ABSTRACT
First feeding marine fish larvae do not have a stomach, so their extracellular digestion of the diet starts in the intestine. The immature digestive tract of the larvae has rised the question of whether they rely on autolysis of the ingested prey in making feed-nutrients available for intestinal absorption or not. Moreover, it has been suggested that the limited success so far with formulated diets for first feeding marine fish larvae is due to lack of digestive capacity. The major contribution to the endogenous digestive capasity of the larvae is provided by hydrolytic enzymes secreted from the pancreatic tissue. By use of a radioimmunoassay technique, with antibodies made against pepsin purified from adult cod, a sharp increase in the content of pepsin was found when the fish reached a standard length of 14 mm. This result fits well with earlier findings that the morphological development of the stomach started at 15 mm standard length.
