The effect of hypoxia on intermediary metabolism and oxidative status in gilthead sea bream (Sparus aurata) fed on diets supplemented with methionine and white tea.
The present study evaluates the influence of previous nutritional status, fish fed on diets supplemented with tea and methionine, on acute hypoxia tolerance and subsequent recovery of Sparus aurata juveniles. Four isonitrogenous (45% of protein) and isolipidic (18% lipid) diets were formulated to contain 0.3% methionine, 2.9% white tea dry leaves or 2.9% of white tea dry leaves+0.3% methionine. An unsupplemented diet was used as control. Hepatic key enzymes of intermediary metabolism and antioxidant status, superoxide dismutase isoenzyme profile, glutathione (total, reduced and oxidized) and oxidative damage markers were determined under normoxia, hypoxia challenge and during normoxia recovery. Dietary white tea inclusion decreased plasma glucose levels under normoxia and seemed to induce an increase in anaerobic pathways as showed by enhanced liver lactate dehydrogenase activity. Hypoxia challenge reversed some of the responses induced by diet tea supplementation. Hypoxia decreased plasma glucose levels, increased glucose 6-P-dehydrogeanse activity, decreased superoxide dismutase activity (especially Mn-SOD and CuZn-SOD isoforms) and increased glutathione peroxidase activity in all dietary treatments. Catalase activity during hypoxia varied with dietary treatments and glutathione reductase was not modified. Antioxidant defenses were insufficient to avoid an oxidative stress condition under hypoxia, independently of dietary treatment. In general, pre-challenge values were recovered for almost all parameters within 6 h recovery time.
CIMAR/CIIMAR-Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal. calaya@ugr.es
Amalia
A
Pérez-Jiménez
Helena
H
Peres
Vera Cruz
VC
Rubio
Aires
A
Oliva-Teles
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D004789:Enzyme Activation; D057075:Enzyme Assays; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D000860:Hypoxia; D007527:Isoenzymes / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D008715:Methionine / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D021541:Sea Bream / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D013662:Tea / Q000378:metabolism*; D013997:Time Factors
D000975:Antioxidants; D001786:Blood Glucose; D007527:Isoenzymes; D013662:Tea; D008715:Methionine; D007770:L-Lactate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase