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Ramifications of protease-based liquefaction of camel semen on physical, kinematic and surface glyco-pattern of cryopreserved spermatozoa

Rateb, S.A., Monaco, D., El-Bahrawy, K.A., Khalifa, M.A., Abd El-Hamid, I.S., Kamel, A.M., Accogli, G., Lacalandra, G.M., Desantis, S.
Animal reproduction science 2019 v.208 pp. 106121
Camelus dromedarius, acrosome, adults, assisted reproductive technologies, breeding season, bromelains, camels, cell membranes, cryopreservation, fluorescence, fucose, lectins, liquefaction, neutralization, papain, polysaccharides, semen, tail, viscosity
The efficiency of incorporating different proteases in the diluent for reducing camel semen viscosity, and subsequent ramifications on morpho-functional and glycan surface properties of cryopreserved spermatozoa were investigated. Ejaculates (n = 48) were collected from three adult camels, Camelus dromedarius, during the breeding season (January - March). A portion of each raw ejaculate was evaluated for sperm physical and morphological traits, whereas the other portion was divided into three aliquots assigned for the following liquefaction treatments: control (untreated), 0.1 mg/mL papain or 5 U/mL bromelain. All samples were diluted with Tris-lactose diluent containing the anti-enzyme E-64 to neutralize both proteases before being processed for cryopreservation. Post-thaw physical and kinematic properties of spermatozoa were analyzed using a computer-assisted sperm analysis (CASA) system. The sperm surface glycocalyx pattern was evaluated with a panel of 14 fluorescent lectins. Although bromelain was more effective in elimination of semen viscosity, there was a negative correlation between bromelain supplementation and values for the variables: normal sperm, intact acrosome and intact sperm cell membrane. Bromelain supplementation, compared to papain-treated and control samples, was positively correlated with secondary sperm abnormalities, increased straight-line velocity (VSL, μm/s) and straightness (%) of spermatozoa. Results from the glycan analysis indicated that both proteases did not affect the N-linked glycan content of the entire sperm surface, whereas the treatment with proteases induced little change in N-acetylgalactosamine and fucose terminating glycans in the tail region of the sperm. Functional studies are needed to evaluate the sperm fertility rates of bromelain- and papain-treated semen for application in camel assisted reproductive technologies.