Dietary carbohydrates improve oxidative status of common dentex (Dentex dentex) juveniles, a carnivorous fish species

Common dentex (Dentex dentex) is an appreciated carnivorous fish with high growth rate and life cycle adaptable to existing farming techniques. Since the use of carbohydrates is an economic and sustainable alternative for a protein-sparing effect, the study of how this macronutrient affects the welfare of carnivorous species must be studied. The aim of the present study was to evaluate the effects of different types and levels of carbohydrates on common dentex oxidative status. Nine isonitrogenous (43%) and isoenergetic (22 MJ kg− 1) diets were formulated combining three types (pregelatinized starch-PS, dextrin-Dx and maltodextrin-Mx) and three levels (12, 18 and 24%) of carbohydrates. The activities of catalase-CAT, superoxide dismutase-SOD, glutathione peroxidase-GPX, glutathione reductase-GR and glucose 6-phosphate dehydrogenase-G6PDH, SOD isoenzymatic profile, lipid peroxidation-LPO and protein oxidation-PO were determined in liver and white muscle. SOD and CAT were not affected. GPX in liver and white muscle and GR in liver increased at higher inclusion carbohydrates levels. The lowest levels of GR and G6PDH in both tissues and LPO in liver were observed in maltodextrin groups. No significant effects by carbohydrate source were observed in liver PO and white muscle LPO. Regarding carbohydrate level effect, 18% and 24% dietary inclusion level decreased LPO in white muscle and PO in liver. LPO in liver was also decreased at 24% inclusion level. Altogether, results indicate the use of carbohydrates as an alternative energy source does not produce negative effects on oxidative status of common dentex, on the contrary, even contribute to their oxidative protection.