COMPARISON BETWEEN TWO METHODS OF STAINING FOR ASSESSMENT OF MORPHOLOGY AND ACROSOME IN DOMESTIC CAT (Felis catus) SPERMATOZOA

Abstract

The objective of this study was to evaluate the efficiency of the modified Karras staining technique (KA) to analyze domestic cat sperm morphology by comparing it with the Fast Green FCF/ Rose Bengal staining (FR), previously used for this species. Four adult cats were used, from which sperm samples were collected four times in alternate days for each tom using an artificial vagina (n=16 ejaculates). Both staining techniques were performed for each ejaculate. For the FR staining technique, the semen in natura was diluted in 2.9% sodium citrate and, afterwards, in the staining solution. After 70 seconds, smears were made onto slide and dried at 37ºC. For the KA staining technique, previously made and formol saline fixed slides were sequentially immersed in Rose Bengal solution, Tannin solution, and Victoria Blue B solution, and dried at room temperature. For sperm evaluation, 200 sperm cells were assessed for each staining technique in all ejaculate samples using a bright field microscope at 1000X magnification. Statistical analysis used the non-parametric Wilcoxon test, establishing significance at p<0.05. For the KA staining technique, higher percentage of distal cytoplasmic droplets and lower percentage of sperm head defects were obtained when compared to the FR staining technique. This way, both staining techniques were not totally efficient for the assessment of morphological defects found in the domestic cat in natura spermatozoa.

KEY WORDS: Acrosome, domestic cat, spermatozoa, sperm morphology, staining.