Addition of chlorogenic acid and caffeine during the processing of cooled boar semen / Adição de ácido clorogênico e cafeína durante o processamento do sêmen suíno resfriado

A study was conducted to evaluate the effect of chlorogenic acid (ChA) added pre-cooling and its combination with caffeine added during warming on cooled-stored boar semen parameters. Ten ejaculates were diluted in commercial extender with or without 4.5mg/ml ChA and stored at 15°C. After 0, 24 and 72 hours of storage, aliquots of these doses were taken and incubated at 37°C in the presence or absence of 8.0mM caffeine. Semen quality was evaluated after 10 and 120 minutes of incubation. The ChA increased (P <0.01) the sperm motility, viability, acrosomal integrity and the percentage of spermatozoa with high mitochondrial activity (PMHA), however, decreased (P <0.01) the malondialdehyde (MDA) concentration. Caffeine increased (P<0.05) the sperm motility, viability, PMHA and the MDA concentration and reduced (P <0.05) the acrosome integrity. When associated (ChA+caffeine), there was an increase (P <0.05) in sperm motility and viability, PMHA and acrosome integrity. The addition of ChA to the dilution medium improves the quality of the swine inseminating doses. The addition of caffeine during re-warming is only recommended when the semen is stored for prolonged periods (72h), and the inseminating dose should be used immediately after its addition.(AU)

O objetivo deste estudo foi avaliar os efeitos da adição de ácido clorogênico (ChA) antes do resfriamento e sua combinação com cafeína adicionada durante o reaquecimento sobre a qualidade do sêmen suíno resfriado. Dez ejaculados foram diluídos em diluidor comercial com adição ou não de 4,5mg/mL de ChA e armazenados a 15°C. Após zero, 24 e 72 horas de armazenamento, 10mL foram retirados e incubados a 37°C na presença ou ausência de 8,0mM de cafeína. A qualidade seminal foi avaliada após 10 e 120 minutos de incubação. O ChA aumentou (P<0,01) a motilidade, a viabilidade, a integridade acrosomal e a porcentagem de espermatozoides com alta atividade mitocondrial (PMHA), entretanto diminuiu (P<0,01) a concentração de malondialdeído (MDA). A cafeína aumentou (P<0,05) a motilidade, a viabilidade, a PMHA e a concentração de MDA e reduziu a integridade acrossomal. Quando associados (ChA+cafeína), houve aumento (P<0,05) na motilidade, na PMHA, na viabilidade e na integridade acrossomal. Conclui-se que a adição de ChA ao meio de diluição melhora a qualidade das doses inseminantes de suínos. A adição de cafeína durante o reaquecimento só é recomendada ao sêmen adicionado de ChA quando esse for armazenado por períodos prolongados (72h), devendo a dose inseminante ser utilizada imediatamente após sua adição.(AU)

Adenosine monophosphate-activated kinase, AMPK, is involved in the maintenance of the quality of extended boar semen during long-term storage.

Boar semen preservation for later use in artificial insemination is performed by diluting semen in an appropriate medium and then lowering the temperature to decrease spermatozoa metabolism. The adenosine monophosphate-activated kinase, AMPK, is a key cell energy sensor that controls cell metabolism and recently has been identified in boar spermatozoa. Our aim was to investigate the role of AMPK in spermatozoa functional parameters including motility, mitochondrial membrane potential, plasma membrane integrity, acrosome integrity, and cell viability during long-term boar semen storage at 17 °C in Beltsville thawing solution. Boar seminal doses were diluted in Beltsville thawing solution in the presence or absence of different concentrations of AMPK inhibitor, compound C (1, 10, and 30 µM) and evaluations were performed at 1, 2, 4, 7, or 10 days. Data demonstrate that AMPK becomes phosphorylated at threonine(172) (active) during storage of boar semen reaching maximum levels at Day 7. Moreover, AMPK inhibition during boar semen storage causes: (1) a potent inhibition of spermatozoa motility; (2) a reduction in the percentage of spermatozoa showing high mitochondria membrane potential; (3) a rise in the percentage of spermatozoa displaying high plasma membrane scrambling; and (4) a loss of acrosomal membrane integrity. Our study suggests that AMPK activity plays an important role in the maintenance of the spermatozoa quality during long-term storage of boar semen.