IL1R1 and colitis: This was supported by analysis of SCFA levels in the stool of control and Il-1r−/−Nlrp1aQ593P/Q593P mice, which showed that in line with increased colitis severity, butyrate was significantly reduced in Il-1r−/−Nlrp1aQ593P/Q593P stool, while propionate was not altered (Fig. 4e, f).