Coenzyme Q10 and melatonin protect cryopreserved equine sperm against lipoperoxidation.

The objective of the experiment was to evaluate the effect of the addition of different concentrations of the antioxidants Coenzyme Q10 (CoQ10) and melatonin to equine semen freezing diluent, alone or in combination, during the cryopreservation process. Twenty ejaculates (n = 5 stallions) were divided in groups: Control (C, without the addition of antioxidants), melatonin 0.75 mM (MEL1), melatonin 1.5 mM (MEL2), CoQ10 40 µg/mL (Q1), CoQ10 200 µg/mL (Q2), and CoQ10 40 µg/mL+ 0.75 mM melatonin (Q1 +MEL1). Q1 and Q2 groups demonstrated intact plasma membrane and high mitochondrial membrane potential after 30 (M-30) and 60 (M-60) min of incubation compared with the control group (Q1: 64.8 % ± 9.9 %, Q2: 65.2 % ± 10.5 %, C: 55.1 % ± 10.0 %; M-30 and Q1: 63.3 % ± 10.4 %, Q2: 64.6 % ± 10.8 %, C: 53.1 ± 10.6 %; M-60; P < 0.05). Melatonin conferred greater membrane stability at all evaluated times compared with the control group (MEL1: 42.1 % ± 6.0 %; MEL2: 44.0 % ± 6.7 %, C: 35.9 % ± 5.9 %; M-0; MEL1: 40.8 % ± 5.6 %; MEL2: 42.6 % ± 7.2 %, C: 33.1 % ± 6.6 %; M-30 and MEL1: 37.5 % ± 7.4 %; MEL2: 39.1 % ± 7.2 %; C: 31.3 % ± 6.5 %; M-60; P < 0.05). The use of antioxidants alone or in combination resulted in lower levels of lipoperoxidation at all times evaluated compared with in the control group (P < 0.05). In conclusion, CoQ10 and melatonin were effective in the cryopreservation of equine semen by decreasing lipoperoxidation and promoting a higher percentage of spermatozoa with a high mitochondrial potential, total and progressive motility, and prevention of membrane lipid disorder.

Use Low Ozone Dosages has Positive Effects on the Cooling and Cryopreservation of Equine Semen.

The aim of this study was to determine an ozone dosage capable of inducing pro-oxidation, and to verify its action on sperm cells during the process of cooling and cryopreservation of equine semen. In this study, we evaluated the ozone concentrations of 2µg/mL,15µg/mL, 30µg/mL e 60 µg/mL added in equine semen cooling and freezing extenders. Samples were evaluated for sperm kinetics patterns, function of sperm structures and lipid peroxidation. In the experiment, the concentration of 15 µg/mL showed higher total and progressive motility when comparing to control (60.3±3 and 40.7±3.4 vs. 54.9±4 e 35.0±4.4, respectively, P < .05) at M24 of cooling; The concentration of 2 µg/mL showed higher percentage of intact plasma and acrosomal membrane when comparing to control at M24 (51.1±3.6 vs. 46.1±3.9, P < .05), M24 after 30 minutes of incubation (43.4±3.1 versus 32.4±2.6, P <.05). The concentration of 2 µg/mL showed higher percentage of intact plasma and acrosomal membrane (P <.05) comparing to control at moments M0 (43.5±5.0 vs. 36.3±3.5), M30 (41.0±3,7 vs. 35.3±2,9) e M60 (39.0±7.0 vs. 31.4±5.4). Thus, it can be concluded that low doses of ozone can lead to a positive response in the sperm kinetics patterns and sperm structures after sperm storage at low temperatures. Higher concentrations (30 and 60 µg/mL) were harmful in the cooling and cryopreservation of equine semen.