Cooling of pirapitinga (Piaractus brachypomus) embryos stored at -10ºC.

Cryopreservation has not been used successfully to preserve fish embryos, although chilling techniques have been used with good results. The aim of this study was to chill Piaractus brachypomus embryos at - 10°C for various storage times. Embryos at the following ontogenetic stages were used: blastoderm - 1.2 hours post-fertilization (hpf); epiboly - 5 hpf; blastopore closure - 8 hpf; and appearance of the optic vesicle - 13 hpf. One hundred embryos were selected from each ontogenetic stage and chilled at - 10°C for 6 or 10 h. The results were analysed using analysis of variance (ANOVA) and Tukey's test at a 5% significance level. A significantly greater number of completely developed live larvae were observed following embryonic treatment with a cryoprotectant solution that contained 17.5% sucrose and 10% methanol. There was no survival for embryos cooled at - 10°C in initial developmental stages (1, 2 and 5 h hpf). Furthermore, higher survival rates were observed when embryos were treated at more advanced developmental stages (8 and 13 hpf). Therefore, P. brachypomus embryos at the blastopore-closure (8 hpf) or appearance-of-optic-vesicle (13 hpf) stages should be used for embryo chilling protocols and chilling should be performed using a 17.5% sucrose with a 10% methanol solution at - 10°C for up to 6 h. The best results were obtained with 13-hpf and 8-hpf embryos and cooling at 6 h of storage.

Resfriamento e criopreservação de embriões de peixes / Cooling and cryopreservation of fish embryos

Nas últimas décadas, as populações naturais de peixes têm diminuído devido à degradação ambiental e pesca excessiva, o qual precipita a descaracterização e o desaparecimento do habitat natural e dos organismos que nele vivem. Isso tem suscitado um grande interesse na criação de bancos de genes para organismos aquáticos selvagens. Visando suprir esse desequilíbrio ecológico e aumentar os benefícios econômicos, a piscicultura tem gerado inúmeros trabalhos no âmbito de técnicas de cultivo, controle de doenças, avaliação dos gametas produzidos em cativeiro e técnicas para congelamento seminal e de embriões. A criopreservação de sêmen de peixes tem sido pesquisada, no entanto ainda é necessário otimizar protocolos de resfriamento para preservação de embriões e escolher o crioprotetor ideal para a espécie. (AU)

In recent decades, the natural fish population have declines due to overfishing and environmental degradation, wich precipitates the disappearance of natural habitat and his living organisms. This situation increased the interest for the creation of gene banks for wild aquatic organism. The fisherie constantly generates numerous research about techniques to control diseases, evaluation of gametes quality produced in captivity and freezing process to sperm end embryos. Sperm cryopreservation has been investigates with success, however it is necessary optimize cooling protocol for embryos. The results of this reviews show the need more research to choose a optimal cryoprotectant for the fish species for embryos.(AU)

Resfriamento e criopreservação de embriões de peixes / Cooling and cryopreservation of fish embryos

Nas últimas décadas, as populações naturais de peixes têm diminuído devido à degradação ambiental e pesca excessiva, o qual precipita a descaracterização e o desaparecimento do habitat natural e dos organismos que nele vivem. Isso tem suscitado um grande interesse na criação de bancos de genes para organismos aquáticos selvagens. Visando suprir esse desequilíbrio ecológico e aumentar os benefícios econômicos, a piscicultura tem gerado inúmeros trabalhos no âmbito de técnicas de cultivo, controle de doenças, avaliação dos gametas produzidos em cativeiro e técnicas para congelamento seminal e de embriões. A criopreservação de sêmen de peixes tem sido pesquisada, no entanto ainda é necessário otimizar protocolos de resfriamento para preservação de embriões e escolher o crioprotetor ideal para a espécie.

In recent decades, the natural fish population have declines due to overfishing and environmental degradation, wich precipitates the disappearance of natural habitat and his living organisms. This situation increased the interest for the creation of gene banks for wild aquatic organism. The fisherie constantly generates numerous research about techniques to control diseases, evaluation of gametes quality produced in captivity and freezing process to sperm end embryos. Sperm cryopreservation has been investigates with success, however it is necessary optimize cooling protocol for embryos. The results of this reviews show the need more research to choose a optimal cryoprotectant for the fish species for embryos.