The spermatocrit for evaluation of spermatic concentration of rainbow trout, Salmo irideus Gibbons

Abstract

With the objective to simplify the evaluation of espermatozoa concentration, at the laboratory or in field conditions, 45 sperm samples of rainbow trout, Salmo irideus Gibbons, were examined at Estação Experimental de Salmonicultura de Campos do Jordão (São Paulo), during the reproductive season of 1981 and 1983. The millimeter measure of column in the capillary tube of microhematocrit after centrifugation (spermatocrit) was related with hemocytometer count of spermatozoa per mm (Neubauer Improved). The regression equation was found to be: Y = 8,174,507 + 482,372.X (r = 0.85*), where Y represents the spermatozoa concentration per mm³ and X, the spermatocrit in millimeter. The average spermatocrit was 16.2 mm ± 4.14 and the average hemocytometer count was 15,988,933 ± 2,357,038 spermatozoa per mm³.