Macroscopic and microscopic evaluation of rainbow trout, sêmen, Salmo irideus Gibbons

Abstract

In order to improve the artificial reproduction in freshwater fishes of economical value, a study of the seminal characteristics of 79 males of rainbow trout, Salmo irideus Gibbons, two years old, was carried out at Estação Experimental de Salmonicultura de Campos do Jordão, during de reproductive season of 1980, 1981 and 1983. The seminal characteristics examined and the values obtained when estimated by confidence interval (95%) were: semen volume : 5.01 to 12.36 ml; sperm concentration: 15.07 to 20.99 x 10⁶/mm³; percentage of sperm motility: 55.86 to 72.94 and percentage of live sperm by differential staining method, 54.13 to 75.75. There was no statistically significant difference between the percentage of sperm motility by microscopic examination and percentage of live sperm obtained by differential staining method, when the data of productive season of 1981 and 1983 were analyzed by the X² (chi-square) test (pâ"°¤ 0.05).