abstract
The study was conducted to determine the influence of N-acetyl-L-cysteine (NAC) and superoxide dismutase
(SOD) on chicken sperm motility, plasma membrane and acrosome integrity, mitochondrial activity,
lipid peroxidation (LPO) and apoptotic changes after freezing–thawing process. Semen samples from fifteen
Greenlegged Partridge roosters were pooled, diluted with EK extender without antioxidants
(control), or supplemented with 5 mM NAC, or 200 U/mL SOD. Samples were subjected to
cryopreservation. After thawing, sperm parameters evaluated by using CASA system and flow cytometry
were assessed.
The extender supplemented with NAC and SOD caused the increase (P < 0.01) in sperm motility and
provided the higher percentage of rapid sperm (P < 0.01) compared to control. The addition of NAC
increased the progressive motility of cells (P < 0.01). In NAC and SOD groups post-thaw plasma membrane
integrity was higher (P < 0.05) and less spermatozoa showed apoptotic changes (P < 0.01,
P < 0.05). Post-thaw percentage of sperm with high mitochondrial activity was the greatest (P < 0.05)
with NAC addition. The SOD supplementation only reduced (P < 0.05) the percentage of sperm with
LPO, following the cryopreservation. These results indicate that the addition of NAC (5 mM) and SOD
(200 U/mL) is beneficial for the function of frozen–thawed chicken spermatozoa. The antioxidants prevented
the reduction in motility, viability and mitochondrial membrane potential, as well as protected
from apoptotic changes in sperm. Lipid peroxidation in sperm plasma membrane was decreased by
SOD supplementation. Therefore, these antioxidants can be recommended as an additional component
of chicken freezing extender.