The objective of this experiment was estimate sperm concentration of "dourado" (Salminus brasiliensis), "curimba" (Prochilodus lineatus), "jundiá" (Rhamdia quelen), "cascudo-preto" (Rhinelepis aspera) and Nile tilapia (Oreochromis niloticus) by the method of spermatocrit. It was used 19, 58, 51, 43 and 85 brood fish of "dourado", "curimba", "jundia", "cascudo-preto" and Nile tilapia, respectively. Except for the Nile tilapia, the fishes were subjected to the hormonal induction process and then submitted to the semen collection. The measurement techniques of the sperm concentration by sperm count in Neubauer chamber (CSPZ) and by spermatocrit (ESPMT) were compared. The results were submitted to the regression analysis at 5% of probability. It was observed that the variables CSPZ and ESPMT presented linear relationship to the "curimba", "jundia" and Nile tilapia with equations y = 6.6624 × 10(9) + 368553 × 10(8)x; y = 2.153 × 10(9) + 4.426 × 10(8)x and y = -9.0897 × 10(8) + 6.0167 × 10(8), respectively. The method of spermatocrit can be used to estimate the sperm concentration of "curimba", "jundiá" and Nile tilapia.
fish reproduction; Oreochromis niloticus; Prochilodus lineatus; Rhamdia quelen; Rhinelepis aspera; Salminus brasiliensis
