This study has shown that the supplementation of
thawed boar semen with 50% seminal plasma caused
a dramatic effect in the plasma membrane status, accompanied by other physiological changes, whereas these
changes were not evident or much lower when adding 10%
seminal plasma. These observations could help explaining
the enhancing effect of seminal plasma on thawed semen
fertility observed in other studies[15,16,19]. The protection
that seminal plasma confers to boar spermatozoa against
cold shock has been known for a long time[25].ThePSP-I/
PSP-II heterodimer (non-heparin–binding spermadhesins
[26]) represent more than half of the seminal plasma
proteins in the boar. This heterodimer seems to be responsible, at least in part, of the beneficial effects of seminal
plasma on stressed spermatozoa (frozen-thawed[15,19],
highly extended[27], and sorted [28]). Other components
could be involved in important events, such as the modulation of the immune response in the uterus [29] or the
formation of the oviductal reservoir [30]. Different studies
have been defining these components and their effects
in vivo andin vitro, which may be very different depending
on the environment[31]