Experimental studies on immunosuppressive effects of peste des petits ruminants (PPR) virus in goats

Effect of virulent and attenuated peste des petits ruminants (PPR) virus on the immune response to nonspecific antigen (ovalbumin) was investigated. Clinical and serological responses were monitored in goats administered with ovalbumin concurrently with either PPR vaccine or virulent virus. Study showed that PPR virulent virus causes marked immunosuppression as evidenced by leukopenia, lymphopenia, and reduced early antibody response to both specific and nonspecific antigen. These observations were predominant particularly during acute phase of disease (4-10 days post-infection). On the other hand, the vaccine virus induced only a transient lymphopenia without significantly affecting the immune response to nonspecific antigen or to itself during this period. Further, the antibody levels to ovalbumin in the group administered with virulent PPRV increased significantly between days 28 and 35 post-infection in comparison to the titers in other two groups given with either ovalbumin alone or in combination with vaccine.     

Relationship between Oxygen Consumption and Sex of Bovine In Vitro Fertilized Embryos

The present study was conducted to examine the relationship between the oxygen consumption rate and sex ratio of bovine in vitro fertilized embryos on each day of blastocyst formation. The quality of blastocysts collected on day 7, 8, and 9 after in vitro fertilization (IVF) were categorized as ranks A and B (excellent and good, respectively) based on microscopic observation of the morphology. The oxygen consumption rate and sex of individual blastocysts were evaluated using two novel techniques: scanning electrochemical microscopy (SECM) and loop-mediated isothermal amplification (LAMP), respectively. The oxygen consumption rates of embryos of rank A were significantly higher (p < 0.05) than those of rank B, irrespective of the day of blastocyst appearance after IVF. Neither did the proportion of male embryos of ranks A and B differ significantly from each other at any of the days examined, nor from the average proportion (53%). The oxygen consumption rate of embryos of rank B collected on day 8 was significantly higher (p < 0.05) in female embryos than in male embryos collected on the same day. However, there were no apparent differences of oxygen consumption rates at each day of blastocyst appearance between male and female embryos of rank A. These results indicate that the oxygen consumption rate of individual embryos reflects their quality but does not correlate with the sex ratio of embryos of excellent quality.