Effect of changes in live body weight and feed conversion ratio as influenced by enzyme supplements on basic post-slaughter measurements of broiler chickens fed cereal-based diets
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Research Institute of Animal Production, Department of Animal Nutrition, 32-083 Balice, Poland
Publication date: 2002-10-11
J. Anim. Feed Sci. 2002;11(4):671–681
The present work was designed to clarify the relationship between carcass yield (CY) and abdominal fat (AF) percentages with changes in final live body weight (LBW) and feed conversion ratio (FCR) in broilers as caused by supplementary feed enzymes. The experimental data set was obtained from a total of eleven growth trials carried out with chickens of currently used commercial strains. In all of the trials the chickens were fed ad libitum with mash diets based on home-grown cereals and soyabean meal, and containing fat additions, mainly as animal blended fat. Different commercial enzyme preparations were added to the diets either alone or in combination. The mean responses to enzymes were +86 g for final LBW, -0.08 g/g for FCR, +0.031% for CY and +0.024% for AF. For main (Pearson) correlation assessments and (linear) regression analysis, the observed values obtained with birds fed enzyme preparations were expressed relative to the data of control birds fed unsupplemented diets (= 1.00). No correlation could be established between enzyme-caused relative changes in: LBW and CY, FCR and CY, and FCR and AF. A highly significant positive correlation was found between relative changes in final LBW of chickens and relative percentage of AF. For this relationship the regression equation was: YAF = -2.882 + 3.735XLBW (R2= 0.529, P≤0.001). It was concluded that augmented abdominal fat accumulation in broilers fed enzyme preparations can be avoided by lowering the quantity of animal fat added to the cereal diets to meet the energy needs of the chickens.