(The methylen-blus reduction-test as prediction of semen quality of rainbow trout, Salmo irideus Gibbons.)

Abstract

This report details a study about methylene-blue reduction test for semen evaluation for freshwater fishes. Semen was collected from 62 samples of rainbow trout (Salmo irideus GibbonS), of the Estação Experimental de Salmonicultura de Campo do Jordão (São Paulo). The test began with each semen sample diluted at the rate of 1 part semen to 1 part of methylene blue. The methylene-blue reduction time was related with total spermatozoa concentration and with the number of live spermatozoa. The correlation coefficients (r) obtained were: -0.36* and -0.40*, respectively, being therefore statistically significant at 5 level of probability. The methylene-blue reduction test can be used as auxiliary method for semen evaluation in the studied species.