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

Abstract

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

Concentration and time of feeding with 17-α-methyltestosterone oil diluted and incorporated to the feed for masculinization of Nile tilapia

“…Faster growth of males (Bardach, Ryther, & McLarney, 1972), positive anabolic effect of the hormone (Yamazaki, 1976), and activation of other endogenous anabolic hormones enhancing growth (Lone & Matty, 1980) are observed in hormone-treated fish, which promoted better performance compared to untreated fish. However, the effect of hormone in fish growth seems to be controversial; androgens may positively or negatively affect the health and growth of fish (Abo-Al-Ela, 2018; Lone & Matty, 1980;Zanoni, Leal, Caetano Filho, Oliveira, & Ribeiro, 2013). In this study, no adverse effect due to hormone use was observed in Nile tilapia.…”

Larviculture of Nile tilapia (Oreochromis niloticus) in biofloc and clear water systems: masculinization with 17 α-methyltestosterone

“…However, despite these advantageous qualities, there are still challenges in the breeding process, such as parental care, high reproductive capacity, and early sexual maturation, which can lead to overpopulation in cultivation nurseries, competition for space and food, and reduced growth rates of individuals (Mendes and Carvalho, 2016;Zanoni et al, 2013). As a result, the production of male-only populations in tilapia fish farming has become a common practice.…”

Effect of oral 17β-estradiol on zootechnical performance, sex ratio and first maturation of mullet Mugil liza Valenciennes, 1836

“…In aquaculture, the production of monosex batches of sh is carried out to explore characteristics associated with the phenotypic sex with the commercial interest, which provides higher pro tability (Reis et al 2016). Usually, single-sex batches for sh farming are obtained by applying sex inversion techniques directly through temperature manipulation (Zanoni et al 2013) The undifferentiated phase in gonad development, known as the labile period, is the period in which the gonads are most sensitive to the action of exogenous steroids (Park et al 2004). During this period the gonads start to develop, and the primordial germ cells can transform into oogonia or spermatogonia, depending on the hormone used.…”