| Summary: | In this overview of the ontogeny of organ structures and functions of larval turbot (Scophthalmus maximus L.) the developmental age of the larvae is determined on the basis of morphologically defined stages. At the onset of exogenous feeding, a functional digestive system is present, with enterocytes capable of protein and lipid absorption, with functional exocrine pancreatic cells, and with intestinal enzymes for nutrient digestion. In addition, key elements for the metabolic utilization of dietary nutrients, such as differentiated liver cells, endocrine factors, and enzymes of key metabolic pathways, exist. During subsequent development, intestine, exocrine pancreas, and liver of turbot larvae undergo mainly quantitative alterations (i.e. growth) but not qualitative alterations (i.e. appearance of new functions). The gills are not functional at first-feeding but differentiate until metamorphosis. The phase of metamorphosis is characterized by the onset of stomach function and by a pronounced increase of glycolytic metabolic activities indicating a change from larval musculature into the adult-type (aerobic) red and (anaerobic) white muscles.
|
|---|