Effects of High Dietary Levels of Selenium and Copper on Growth Performance, Selected Blood Biochemical Parameters and Antibody Production Against Newcastle Disease Vaccine Virus in Broiler Chickens

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 production 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 received 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 copper 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 triglycerides 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 selenium (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.