Effects of dietary copper deficiency on relative food intake and growth efficiency in rats.

Weanling male rats were fed either copper-adequate (CuA) or copper-deficient (CuD) diets ad lib for 20 wk. A pair-fed group was also studied. Two relative food intake indices (RFIs) and a growth efficiency (GE) index were calculated. Body weights of the CuD group became reduced compared to the CuA group starting the sixth week of the study. Copper deficiency was found to affect both of the RFI indices and the GE index in a time-dependent manner. RFIs and GE were reduced early, but recovered towards the control values during the last half of the experimental period. At the end of 20 wk, organ copper content and serum ceruloplasmin was reduced in the CuD group. Dietary copper deficiency reduces growth rate through effects both on food intake and efficiency of food utilization for growth.