Abstract
Effects of a large-sized cage with a low metabolizable energy and low crude protein (LME-LCP) diet on growth performance, feed cost, blood biochemistry, and antibody response of growing layers were evaluated. A total of 668 one-day-old female Gushi chicks were randomly allocated into three different cages, namely, large, medium, and small cages, referred to as Group A, Group B, and Group C, respectively, and fed LME-LCP diets. A fourth group of birds raised in small cages and fed a standard diet (STD) was designated Group D i.e. the control. Equal stocking densities were maintained among the four groups throughout the experiment, from 50-20 birds/m(2). Large cages with LME-LCP diet (Group A) increased the shank length and girth as chicks grew, improved the activities of serum creatine kinase, and reduced serum triglyceride and cholesterol concentrations. The total feed intake in birds from Group A was higher than those from the other groups at every stage. The total cost (rmb/bird) of feed was 6.70% lower in Group A than that in Group D, which indicated the cost-effectiveness of large cages. In conclusion, large cages with LME-LCP diets have positive effects on body weight, shank growth, and serum biochemical indices of growing Gushi chicks, and can reduce feed costs.