Alterações de cromatina em espermatozóides de ovinos e caprinos avaliadas por azul de toluidina e alaranjado de acridina

Abstract

Males with normal spermogram can behave as subfertile or pass for periods of subfertility. Chromatin alterations of spermatozoa can account for such behavior. The objective of the present work was to test the efficacy of toluidine blue (TB) and acridine orange (AO) in the identification of alterations in chromatin compaction in spermatozoa from rams and goats, in addition to evaluate the correlation between those alterations and the ones of spermatic morphology. In order to do that, samples of semen from 15 rams and 15 goats were evaluated with 10 replications for each method. Mean, standard deviation and coefficient of variation were calculated for each animal and technique. Student's t-test was used to evaluate differences between the averages of two methods. Pearson correlation coefficient, weighted and non weighted kappa coefficient were also calculated to evaluate the agreement between methods with TB and AO. It was verified that morphological alterations of head not always are accompanied by alterations in chromatin identified by the methods used in this work. The TB method is more stable and sensitive than AO method for both species and this is most appropriate for goats. However, due to the very low repeatability, both methods are not indicated for evaluating ram spermatozoa.