INTEGRIDADE E FUNCIONALIDADE DOS ... - Ainfo - Embrapa
INTEGRIDADE E FUNCIONALIDADE DOS ... - Ainfo - Embrapa
INTEGRIDADE E FUNCIONALIDADE DOS ... - Ainfo - Embrapa
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Abstract 195<br />
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ABSTRACT<br />
AZEVEDO, H. C. Spermatic integrity and function in ram cryopreserved semen<br />
after incorporation of cholesterol, desmosterol, oleic-linoleic acid and αlactalbumin.<br />
Botucatu, 2006. 195p. Thesis (PhD) – College of Veterinary<br />
Medicine and Animal Science, Sao Paulo State University.<br />
In order to evaluate the protecting action of some substances on ram<br />
spermatozoa, semen samples of 25 rams were collected and submitted to<br />
cryopreservation after treatment with cholesterol, desmosterol, oleic-linoleic<br />
acid or α-lactalbumin. Before the processing and after the procedures of<br />
cooling, freezing-thawing and incubation, semen was evaluated as to kinetics<br />
by subjective and computerized analyses (CASA), morphology, simultaneously<br />
to plasma membrane integrity (PMI), acrosome integrity (ACI) and mitochondrial<br />
membrane potential (MMP) by isothiocyanate-conjugated Pisum sativum (FITC-<br />
PSA), propidium iodide (PI) and JC-1 combination and as to sperm capacitation<br />
and acrosome reaction determined by chlortetracycline (CTC) assay. The<br />
influence resulted from the additives in a few parameters was not enough to<br />
suggest the superiority of any treatments. The cryopreservation process,<br />
especially the freezing-thawing, promotes damages to kinetics, PMI, ACI, MMP<br />
and induces accelerated capacitation and acrosome reaction in spermatozoa.<br />
Differences among groups of rams were observed regarding capacitation status<br />
in fresh semen as well as the sensibility of their semen to cryoinjury and<br />
cryocapacitation. Higher and more accelerated capacitation-like changes were<br />
observed in groups of rams presenting lower plasmatic membrane<br />
cryoresistance after thawing. The segregation of rams in different levels of PMI<br />
influenced the behavior of several other parameters. It was concluded that<br />
cholesterol, desmosterol, oleic-linoleic acid and α-lactalbumin do not protect the<br />
ram semen against the cryoinjuries as well as freezing-thawing is more harmful<br />
than cooling. Important differences among groups of individuals were noticed as<br />
for the spermatozoa resistance to the damages provoked by cryopreservation<br />
such as the cryocapacitation susceptibility.<br />
Key Words: semen, ram, cryopreservation, cholesterol, desmosterol, oleic-<br />
linoleic acid, α-lactalbumin, sperm capacitation, acrosome reaction and<br />
spermatic membranes integrity.