Growth performance and antioxidant status of growing rabbits fed on diets supplemented with Eucommia ulmoides leaves

The present study evaluated the effect of dietary Eucommia ulmoides leaves (EUL) on growth performance and antioxidant status of growing rabbits under heat stress condition. Four hundred and fifty weaned New Zealand male rabbits (6 wk old) were randomly divided into 3 equal groups (150 rabbits/group) and fed with a basal diet (control, digestible energy (DE): 15.92 MJ/kg and crude protein (CP): 19.24%) or the basal diet supplemented with 1 or 5 g of EUL/kg of diet (EUL1 and EUL5), in which the same quantity of barley meal was replaced. During the 21 d of experiment (43 to 63 d of age), the temperature and relative humidity of the rabbit house ranged from 27.5 to 32.5°C and from 65 to 73%, respectively. We analysed feed intake, growth performance and antioxidant status of growing rabbits. Compared with the control group, at the end of the experimental period, EUL supplementation significantly reduced the average daily feed intake (92.0, 92.8 and 100.7 g/d for EUL1, EUL5 and control, respectively; P<0.05), improved the feed conversion ratio (3.80, 3.81 and 4.59 for EUL1, EUL5 and control, respectively; P<0.05), increased the activities of glutathione peroxidase (+35.5 and +35.0% in plasma and liver of rabbits in EUL5 vs. control group, respectively; P<0.05) and reduced those of malondialdehyde (–12.0 and –46.0% in plasma and liver of rabbits in EUL5 vs. control group, respectively; P<0.05). These results suggest that inclusion of EUL in the diet of growing rabbits improved the growth performance and antioxidant status in growing rabbits.