Studies on energy transformation in the freshwater snail Pila globosa. Influence of feeding rate

Abstract

The effects of eleven chosen feeding levels ranging from 0 to 198 mg damp dry (plant) Ceratophyllum/g live snail/day on the absorption, conversion and metabolism of the snail Pila globosa (of 1 -9 g body weight) have been studied. Absorption rates increased from 3-0 to 21-0 mg dry food/g live snail/day in snails fed 3-4-28-8 mg dry food/g live snail/day. In these snails, absorption efficiency decreased from 87.5 to 73.0%. Conversion rates increased from 0-3 mg/g/day for snails receiving 23-4 mg/g/day to 2-7 mg/g/day for those fed maximum amounts, and the efficiency (K₂) also increased from 1-9% to 130%. When compared to other gastropods, Pila globosa appears to be a poor convertor. During 30 days' starvation, the test individuals lost 4.4 mg dry body substance/g/day i.e. the maintenance cost was 14-7 cal/g live snail/day. The SDA increased by four times for those feeding on maximum rations in comparison to those receiving about 5 mg/g/day, i.e. the energy cost for converting food was increased four times.