Diet dilution and compensatory growth in broilers

Two experiments were conducted to note the response of broiler chickens to degrees of diet dilution from 4 to 11 days of age. In Experiment 1, broilers were fed conventional broiler diets from 0 to 4 and 11 to 56 days of age. From 4 to 11 days, birds were fed a conventional corn and soybean meal broiler starter, or the same diet in which major nutrients were replaced with 25, 40, or 55% ground rice hulls. Mineral and vitamin sources were not affected by dilution. Each of the three diluted diets together with an undiluted control diet was fed to three replicate floor pen groups of 30 male or 30 female broilers. In a second similar experiment, male birds were fed a regular broiler starter from 4 to 11 days or a diet diluted with 50% rice hulls. In this second experiment, rice hulls were substituted for all ingredients including those providing vitamin and mineral supplements. In Experiment 1, diet dilution resulted in a significant (P less than .05) reduction in body weight at 11 days of age, although by 42 days there was complete recovery of body weight with no change in overall efficiency of feed utilization. This same trend was seen in both sexes. Calculation of energy balance suggests these birds to have used energy very efficiently during the period of undernutrition. Diet dilution had no effect on carcass characteristics at 42 days, although for males at 56 days there was an indication of reduced abdominal fat content (P less than .05). In Experiment 2, compensatory gain was incomplete, although results were confounded due to an outbreak of infectious bronchitis.(ABSTRACT TRUNCATED AT 250 WORDS)