Oxidative status and gut morphology of white sea bream, Diplodus sargus fed soluble non-starch polysaccharide supplemented diets

The present work aims to study the effect of a soluble non-starch polysaccharide (NSP), guar gum on white sea bream intestinal health through oxidative status and distal intestine morphology evaluation. A control diet was formulated to contain 40% crude protein, 14% crude lipids and 35% pregelatinized maize starch. Three other diets were formulated to include the same levels of all ingredients as control diet except for guar gum, which was included at 4% (diet GG4), 8% (diet GG8) or 12% (diet GG12). Compared to the control, lower catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR) activities and higher SOD, glutathione peroxidase (GPX) and glucose-6-phosphate dehydrogenase (G6PD) activities were observed in the whole intestine of fish fed with diets GG4 and GG12, respectively. Thiobarbituric acid-reacting substances (TBARS) levels were unaffected by diet composition. No morphological alterations in the distal intestine were found among groups. Overall, data on key enzymes of the antioxidant enzymatic defense mechanism suggested that diet-induced reactive oxygen species (ROS) generation is dependent on guar gum inclusion levels and low dietary inclusion of soluble NSP (up to 4%) may have a gut oxidation stress prevention effect.

► Guar gum effect on white sea bream oxidative status and distal intestine morphology.
► Key enzymes with antioxidant activity were lower in fish fed with 4% of guar gum.
► Higher activities were recorded in fish fed with 12% of guar gum.
► Diet-induced reactive oxygen species generation depends on guar gum inclusion levels.
► Guar gum up to 4% may have a gut oxidation stress prevention effect.