Immunostimulant potential of Cannabis (Cannabis sativa) seed oil in rainbow trout (Oncorhynchus mykiss) culture

The study was performed to examine the efficacy of dietary cannabis seed oil (Cannabis sativa) on the immune response and growth performance of rainbow trout, Oncorhynchus mykiss. With this aim, fish were divided into 4 different groups containing control (0%), 0.5% (K0.5), 1% (K1) and 2% and fed with the diets during 60 days. At the end of the study, growth performance, digestive enzyme activity, humoral immune responses such as oxidative radical production, lysozyme and myeloperoxidase, and also cytokine gene expression including IL-1β, IL-8, IL-10 and IL-6 were investigated. In the study, K0.5 group showed highest growth compared to all other groups (P<0.05). FCR was significantly decreased in K0.5 group and SGR was determined the highest. Oxidative radical production was determined higher that other groups at the 30th day of the study. Trypsin was significantly increased on K0.5 and K1 30th day and on K1 6oth day of the study (P<0.05). Similar results were observed on pepsin activity. No differences were observed on amylase activity in any experimental groups and any sampling time. No differences were observed on 60th days' oxidative radical production. Lysozyme was significantly decreased on all experimental groups compare to control eth the 30th day of the study. Myeloperoxidase was determined higher on K1 and K2 groups compared to control and K0.5 at the 30th day of the study. Kidney IL-1β expression was up-regulated on K2 group compared to all other groups significantly decreased in intestine on K1 and K2 groups. 60th day of the study, increased IL-1β expression was determined on K2 group. IL-8 was up-regulated on K0.5 and K2 groups compared to other groups both sampling time (P<0.05) in kidney. In intestine, K0.5 at he 30th day, and on K1 group at the 60th day of the study IL-8 gene expression was elevated. Similar results were observed on IL-10 gene expression in both kidney and intestine. was significantly up-regulated on K0.5 at the 30th day, and K2 group at the 60th day of the study compared to control group in kidney. IL-6 was upregulated on K2 group compared to control both sampling time (P<0.05). No differences were observed on survival rate s on the groups compared to control challenged with Aeromonas hydrophila. According to results of the study, addition of cannabis seed oil into fish feed at the rate of 0.5 % could be recommended.