Statistical Analysis
Data were analyzed as a 2 × 2 × 2 factorial arrangement
using the GLM procedure for parameters
measured at slaughter and the Mixed Model procedure
for other performance parameters and serum and
blood data (SAS 9.3; SAS Inst. Inc., Cary, NC) with
pen as experimental unit for all parameters. For all
data, the normality of the distribution of Studentized
residuals was assessed by the Shapiro–Wilk statistic.
If required, transformation of data was performed to
obtain normal distribution of residuals. Values are presented
as least squares means ± SEM, and effects were considered significant at P ≤ 0.05 and a trend was defined
as 0.05 < P ≤ 0.10. Sanitary condition, dietary
CP level, and AA profile, batch, and their interactions
were used as fixed effects. Phase was added in the
model as a fixed effect and phase × sanitary condition
as an interaction for all blood parameters and ATTD of
N and DM. The effect of room within sanitary status
was used as a random effect to correct for differences
between rooms. The Kenward–Roger statement was
used to correct for the degrees of freedom for batch.
The difference between individual start BW and average
BW of the treatment group (sanitary conditions and batch) was used as covariate in the model in the
first statistical evaluations but finally omitted because
of absence of statistical significance.