Effect of glucose concentration and cryopreservation on mitochondrial functions of bull spermatozoa and relationship with sire conception rate

Thymoquinone improves motility, plasma membrane integrity and DNA integrity of frozen–thawed ram semen

“…Furthermore, thermal damage, also known as cold shock, is heightened in rams due to their low intramembrane cholesterol-to-phospholipid ratio in the spermatozoon membrane (Salamon & Maxwell, 1995). Understanding sperm metabolism is necessary for the development of new extender compounds for increasing frozen semen quality (Moraes et al, 2021).…”

The sperm mitochondria: clues and challenges

“…After a relatively long period in which sperm metabolism was not the center of the studies in bull semen, new interest was focused on these features. ( Bulkeley et al, 2021 ; Chatterjee et al, 2001 ; Contri et al, 2010 ; Moraes et al, 2021 ; Thys et al, 2009 ). Bull sperm cells are probably the most widely used in AI techniques all over the world and, generally speaking, they are easily cryopreserved; as a consequence, we register a great advance in the application of AI techniques in spite of basic research on metabolic features.…”

“…Bull spermatozoa can rely both on glycolysis and oxidative phosphorylation pathways: in normal conditions the two pathways play an integrated role as expected from somatic cells metabolism ( Vishwanath and Shannon, 2000 ). In these conditions, mitochondria are “coupled” and their functionality guarantees a good function of the metabolic machinery ( Bulkeley et al, 2021 ; Moraes et al, 2021 ) and sustains motility. Anyway, after cryopreservation, bull sperm mitochondria do not work properly, probably because of cryo-injuries, as we demonstrated in recent research from our labs ( Algieri et al, 2022 ), in which we showed that bull frozen sperm mitochondria are uncoupled, as mitochondrial respiration does not support the ATP synthesis, in contrast with what was observed by other Authors in freshly ejaculated semen ( Bulkeley et al, 2021 ).…”

Metabolism of Spermatozoa

“…However, mitochondrial function was more pronounced in thawed sperm than in natural sperm (p<0.05). This increase is thought to be due to "nonproductive" oxygen consumption to maintain the mitochondrial proton gradient (Moraes et al 2021). Melatonin has been reported to inhibit mitochondrial permeability transition pore (MPTP) inauguration and lactate concentration and to improve ATP production and acetyl-CoA concentration, as well as sperm motility and viability.…”