COMPARATIVE STUDY OF THE EFFECT OF DIETARY ENERGY ON FEMALE CARCASS QUALITY AND CHEMICAL COMPOSITION OF TWO BROILER STRAIN CROSSES

Abstract

ABSTRACT
This study was conducted at the Poultry Farm of the Animal Resources Department during the first three months of 1999, College of Agriculture and Forestry - University of Mosul, to investigate the effect of using different dietary levels of metabolizable energy on the carcass quality and chemical composition of two female broiler strains reared under conventional environmental conditions in Iraq . One - day old White Ross and Iraqi Fawbro broiler chicks were reared on a deep litter at the rate of 180 birds per strain . The birds from each strain were randomly distributed to three dietary treatments with different metabolizable energy levels (2812,2709,2896) and (2839,2744,2918) for Tl, T2, and T3 during both starting and growing periods, respectively.Eacb treatment contained three replicates with 20 birds per replicate.
The results revealed that no significant differences among female broilers of both strains in carcass yield were observed . Females of White Ross fed the low level energy diet showed no significant differences in the percentage weights of giblets and abdominal fat, but a relative decline was observed , whereas those of Fawbro gave high percentages . Ross female broilers on the high energy diet showed a significant ( p < 0.01 ) increase in breast cut yield , but no differences in leg quarters yield were observed .
Carcass leg quarters of Ross female broilers fed on the low energy diet showed significantly ( p < 0.01 ) high levels of moisture and protein and low levels of fat and ash. Ross female broiler breast cut contained significantly ( p< 0.01) higher level of protein and lower level of fat than that of Fawbro females.
The results also indicated that differences exist between Ross and Fawbro broilers in the percentage weight and chemical composition of female carcass parts; and that dietary energy level has an effect on these parameters. The data further suggest that Fawbro broilers would probably be considered as slow growing strain.