The influence of aging on brain fatty acids and phospholipids of Poecilia formosa and Carassius auratus

The influence of aging on the total brain fatty acids and major brain phospholipids were examined in the Poecilia formosa (Amazon molly) and the Carassius auratus (common goldfish). Young adults (6-10 mo. old mollies and 1-2 yr. old goldfish), middle age adults (10-12 mo. old mollies and 5-6 yr. old goldfish), and old adults (13-15 mo. old mollies and 8-11 yr. old goldfish) were examined for changes in total brain fatty acids. In both species the monoenoic acids, palmitoleic (16:1) and oleic (18:1) increased with age while palmitic acid (16:0) and stearic acid (18:0) decreased. Stearic acid showed a greater decrease than palmitic. The frequency of shorter chain (<16:0) acids increased with age. The major fish brain phospholipids, phosphatidyl choline (PC), phosphatidyl ethanolamine (PE), and phosphatidyl serine (PS) were analyzed in young and old adults of both species. The fatty acid changes in PC and to a much lesser extent in PE reflected the changes in the total brain fatty acid fraction. PC and PE decreased with age while PS remained at a relatively constant level. PE decreased more in the short life span fish, the Amazon molly. Assuming a relationship between the erythrocyte asymmetrical membrane structure and that of the neuronal membrane, it was suggested that the inner membrane phospholipids deteriorate more rapidly in the Amazon molly compared to the long life span goldfish. The data support the hypotheses that (1) the stress of aging produced a metabolic response in brain phospholipids similar to that produced by the temporary effect of cold water and (2) this response perturbs the oxidative desaturation mechanism which increases the fluidity of the neuronal memborane, and (3) the effect of aging on brain phospholipids in fish is similar to that in mammalian brain.