The Effect of Diet on Growth Rate and Feed Efficiency in the Normal Rat

Abstract

Long-term studies of the effect of the level of dietary protein and fat on the rate of body weight gain and on the caloric efficiency of feed utilization in male weanling rats have been described. When rations based on casein, sucrose and lard or corn oil were fed ad libitum, the rate of body weight gain and the caloric efficiency of feed utilization increased with progressive increases in protein:calorie ratios, and further increases were observed for each protein:calorie ratio studied, when the fat:calorie ratio was increased by a factor of 4. Dilution of the experimental rations by the addition of either fat or sucrose resulted in decreased response and efficiency when protein was limiting for growth, but such dilution was without effect at higher protein levels. No significant differences in response to the feeding of lard or corn oil were observed.