AVALIAÇÃO DOS MÉTODOS DE COLORAÇÃO DA MORFOLOGIA ESPERMÁTICA DE CÃES (Canis familiaris)

Abstract

Semen quality assessment helps estimate the reproductive capacity of dogs, and sperm morphology is important for identifying abnormalities that may compromise reproductive potential. This study aimed to evaluate different staining methods for assessing canine sperm morphology. Five mixed-breed male dogs, aged one to seven years, underwent complete andrological examinations. Seminal samples were stained using Panoptic Rapid, Giemsa, Methylene Blue, Rose Bengal, and Congo Red. Two hundred spermatozoa per animal were evaluated for each staining method, using a randomized block design, with each dog considered a block. Data were subjected to analysis of variance (ANOVA) and Tukey’s test, with a significance level of 5%. Two dogs (40%) presented scrotal skin abnormalities, with no changes in the other reproductive organs. Ejaculate volume ranged from 1 to 3 mL, motility from 20% to 95%, and vigor scores from 4 to 5. Significant differences among staining methods (p < 0.05) were observed in the percentages of normal spermatozoa and major, minor, and total defects. The percentage of normal spermatozoa ranged from 46% to 71%, with no consistent pattern among dogs. Panoptic Rapid staining enhanced head shape assessment; Giemsa and Congo Red highlighted the midpiece and tail; Rose Bengal provided good visualization of the nucleus; and Methylene Blue showed lower contrast in the head region. It is concluded that staining methods influence the visualization of sperm structures and the identification of morphological defects in dogs.