Carbohydrate digestion in Penaeus monodon

Using crude homogenates from the digestive system of pond-cultured Penaeus monodon, carbohydrase activity was demonstrated toward a wide variety of substrates differing in sources and complexity. The largest concentration of this activity was found to be localised within the midgut gland. Multiple pH optima for the hydrolysis of starch suggested the presence of more than one amylase, which was confirmed by partial purification using chromatofocusing. Enzyme characterisation of the amylase activity suggested exohydrolysis in the form of a glucoamylase and possible endohydrolysis in the form of an -amylase. The complexity of the enzyme profile demonstrated in P. monodon is discussed in relation to possible sources of carbohydrate found in natural food items.