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Low-density lipoproteins, quercetin, and resveratrol have been used for sperm preservation to improve sperm quality in different species.
Methods: To evaluate the effects of low-density lipoproteins, quercetin, and resveratrol during the cooling of boar semen, fifteen boar semen samples were diluted in a BTS extender supplemented with the treatments: low-density lipoproteins at 6%, quercetin at 10 μM (Q10), 30 μM (Q30) and 50 μM (Q50), or resveratrol at 10 μM (R10), 30 μM (R30) and 50 μM. A control without supplementation was included. The semen was stored by cooling at 16°C for 96 h. Every 24 h, sperm motility and kinetics were evaluated using a computer-assisted sperm analyzer. At 24 and 96 h of cooling, functional membrane integrity and mitochondrial membrane potential of sperm were evaluated by the hypoosmotic swelling test and flow cytometry with JC-1 probe, respectively.
Results: Low-density lipoproteins improved the progressive motility of sperm during cooling. Likewise, low-density lipoproteins increased average path velocity and straight-line velocity and/or curvilinear velocity during the first 48 h of cooling. The use of quercetin between 10 and 30 μM caused a reduction in total motility, progressive motility and amplitude of the lateral head displacement during the entire cooling period, as well as a decrease in average path velocity, straight-line velocity and curvilinear velocity at 96 h of cooling. Low-density lipoproteins, Q10, Q30 and Q50 modulated mitochondrial activity by reducing high-mitochondrial membrane potential sperm at 0 and 96 h of cooling. During the cooling of the boar semen prior to artificial insemination, the parameters of sperm quality that could influence fertility decrease; however, the inclusion of antioxidants and additives that protect the plasma membrane, such as low-density lipoproteins, could mitigate the damaging effects on spermatozoa.
Conclusion: It is concluded that low-density lipoproteins can improve the motility and kinetics of boar semen during cooling while it could modulate the sperm's mitochondrial activity. On the contrary, quercetin could alter the motility and kinetics of boar sperm during the cooling period.
González D, Rojas M, Rojano B, Restrepo G. Low-density lipoproteins, resveratrol and quercetin as alternative additives to improve boar semen cooling. Reproduction in Domestic Animals. 2023; 58(10): 1420-1427. https://doi.org/10.1111/rda.14457