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Cryopreservation of paddlefish sperm in 5‐mL straws
Author(s) -
Horváth Á.,
Urbányi B.,
Wang C.,
Onders R. J.,
Mims S. D.
Publication year - 2010
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/j.1439-0426.2010.01551.x
Subject(s) - sperm , human fertilization , biology , hatching , cryopreservation , andrology , straw , semen , zoology , cryoprotectant , botany , anatomy , embryo , fishery , agronomy , medicine
Summary Experiments were conducted to test the feasibility of using 5‐mL straws for the cryopreservation of paddlefish ( Polyodon spathula ) sperm. In experiment 1, the effects of 5% or 10% methanol as a cryoprotectant in combination with cooling times of 5 or 7 min on paddlefish sperm stored in 5‐mL straws were evaluated for fertilization and hatching rates. Highest fertilization rate of 48 ± 5% (mean ± SE) and hatching rate of 47 ± 10% were observed using sperm cryopreserved with 5% methanol and a 5‐min cooling time in liquid nitrogen vapors. However, fertilization and hatching rates were significantly lower with cryopreserved sperm than with fresh sperm (fertilization 77 ± 6%; hatching 66 ± 13%). In experiment 2, the effects of sperm : egg ratios on fertilization rates were investigated. When fresh sperm was used, fertilization rate was quadratically related to sperm : egg ratio ( y = −13.19 x 2 + 55.90 x + 38.44, r 2 = 0.823) and the optimum range of sperm : egg ratios was between 1.379 × 10 6 and 2.758 × 10 6 . When sperm were cooled for 5 min with 5% methanol, fertilization rate was linearly related to sperm : egg ratio ( y = 22.51 x + 23.26, r 2 = 0.75) but optimum sperm : egg ratio was not reached. In experiment 3, the hatching rates were not significantly different between the three‐straw treatment and the control. With cryopreserved sperm, the relationship between the sperm and egg ratios and the hatching rates were best described by a quadratic equation ( y = −29.65 x 2 + 119.2 x − 51.04, r 2 = 0.837). Therefore, when cryopreserved sperm is used, sperm : egg ratio should be increased significantly to optimize fertilization and hatching rates. This can be achieved either by increasing the total volume of cryopreserved sperm by at least 30% or by further research to improve the procedure to increase the viability of post‐thawed sperm per straw.