Response of finishing broiler chickens fed three energy/protein combinations at Fixed E:P ratio

Abstract

A feeding experiment was conducted to investigate the response of finishing broiler chicken to diets containing three metabolizable energy (ME)/crude protein (CP) combinations (3203.76 ME vs 19.90 %CP, 2884.15 ME vs 18.10 %CP and 2566.42 ME vs 18.10 %CP) at fixed ME:CP ratio of 160:1. A total of 126 four weeks old broiler chickens were randomly allotted to three dietary treatments replicated thrice. The final live weight, weight gain, feed intake, feed conversion and PER were generally higher in the birds fed the control diet (3203.76 ME vs 19.90 %CP). There were significant (P<0.05) differences among treatments in terms of final live weight, protein intake, energy intake, CP: Gain and ME:Gain, while weight gain, feed intake, feed conversion ratio and percentage mortality were statistically the same (P>0.05) across the treatments. Cost per kg feed decreased as the energy and the protein density of the diets decreased while the cost per kg weight gain decreased with increase in energy and protein density. The digestibility percentages showed a decreasing (P<0.05) trend while nitrogen retention increased with decrease in energy-protein density of the diets. Values for the haematological parameters and blood chemistry were significantly (P<0.01) higher in birds fed control diet and the values decreased with decreased levels of dietary energy and protein. The results suggest that when both energy and protein density of broiler finisher diet are reduced at fixed E:P ratio the feed intake would increase while the feed utilization efficiency decreases.