Specific dynamic action as an indicator of carbohydrate digestion in juvenile spiny lobsters, Jasus edwardsii

Abstract

Commercial aquaculture of crustaceans depends on the development of artificial diets, the effectiveness of which is usually determined from captive growth experiments. As an alternative, this research examines the use of a physiological measure of energy expenditure, the specific dynamic action (SDA) using closed box respirometry to determine the potential of different carbohydrates for artificial diets for the spiny lobster Jasus edwardsii. Juvenile lobsters were provided with meals composed of glycogen, maltose, sucrose, glucose, or fructose in a gelatine base, or with gels of the algal carbohydrates, agar, alginate and carrageenan. Lobsters feeding on most of the general carbohydrate diets elicited a typical SDA response with an immediate rise in oxygen consumption, which was not exhibited in unfed controls. Lobsters fed algal carbohydrates did not show a SDA response but did show an increase in ammonia excretion. It is concluded that spiny lobsters are able to use carbohydrates as part of their diet and the SDA provides a useful means of rapidly determining which carbohydrates may be best used in formulated diets. It is suggested that the SDA would be a quick and effective way to determine food digestibility of components or ingredients used in crustacean aquaculture.