Concentração iônica plasmática e biliar do "curimbatá" Prochilodus scrofa Steindachner (Osteichthyes, Characiformes) em relação aos estádios de repouso e maduro do ciclo reprodutivo Plasmatic and biliar ionic concentration of the freshwater teleost fish Prochilodus scrofa Steindachner (Osteichthyes, Characiformes), in relation of maturation cycle

<abstract language="eng">Body fluid ionic content of fishes varies with ambient. Variations in the plasmatic ionic concentration have also been related with sex or maturation cycle, once that reproduction modifies metabolic processes. In fishes, the gallbladder is an important osmoregulatory organ. So, the present work has been focused on the relation of plasmatic and biliar electrolytes with sex and maturation cycle, of the teleost fish Prochilodus scrofa at the resting and mature stages of gonadal cycle. The animals (28 males and 30 females) were collected at Cachoeira de Emas (Pirassununga, São Paulo) and they were fasted for three days before the experiments. Deteminations of Na+, K+, Mg++, and Ca++ were made by spectophotometry and Cl- by microtitulation. Comparisons of ionic content between sex and maturation cycle were assessed using analysis of variance and Student-Newman-Keuls test. In this work it was seen that in males and females at resting and mature stages, there are no difference at ionic plasmatic content. K+ contents were higher in the bile of mature males than in resting ones. Mg++ biliar contents were higher in resting males than in resting and mature males. Na+, Ca++ e Cl- contents have no difference. Na+, K+, Ca++ and Mg++ contents were higher in the bile than in the plasma. Cl- content was higher in plasma than in bile. Variations related with proteic synthesis, and another metabolic processes during cycle, may be the reason of variations in the biliar ionic content