ABSTRACT
For a long time, it has been hypothesized that marine fish larvae possessed insufficient digestive enzyme capacity to handle compound diets when compared to juvenile fish. Several weaning strategies were then built on the supply of exogenous enzymes (Kolkovski, 2001) but were never very conclusive. More recently, it was considered that ontogenetic differences between the larval type and adult type organ function do not mean that larvae face physiological or digestive deficiencies during early life stages. Rather than primitive organisms, fish larvae shall be considered a transitional age in which both ontogeny and growth cause substantial changes in structure, physiology, size and body shape. The basic mechanisms of organ development are similar in all teleosts, even though there are considerable differences regarding the relative timing in the ontogeny. The time in organ development and its associated physiological functions are affected by the general life history of each species and a number of abiotic and biotic factors, such as water temperature, food availability and composition during early life stages. These changes determine the nutritional and physiological performances of a fish and, therefore, its ability to deal with challenges during its subsequent life (Fuiman, 1997).
