Anormalidades espermáticas de Piaractus mesopotamicus após descongelamento utilizando diferentes metodologias

PALAVRAS CHAVE ADICIONAISMotilidade espermática. Peixe. ADDITIONAL KEYWORDSSperm motility. Fish. RESUMOObjetivou-se avaliar a influência de ativadores com diferentes osmolaridades e taxa de diluição na ativação de sêmen criopreservado de curimba (Prochilodus lineatus). Foram utilizados quatro reprodutores machos capturados na Estação de Piscicultura da CEMIG, Itutinga, MG. As amostras de sêmen foram diluídas em duas soluções (DMSO + lactose e metanol + lactose) na proporção de 1:4 e congeladas. Foram avaliadas as taxas (%) e duração (s) da motilidade espermática dos tratamentos. Na ativação foram utilizados ativadores contendo as respectivas osmolaridades: 30, 99, 183 e 293 mOsm nas taxas de diluição de 1:2, 1:4, 1:6, 1:8 sêmen: ativador. A taxa de diluição 1:2 e 1:8 foram estatisticamente significativas para duração da motilidade para o sêmen criopreservado com DMSO. Para a diluição 1:2, o sêmen ativado com o ativador contendo 30 mOsm, apresentou duração de motilidade maior em relação ao sêmen ativado com ativadores com 183 e 293 mOsm. No entanto, para a utilização do ativador com 30 mOsm, se obteve maior duração da motilidade na diluição de 1:2 em relação a diluição de 1:4. Na taxa de diluição 1:6, quando o sêmen foi ativado com o ativador de 30 mOsm, a taxa de motilidade foi superior à apresentada pelo sêmen que foi ativado com 293 mOsm. Na taxa de diluição de 1:8, o uso de ativador contendo 99 mOsm apresentou maior duração de motilidade em relação ao uso do ativador com 293 mOsm. Ativadores contendo altas osmolaridades podem proporcionar menores taxas e duração da motilidade em sêmen de curimba (Prochilodus lineatus) criopreservado com os crioprotetores metanol ou DMSO. SUMMARYThe objective of this work was to evaluate the influence of activators with different osmolarities and dilution rate in the activation of cryopreserved semen of curimba (Prochilodus lineatus). We used four breeding males captured in the Fishfarming Station of CEMIG, Itutinga, MG. Semen samples were diluted in two solutions (DMSO + methanol and lactose + lactose) at 1:4 ratio and frozen. The rates (%) and duration (s) of sperm motility for treatments were assessed. Activators with respective osmolarities: 30, 99, 183 and 293 mOsm at dilution rates of 1:2, 1:4, 1:6, 1:8 (semen: activator) were used. The dilution rates of 1:2 and 1:8 influenced duration of motility in semen cryopreserved with DMSO. For the 1:2 dilution, the semen activated with the activator containing 30 mOsm, presented greater motility duration than semen activated with activators with 183 and 293 mOsm. However, for the activator with 30 mOsm, it was obtained longer motility duration at a dilution of 1:2 compared to 1:4 dilution. At 1:6 dilution rate, when the semen was activated with the activator 30 mOsm, the motility rate was higher than that provided by the semen that was activated with 293 mOsm. At the dilution rate of 1:8, the use of activator containing 99 mOsm showed longer motility duration in relation to use of the activator with 293 mOsm. Activators containin...

Abstract:This study was designed to identify and measure the gametes of neotropical fish using ultrastructural analysis. Number, shape and size of micropyle and ultrastructure of egg membrane and of the micropyle canal; the number and length of the longest and shortest ridge in the micropyle region beyond the structures of the sperm cell have been used as taxonomic tool in ichthyology . Gametes of six breeding pairs of Piaractus mesopotamicus, Brycon orbignyanus, Salminus brasiliensis and Prochilodus lineatus were collected, fixed and subjected to scanning electron microscopy for the observation and measurement of the structures. The results showed many similarities between the gametes of the studied species. An array of grooves and folds was observed in the micropyle in all species but not in the Prochilodus lineatus oocytes. The micropyle was funnel-shaped in all species. The oocytes showed a great variation in the diameters of major and minor micropyle ostium, evidencing different reproductive strategies. The sperm cells showed simple structures with ovoide heads, a cylindrical midpiece with a single flagellum and no acrosome. This study may contribute to a better understanding of fish reproductive biology, conservation genetics and breeding studies. Eight hours after the second CECP dose, fish were removed from the aquarium and had their urogenital papilla cleaned and dried with a towel. The collection of gametes began after delicate manual massage of the coelomic wall. This procedure was performed in accordance with the Ethical Principles of Animal Experimentation, Protocol 040/2009 of Lavras Federal University-UFLA. Keywords Ultrastructural analysis of gametesPost-fixation methodology was accomplished in accordance to the methodology employed in the Laboratory of Eletronic Microscopy and Ultrastructural Analysis of Lavras Federal University-UFLA. Samples containing 1mL of semen or 30 oocytes of each species were fixed separately in microtubules containing a solution of 2.5% glutaraldehyde and 2.0% paraformaldehyde in 0.05 M sodium cacodylate buffer, pH 7.2, calcium chloride 0.001 M. The samples were maintained for 24 hours at 4°C. After this, samples were immersed in 1% osmium tetroxide for 4 hours at room temperature and subsequent dehydration through in ascending series of acetone (25%, 50%, 75%, 90% and 100%).Before evaluation in the electron scanning microscope, the oocytes and spermatozoa were dehydrated with a CPD030 critical point instrument. The samples were coated with gold in a SCD 050 vacuum evaporator according to protocols designed in Ultrastructural Analysis and Electronic Microscopy Laboratory of Federal University of Lavras, Brazil. Morphometric analysis of the gametesIn the morphometry of the oocytes, was valued the major diameter (Md), minor diameter (md), total volume and the sperm head width ratio and the major diameter of major micropyle ostium (MSH/MO). In the morphometry of the micropyle (Figure 1) in the oocytes surface, was measured the diameters of the major ostium (MO) and minor...