Nutritional physiology of the freshwater shrimp macrobrachium rosenbergii (de man)-I. Substrate metabolism in fasting juvenile shrimp

Abstract 1. 1. A respiratory quotient, O:N ratio, metabolic substrate ratio and other physiological indices were generated from measurements of oxygen consumption, nitrogen excretion and CO 2 production and used to describe substrate metabolism in fasting juvenile Macrobrachium rosenbergii (de Man). 2. 2. Energy metabolism was dominated by oxidation of carbohydrate; lipid and protein were utilized as secondary and tertiary substrates, respectively. 3. 3. Extending the period of starvation from 4 to 8 days led to a reduction in the role of carbohydrate substrates accompanied by a two-fold increase in the oxidation of lipid and protein. 4. 4. A comparative analysis of energy metabolism in crustaceans revealed a wide range of substrate hierarchies dependent upon size, trophic position and nutritional input.