The three high oil poultry by-product meal (PBPM) samples were obtained from three poultry slaughterhouses in East Azerbaijan Province, Iran. For evaluating of protein quality, 126 male broiler chicks in a completely randomized design as factorial arrangement was used and fed xperimental diets from 8 to 17 days of age. The experimental diets consisted of a nitrogen-free basal diet based on corn starch and glucose and six semipurified diets. Semipurified diets were obtained by replacing each of the three PBPM samples with portion of cornstarch and glucose in the nitrogen-free basal diet to provide 6 and 10% crude protein (CP). Sixteen cecectomized roosters (4 roosters per PBPM sample and 4 roosters for determining endogenous energy loss) were used for determination of true metabolizable energy (TMEn) content of PBPM samples. TMEn content of PBPM samples was different significantly (p<0.05) and was 3696 kcal/Kg as average. PER and NPR values varied from 1.29 to 1.727 and 2.463 to 3.001 and showed significant differences among PBPM samples (p<0.05). The results showed that with increasing CP level, protein efficiency ratio (PER) values was increased (p<0.05). Net protein ratio (NPR) value was not affected by CP level. As the assay length increased from 6 to 10 days, PER and NPR values decreased (p<0.05). Protein quality ranking, with PER, among three PBPM samples is the same in two period assays.
