Sperm cryopreservation of lane snapper Lutjanus synagris(Linnaeus, 1758) / Criopreservação do sêmen do ariocó Lutjanus synagris (Linnaeus, 1758)

This study aims developing and evaluate a protocol of semen cryopreservation of the lane snapper Lutjanus synagris. Firstly, sperm motility rate, motility time, density and spermatocrit were appraised to characterize the sperm quality of the lane snapper. The effect of three extenders with distinct ionic compositions and pH values combined with seven concentrations of cryoprotector dimethylsulfoxide (0; 2.5; 5.0; 7.5; 10.0; 12.5 e 15.0%), five cooling rates (110, 90, 60, 45 e 30°C –min), nine equilibration time (1; 2,5; 5; 10; 15; 20; 25; 30 e 60 minutes) e five dilutions ratio (1:1; 1:3; 1:6; 1:10 e 1:20) on the sperm motility rate and motility time were analyzed. Fertilization test was accomplished to evaluate the viability of the cryopreserved sperm. The higher sperm motility rate and motility time (P<0.05) was achieved by combining extender with pH 8.2 with 10% concentration of dimethylsulfoxide and cooling rate 60°C –min, 1 minute of equilibration time and 1:3 (v/v) dilution ratio. The use of cryopreserved sperm presented fertilization rates >60% validating the present protocol for lane snapper. The cryoconserved sperm of lane snapper is a viable alternative, being possible to maintain appropriate sperm viability.(AU)

Este estudo teve a finalidade de desenvolver e avaliar um protocolo de crioconservação do sêmen do ariocó Lutjanus synagris. Para caracterizar o sêmen foram avaliados a taxa de motilidade, a duração da motilidade, a concentração espermática e o espermatócrito. Em seis experimentos foram analisados os efeitos de três diluentes, com distintas composições iônicas e valores de pH distintos, combinados com sete concentrações de dimetilsulfóxido (0; 2,5; 5,0; 7,5; 10,0; 12,5 e 15,0%), cinco velocidades de congelamento (–110, –90, –60, –45 e –30°C/min), nove tempos de equilíbrio (1; 2,5; 5; 10; 15; 20; 25; 30 e 60 minutos) e cinco proporções de sêmen:diluente (1:1; 1:3; 1:6; 1:10 e 1:20) sobre a taxa de motilidade e a duração da motilidade espermáticas. Posteriormente um teste de fertilização foi realizado para avaliar a viabilidade do sêmen crioconservado. O tratamento que propiciou maior taxa de motilidade e duração da motilidade espermáticas (P<0,05) foi aquele proporcionado pelo emprego do diluente com pH 8,2 com dimetilsulfóxido a 10%, em uma velocidade de congelamento de –60°C/min, com tempo de equilíbrio de 1 minuto e na proporção de 1:3 (v/v). O sêmen crioconservado apresentou taxa de fertilização superior a 69% validando o presente protocolo para o ariocó. A crioconservação do sêmen do ariocó é uma alternativa viável, sendo possível manter uma apropriada qualidade espermática.(AU)

Water-induced hypo-osmotic test for the evaluation of canine sperm membrane integrity

The purpose of this study was to investigate the efficiency of the water test to evaluate the functional membrane integrity of ejaculated canine sperm after collecting, cooling, and freezing-thawing. Twenty-five ejaculates were obtained from 12 stud dogs by digital manipulation. Sperm-rich fractions were evaluated, diluted, cooled at 5ºC and frozen-thawed. A conventional hypo-osmotic swelling test (HOST) using a fructose solution (60 mOsm/l) was compared with a HOST using distilled water (0 mOsm/l), for evaluation of the functional integrity of the plasma membrane in fresh, cooled, and frozen-thawed semen. Distilled water detected a higher percentage of reacted sperm in fresh semen (91.2 ± 0.1%) than the conventional HOST (90.6 ± 0.1%; P < 0.05). For cooled and frozen-thawed semen, the water test was as efficient as the conventional HOST (81.2 ± 0.3% and 80.3 ± 0.3%, respectively), for detecting functional membrane integrity (P > 0.05). Regardless of the test used, there was a decrease in the mean percentage of reacted sperm after equilibrium and freezing-thawing (P < 0.05). In conclusion, this study demonstrated that water can efficiently replace conventional fructose-based hypo-osmotic media for evaluation of the functional integrity of the plasma membrane of ejaculated fresh, cooled, and frozen–thawed canine sperm.(AU)

Water-induced hypo-osmotic test for the evaluation of canine sperm membrane integrity

The purpose of this study was to investigate the efficiency of the water test to evaluate the functional membrane integrity of ejaculated canine sperm after collecting, cooling, and freezing-thawing. Twenty-five ejaculates were obtained from 12 stud dogs by digital manipulation. Sperm-rich fractions were evaluated, diluted, cooled at 5ºC and frozen-thawed. A conventional hypo-osmotic swelling test (HOST) using a fructose solution (60 mOsm/l) was compared with a HOST using distilled water (0 mOsm/l), for evaluation of the functional integrity of the plasma membrane in fresh, cooled, and frozen-thawed semen. Distilled water detected a higher percentage of reacted sperm in fresh semen (91.2 ± 0.1%) than the conventional HOST (90.6 ± 0.1%; P 0.05). Regardless of the test used, there was a decrease in the mean percentage of reacted sperm after equilibrium and freezing-thawing (P < 0.05). In conclusion, this study demonstrated that water can efficiently replace conventional fructose-based hypo-osmotic media for evaluation of the functional integrity of the plasma membrane of ejaculated fresh, cooled, and frozen–thawed canine sperm.