Fecal assays

To assess total fecal protein, 10mg of feces were re-suspended in lysis buffer (2% SDS, 150mM NaCl, .5M EDTA), sonicated, and protein concentration assessed using BCA assay according to manufacturer’s instructions. Total fecal protease activity was measured as previously described²⁹. Briefly, 10–30 mg of fecal matter was resuspended in 1mL of buffer A (.1%Triton X-100, .5M NaCl, 100 mM CaCl2), sonicated, and centrifuged. The supernatant was then incubated with 3% Azo-Casein (Sigma A2765) 37°C for 60 min. The reaction was stopped using 8% trichloroacetic acid and centrifuged. The absorbance of the supernatant (366 nm) was measured using a spectrophotometer. Total fecal lipids were measured as previously described³⁰. Briefly, 1,000 mg of feces were collected and lipids extracted using 2:1 Chloroform to Methanol. The lipid fraction was dried using a stream of gaseous nitrogen and vials weighed.