*2.3. Statistical Analysis*

Treatment effects on the investigated parameters were analysed according to a completely randomised 2 × 2 factorial design, with a factorial arrangemen<sup>t</sup> of treatments using two-way ANOVA, followed by Tukey's post hoc multiple comparisons test with individual variance computed for pair-wise comparisons, where appropriate. The statistical model included the treatment effects (fibre and zinc source) and their interaction. When the interaction was significant, Fisher's Least Significant Difference test (Fisher's LSD) was applied post hoc to determine significant differences among the means. Two-way ANOVA with the main effect was also included to estimate the effect of pH on in vitro solubility of Zn sources and the effect of the digestion phase on in vitro solubility of TEs. All statistical analyses were performed with the GraphPad Prism statistical software (GraphPad Prism version 9.0.0., GraphPad Software, San Diego, CA, USA). Differences between the mean values of the different dietary treatments were considered statistically significant at *p* < 0.05. Data are expressed as means with standard errors of the difference between column means (SE).
