Abstract :
The aim of this study was to determine the effects of the antioxidants curcumin, inositol and
carnitine on microscopic seminal parameters, lipid peroxidation (LPO) and the antioxidant
activities of sperm, following the freeze-thawing of Angora goat semen. Ejaculates were
collected via artificial vagina from three Angora goats and microscopically evaluated and
pooled at 37 ◦C. The pooled semen samples were diluted in a Tris-based extender, including
curcumin (2.5, 5 or 10 mM), inositol (2.5, 5 or 10 mM), carnitine (2.5, 5 or 10mM) and no
antioxidant (control). The diluted semen was slowly (at a rate of 0.2–0.3 ◦C/min) cooled to
5 ◦C and then cryopreserved in 0.25mL French straws. Frozen straws were thawed individually
at 37 ◦C for 20 s in a water bath, for microscopic sperm evaluation. The freezing
extender supplemented with 2.5mM curcumin led to higher percentage of computerassisted
semen analyzer (CASA) sperm motility (65±3%), when compared to the control,
inositol and the 10mM carnitine (P < 0.01) groups, following the freeze-thawing process.
The addition of antioxidants did not provide any significant effect on the percentages of
post-thaw subjective analyses and CASA progressive motilities, as well as sperm motility
characteristics (VAP, VSL, LIN and ALH), compared to the controls. Freezing extenders with
antioxidants at three different doses led to lower percentages of acrosome and total sperm
abnormalities, when compared to the controls (P < 0.001). However, the addition of 5mM
inositol did not induce any difference in total sperm abnormalities, when compared to the
controls. The antioxidants also did not show any effectiveness in the elimination of malondialdehyde
(MDA) formation and the maintenance of glutathione peroxidase (GSH-PX)
activity, when compared to the controls. Superoxide dismutase (SOD) activity was found
to be higher in the presence of curcumin at all three dose levels and carnitine at 5mM,
compared to the other groups. Glutathione (GSH) concentration was demonstrated to be
maintained at a higher level with the addition of inositol, compared to the other groups.
However, these differences in SOD and GSH levels were not significant, compared to the
controls. All the antioxidants at all three dose levels resulted in a better protection of the
sperm morphology (except for 5mMinositol with respect to the total sperm abnormalities),
compared to the control samples. According to CASA, the best post-thawing sperm motilityrate was recorded when the freezing extender was supplemented with 2.5mM curcumin.
Further studies are required to obtain more conclusive results regarding the characterization
of microscopic and oxidative stress parameters in cryopreserved goat sperm, using the
different antioxidants
