Energy and Protein Utilization in Newly-hatched Broiler Chicks

Studies on the Early Nutrition of Poultry

Abstract

Characteristics of newly-hatched broiler chicks in utilization of nutrients were investigated. Chicks were given ad libitum an experimental diet (ME 3.1kcal/g and CP 22%, calculated) from the day of hatch up to 14 days of age. Residual yolk in the abdomen was quantified daily in order to estimate its nutritional contribution. Feed efficiency was the highest on the 3 day or the 4 day and averaged about 80% during 14 days after the hatch. During the first 3 days after the hatch, energy and protein originated from the residual yolk accounted for 22% and 30%, respectively, of total amounts from the diet plus the yolk, implying that the residual yolk plays a substantial role in providing energy and protein in the newly-hatched chicks. Metabolizable energy of the diet was the highest (3.6kcal/g) at the day of hatch, decreased rapidly to the lowest (2.6kcal/g) on the 4 day and then gradually increased. Efficiencies of retention of energy and protein supplied from the diet plus yolk were 37 and 67%, respectively, during the first 7 days after hatch, and 46% and 65%, during the next 7 days. These results suggest that the nutrition of newly-hatched chicks is characterized by a significant change in metabolism of energy-yielding nutrients.