The annual cycle of fatty acid composition in a starfish

Abstract

1. 1. Fatty acid levels (C-14 and above) were followed in the digestive glands and gonads of the Tampa Bay starfish, Echinaster, throughout its annual cycle of growth and reproduction. 2. 2. Thirty-four chromatographic peaks were identified in most samples, with the fatty acids, 18:1, 26:1, 20:1, 20:2, 20:4, 20:5, and 16:0 predominating. Generally, branched chain and odd-numbered components were abundant in the lower chain lengths, and poly-unsaturated forms in the higher. 3. 3. With some exceptions, the same patterns of fatty acids were found in the gonads of both sexes as in the digestive glands. Testes levels were always low, while those of the mature ovary often exceeded diminished values in the digestive glands. 4. 4. All major fatty acids follow cycles of concentration indicative of an early fall buildup in the digestive glands and subsequent transfer to the developing gonads. 5. 5. While the basic pattern of fatty acid content could be tied closely to the preferred food source of the animals (sponge aggregates), higher tissue proportions of 18:1 indicated possible additional de novo synthesis. 6. 6. The fatty acid patterns of the specimens studied were quite different from those of a closely related starfish, Echinaster modestus, providing evidence supporting the taxonomic separation of the two forms.