Ecometabolomics of Loggerhead Sea Turtles (Caretta caretta): The Impact of Age on Metabolomic Profiles.

To investigate the impact of age on the metabolomic profile of loggerhead sea turtles (Caretta caretta), this study analyzed 100 plasma samples of individuals across two age groups-50 post-hatchlings and 50 juveniles-from various locations along the Mediterranean coastline. Both targeted and untargeted metabolomic analyses were performed on the samples. Our results demonstrated a significant age-related effect on the metabolomic profiles in both analyses. Specifically, post-hatchling turtles exhibited increased levels of urea (p < 0.001), triglyceride (p = 0.0003), cholesterol (p < 0.001), lysoPE (18:1/0:0) (p < 0.001), 7-HDoHE (p = 0.0121), pyrrolidinebutanoic acid (p < 0.001), formiminoglutamic acid (p < 0.001), pyroglutamic acid (p < 0.001), lysoPC (0:0/20:4) (p < 0.001), lysoPE (22:6/0:0) (p < 0.001), 1-acyl-sn-glycero-3-phosphocholine (p < 0.001), DL-homocysteine (p < 0.001) and gamma-Glutamyltyrosine (p < 0.001). Conversely, post-hatchlings showed reduced levels of total protein (p < 0.001), glucose (p = 0.0002), uric acid (p < 0.001), inorganic phosphorus (p = 0.0018) and calcium (p = 0.0410) compared with juveniles. These findings suggest significant physiological changes between the age groups, likely due to differentiated feeding patterns. Further research is needed to better understand the metabolic profiles and complex physiological and nutritional interactions of this species.