TRUE-N CONVERSION FACTOR FOR DIET AND EXCRETA IN EVALUATING PROTEIN-QUALITY

True N conversion factor (F-t) of thermally processed red kidney beans , rat feces and rooster excreta were determined based on Kjeldahl nitr ogen and amino acid composition. F, of processed beans ranged from 5.6 3 to 5.67, F-t of feces from rats fed the beans ranged 5.43 to 5.62, a nd F-t of excreta from roosters fed the beans ranged 3.06 to 4.18. The conventional N conversion factor (F-c) of 6.25 overestimated the prot ein intake and output, and underestimated the protein quality of the b eans. The difference of NPR (also AAS, EAAI, ALV, C-PER, PER, P-PER, a nd RNPR) values calculated by F-c and by F-t depends on the ratio F-c/ F-t of the beans. The difference of TDP (also TDAA, BV and NPU) values calculated by F-c and by F-t is mainly dependent on the ratio F-t of diet/F-t of feces (excreta). F-c and F-t have a mixed effect on AAS(TD P) and AAS(TDAA).