protective effects of dietary spirulina platensis against cadmium-induced oxidative stress in gills of rainbow trout

Background: contamination of feeds with cadmium leads to oxidative stress in vital tissues such as gills and affects the fish survival. therefore, an increase in the capacity of the antioxidant defense system and detoxification system of fish may reduce adverse effects of pollutants. this study investigated the protective effects of microalga spirulina platensis against oxidative stress in gills of cadmium-treated rainbow trout. methods: this study was conducted at fish farm, almas-dime village, koohrang, charmahal & bakhtiari province, iran from april to july 2016. rainbow trout were allocated into five groups of which one group received normal feed and served as control. fish from group ii received 0.2 mg cdcl2 per 1 kg feed. groups iii-v were fed with enriched diet with 2.5, 5 and 10 g s. platensis per 1 kg feed, respectively and simultaneously treated with 0.2 mg kg^-1 cdcl2 for 21 d. changes in biochemical parameters including alanine aminotransferase (alt), aspartate aminotransferase (ast), alkaline phosphatase (alp) and lactate dehydrogenase (ldh), malondialdehyde (mda) as marker of lipid peroxidation and cellular total antioxidant capacity were evaluated. results: oral exposure to cdcl2 caused a significant increase in mda levels and altered ast, alt, alp and ldh activities in gills (p<0.05). the cellular antioxidant capacity was significantly lowered in cdcl2-treated fish as compared to the control group (p<0.05). oral administration of s. platensis significantly ameliorated these changes in certain biochemical parameters in gills of cdcl2-treated fish. conclusion: the findings indicate that s. platensis has protective effects against toxic influence of cdcl2 on certain biochemical parameters in gills of fish.