Abstract: [Objective] To assess the effect of extracts from Epimedium brevicornu on growth performance of red claw crayfish （Cherax quadricarinatus）, and to evaluate the clinical safety of the extracts on target animal red claw crayfish.[Method] A total of 150 healthy red claw crayfishes were randomly assigned into 5 groups control group, recommended dose group, 3 times recommended dose group, 5 times recommended dose group, and 10 times recommended dose group. The basal diet of the 4 treatment groups was supplemented with 0.1%, 0.3%, 0.5%, and 1.0% extracts from Epimedium brevicornu, respectively. There were three parallel treatments for each group and 10 red claw crayfishes in each parallel treatment. The experimental red claw crayfishes were fed in separate boxes. After a 7-day-long administration of the extracts by mixed feeding method, the clinical symptoms, morphological parameters, blood physiological and biochemical indicators, and hepatopancreatic index were observed and measured. [Result] Compared to the control group, the extracts from Epimedium brevicornu had no significant （P>0.05） effects on weight gain rate, specific growth rate and condition factor of the red claw crayfish within the range of 10 times clinical recommended dose; the recommended dose and 3 times recommended dose of the extracts extremely significantly （P<0.01） elevated the total hemocyte counts and the serum TP level, and extremely significantly （P<0.01） reduced the ALT activity; the recommended dose of the extracts significantly （P<0.05） decreased the large-granule cell ratio. There were no significant （P>0.05） differences in serum TG, BUN and T-CHO levels and hepatopancreatic index between the treatment groups and the control group, and the histological structure of the hepatopancreas of the red claw crayfish in the treatment groups was normal. [Conclusion] Feeding the diet supplemented with extracts from Epimedium brevicornu within 3 times recommended dose for consecutive 7 days was safe for red claw crayfish.

Key words: extracts from Epimedium brevicornu, red claw crayfish, safety