Studies on the digestive secretions in fish can elucidate certain aspects of their nutritive physiology and thereby resolve some nutritional problems, such as matching of an artificial diet to the nutritional needs of the fish. The aim of the present study was to analyse the digestive protease, amylase, and lipase activity in the Adriatic sturgeon and compare it with that of rainbow trout. The results show that the sturgeon is not only capable of digesting fat and protein, like any other carnivorous fish, but can also digest carbohydrates at levels characteristic of an omnivore. In turn, the proportion of acid-protease enzymes indicates the need for major gastric digestion.