Abstract:
This study was designed to evaluate the in vitro effects of L-carnitine and glutamine (Gln) on the sperm
quality parameters of liquid-stored rabbit semen maintained up to 24 h at 5 C. Pooled and extended
ejaculates were divided into two equal portions. L-Carnitine doses of 0.5, 1 and 2 mM were added to
the first portion, and glutamine was added at the same doses to the second portion. All samples were
cooled to 5 C and examined at 0, 6, 12 and 24 h of liquid storage. Supplementation of the semen extender
with three different doses of L-carnitine provided significant increases in the percentage of motile sperm
at 12 h (P < 0.01), and 24 h (P < 0.001) and enabled significant protection of the sperm plasma membrane
(P < 0.01) at 12 and 24 h of cool-storage, in comparison to the control samples. Only the 2 mM dose of
L-carnitine significantly (P < 0.01) decreased the rate of acrosomal damage when compared to the control
group. Furthermore, all doses of Gln caused a significant (P < 0.01) decrease in acrosomal damage at 6 h,
and provided significant improvement (P < 0.01) in sperm motility, acrosomal and plasma membrane
integrities at 12 and 24 h of liquid storage, when compared to the controls. In conclusion, the supplementation
of liquid-stored rabbit semen with L-carnitine and Gln provided a protection for sperm against cool
storage-induced functional and structural damages.
