(Fertility of rainbow trout Salmo irideus Gibbons sêmen, diluted at various levels.)

Abstract

This experiment was carried out at Trout Culture Experimental Station of Campos do Jordão, São Paulo Brazil (22°45'S and 45°30'W) in order to determine the minimum amount of live spermatozoa necessary to fertilize one egg of rainbow trout, Salmo irideus, during the reproductive season of 1985. Various dilution levels were done with a semen pool of the four males, with seminal plasma, so that the lower density was 10 x 10³ and the higher density was 10 x 10⁶ sperm cell/egg. The best results of fertilization were obtained from 200,000 sperm/egg (80.83%) upwards. The present investigation will improve the artificial reproduction with fresh or frozen semen, the possibility to reduce the stock of males at intensive fisheries and a rational exploration of selected sires and will decrease the production cost.