Biologia reprodutiva e uso de biotécnicas em machos de peneídeos

Abstract

The development of technologies applied to aquaculture contributes significantly to the expansion of this segment. Reproductive biotechnologies in carcinicultre have been improved over the years, but still have many issues to be explored. This study aimed to collaborate with knowledge of reproductive characteristics and suggests a new approach to sperm cryopreservation of penaeid shrimps with the vitrification method. The first chapter presents an updated literature review comprising the main topics on penaeids males reproduction. The second chapter provides the first description, by scanning electron microscopy, of the spermatophore and spermatozoa of the pink shrimp Farfantepenaeus subtilis, which presented similar features of Farfantepenaeus subgenre, highlighting the peripheral positioning of sperm mass, near the outer cuticle of the spermatophore. In the third chapter it was evaluated the cadaveric sperm viability in the white shrimp Litopenaeus vannamei stored for up to 96 hours at different temperatures (26, 4 and -18°C). Sperm kept at 4°C showed excellent conditions for up to 96 hours of storage. Meanwhile the worst conditions were found in sperm kept at -18°C that presented high mortality rates for all tested periods. In the fourth chapter we aimed to develop a sperm cryopreservation protocol in the white shrimp Litopenaeus vannamei by vitrification method. The most appropriate cryoprotectants to vitrification were selected by toxicity tests. Thus methanol and lecithin, intra and extracellular cryoprotectants respectively, were used singly or in combination. After vitrification the sperm was stored in liquid nitrogen for up to 120 days. The high sperm viability rates observed suggests that vitrification method is efficient for L.vannamei sperm cryopreservation. In the fifth chapter, females were inseminated with sperm cryopreserved by vitrification method. The efficiency of the method was evaluated by fertilization and hatching nauplii rates. As sperm viability, the fertilization rate was satisfactory in all treatments. However, only the control group had nauplii hatching. Therefore, by comparing the fertilization and hatching rates, it is suggested that some unknown factor is interrupting embryo development.