Abstract
The presence of antioxidant enzymes in helminth parasites is well known. These enzymes help the parasites to survive in their hosts by detoxifying host-generated reactive oxygen species (ROS). The literature survey reveals that most of the studies related to antioxidant enzymes in helminth parasites are restricted to the adult stage while the larval stages are neglected. The present investigation is designed to evaluate the level of antioxidant enzymes in the adult and larval stages of rumen-infecting paramphistome parasites, Gastrothylax crumenifer. The larval stages include 0-day eggs, 4-day eggs, and eggs containing mature miracidia, cercariae, and metacercariae. Antioxidant enzyme assays were performed using standard assay protocols. Our findings revealed an increasing pattern in the level of Glutathione-S-Transferase (GST), Superoxide Dismutase (SOD), Glutathione Reductase (GR), and Glutathione Peroxidase (GPx) antioxidant enzymes during the development from 0-day eggs to the adult stage. Overall analysis shows that adult worms have higher antioxidant enzyme activity as compared to the larval stages, indicating that adult flukes are more adapted to oxidative stress. It can be concluded that the miracidia, cercarial, and metacercarial developmental stages of G. crumenifer possess a considerable level of antioxidant enzymes suitable to overcome the oxidative stress encountered during the development and help them in the completion of the life cycle and survival in the definitive host.