Estudo morfológico e morfométrico de gônadas da tilápia do Nilo (Oreochromis niloticus) submetidas a tratamentos hormonais com 17 metil testosterona e β – estradiol.

Abstract

The global aquaculture is growing faster than any other activity of the primary sector. The Brazil has extremely favorable conditions for fish farming, in addition to the great market potential, the country has favorable climate, good availability of areas, large crops of grain and enviable water potential. Tilapia are native to Africa and Asia Minor. About 70 species are taxonomically classified. The tilapia is widely distributed throughout Brazil and is created in various production systems. The development and intensification of farming are dependent on the successful control and manipulation of some physiological functions, among them, playing. In recent years, research has focused on the demand for reliable methods of producing progeny of individuals of one sex. The most practical technique of obtaining populations monosex tilapia is handling the phenotypic sex of the fish by treatment with sex steroids. This study aimed to evaluate the performance of gonadal growth of Nile tilapia (Oreochromis niloticus) in the first 30 days and final fattening phase; fed with added hormones  -17 methyl testosterone and β - estradiol, used to induce phenotypic sex reversal as well as perform morphological study of the gonads of male and female populations, not undergoing hormonal treatment. The experiment was conducted on the basis of the fish UFRPE and Laboratory of Histology DMFA / UFRPE. A total of 400 adults and 30 larvae of Nile tilapia (Oreochromis niloticus). The larvae were divided into 03 distinct groups: Group T1: 100 animals fed with commercial feed with added β - estradiol (20 mg / kg). T2: 100 animals fed with commercial feed with added 17 -  - methyltestosterone (60 mg / kg) Control Group (CG): 200 animals fed with commercial diet free of additives. Mice from all groups were fed five times a day for 35 days. The adults were cultured for 24 weeks in tanks fed diet added network of hormones in the first 30 days and commercial diet free of additives and specific to each stage of cultivation in the later stages. The histological material was collected, processed and analyzed according to the usual methods for routine histology. Statistical analyzes were applied ANOVA Tukey.c