Farias Renata da Silva, Oliveira Karolayne Ribeiro da Silva, de Souza Marília Espíndola, Ferreira Dijaci Araújo, Silva Alluanan Adelson do Nascimento, da Silva Valdemiro Amaro, Dunham Rex, Coimbra Maria Raquel Moura
Departamento de Pesca e Aquicultura, Universidade Federal Rural de Pernambuco, Recife, PE, Brasil.
Colégio Agrícola Dom Agostinho Ikas, Universidade Federal Rural de Pernambuco, São Lourenço da Mata, PE, Brasil.
Anim Reprod. 2023 Mar 6;20(1):e20220080. doi: 10.1590/1984-3143-AR2022-0080. eCollection 2023.
The females of yellowtail tetra (), known as the freshwater sardine, are approximately 1.33 times larger than males, and thus, all-female monosex culture would increase production and reduce size variability. The present work aimed to identify the optimal dose of 17α-methyltestosterone (MT) to be used in the masculinization of for indirect sex reversal. Three different concentrations of MT (20, 40, and 60 mg/kg of feed in the diet) were fed to the fry for 30 days. Thirty adult individuals from each treatment, including the control (0 mg MT/kg), were evaluated for gonadal development, morphological and histological sexual identification, zootechnical performance, and the possible genotoxic effect caused by prolonged exposure to MT. MT significantly (<0.01) affected the differentiation of the gonads, with the presence of possible inhibitory effects in all treatments. Intersex individuals were present in the 20 and 60 mg MT/kg treatments. All treatments were able to masculinize and the treatment with the lowest hormone concentration produced the highest percentage of males 76.7%, while the control had 46.7% males. The presence of erythrocyte nuclear alterations indicated a possible cytotoxic effect of MT in treatments 40 and 60 mg MT/kg, however, the use of the hormone did not affect the growth and the survival of the individuals. Thus, the use of MT is a viable option for obtaining neomales as a first step into the production of all-female progenies.
黄尾魮脂鲤（俗称淡水沙丁鱼）的雌性个体比雄性个体大约大1.33倍，因此，全雌单性养殖将提高产量并减少体型差异。本研究旨在确定用于黄尾魮脂鲤雄性化间接性逆转的17α-甲基睾酮（MT）的最佳剂量。将三种不同浓度的MT（饲料中分别为20、40和60 mg/kg）投喂给鱼苗30天。对每个处理组（包括对照组（0 mg MT/kg））的30只成年个体进行性腺发育、形态学和组织学性别鉴定、畜牧学性能以及长期接触MT可能产生的遗传毒性效应评估。MT对性腺分化有显著影响（<0.01），所有处理组均可能存在抑制作用。在20和60 mg MT/kg处理组中出现了雌雄同体个体。所有处理组均能使黄尾魮脂鲤雄性化，激素浓度最低的处理组产生的雄性比例最高，为76.7%，而对照组雄性比例为46.7%。红细胞核改变表明在40和60 mg MT/kg处理组中MT可能具有细胞毒性作用，然而，激素的使用并未影响个体的生长和存活。因此，使用MT是获得新雄性个体作为生产全雌后代第一步的可行选择。
