Effect of varying levels of energy and protein on nutrient utilization in coloured crossbred broilers.

Eight different coloured crossbred broiler combinations were used to study the effect of varying levels of energy and protein on nutrient utilization. Among seven dietary treatments, six treatment diets (T1-T6) were formulated having two level of metabolizable energy i.e. 2700 and 2900 kcal/kg each with three levels of crude protein i.e. 20, 22 and 24% and one treatment diet (T7) with 2400 kcal/kg with 16% crude protein, were offered ad-libitum from 0- 56 days of age. The dietary treatments had significant (P<0.05) effect on protein intake (PI), protein efficiency ratio (PER), metabolizable energy intake (MEI) and energy efficiency ratio (EER) in all crossbred except crossbreds of White Leghorn and Frizzle. Crossbreds fed diet containing high protein (24%) irrespective of energy contents had high PI. However, crossbreds fed with diet containing low protein (20%) with high energy (2900 kcal ME/kg) had high PER. Crossbreds fed with diet containing 20% and 22% protein with 2900 kcal ME/kg had high MEI, whereas, EER was higher but approximately similar in all dietary treatments except 16% protein with 2400 kcal ME/kg energy diet.