P. Zhu, R.P. Evans, C.C. Parrish, J.A. Brown, P.J. Davis-1997
Bull. Aquacul. Assoc. Canada, 97(2): 48-50
Abstract:
Over the past decade, two major endogenous nutrients, lipids and free amino acids, in developing marine fish embryos and larvae have been studied extensively in order to elucidate the nutritional requirements of these animals. However, the connection between amino acid and lipid metabolism has rarely been investigated. Based on our data for Atlantic halibut (Hippoglossus hippoglossus) embryos and larvae, and previous studies on other species, we propose that in the later embryonic stages, towards hatching, a significant amount of amino acid is catabolized to serve as carbon skeletons for lipogenesis. The synthesis of lipid may be related to buoyancy and osmolality regulation during embryogenesis, modification of membrane structure, and may also be an adaptation to hypoxic conditions that may occur at hatch. Although lipogenesis is an energetically inefficient process, its physiological importance may override this disadvantage. These findings suggest that in embryos and larvae there is an interaction between lipid and amino acid metabolism which may relate to physiological and environmental conditions. Thus, from the perspective of broodstock and larval nutrition, lipid and amino acid metabolism should not be considered separately.
(Ocean Sciences Center, Memorial University of Newfoundland, St. John's, NF Canada A1C 5S7)