ABSTRACT
This study evaluated the reproductive dynamics and gonadal morphology of piaparas (Leporinus obtusidens) captured downstream from the Funil Hydroelectric Power Station. The 107 piaparas evaluated were captured monthly from Sep 2006 to Aug 2007. The data were stratified among the seasons to evaluate gonad maturation and the reproductive period was determined by assessing the gonadosomatic index, hepatosomatic index, abdominal fat index (AFI), weight:length ratio, condition factor and sexual proportion. The reproductive period lasted from winter to summer (Jul-Mar) in females and from spring to autumn (Sept-Jun) in males. AFI was high during and after the reproductive period in females and only during the reproductive period in males. The highest HIS values for males and females were obtained in spring and summer (Sept-Mar). The females observed did not spawn and showed follicular atresia. These characteristics suggest that L. obtusidens does not use the study area as a reproductive site and probably migrates for this purpose.
Este estudo avaliou a dinâmica reprodutiva e a morfologia gonadal de piaparas (Leporinus obtusidens) capturados a jusante de uma usina hidrelétrica. Os 107 exemplares avaliados foram capturados mensalmente, de setembro de 2006 a agosto de 2007. Os dados foram estratificados entre as estações do ano para se avaliar a maturação gonadal, e o período reprodutivo foi determinado por meio da avaliação do índice gonadossomático, índice hepatossomático, índice de gordura abdominal (AFI), relação peso:comprimento, fator de condição e proporção sexual. O período reprodutivo foi observado do inverno para o verão, julho-março, para as fêmeas, e da primavera para o outono, setembro-junho, para os machos. AFI foi alto durante e após o período reprodutivo em fêmeas e apenas durante o período reprodutivo em machos. Os maiores valores para machos e fêmeas foram obtidos na primavera e no verão. As fêmeas observadas não desovaram e mostraram atresia folicular. Essas características sugerem que L. obtusidens não usa a área de estudo como sítio reprodutivo e, provavelmente, realiza migração.
Subject(s)
Animals , Follicular Atresia/physiology , Gonads/anatomy & histology , Fishes/anatomy & histology , Fishes/growth & development , Fishes/physiology , Hydroelectric Power Plants (Environmental Health)ABSTRACT
This study investigated the application of intra- and extra-cellular cryoprotectant combinations on the quality of curimba Prochilodus lineatus semen subjected to cryopreservation. Semen treatments were tested with 8% DMSO or methanol as intracellular cryoprotectant, 5% egg yolk or lactose as extracellular cryoprotectant and 5% BTS. These cryoprotectant combinations are suitable for curimba but have not been tested at the lesser concentrations proposed or in combination with BTS. Semen samples collected from 19 curimbas were diluted into one of four cryoprotectant combinations: DMSO+yolk; DMSO+lactose; methanol+yolk; and methanol+lactose. After dilution, semen samples were cryopreserved in 0.5 mL straws for 10 days in a liquid nitrogen tank. Semen was thawed in a water bath at 60°C for 8s. We evaluated the quality of fresh, diluted (pre-freezing) and post-freezing semen according to sperm motility rate (%) and duration (s). Sperm morphology was also analyzed in thawed semen. Sperm motility rate decreased progressively after dilution and thawing. The motility rate in post-freezing semen was higher in the treatments using DMSO+lactose and methanol+yolk. Sperm motility duration in post-freezing sperm was greater in the treatments using methanol rather than DMSO as intracellular cryoprotectant, irrespective of the extracellular cryoprotectant used. Abnormality frequency in thawed sperm was less in semen treated with egg yolk than with lactose. Thus the use of methanol intracellular cryoprotectant is recommended along with yolk extracellular cryoprotectant in the cryopreservation process for curimba semen.
