ABSTRACT The use of carp pituitary extract (CPE) in fish reproduction may have drawbacks, whereas analogues of mammalian (aGnRHm) or salmon (aGnRHs) gonadotropins containing dopamine inhibitor (DI) may offer greater advantages. The objective of this study was to evaluate the effect of different hormone inducers on the reproduction of Prochilodus brevis males. A total of 44 specimens of P. brevis were divided into six groups, namely, CPE 4.0 mg; saline solution 1.0 mL; aGnRHm + DI 0.3 mg and 0.5 mg; and aGnRHs + DI 0.25 mL and 0.35 mL kg-1 of live weight. The number of ejaculates, seminal volume, curvilinear velocity (VCL), straight-line velocity (VSL), average path velocity (VAP), sperm morphology and concentration, and membrane and DNA integrity were determined. Sample normality was examined using the Shapiro-Wilk test, and homogeneity using the Levene test. Analysis of variance (ANOVA) was conducted, followed by Tukey's test to compare means, with statistical significance set at p < 0.05. Notably, all fish induced with CPE 4.0 and aGnRHm + DI demonstrated ejaculation, yielding a greater seminal volume. Sperm concentration under aGnRHs + DI 0.35 exceeded that with aGnRHm + DI 0.3 and CPE 4.0. Regarding velocity, aGnRHm + DI 0.3 outperformed aGnRHs + DI 0.35 in VCL, while aGnRHm + DI 0.3 and 0.5 and aGnRHs + DI 0.25 led to higher VSL than aGnRHs 0.35. Additionally, VAP was elevated under aGnRHm + DI 0.3 and CPE, in contrast to aGnRHs + DI 0.35. Improved sperm morphology was observed with aGnRHm + DI 0.5 and aGnRHs + DI 0.25 compared to aGnRHm + DI 0.3. The remaining parameters did not differ significantly.

Abstract The action of substances with non-permeable cryoprotectant potential, besides glucose, has not yet been studied for the species Prochilodus brevis. The objective of this work was to evaluate the action of four non-permeable cryoprotectants on this species sperm cryopreservation. Five pools were cryopreserved in a solution of 5% glucose and 10% dimethyl sulfoxide (Me2SO) associated or not (control) with cryoprotectants egg yolk (5, 10 or 12%), soy lecithin (2.5, 7.5 or 10%), sucrose (5, 10 or 20%) and lactose (5, 8 or 15%). After thawing, samples were evaluated for sperm kinetics (total motility, motility duration, velocities, and wobble - WOB), morphology and membrane and DNA integrity. The treatments containing egg yolk improved significantly (P<0.05) results when compared the control for the membrane integrity parameter. When compared to other treatments, egg yolk, at any concentration, presented higher results (P<0.05) for membrane integrity, total motility, curvilinear velocity (VCL) and average path velocity (VAP) parameters. Egg yolk also showed the best results for WOB, but it did not differ from 5% and 8% lactose and 5% and 20% sucrose. Soy lecithin had the lowest percentages of morphologically normal sperm (P<0.05), while the other treatments did not differ from each other. There was no difference regarding DNA integrity data. Thus, 5% egg yolk is indicated as a non-permeable cryoprotectant for P. brevis, in association with 5% glucose and 10% Me2SO.