Opium poppy (Papaver somniferum L.) aqueous methanolic extract in rainbow trout (Oncorhynchus mykiss) against Aeromonas hydrophila pathogen with immunity reaction and performance on growth

In this study, changes in immune responses, growth performance and digestive enzyme activities of rainbow trout (Oncorhynchus mykiss) fed with aqueous methanolic extract of white poppy (Papaver somniferum) were investigated, and also its protective activity against Aeromonas hydrophila was determined. For this purpose, fish were fed ad-libitum for 45 days with feeds containing 0% (Control), 0.1% (B01), 0.5% (B0.5) and 1% (B1) white poppy methanolic extract. Blood and tissue (intestine and anterior kidney) samples were taken from the fish every 15th, 30th and 45th days of the study, and changes in immune responses were examined. At the end of the study, the fish were injected intraperitoneally with Aeromonas hydrophila and the survival rates of the fish were recorded during 7 days. The results showed that growth was significantly increased in all experimental groups compared to control (P<0.05). The highest growth was determined on B1 group (P<0.05). Digestive enzymes were not affected in any sampling time except lipase. Lipase was increased at the end of the study on B1 group compared to all other groups (P<0.05). Oxidative radical production and potential killing activity as elevated on B1 groups only at the end of the study (P<0.05). Lysozyme, myeloperoxidase, total protein, Immunoglobulin-M, was significantly increased in all experimental groups at all sampling time compared to control. Anti-protease activity was increased on all experimental groups at the end of the study. The transcription levels of interleukin-1β, TNF-α, TGF-β, IFN-1, and IL-12 were significantly up-regulated in the fish fed with B in head kidney. Elevated cytokine responses in the intestine were determined only TGF-β, IFN-1, and IL-12. According to the survival rate results, it was determined that the experimental groups had a higher survival rate than the control group, especially the B1 group (P<0.05). All these results suggest that white poppy methanolic extract could be used as immunostimulant for rainbow trout.