Impact of larval trematode infection on the nitrogen excretion and ornithine-urea cycle enzymes of the pulmonate snail host,Lymnaea luteola

The freshwater gastropod Lymnaea luteola infected with xiphidiocercariae of Prosthogonimus sp. showed striking changes in nitrogen excretion. Infected snails excreted significantly less total Kjeldahl nitrogen into the amibient medium. A significant drop in urea nitrogen alone accounted for this drop in total nitrogen excreted, as there was no change in ammonia excretion. While no significant change was seen in the activity of ornithine carbamyltransferase and arginosuccinate lyase in infected snails, arginase activity invariably dropped. The present study thus has revealed that it is not the urea production that occurs in the digestive gland that is affected upon infection, but it is arginolysis that occurs in other tissues, like foot and mantle, that is curtailed.