Abstract :
The objective of this study was to evaluate the effects of reduced glutathione (GSH) and
catalase (CAT) supplementation on the kinematics and membrane functionality of sperm
during the liquid storage of ram semen, cooled at 5 ◦C, for up to 24 h. Semen samples from
four rams were pooled, diluted with Tris-egg yolk extender without antioxidants (control)
or supplemented with either CAT (100, 200, and 400 U/mL) or GSH (100, 200, and 400 mM)
at a final concentration of 50 × 106 sperm/mL. Sperm kinematics, which was analyzed by
computer-assisted sperm analysis (CASA), and membrane functionality, which was analyzed
using the hypo-osmotic swelling test (HOST), were determined after the addition
of the semen samples at different processing times (fresh/diluted, 1.5, 6, 12, and 24 h, at
5 ◦C). No significant differences were recorded in the kinematics or membrane functionality
between treatments at different times. The supplementation of diluents with 100 and
200 U/mL of CAT prevented the harmful effects of cooling on total sperm motility. No significant
differences were observed in progressive sperm motility throughout processing,
regardless of the treatment and time of evaluation. Supplementation with 400 mM GSH
resulted in an earlier reduction (P < 0.05) of total sperm motility, a decrease in rapid sperm
rate and a reduction in curvilinear velocity during incubation, at 5 ◦C. The cooling induced a
reduction (P < 0.05) in the percentage of sperm with a functional plasma membrane (HOST),
especially after 1.5 h of incubation. Based on the results of the present study, the addition of
CAT (100 and 200 U/mL) reduced the deleterious effects of cooling on total motility in ram
sperm maintained at 5 ◦C for 24 h, although it did not affect the functionality of the sperm
membranes. However, the addition of 400 mM GSH caused negative effects on the velocity
parameters of the sperm