2.6. The measurement of endotoxin
Colon contents endotoxins were extracted in with 0.05% Tween-20 in pyrogen-free water (Lai, 2017). Fecal endotoxins were determined using Limulus amaebocyte lysate (LAL) kit (ThermoFisher, USA) as described previously (T. R. Wu et al., 2019).