It is well known that the diet fed to early stages of fish affects their survival and growth. But recent experiments have demonstrated that nutrition also affects fish morphogenesis. Insufficiency or excess in some nutrients conducts to the appearance of different skeletal malformations, such as lordosis, scoliosis, vertebrae fusion, neurocranium deformities, and anomalies in pre-maxillary, maxillary and dental. At first, a food deprivation during some days in early stages may conduct to an increase in skeletal deformity occurrence. Incorporation of phospholipids and hydrolysed protein in diet fed to sea bass larvae from mouth opening reduces the number of deformities. Recently, it has been evidenced that an excess of vitamin A in diet induces skeletal malformations in sea bass as in Japanese flounder. Vitamin A (retinol) is known to be an important morphogen in mammals and birds through its derivate called retinoic acid. Excess in HUFA also induces skeletal deformities, and led to the development of one surnumerous vertebra in sea bass (26 instead of 25), when an excess in vitamin A led to the loss of one vertebra. This nutrients act on genes such as BMP4 (Bone Morphogenetic protein 4), RAR (Retinoic Acid receptor), RXR (Retinoid X Receptor), involved in postembryonic larvae development. The study of the regulation of genes by nutrients will be helpful to improve the compound diets formulated for fish early stages.

Chantal Cahu, PhD, works in the Fish Nutrition Laboratory, a twin unit INRA-IFREMER (Brest, France). She was involved during 10 years in shrimp culture and nutrition. Now, she studies particularly digestive physiology and nutritional requirements of fish larvae, in collaboration with several European teams. She has co-authored more than 35 publications in this field. The results obtained in her team led to the formulation of practical compound diets for marine fish larvae.