The Effects of Different Levels of Dietary Galactooligosaccharide on Antioxidant Defence in Zebra Fish (Danio rerio)

Inroduction & The aim of the study was to study the effects of different levels of prebiotic galactooligosaccharide (GOS) on antioxidantdefense system in zebrafish (Danio rerio) as model organism.
Material and A total number of 420 fish (45±0.1 mg) were supplied and randomly stocked in 60 L aquariums assigned to four treatments repeated in triplicates. Fish were with four experimental diets contain0, 0.5, 1 and 2% prebiotic for 8 weeks. At the end of feeding trial, total antioxidant activity as well as expression of antioxidant defense related genes Catalase (CAT) and Superoxide dismutase (SOD).
The obtained results revealed that administration of different levels of GOS had no significant effects on total antioxidant activity (P>0.05). Also, gene expression studies showed that CAT expression was remarkably down-regulated in fish fed 0.5 and 2% GOS (P0.05). Evaluation of SOD gene expression revealed significant down regulation in prebiotic fed fish (0.5, 1 and 2%) compared control group (P0.05).
Counclusion: Based on these results, it seems that administration of GOS in zebra fish diet downregulates antioxidant defense related genes without any effect on total antioxidant activity.