Adhesiveness neutralization in eggs of Pseudoplatystoma fasciatum (Teleostei: Siluriformes: Pimelodidae)

Abstract

The aim of this study was to remove the adhesiveness of Pseudoplatystoma fasciatum eggs using solutions of urea for 10, 30, 60 or 90 min (treatments T0 to T3) or in urea for 10 min and washed in tannin (T4). In the control group, eggs were kept in water. After two experiments, we observed that eggs of control group presented the best embryo viability rates, even maintaining egg adhesiveness, being better than the other treatments. The T4 had the worst embryo viability rates. We observed that embryos of the T4 treatment presented reduced growth and formed a separate group when analyzing morphological parameters (egg diameter, total egg area, embryo area and yolk sac area) by multivariate analysis. Concluding, the control group, free of chemicals, provided the best results and is considered the best alternative for the immediate conservation and aquaculture production of P. fasciatum.