Cryopreservation‐induced morphological changes in the sperm of South American silver catfish ( Rhamdia quelen )

Abstract

The cryopreservation protocols are species‐specific owing to variable sperm sensitivity towards temperature reduction and contact with cryoprotectant solutions. However, little is known about spermatic pathologies, especially after the cryopreservation process. Thus, the objective was to evaluate the effect of cryopreservation on morphological changes in semen of jundiá (Rhamdia quelen). Sperm pool of five males, with >80% motility, as collected, diluted in a cryoprotectant solution and frozen in liquid nitrogen (−196°C). There was a reduction in the percentage of normal cells and sperm motility, accompanied by an increase in the percentage of sperm abnormalities after cryopreservation of R. quelen spermatozoa, indicating a substantial fragility of the spermatozoa towards the cryopreservation process. The most frequent types of morphological changes in the cryopreserved semen were macrocephaly, folded tail, strongly curled tail and distally curled tail. This is the first study to evaluate the spermatic morphology of R. quelen before and after cryopreservation, paving way for further investigations on morphological alterations and for a new classification of these changes in fish semen due to cryopreservation.

Morphological abnormalities in cryopreserved semen from South American neotropical fish: A meta‐analysis

“…The removal of another study (Galo et al, 2019) increased the combined estimate, leaving the MD = −1.28%. For the percentage of cells with secondary abnormalities, the sensitivity analysis showed that the removal of three studies (Da Costa et al, 2019; Galo et al, 2011, 2019) increased the MD by 0.26% to 0.81, 0.46 and −0.32 respectively. On the other hand, the removal of the study by Streit et al (2009) decreased the combined estimate (MD = −0.15).…”

“…Freshwater fish sperm preserve their motility for a very short time (Billard & Cosson, 1992), during which they must penetrate the oocyte through the micropyle (Suquet et al, 1995). Hence, the increase in the number of morphological lesions caused by cryopreservation in sperm can generate ineffective fertilization (Da Costa et al, 2019). Galo et al (2019) revealed that the percentage of primary abnormalities in P .…”

“…The success of cryopreservation depends on reducing the damage caused to the sperm cells (Da Costa et al, 2019) that may compromise the viability of the reproductive cells (Figueroa et al, 2016). These damages occur due to the formation of intracellular ice, solution effect, cryoprotectant toxicity and oxidative stress (Aramli et al, 2016), leading to morphological, biochemical and physiological changes that can affect sperm quality (Figueroa et al, 2016).…”

Effect of glutamine and cysteine supplementation on quality of cryopreserved sperm of South American silver catfish

“…After, straws were transferred and stored in liquid nitrogen at −196ºC in a cryogenic tank at a standard freezing rate. During pre‐freezing, straws were frozen from room temperature (23°C) to −170°C at a rate of approximately −35.6°C min −1 (Adames et al, 2015; Da Costa et al, 2019).…”

“…Straws were thawed in a water bath at 25°C for 10 s (Adames et al, 2015), and motility was subjectively determined under optical microscopy (0–100%). Each sperm pool was activated in 58 mM NaCl solution (1 μL of sperm in 800 μL of activation solution) (Da Costa, Marques, Lassen, Rodrigues, & Streit, 2019). The mean sperm motility of fresh pools was 87.00 ± 5.70%.…”