LAUSR

Abstract: Blood fatty acid profiles can indicate an animal's wild-type diet composition and fatty acid status, but have not been reported in sea turtles. Newer technologies allow for fatty acid profiles from very small (less than three drops) samples of whole blood. This study examined whole blood fatty acid profiles of presumably healthy, neritic, juvenile, wild green (Chelonia mydas) (n = 9; 6 males, 3 females) and Kemp's ridley (Lepidochelys kempii) (n = 8; 6 males, 2 females) turtles from North Carolina, USA. Saturated fatty acids, which can be synthesized de novo, consisted primarily of 16:0, although green turtle blood had a higher proportion of 18:0 (P < 0.001) than Kemp's ridleys, while Kemp's ridley blood had higher proportions of 17:0 (P = 0.007), 20:0 (P = 0.03), 22:0 (P= 0.002), and 24:0 (P < 0.001) as compared with green turtles. Total monounsaturated w7 fatty acids, which can be synthesized de novo or may be diet derived, were higher in Kemp's ridleys and predominantly in the form of 16:1 and 18:1w7 fatty acids. Kemp's ridley blood had more than double the relative proportion of 16:1w7 as compared with green turtles (P= 0.03). Green turtles had higher levels of 18:2w6 than Kemp's ridleys (P= 0.02). In both turtle species, 20:4w6 was detected, despite predicted low dietary proportions, suggesting bioconversion from precursors. Finally, green turtles had higher levels of 18:3w3 compared with Kemp's ridleys, while Kemp's ridleys had higher proportions of 20:5w3 compared with green turtles (P < 0.001, = 0.007, respectively). Whole blood fatty acid profiles generally correlate to previous work with lipid depots, supporting the use of this less invasive methodology to advance the understanding of fatty acid nutrition of sea turtles. These data can be used to assess and guide nutrition and health programs for sea turtles under human care.