Effects of High Dietary Levels of Selenium and Copper on Growth Performance, Selected Blood Biochemical Parameters and Antibody Production Against N

An experiment was conducted to evaluate the effects of high dietary levels of selenium (as sodium selenite) and copper (as copper sulphate) on growth performance, serum biochemical parameters and antibody pro-duction against Newcastle disease vaccine (NDV) virus in broiler chickens. A total of 160 Ross 308 un-sexed day old broiler chickens were randomly allocated into four treatment groups (n=40 per group) each comprising four replicates (n=10 per replicate). Group 1 was served as control and the chickens in this group were fed a standard diet without any selenium or copper supplementation. Chickens in Group 2 re-ceived a diet with selenium supplementation at the rate of 1 mg/kg of feed; Group 3 received a diet with copper supplementation at the rate of 200 mg/kg of feed; Group 4 received a diet supplemented with a combination of 1 mg/kg selenium and 200 mg/kg copper. Combined supplementation of selenium and cop-per decreased feed intake and body weight gain and increased feed conversion ratio (P < 0.05). These effects were not observed when selenium or copper was supplemented alone (P > 0.05). Serum uric acid and triglyc-erides concentrations decreased (P < 0.05) and tended to be increased (P=0.11), respectively, by feeding copper and selenium. Moreover, serum albumin concentration was significantly increased in chickens given copper supplementation alone (P < 0.05), but not in those supplemented with copper and selenium (P > 0.05). Dietary treatments had no effects on antibody titres against NDV at day 28 of age (P > 0.05); antibody titres against NDV, however, decreased at day 42 of age in broilers receiving a combination of copper and sele-nium (P < 0.05). The results clearly indicate a negative interaction between the usage of sodium selenite and copper sulphate on growth performance in broiler chickens. More studies should be performed to clarify the action modes of such effects.