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Ions and osmolality on post‐thaw sperm motility activation of the endangered Brycon insignis (Characiformes)
Author(s) -
Viveiros Ana T.M.,
Motta Naiara C.,
Isaú Ziara A.,
Almeida Izabella L.G.,
Leal Marcelo C.
Publication year - 2019
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/jai.13857
Subject(s) - osmole , motility , biology , sperm motility , sperm , osmotic concentration , sodium , zoology , andrology , biochemistry , chemistry , endocrinology , botany , medicine , organic chemistry , genetics
Summary The aim of this study was to evaluate the effects of osmolality and the presence of ions on the activation of post‐thaw sperm motility of Brycon insignis . Sperm was frozen under a standardized methodology for this species. In experiment 1, 11 solutions were prepared with reverse osmosis (RO) water (∼0 mOsm/kg) and glucose or NaCl adjusted to an osmolality of 50, 100, 150, 200 and 250 mOsm/kg. In experiment 2, six solutions were prepared with RO and adjusted to ~100 mOsm/kg with one of the following chemicals: NaHCO 3 , sodium citrate (Na 3 C 6 H 5 O 7 ), NaCl, KCl, CaCl 2 or glucose (as ion‐free control). Post‐thaw sperm of both experiments was evaluated for motility rate, velocities (curvilinear = VCL, among others) and beat‐cross frequency (BCF). In experiment 1, sperm motility rate and velocities were higher ( p < 0.05) when triggered in solutions at osmolalities from 0 to 200 mOsm/kg (62–80% motility; 139–167 µm/s) than that at 250 mOsm/kg (36–44% motility; 94–99 µm/s VCL). BCF was not affected by osmolality and varied from 19 to 24 Hz in all samples. In experiment 2, samples activated in NaHCO 3 , citrate, NaCl and KCl solutions yielded higher motility rates (76–85%) and BCF (24–25 Hz) compared to those activated in CaCl 2 (50%; 14 Hz). Samples activated in ion‐free control solution yielded higher motility rate (87%) than those activated in NaHCO 3 and in CaCl 2 . Curvilinear velocity was higher in samples activated in NaHCO 3 , citrate, KCl and control solutions (144–160 µm/s) than in those activated in CaCl 2 (104 µm/s); samples activated in NaCl yielded intermediate VCL values (127 µm/s). Post‐thaw sperm achieves maximum motility rate and velocities when activated in solutions composed of sodium citrate, NaCl, KCl or glucose. Thus, post‐thaw sperm motility of B. insignis can be triggered in ionic and non‐ionic solutions at osmolality between 0 and 200 mOsm/kg. The use of solutions containing calcium, however, should be avoided.