RESUMEN
Investigating the physiological and biochemical changes of ectothermic species before entering hibernation would contribute to the understanding of how they adapt to low-temperature environments. Here, red-eared slider turtle (Trachemys scripta elegans) hatchlings were maintained under different thermal treatments (24 °C, slowly decreasing temperatures from 24 °C to 14 °C, and to 4 °C). Hepatic metabolite alterations were measured to assess the metabolic impacts of low-temperature stress in this species. Of these differentially changed metabolites, some (e.g., raffinose, spermidine, allocholic acid, taurohyocholate, 2-ketobutyric acid, acetylcysteine) were shown to decrease, while others (e.g., stearolic acid, D-mannose) increased in low-temperature treatments. Our results indicated that short-term low-temperature stress might have limited impacts on lipid and energy metabolism in this species. The changes in other metabolites (e.g., allocholic acid, taurohyocholate, spermine, acetylcysteine) might be associated with a low food intake (and thus reduced digestive performance) and weakened immune ability of low-temperature-exposed animals.
RESUMEN
Organophosphorus flame retardants, such as triphenyl phosphate (TPhP), exist ubiquitously in various environments owing to their widespread usage. Potential toxic effects of residual flame retardants on cultured non-fish species are not concerned commonly. TPhP-induced physiological and biochemical effects in an aquatic turtle were evaluated here by systematically investigating the changes in growth and locomotor performance, hepatic antioxidant ability and metabolite, and intestinal microbiota composition of turtle hatchlings after exposure to different TPhP concentrations. Reduced locomotor ability and antioxidant activity were only observed in the highest concentration group. Several metabolic perturbations that involved in amino acid, energy and nucleotide metabolism, in exposed turtles were revealed by metabolite profiles. No significant among-group difference in intestinal bacterial diversity was observed, but the composition was changed markedly in exposed turtles. Increased relative abundances of some bacterial genera (e.g., Staphylococcus, Vogesella and Lawsonella) probably indicated adverse outcomes of TPhP exposure. Despite having only limited impacts of exposure at environmentally relevant levels, our results revealed potential ecotoxicological risks of residual TPhP for aquatic turtles considering TPhP-induced metabolic perturbations and intestinal bacterial changes.