Lipids and lipid antioxidant systems in developing eggs of salmon (Salmo salar)


Cowey CB, Bell JG, Knox D, Fraser AJ & Youngson A (1985) Lipids and lipid antioxidant systems in developing eggs of salmon (Salmo salar). Lipids, 20 (9), pp. 567-572.

Lipid class and fatty acid analyses were carried out on developing salmon eggs at four clearly defined pre-feeding stages, namely, fertilization, eyed egg stage (50 days), hatching (yolk sac fry, 98 days) and swim up fry (138 days). Measurements of components of the system considered to be involved in defense of cells against lipid peroxidation (glutathione peroxidase, EC, glutathione S-transferase, EC, reduced glutathione [GSH], α-tocopherol and ascorbic acid) were made at the same time. Levels of triacylglycerol decreased markedly during development, but there were few changes in fatty acid composition, indicating a non-selective utilization of fatty acids. Phosphatidylcholine was the dominant polar lipid (greater than 94% by weight) in fertilized eggs. It was used preferentially during development so that in swim up fry the ratio phosphatidylcholine: phosphatidylethanolamine approached that found in fish muscle. Amounts of docosahexaenoic acid and arachidonic acid in polar lipids were significantly greater (p less than 0.01) in swim up fry than in fertilized eggs. Activities of the two enzymes were very low in the fertilized egg and remained low until hatching, when there was a concerted increase in their activity and in the concentration of GSH. Egg tocopherol concentrations decreased significantly during development, but whole body concentrations in swim up fry were not dissimilar from those in normal juvenile fish. Ascorbic acid, on the other hand, declined to very low levels in swim up fry; the restoration of this vitamin during first feeding seems vital to the well being of the fish.

Lipids: Volume 20, Issue 9

Publication date30/09/1985