The effect of nutrient density and restricted feeding on the performance of commercial layers

Studies were conducted to determine the effects of dietary density and ad libitum versus restricted feeding on the performance of layers from the same commercial genetic pool. Eight diets of different nutrient densities were designed to supply the same amount of protein, energy, vitamins, calcium, phosphorus and salt in 85, 90, 951 100, 105, 110, 115 and 120 grams of daily feed intake. The amounts of these nutrients were those consumed daily by positive control birds fed ad libitum in many previous experiments. These eight diets were restrictively fed caged layers in groups of four replications of ten birds each. These eight groups plus a positive control group (fed ad libitum a diet that had given excellent performance) were studied individually and compared with nine corresponding groups receiving the same diets ad libitum. Veight of daily feed consumption by the ad libitum group varied inversely with nutrient density. Feeding of the high density diet significantly increased body weight (diets 3 and 4), feed efficiency (diets 2 and 4), feed cost (diets 2, 3 and 3), egg weight (diets 2, 4 and 5), shell thickness (diets 2 and 4), yolk color score (diets 2, 4 and 5), and percent protein in the whole egg (diets 2 and 3), but significantly decreased egg production (diets 2, 3 and 5), Haugh Unit score (diets 2, 4 and 5), percent fat in the whole egg (diets 2 and 3), and the gizzard to body weight ratio. ..