Responses of chicks to dietary supplements of copper sulphate

Abstract

Synopsis Sixteen groups of 20 1‐d‐old male chicks of a hybrid laying strain were reared for 25 d and given free access to diets supplemented with o, 100, 200 or 350 p.p.m. copper (as CuSO4.5H2O), with or without antibiotic. The unsupplemented diet, based on cereals, fish and soyabean meals, contained 9.6 p.p.m. copper. Live‐weight gains, food intakes and hepatic copper concentrations were measured. The mean hepatic copper concentration was 10.0 p.p.m. (of dry tissue) in 1‐d‐old chicks, and after 25 d rose to a mean concentration of 15.3 p.p.m. in birds fed the diets without added copper and 17.6, 32.9 and 148 p.p.m. in birds fed diets supplemented with 100, 200 and 350 p.p.m. copper respectively. In relation to copper supplementation, two trends in live‐weight gain were noted: (1) an increase in weight gain reaching an average of +2.3 per cent at 100 p.p.m. copper, (2) a depression of weight gain at 350 p.p.m. copper averaging ‐7.5 Per cent. Only the latter trend was statistically significant. Chicks given the antibiotic supplement gained 3.6 per cent more weight than those fed the diets without antibiotic. All these differences in weight gain were associated with differences in food consumption; food conversion efficiency was almost uniform. There were no overt signs of poisoning nor any. apparent relation between the weight gains and hepatic copper concentrations of individual chicks given the 350 p.p.m. copper supplement.