Comparative study of the formation and excretion of anaerobic fermentation products in bivalves and gastropods

Abstract

1. 1. Marine bivalves and gastropods, freshwater bivalves and gastropods and land gastropods were studied for accumulation of lactate, alanine, aspartate, succinate and volatile fatty acids during 24 hr of anaerobiosis at 14°C. 2. 2. Lactate was the major fermentation product in land gastropods and was formed in significant amounts in the freshwater gastropod Lymnaea stagnalis and the marine bivalve Cardium edule. 3. 3. Accumulation of alanine occurred concomitantly with the conversion of aspartate to oxaloacetate in marine bivalves and gastropods. Land gastropods use other sources of NH 3 for pyruvate→alanine conversion in addition to aspartate. 4. 4. Alanine and acetate accumulation are interrelated. Freshwater animals with low free aspartate levels convert more pyruvate into acetate, than into alanine. 5. 5. All species accumulate succinate. 6. 6. Conversion of succinate to propionate within 24 hr of anaerobiosis was observed in all bivalves, but was absent in the gastropods, except Buccinum undatum. 7. 7. Many species excrete volatile fatty acids, but some species, e.g. Lymnaea stagnalis, also excrete lactate and succinate.