Effects of complex immune stress on the growth performances and antioxidant capacity in broilers

[Objective]The study was to investigate the effects of the complex immune stress induced by Newcastle Disease IV Series and lipopolysaccharides(LPS) on the growth performance and antioxidant capacity in broilers.[Methods]One hundred and twenty eight 1-day-old broilers were randomly divided into 4 groups.Group A was the control group,and saline was given as blank control;groups B,C,D were vaccinated with conventional dose of Newcastle Disease IV Series by putting drop in noses on the 15 d and 28 d,and also group C and group D were intraperitoneally injected with LPS 250 μg/kg body weight and 500 μg/kg body weight on 12,15,18 and 21 d for 4times.After 7,14,21,28 day of inoculation,eight chicken serum samples from each groups were collected to detect the content of malondialdehyde(MDA),and the activities of superoxide dismutase(SOD) and glutathione peroxidase(GSH-PX).The slaughter weight and feed consumption were recorded,the average daily gain weight and feed conversion ratio were also detected.[Results]The res