Investigation of some mucosal and serum indices in exposed common carp (Cyprinus carpio) with salinity stress

The present study was conducted to evaluate some of the mucosal and serum indices of common carp (Cyprinus carpio) that exposed to salinity stress. In this regard one hundred and eighty fish (mean weight 50 ± 0.62 gr) were obtained from, after two weeks of adaptation randomly stocked in nine tank assigned to three treatments with three replicates including fresh water, Caspian Sea water (14ppt) and 50% sea water and 50% fresh water (7ppt). For measurement of immune factors after 3, 6 and 9 days of exposure, nine fish were taken from each treatment and anesthesia with clove powder. Serum and mucus were collected from different treatment and stored at -20 °C until use. The results showed different salinity had a significant effect on total protein, alkaline phosphatase and lysozyme of serum and mucosal (p < 0.05). But there wasn’t significant effect on protein content of mucus among treatments. According to the overall conclusion of the present study, results showed that mucusal lysozyme decreased with increase of water salinity in all measuring periods, but the amount of mucosal alkaline phosphatase in initial days decrease in 7 ppt salinity and in final days increase in 14 ppt salinity treatment, but serum alkaline phosphatase in first days of exposure to salinity decreased and then increase during experiment period. Total protein of mucus didn’t statistically affect during experiment. Serum total protein in initial days of exposure, increase and decrease during experiment. increased in the early and final days of sea water treatment. There was no significant difference among protein content of mucus in all treatment. The lysozyme and total protein parameters of the blood serum increase in the early days of exposure to salinity stress, but during the exposure total protein content of the serum reduced. The amount of alkaline phosphatase decrease in the early days of exposure to salinity stress, but increases with salt in time.