Effect of Formulating Diets with Different Assigned Energy Data for Poultry By-Product Meal on the Performance and Abdominal Fat Content of Finishing Broilers1

ABSTRACT Two experiments were conducted to determine how formulating poultry by-product meal (PBM) in pelleted broiler diets with differing data on assigned energy would affect the performance and abdominal-fat (AF) content of male broilers from 3 to 7 wk of age. In the first experiment, a com-soybean meal (CS) diet or diets were fed containing 10 % PBM with assigned MEn data of 2,670,2,985, or 3,300 kcal/ kg. The diet specifications were 3,200 kcal ME„/kg and 20 % protein. No significant differences were observed in body weight gain (BWG), feed intake (FI), or feed conversion (FC), but the AF was significantly lower for the birds fed the CS diet. Determining the ME,, for the four diets by assay with young chicks resulted in values of 3,172,3,182,3,137, and 3,080 kcal/kg, respectively. In a second experiment, chicks were fed the CS diet or diets with 10 % PBM with assigned MF ^ values of 2,670,2,985, 3,300, 3,615, or 3,930 kcal/kg. Again, no significant differences were observed in BWG, but the FC was significantly better for the birds fed the diets with values of 2,670,3,300, and 3,615 MEn PBM than for those fed the CS diet. A consistently higher AF was observed for all groups fed the PBM rather than the CS diet, but only the PBM diet with 2,670 ME„ was significantly higher. Determining the MEQ for the six diets by assay with young chicks resulted in values of 3,054, 3,286, 3,124, 3,109, 3,096, and 3,037 kcal/kg. respectively. The data show that the performance of finishing broilers fed a PBM diet does not conform to expectations based on ME „ determinations with younger chicks. (Key words: poultry by-product meal, metabolizable energy values, broilers, performance, abdominal fat