Paradoxical Effect of Quercetin Antioxidant on Goat Sperm Parameters After Cryopreservation

BACKGROUND

Some antioxidants have been used in semen extenders to reduce adverse effects caused by excessive reactive oxygen species (ROS) production. The study was carried out to assess the effect of quercetin (QC) antioxidant therapy on goat semen submitted to cryopreservation.

OBJECTIVE

To evaluate the effect of quercetin incorporation in different phases of the cryopreservation process of goat spermatozoa.

MATERIALS AND METHODS

Five ejaculates from each of four goats (n= 20) were collected and split into four groups: Control (G1), without QC; G2, 15 μM of QC added to semen before centrifugation; G3, 15 μM QC added to semen after centrifugation; G4, 15 μM QC added to semen before centrifugation and 15 μM of QC added to semen after centrifugation (total of 30 μM of QC); and cryopreserved. All semen samples were evaluated after thawing for sperm kinetics, plasma membrane integrity, and ROS levels.

RESULTS

Although lower concentrations of ROS were associated with groups that received antioxidant supplementation (P=0.0213), linear and dose dependent (P<0.05) reductions of the total and progressive sperm motility, velocity and percentage of fast cells were related to the QC groups. Likewise, plasma membrane integrity was better preserved (P=0.0154) in the control group (35.5%) than in groups that received QC (G2=32.6%, G3=32.4% and G4=26.7%).

CONCLUSION

Although quercetin was efficient at reducing the oxidative stress related to sperm cryopreservation, it exerted a deleterious dose-dependent effect on the kinetics and integrity of the frozen goat semen, contradicating its use in the tested concentrations.

Report of Enodiotrema megachondrus (Looss, 1899) Looss, 1901 (Digenea: Plagiorchiidae) in a green turtle Chelonia mydas Linnaeus, 1758 (Testudines, Cheloniidae) from Brazil

This paper describes the occurrence of Enodiotrema megachondrus (Looss, 1899) Looss, 1901 in a juvenile green sea turtle (Chelonia mydas Linnaeus, 1758) found on the coast of Brazil. This parasite has been described in Caretta caretta from Egypt, France, the Mediterranean Sea, the Madeira Archipelago, the Adriatic Sea and the USA, in C. mydas from Egypt and the USA, in Eretmochelys imbricata from Cuba, in Lepidochelys olivacea from Mexico and Costa Rica and in Lepidochelys kempii from USA. This note represents the first report of E. megachondus in a green sea turtle in the South-West Atlantic Ocean.