Effects of sex, age and food intake upon metabolisable energy values in broiler chickens

Abstract

1. Nitrogen‐corrected apparent metabolisable energy (AME_n) values of 2 diets with different energy: protein ratio were estimated in an experiment with 8 groups of female and 8 of male chickens in 15 sequential 3‐day balance periods from the 12th to the 56th d of age.

2. The effect of sex on AME_n values was not significant.

3. The effect of age was highly significant. AME_n values of the mixture with the narrower energy: protein ratio increased with age. The dependence of AME_n of the diet with the wider energy: protein ratio on age was parabolic, AME_n values increasing only until the 37th day of life.

4. Under conditions of ad libitum feeding, AME_n of the mixture with the wider energy: protein ratio given to female chickens decreased significantly with increasing food intake.