Effect of refrigeration at -1°C on spermatozoa quality of domestic cats
Efeito da refrigeração a -1°C na qualidade de espermatozoides de gatos domésticos
Pesqui. vet. bras; 40 (4), 2020
Publication year: 2020
The objective of this study was to evaluate the sperm quality obtained of domestic cats by electroejaculation and recovery of the tail of the epididymis after cooling at -1°C and 4°C for 24 and 48 hours. Twenty-nine adult cats (2 to 6kg) were used. Sperm collection was performed by electroejaculation (EEJ), and after 48 hours, the cats were orchiectomized, and sperm sample was obtained from the vas deferens and epididymis tail (EPD). The samples were diluted in ACP-117® extender, and the sperm characteristics were evaluated at three different moments: when still fresh, 24 and 48 hours after cooling. The objective of this study was to evaluate the sperm quality obtained of domestic cats by electroejaculation and recovery of the tail of the epididymis after cooling at -1°C and 4°C for 24 and 48 hours. Twenty-nine adult cats (2 to 6kg) were used. Sperm collection was performed by electroejaculation (EEJ), and after 48 hours, the cats were orchiectomized, and sperm sample was obtained from the vas deferens and epididymis tail (EPD). The samples were diluted in ACP-117® extender, and the sperm characteristics were evaluated at three different moments: when still fresh, 24 and 48 hours after cooling. In order to compare the two refrigeration temperatures, the first stage was to analyze if there was a difference between the harvesting techniques. After this, two experiments were conducted: in the first, sperm sample from 14 cats were used and the cooling was performed at -1°C; and in the second, sample from 15 cats were used and the sperm were refrigerated at 4°C. Sperm kinetics were evaluated by computerized analysis (CASA) and concentration by Neubauer chamber, spermatic morphology was evaluated by modified Karras staining, and membrane integrity was evaluated by eosin nigrosine. The results obtained were analyzed in R software, version 3.2.5 using the Mann-Whitney test for variables with abnormal distributions, considering significance at the level of 5%. In ejaculate samples, higher values of total morphological defects were observed after 24 and 48 hours of refrigeration at 4°C (P<0.022) compared to refrigeration at -1°C, using Friedman test. To quantify the decrease in sperm quality, parameter reductions were calculated among time points (F-24h/F-48h/24h-48h). In EPD samples, a greater reduction in sperm quality was detected after 24 hours of refrigeration at 4°C, both in motility and sperm kinetics and in the movement and velocity indices, compared to refrigeration at -1°C. Based on the results, it can be concluded that cooling of feline spermatozoa at -1°C for up to 48 hours was efficient in maintaining spermatic quality collected by EEJ and EPD, and it could be an alternative to spermatozoa cryopreservation in domestic felines.(AU)
O objetivo deste trabalho foi avaliar a qualidade espermática de gatos domésticos obtidos por eletroejaculação e recuperação da cauda do epidídimo após a refrigeração a -1°C e a 4°C por 24 e 48 horas. Vinte e nove gatos adultos (2 a 6kg) foram utilizados. A colheita de espermatozoides foi realizada por eletroejaculação (EEJ) e, após 48 horas, os gatos foram orquiectomizados, e as amostras espermáticas foram obtidas a partir do ducto deferente e da cauda do epidídimo (EPD). As amostras foram diluídas em ACP-117® e as características espermáticas foram avaliadas em três momentos distintos: fresco, 24 e 48 horas após a refrigeração. Para ser possível comparar as duas temperaturas de refrigeração, a primeira etapa foi analisar se havia diferença entre as técnicas de colheita. Após isto, dois experimentos foram conduzidos: no primeiro, espermatozoides de 14 gatos foram utilizados e a refrigeração foi realizada a -1°C; e no segundo, amostras de 15 gatos foram utilizados e os espermatozoides foram refrigerados a 4°C. A cinética espermática foi avaliada por análise computadorizada (CASA), a concentração por câmara de Neubauer, a morfologia espermática foi avaliada pela coloração de Karras modificada, e a integridade da membrana foi avaliada por eosina nigrosina. Os resultados obtidos foram analisados no software R, versão 3.2.5, utilizando o teste de Mann-Whitney para variáveis com distribuições anormais, considerando significância ao nível de 5%. No ejaculado, maiores valores de defeitos morfológicos totais foram observados após 24 e 48 horas de refrigeração a 4°C (P<0,022) em comparação com refrigeração a -1°C, usando o teste de Friedman. Para quantificar a diminuição na qualidade espermática, as reduções dos parâmetros foram calculadas entre os pontos de tempo (F-24h/F-48h/24h-48h). Na EPD, uma maior redução na qualidade espermática foi detectada após 24 horas de refrigeração a 4°C, tanto na motilidade e na cinética espermática quanto nos índices de movimento e velocidade, em comparação com a refrigeração a -1°C. Com base nos resultados, pode concluir-se que a refrigeração dos espermatozoides felino a -1°C, até 48 horas, foi eficaz na manutenção da qualidade espermático colhidos por EEJ e EPD, e pode ser uma alternativa para a criopreservação de espermatozoides em felinos domésticos.(AU)