Calculations and Statistical Analysis

The FA apparent ileal digestibility coefficients were calculated as follows: ileal digestibility coefficient = 1-{(TiO₂/FA)_d/(TiO₂/FA)_i}, where (TiO₂/FA)_d is the concentration of the inert marker and the FA in the diet, and (TiO₂/FA)_i is the concentration of the inert marker and the FA in the ileal digesta.

Pen means (24 birds) were used as the experimental unit for performance parameters (12 replicates per treatment). In the case of the digestibility balance and the FA profile of AFP, pen means (3 birds) were used as the experimental unit (6 replicates per treatment). Microbial counts (log transformation for statistical analysis) and histomorphometric analysis were performed on T1 and T5, the pen being the experimental unit (6 replicates per treatment). A Shapiro-Wilk test indicated a normal distribution of the data. Data were analyzed by one-way ANOVA using R Statistics (version 3.3.1; R Core Team, Vienna, Austria), with treatment as the main factor and residual standard error estimated the average deviation of any point from the statistical model. Tukey's multiple range test was performed to determine whether means were significantly different (P ≤ 0.05).