Changes in Juvenile Rainbow Trout (Oncorhynchus mykiss) Growth Performance, Digestive Enzyme Activity, Hematological Profile and Serum Biochemical Markers After Dietary Administration of γ-irradiated Cinnamon (Cinnamomum verum) Ethanolic Extract

The aim of this study was to investigate the effects of dietary supplementation of γ-irradiated cinnamon ethanolic extract on the growth performance, digestive enzymes, lysozyme activity level and hematological factors in the juvenile rainbow trout. The fish were divided into five groups, including control group and four experimental groups (received diets enriched with 10 g/kg of non-irradiated or irradiated CEE at the radiation doses of 10, 20 and 40 KGy. At the end of the feeding trial (60` days), 10 fish were sampled from each tank after 12 h of feed deprivation. The results showed that the fish dietary irradiated CEE at doses of 10 KGy and 20 KGy had significantly higher final weights, weight gain, specific growth rates and growth hormone levels, and lower feed conversion ratios compared to the other groups (P≤0.05). The blood glucose level significantly lowered in the fish group fed with dietary γ-irradiated CEE, and increased the activity of lysozyme activity level and digestive enzymes compared to the control group (P≤0.05). In conclusion, dietary supplementation of γ-irradiated CEE at a dose of 10 KGy can enhance the positive effects of cinnamon extract and improve the growth performance, digestion and lysozyme activity in juvenile rainbow trout.