Investigation of blood serum enzymes and antioxidant system of liver in grey mullet ,Mugil cephalus Linnaeus 1758, fed with different levels of Saccharomyces cerevisiae yeast

The potential use of dietary probiotics to enhance the immunity and health of aquatic animals has recently attracted intensive attention. The purpose of this study was to investigate the effect of different levels of Saccharomyces cerevisiae yeast  on blood serum enzymes (aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP)) and antioxidant systems (Superoxidase dismutase (SOD), Glutathione peroxidase (GPX), Malondialdehyde (MDA) catalase (CAT)) in grey mullet, Mugil cephalus for 60 days. This experiment was designed as a completely random design in four treatments and each in three replicates. S.cerevisiae was added to the basic food in four rations of 0,2, 4 and 6 %, of the food weight. Grey mulletل with an initial weight of 5.56g were randomly distributed on  12 fiberglass tanks of 60 litres with twenty fish in each tank.. AT the end of the experiment, the results showed that the highest activity of CAT, SOD, and the lowest activity of ALT, ALP enzymes and MDA level were observed in group containing 6% of yeast that had significant difference with other treatments  (P<0.05). Tthe results of this study showed that. S.cerevisiae yeast had desirable effects on the amount of serum enzyme activities and antioxidant systems of liver of M. cephalus