, alterações morfológicas, proporção sexual AbstractThis experiment evaluated the effects of temperature on sex inversion survival and presence of deformities in larvae of tilapia subjected to the following treatments control (28ºC + diet 60 mg kg-1 of 17 α-methyltestosterone), 28, 30, 32 and 34ºC. The results showed a statistical difference between the proportion of males, with temperatures control, 32 and 34ºC (98, 91, 96%, respectively) showed better results than those obtained for treatments 28 and 30ºC (71 and 82%). The survival observed in different treatments were 90.74, 90.49, 88.20, 85.43 and 82.16 for the control, 28, 30, 32 and 34ºC, respectively, and there was statistical difference between treatments 32 and 34 ºC, only when these were compared with the control. In the analysis of the radiographs was not possible to observe the presence

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“…This starter feed (0.3-0.5 mm) was ground and sieved to a small particle size. Larvae were fed three times daily by hand (Wessels and Horstgen-Schwark, 2007). The diet was stored at (4ºC) during the experimental duration to avoid the nutrients deterioration.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of Using Decapsulated Artemia Cysts and Artemia Nauplii or Commercial Feed as Starter Feed for Freshwater Prawn Macrobrachium rosenbergii Larvae

Ali

Mohamed

2014

Mediterranean Aquaculture Journal

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Abstract:The present study was carried out to evaluate the effect of decapsulated Artemia cysts as direct food for Macrobrachium rosenbergii larvae on the growth and survival rate. Macrobrachium rosenbergii larvae (48 hour after hatching) weighted about 0.03 mg were reared (50 larvae/L) in cylindro-conical rearing fiberglass tanks (10 L) under controlled conditions. The larvae were fed on Commercial diet 46% crude protein (T 1 ), DE capsulated Artemia cysts (T 2 ), Artemia naupli (T 3 ) and DE capsulated cysts & Artemia naupli at constant ratio (1:1) (T 4 ). Three replicates for each treatment. Water parameters in all tanks were recorded. After 21-days rearing period, feeding of the larvae with commercial diet resulted in a significantly (P≤0.05) lower average weight (0.18 mg), mean length gain (4.80 mm), weight gain (0.15mg), K factor (0.16) and SGR (8.53%/d) compared to the other groups. Group T2 (fed with DE capsulated Artemia cysts) resulted in good survival (87%) of larvae, which was not significantly different from T4 (fed with 1:1 ,86.4%) and T3 (fed with Artemia nauplii ,86%). These results indicated that the use of decapsulated Artemia cysts (low price) appear to be a suitable feed for exogenous feeding in M. rosenbergii larvae. However, Artemia nauplii are more expensive than some commercial feeds.

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Selection experiments to increase the proportion of males in Nile tilapia (Oreochromis niloticus) by means of temperature treatment

Cited by 72 publications

References 14 publications

Environmental Effects on Fish Sex Determination and Differentiation

Environmental Effects on Fish Sex Determination and Differentiation

Inversão sexual de alevinos de tilápias do Nilo (Oreochromis niloticus) variedade Supreme, submetidos a diferentes temperaturas durante fase de diferenciação sexual

Evaluation of Using Decapsulated Artemia Cysts and Artemia Nauplii or Commercial Feed as Starter Feed for Freshwater Prawn Macrobrachium rosenbergii Larvae

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