Differential absorption and esterification of dietary long-chain fatty acids by larvae of the dragonfly, Aeshna cyanea.

摘要

The absorption of dietary long-chain fatty acids was evaluated in larvae of Aeshna cyanea. Larvae received 5μl oral doses containing combinations of two radiolabelled fatty acids at nearly equal radioactive and nmolar concentrations: 3H-oleic and 14C-palmitic acids; 3H-oleic and 14C-stearic acids; and 3H-palmitic and 14C-stearic acids. After 3 h or 1 day, haemolymph samples, midgut tissue, midgut contents and fat body tissue were collected and assayed for labelled fatty acids. The 3H:14C ratios indicated that there was a preference for absorption of the monounsaturated oleic acid over both saturated palmitic and stearic acids and that the shorter palmitic acid was absorbed at a higher rate than the longer stearic acid. There were also differencesin the 3H:14C ratios of the various lipid classes of the midgut wall, haemolymph, and fat body that reflected differential esterifications and transport of these fatty acids.