Motilidade espermática de Jundiá (Rhamdia quelen) em diferentes temperaturas e fontes de água

Abstract

For efficient fertilization, the quality of the semen, in addition to other factors, such as the water used in the fertilization process, should be evaluated. Physical and chemical factors of water interfere with fertilization as they may act on the viability of the semen. The sperm evaluation consists of analyzing the physical characteristics of the semen. The objective of this work was to evaluate the sperm motility of jundiás, with activation of semen in superficial and subterranean water at different temperatures, at the end of the breeding season. The experiment was carried out at the Center for Technology in Fisheries and Aquaculture (CTPA) at the Federal University of Pampa (UNIPAMPA) - Campus Uruguaiana. The experimental design was of randomized blocks, considering each fish as a block. The treatments were distributed in a 2x4 factorial scheme, evaluating two waters (artesian well or dam water) and four semen activation temperatures (15, 20, 25 and 30ºC). Four males of jundiá, hormonally induced with human chorionic gonadotrophin (HCG), were used in the dosage of 200 IU / kg of fish. Twelve hours after induction, the animals were captured to collect semen, and stored in tubes with inactivating solution (glucose 5%) and kept in a refrigerated environment. Sperm kinetics were evaluated from a drop of 10μL of diluted semen, with a concentration of 50x10 6 spermatozoa / mL, in semipermanent Sperm Class Analyzer (SCA). A random field of the slide was evaluated, considering mobile, fast, medium and slow spermatozoa, besides progressive velocity, curvilinear velocity and linear velocity. The sperm motility time was determined from the activation of the sample, until 50% of the cells lost their motility, and there was no difference in the total motile time in the different treatments. The sperm concentration was determined by the sperm counting method in the Neubauer chamber, where the sperm concentration of the jundias was 1.27 ± 0.25x1010. A significant difference was found only for water type, with a higher number of mobile and fast spermatozoa observed when the semen was activated with dam water compared to well water, independent of temperature. No differences were observed for sperm motility time. It is concluded that at the end of the reproductive season, the use of superficial water for semen activation provides better motility indexes.