Calculations and Statistical Analysis. Values for
AID, endogenous losses, and SID of CP and AA were
calculated for all diets except the N-free diet (Stein et al.,
2007). Data from the SBM diet were used to calculate
the contribution of AA from SBM to the other diets,
which allowed for calculation of the digestibility of AA
in chicken meal, poultry byproduct meal, hydrolyzed
porcine intestines, and the spent hen–SBM mixture using
the difference procedure (Mosenthin et al., 2007). Data
were analyzed by ANOVA using the MIXED procedure
(SAS) as explained for Exp. 1.