Nutritional
components affecting skeletal development in fish larvae
Ch. Cahu, J. Zambonino Infante, T. Takeuchi
Aquaculture, 227(1-4): 245-258
Abstract:
Marine fish larvae undergo major functional and
morphological changes during the developmental stages and several factors
can interfere with the normal development of larvae and affect fry quality.
Skeletal malformations, such as spinal malformation––scoliosis,
lordosis, coiled vertebral column-, missing or additional fin rays, bending
opercle or jaw malformations, are frequently observed in hatchery-reared
larvae. This paper reviews the effects of some nutritional components on
skeletal development in larvae of a number of fish species. In the dietary
lipid fraction, for instance, it was proven that the phospholipid
concentration affected the spinal malformation rate in sea bass fed a
compound diet from mouth opening onwards. Phosphatidylinositol, in
particular, seems to prevent skeletal deformities. Highly unsaturated fatty
acids, and particularly DHA enrichment in live prey, induce a decrease of
opercular deformities in milkfish. It is known that highly unsaturated fatty
acids have profound effects on gene expression, leading to changes in
metabolism, growth and cell differentiation, and these effects are worth
investigating in developing fish. The nature of the dietary protein fraction
also affects the quality of fish larvae development. It appears that dietary
incorporation of 20 amino acid peptides or di- and tripeptides leads to a
reduction of spinal malformations in sea bass. Among vitamins, the
teratogenic effect of retinoic acid is now well documented in vertebrates.
High dietary retinoic acid levels result in higher incidence of bone
deformities, such as vertebral curvature, central fusion and compression of
vertebra in Japanese flounder larvae. The teratogenic effect of retinoic
acid observed in embryonic and postembryonic stages was explained by a
depression of shh expression. As for vitamin C, opercular
abnormalities in milkfish larvae, associated with distortion of gill
filament cartilages, were reduced by 50% when feeding larvae with ascorbic
acid enriched rotifers and Artemia, compared to control fish.
(Unité Mixte INRA IFREMER de Nutrition des Poissons,
B.P. 70, 29280 Plouzané, France, e-mail: Chantal.Cahu@ifremer.fr)