Effects herbal immunostimulant (Grophit) on growth, survival and non-specific immune parameters in rainbow trout (Oncorhynchus mykiss)

Improving the efficiency of the fish's immune system is one of the most important ways to prevent disease and improve growth. Among the safety stimuli, natural types, especially plant stimulants, have recently received more attention due to less damage to fish and the environment. In this study, the effects of improving the growth and immune stimulation of graphite as a plant safety stimulant in rainbow trout with an average weight of 15.79±3.36 g for 60 days were investigated. After 2 weeks of adaptation, 0.5, 1.5 and 1.5 g of graphite powder were added to each kg of fish feed and a graphite-free diet was used as a control. Biometrics were recorded every 10 days and mortality was recorded daily and growth and survival indices were compared between different groups. In order to measure the amount of lysozyme, the tissues of liver, spleen and all fish were isolated and after homogenization and using turbidity method, the amount of lysozyme was determined. The results showed that the addition of graphite to the diet did not cause a significant change in any of the growth indices (P>0.05). In all groups that received graphite with food, the amount of lysozyme in different tissues was higher than the control group, but this difference was only in the amount of lysozyme in the tissue of all treatments of 1.5 and 1.5 g of graphite compared to the group. There was a significant difference between control and two treatments (P<0.05). According to the results of this study, the addition of graphite to the salmon diet improves the innate immunity of kidney tissue.