Alireza Afzali-Kordmahalleh - Post-graduate of Veterinary Medicine, Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran
Saeid Meshkini - Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran

The effects of resveratrol as an anti-oxidant in improving growth and health have been shown in several experiments. This study aimed to evaluate the effects of different dietary resveratrol inclusion levels on digestive enzymes activity and serum biochemistry of rainbow trout (Oncorhynchus mykiss). Accordingly, ۲۲۵ juvenile rainbow trout with an average body weight of ۱۰.۰۰ ± ۱.۵۰ g were stocked in nine experimental units. The study was performed as a completely randomized design including three dietary levels of resveratrol as follows: ۰.۰۰, ۴۰۰ and ۸۰۰ mg kg-۱ feed. During the experiment, fish were fed based on their respective body weight using standard feeding tables at three feeding times for ۸ weeks. Nine fish were randomly selected from each treatment at the end of the ۴th and ۸th weeks of the experiment. Results revealed that supplementing ۸۰۰ mg kg-۱ feed resveratrol significantly increased lipase activity (۳۱.۴۰ ± ۰.۳۲ U mg-۱ protein) compared to the control group (۲۹.۹۲ ± ۰.۵۲ U mg-۱ protein) at the end of week eight. Also, at the same time, it increased serum high-density lipoprotein (۱۲۳.۰۴ ± ۱.۵۷ mg dL-۱) compared to the control group (۹۷.۰۵۵ ± ۱.۴۶۳ mg dL-۱). In addition, dietary supplementation of ۸۰۰ mg kg-۱ feed resveratrol effectively reduced serum alanine aminotransferase, alkaline phosphatase and aspartate aminotransferase activities along with glucose, cortisol and cholesterol. In conclusion, resveratrol can be used as a suitable food supplement to improve fish health by increasing digestive enzymes activities.

Digestive Enzymes, Rainbow trout, Resveratrol, Serum biochemistry