Effect of different levels of apple cider vinegar on some parameters of non-specific immune system of blood serum on common carp (Cyprinus carpio) fingerlings

Organic acids are natural crops and produced byo fermentation in plants and have a high potential for the replacement of antibiotics in the aquaculture industry. Hence, in this study, apple vinegar was used as a kind of organic acid in the diet of common carp fingerling. The aim of this study was to evaluate the effect of apple vinegar in different concentrations (0, 1, 2 and 4% of apple vinegar on basal diet) on some non-specific immune parameters of serum of common carp such as albumin (A), globulin (G), A/G ratio, total protein, lysozyme enzyme and alkaline phosphatase (ALP). Common carp fingerling with average weight of 15±0.5 g were fed with experimental diet for 60 days. At the end of the experiment, 10 fish pieces were randomly slaughtered in each replicate and anesthetized in clove solution and blood samples were taken. The amount of albumin and globulin measured in nutritional treatments did not show a significant increase compared to the control group (p>0.05). However, total protein increased significantly at 2% level compared with other treatments and control group (p < 0.05); also, in 2% apple vinegar, a significant increase in lysozyme activity was observed (p < 0.05). There was no significant difference in the level of alkaline phosphatase between nutritional treatments and control group (p>0.05).