EFFECTS OF THE LOW INTENSITY CENTRIFUGATION AND THE BREED ON THE QUALITY OF FRESH CANINE SEMEN

The effect of the low intensity centrifugation (300xg), as well as the breed variation were evaluated. To this, semen of 12 dogs of the Beagle (n = 3), Schnauzer (n = 3), Doberman (n = 3) and Boxer (n = 3) breeds, 3 ejaculates collected per individual, totaling 36 ejaculates were used. The direct microscopic evaluation of the motility parameters and the hypoosmotic and supravital staining tests were used. The individual means of sperm vigor and motility varied from 3.5 to 5.0 and from 63 to 90% respectively, while the breed means ranged from 4.4 to 4.9 and from 80 to 90%, respectively. No significant difference was observed in any of the parameters evaluated in fresh or centrifuged semen of dogs among the different breeds studied. Centrifugation of semen resulted in a reduction of about 13% in sperm vigor and 14% in motility and sperm index. The analysis of the parameters of viability and sperm membrane integrity shows a 38% and 14% reduction in the percentage of reactive cells to the hypoosmotic test and supravital staining respectively. These results allow us to conclude that the centrifugation protocol, even at low intensity, significantly reduces sperm motility, the membrane integrity and sperm viability, this effect being more clearly perceived through the hypoosmotic test. RESUMEN El efecto de la centrifugacion a baja intensidad (300xg), asi como la variacion racial fueron evaluados. Para esto, semen de 12 perros de las razas Beagle (n=3), Schnauzer (n =3), Doberman (n = 3) y Boxer (n = 3), 3 eyaculados colectados por individuo, totalizando 36 eyaculados fueron usados. La medicion por microscopia directa de los parametros de motilidad, asi como el test hipoosmotico y la tincion supravital fueron usadas. La media individual del vigor espermatico y la motilidad variaron desde 3,5 a 5,0 y desde 63 a 90% respectivamente, mientras que las medias de las razas variaron desde 4,4 a 4,9 y desde 80 a 90%, respectivamente. No se observaron diferencias significativas en los parametros evaluados el semen fresco y centrifugado entre las razas estudiadas. El analisis de los parametros de vitalidad y la integridad de la membrana espermatica muestra una reduccion de 38% y 14% en el porcentaje de celulas reactivas al test hipoosmotico y a la tincion supravital respectivamente. Estos resultados llevan a la conclusion de que el protocolo de centrifugacion, aun a baja intensidad, significativamente reduce la motilidad espermatica y la integridad de la membrana y vitalidad espermatica, siendo este efecto percibido mas claramente a traves del test hipoosmotico.