Ameliorative Effect of Ascorbic Acid and Glutathione in Combating the Cryoinjuries During Cryopreservation of Exotic Jack Semen.

The present study was designed to study the adverse effects of cryopreservation and evaluation of the cryoprotective effect of reduced glutathione (GSH) and ascorbic acid (AA) supplementation on exotic jack semen in combination or alone. For this, 24 semen samples from four adult and fertile jacks were collected via artificial vagina using an estrus jenny as dummy. After semen collection, the semen was evaluated for various qualitative and quantitative parameters in fresh, cooled, and frozen-thawed semen. The semen pellet was extended with the freezing extender containing either AA (0.9 g/L), GSH (2.5 mM), or combination of both (AA 0.9 g/L + GSH 2.5 mM), and another aliquot was kept as control without adding the antioxidants. The jack semen underwent cryodamage, which was evident by the observation of significant (P < .05) decline in the seminal quantitative parameters at various stages of cryopreservation process. Prefreeze and postthaw semen evaluation revealed that the values of plasma membrane, acrosome integrity, and chromatin integrity were found to be significantly higher (P < .01) in the group of samples supplemented with the combination (0.9 g/L AA +2.5 mM GSH) than AA- and GSH-alone or control groups. Supplementation of antioxidants to the freezing extender improved jack prefreeze and postthaw semen quality with the superiority of GSH over AA alone. From the present study, it was inferred that, exotic jack spermatozoa are susceptible to injuries because of cryopreservation, but these cryo-induced damage can be ameliorated significantly (P < .05) with the use of antioxidants and contribute to the improvement of semen cryopreservation procedures.

An update on Mycobacterium avium subspecies paratuberculosis antigens and their role in the diagnosis of Johne's disease.

Mycobacterium avium subsp. paratuberculosis (MAP) is responsible for Johne's disease (JD) or paratuberculosis. Diagnosis of MAP infection by measuring host cell-mediated and humoral immune responses has been a major focus in MAP research. For this purpose, several MAP antigens such as secreted protein, cell envelope protein, cell-mediated immune and lipoprotein antigens have been identified and tested to measure their diagnostic utility with varying degree of success. Identifying the optimal antigen or antigen combinations for diagnosis of infected animals is hindered by the complex nature of the disease, prolonged subclinical infection, the differential expression of antigens and scarcity of well characterized MAP-specific epitopes making selection of a single MAP antigen very difficult. Thus, multiplexing of antigens with larger scale and longitudinal studies may lead to development of cost-effective next generation serodiagnostics. This mini review focuses on the role of different MAP antigens in the diagnosis of JD.