Tuan van Nguyen and Sompong Te-Chato

pp. 1171 - 1178

Abstract

Four hundred and sixteen one-day-old Betong chicks were used to determine the effect of dietary
protein and energy levels on growth performance and carcass characteristics. The chicks were randomly
allotted into 4x2 factorials in a completely randomized design. Four levels of dietary proteins (23, 21, 19, and
17% CP) and two levels of energy (3,200 and 3,000 ME kcal/ kg) were offered ad libitum to the chicks from
0-42 days of age. There was no significant interaction effect between dietary protein and energy levels in the
diets. At 0-21 days of age, the Betong chicks fed with the lowest protein diet (17% CP) showed reduced live
weight and weight gain, but not at 22-42 days of age. Dietary protein levels higher than 17% CP did not show
any significant effect on growth performance, although increasing dietary protein levels positively improved
growth performance and feed utilization. However, the Betong chicks fed with lower protein diet converted
protein to body weight gain more efficientcy than those fed higher protein diets (P<0.01). Dietary energy
contents of 3,000 and 3,200 ME kcal/kg did not alter the growth performance of the Betong chicks, while
higher energy (3,200 ME kcal/kg) increased abdominal fat yield from 0.39% to 0.57% (P<0.05). In contrast, dietary protein levels linearly reduced abdominal fat in these animals. In conclusion, protein levels in the
diets at 19% CP and energy contents between 3,000-3,200 ME kcal/kg were met or over requirements for
growth performance and carcass quality.