The effect of enzyme predigestion on the nutritional quality of prepressed turkey feather meal

Abstract

Three experiments were conducted to determine the protein efficiency ratio (PER), pepsin digestibility, TMEn, and true amino acid availability (TAAA) of prepressed turkey feather meal (PFM), enzyme-digested PFM (EPFM), and commercial feather meal (CFM). Turkey feathers from a commercial processing plant were mechanically pressed alone or mechanically pressed, followed by treatment with a mixture of protease, lipase, and amylase prior to autoclaving. In the first study, feather meal diets containing 16,20, or 24% CP from PFM, EPFM, or CFM were fed to starter poults for 10 d. All diets resulted in negative or negligible growth. In a second study, PFM, EPFM, and CFM were again the primary sources of CP, but dietary protein levels were increased to 20, 24, and 28% CP, and all diets contained 20% corn and 10% soybean meal (PFMCS, EPFMCS, CFMCS), respectively, to allow for a basal level of growth. Performance and PER of the poults fed the diets with PFMCS, EPFMCS, and CFMCS were similar. The efficiency of use of the PFMCS diet was numerically lower (P < or = 0.1) when compared with the EPFMCS and CFMCS diets. Similarly, pepsin digestibilities of EPFM and CFM were higher than PFM. The TAAA of PFM (82.1%) and EPFM (80.6%) were not significantly higher than that of CFM (71.4%); however, the availabilities of lysine, threonine, aspartate, glutamate, proline, and histidine were significantly higher. Digestion of pressed turkey feathers with an enzyme mixture prior to autoclaving could have a positive impact on its protein and amino acid nutritional values.