Parkinson’s disease patients with freezing of gait have more severe voice impairment than non-freezers during “ON state”

Successful short term sperm cryopreservation in brown-marbled grouper (Epinephelus fuscoguttatus) with the utility of ultra-freezer (-80 ℃)

Production of cryopreserved semen in fish generally requires liquid nitrogen (LN), which is not always easily available in remote areas. To reduce reliance on LN, the aim of the present study was to evaluate if electric freezer could be a feasible LN-free alternative to cryopreserve brown-marbled grouper sperm. After loading, semen straws were put directly in freezers (-30 or -80 ℃) for frozen and then transferred to LN for storage.

Compared with the conventional LN vapor freezing (straws were put horizontally 3 cm above the surface of LN), there was a significant reduction in all tested post-thaw sperm quality parameters in samples frozen at -30 ℃ for 10 min, including kinetic parameters (total motility: 85.0% vs 48.6%), viability (84.7% vs 51.7%), high mitochondrial membrane potential (86.4% vs 63.7%), ATP content (106.9 nM/10⁹ cells vs 72.9 nM/10⁹ cells) and hatching rate (86.3% vs 45.7%), accompanied with an increasing lipid peroxidation level (MDA content: 11.9 nM/10⁹ cells vs 4.9 nM/10⁹ cells).

In contrast, frozen with -80 ℃ ultra-freezer (10 min or 12 h) produced similar sperm quality parameters to those using LN, except that temporary storage (12 h) at -80 ℃ yielded lower average path velocity. In conclusion, this study confirmed that -80 ℃ ultra-freezer is an effective alternative to LN for sperm freezing in brown-marbled grouper.