Physiological Adaptations in the Gastrointestinal Tract of Crayfish

Abstract

SYNOPSIS. Crayfish are the dominant macrocrustacean in many aquatic ecosystems and are the largest crustacean aquacultural industry in the United States, yet we know relatively little about their preferred and nutritionally important foods, as well as their ability to utilize those foods. This review focuses on the ability of crayfish to detect foods, reduce food particle size, digest macronutrients and the control of those functions. Of particular interest are the enzymatic capabilities of crayfish, especially trypsin, an alkaline protease, cellulase, muramidase, and possibly chitinase and chitobiase. The coordinated neural control of crayfish food location, ingestion and movement has been well documented, while hormonal control mechanisms have not. The conclusion we must draw from our current state of knowledge is that crayfish have ample abilities to taste and locate potential foods and enzymatic adaptations developed in crayfish that allow use of many of the foods they encounter in a benthic aquatic environment; other adaptations are lacking or have not been elucidated.