Effect of thermal stress on metabolic and oxidative stress biomarkers of Hoplosternum littorale (Teleostei, Callichthyidae)

ROSSI, ANDREA; BACCHETTA, CARLA; CAZENAVE, JIMENA

ECOLOGICAL INDICATORS

ELSEVIER SCIENCE BV

Año: 2017 vol. 79 p. 361 - 370

1470-160X

The present study aimed to investigate in Hoplosternum littorale (Hancock, 1828) theeffects of different water temperatures (10 °C, 25°C-control group- and 33 °C) on physiologic and metabolic traits followingacute (1 day) and chronic (21 days) exposures. We analyzed several biomarkerresponses in order to achieve a comprehensive survey of fish physiology and metabolism under the effect of this natural stressor. Wemeasured morphological indices, biochemical and hematological parameters aswell as oxidative stress markers. To evaluate energy consumption, muscle andhepatic total lipid, protein and glycogen concentrations were also quantified. Extreme temperatures exposuresclearly resulted in metabolic adjustments, being liver energy reserves andplasmametabolites the most sensitive parameters detecting those changes. Weobserved reduced hepatosomatic index after acute and chronic exposure to 33 °Cwhile glycogen levels decreased at both temperatures and time of exposure tested.Additionally, acute and chronic exposures to 10 °C increased liver lipidcontent and plasma triglycerides. Total protein concentration was higher inliver and lower in plasma after chronic exposures to 10 °C and 33 °C. Acuteexposition at both temperatures caused significant changes in antioxidant enzymes tested in the different tissues without oxidative damageto lipids. Antioxidant defenses in fish failed to protect them when they were exposed for21 days to 10 °C, promoting higher lipid peroxidation in liver, kidney andgills. According to multivariate analysis, oxidative stress and metabolicbiomarkers clearly differentiated fish exposed chronically to 10 °C. Takentogether, these results demonstrated that cold exposure was more stressful for H. littorale than heat stress.However, this species could cope with variations in temperature, allowingphysiological processes and biochemical reactions to proceed efficiently at different temperatures and times of exposure. Our study showed the ability of H. littorale to resist a wide range of environmental temperaturesand contributes for the understanding of how this species is adapted toenvironments with highly variable physicochemical conditions.