Effects of different proportions of naturally oxidized oil on the β-diversity of cecal microbiota. The β-diversity was evaluated by partial least squares discriminant analysis (PLS-DA). Abbreviations: OXA, basal diet with 0% naturally oxidized oil; OXB, basal diet with 25% naturally oxidized oil; OXC, basal diet with 50% naturally oxidized oil; OXD, basal diet with 75% naturally oxidized oil; OXE, basal diet with 100% naturally oxidized oil.