Effect of dietary enrichment of Padina algae (Padina astraulis Hauck) on serum immune indices of Common carp Cyprinus carpio in exposure to zinc oxide nanoparticle

The use of immune stimulants such as algae has a key role in enhancing of immunity. On the other hand, the presence of nanoparticles affects the physiological status of fish and reduces their immune function. Therefore, the purpose of this study was to investigate the effect of enrichment of diet with algae on carp serum immune parameters in exposure to zinc oxide. 250 common carp were divided in four groups for 42 days, algae-free (treatment 1, control), food containing 0.5% algae (treatment 2), food containing 1% algae (treatment 3) and food containing 2% algae (treatment 4), then 50% of acute concentration of zinc oxide nanoparticles (1.5 mg/l) was added to each of the groups over a period of fourteen days. The results of this study showed that in general, experimental treatments had a significant effect on serum protein, immunoglobulin and serum albumin levels (P<0.05), but there was no significant effect on serum glucose (P>0.05). Also, experimental treatments had a significant effect on ASA, ALP and ALT levels (P<0.05). The significantly increased rate of these indices was due to treatments fed with algae. Also, these indices increased significantly in treatment of zinc oxide and also in zinc with algae group. Experimental treatments did not had a significant effect on blood glucose level (P>0.05). It can be concluded that Padina algae may partially improve the reducing effect of nano-oxide on serum total protein and immunoglobulin levels, which requires further research in this regard.