The aim of this work was to evaluate the effect of relaxin on
fertility parameters of buffalo frozen/thawed sperm. Sperm
were incubated in the absence of capacitating agents (negative
control), with a known capacitating agent such as heparin
(positive control) and with 50 and 100 ng/ml relaxin for 2 and
4 h. Sperm viability, motility, capacitation and the effect of
relaxin on the fertilizing ability after heterologous IVF were
evaluated. Although viability was not affected, relaxin
increased (p < 0.05) sperm motility compared to the negative
and positive controls both after 2 h (60.0
2.0, 60.0
3.1,
68.3
1.7 and 69.4
2.7, respectively, in negative control,
positive control, 50 and 100 ng/ml relaxin) and 4 h
(55.0
2.5, 53.3
3.0, 62.2
3.0 and 65.0
3.2, respectively,
in negative control, positive control, 50 and 100 ng/ml
relaxin) incubation. When sperm were incubated with both
100 ng/ml relaxin and heparin, a decrease (p < 0.01) of pattern
A, that is low capacitation level, was observed compared
to the negative control both after 2 h (54.4, 34.3 and
36.4%, respectively, in negative control, positive control and
100 ng/ml relaxin) and 4 h (51.9, 35.0 and 34.3%, respectively,
in negative control, positive control and 100 ng/ml relaxin).
Moreover, an increase (p < 0.01) of pattern EA, that is high
capacitation level, was recorded with 100 ng/ml relaxin and
heparin compared to the negative control both after 2 h (44.1,
59.3 and 57.7%, respectively, in negative control, positive
control and 100 ng/ml relaxin) and after 4 h (43.0, 54.4
and 56.0%, respectively, in negative control, positive control
and 100 ng/ml relaxin). Finally, relaxin increased (p < 0.01)
cleavage rate compared to the negative control (57.1
4.4,
72.5
6.0, 71.4
5.5 and 73.6
2.9, respectively, in negative
control, positive control, 50 and 100 ng/ml relaxin). In
conclusion, relaxin has a beneficial effect on motility,
capacitation and fertilizing ability of frozen–thawed buffalo
sperm.