Comparative evaluation of reproductive parameters between normal XX females and XY inverted females of Tilapia Oreochromis sp

• Grant number: 22/06612-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2022
• End date: December 31, 2023
• Field of knowledge: Agronomical Sciences - Fishery Resources and Fishery Engineering - Aquaculture
• Principal Investigator: Rafael Vilhena Reis Neto
• Grantee: Fabio Augusto Paiva Camisa Nova
• Host Institution: Faculdade de Ciências Agrárias. Universidade Estadual Paulista (UNESP). Campus do Vale do Ribeira. Registro , SP, Brazil

Abstract

The proposal aims to comparatively analyze the reproductive parameters of normal XX females and XY neofemales of Tilapia. The experiment will be carried out at the AquaVale fish farm located in the city of Registro/SP in the Vale do Ribeira. At first, a group of animals will undergo the feminization process to obtain XY females following three steps. First, newly generated larvae, still undifferentiated, will be submitted to diets containing the estrogen hormone 17-²-estradiol to produce XY females (neofemales), then 100 individuals with about 20 g obtained in the 1st stage will be chosen to be evaluated by molecular techniques using a Y chromosome specific marker (SNP), finally the XY females identified in the second stage and the normal XX females will be mated with normal XY males to compare the reproductive performance of the two groups. The following reproductive parameters will be evaluated from 36 females, 18 XX and 18 XY: quantification and classification of oocytes, hatching rate, fecundity, fertility. For classification of oocytes, at least 6 females will be sacrificed throughout the reproductive cycle for histological evaluation. A completely randomized design (DIC) will be used with two treatments (normal XX females and XY females) with 18 replications (animals). The data obtained will be previously tested for pre-assumptions and subsequently submitted to analysis of variance using the R software.