Effects of Dietary Nutrient Density on Performance and Carcass Quality of Broilers 42 to 49 Days of Age

Abstract

Approximately 25% of the total feed consumed by broilers is eaten in the week prior to processing (from 42 to 49 days of age). Four experiments were conducted to determine the effects of varying dietary nutrient density on performance and carcass characteristics of commercial strain broilers during this period. Broilers were fed nutritionally complete diets with 3200 ME kcal/kg until 42 days of age. From 42 to 49 days of age, they were fed pelleted diets formulated to contain 3080 to 3465 ME kcal/kg in increments of 55 ME kcal/kg. All essential nutrients were maintained in proportion to energy. Body weight gain (WG) and feed consumption (FC) were determined. Samples of birds were processed to determine carcass yield and abdominal fat content. Male and female broilers responded similarly to dietary differences in nutrient density. Regression analysis indicated a significant decrease in WG as nutrient density increased. There was a significant reduction in FC as nutrient density increased, with a concomitant reduction in feed required per unit of gain. Calorie intake was similar among treatments, but caloric efficiency (kcal ME/kg gain) was depressed significantly as nutrient density increased. Dressing percentage and abdominal fat content decreased significantly as nutrient density increased. These data indicate that the dietary density levels examined in this study influence feed intake and calorie utilization. The economics of modifying dietary nutrient density levels must be considered.