Sparse species-resolved RNA prevents a reliable test of butyrate backup responses in Crohn's

Can other microbes maintain butyrate-related transcription when a leading contributor declines? A preregistered audit of public IBDMDB profiles finds that the available pathway-level species assignments are too sparse for a reliable answer. Among 375 retained paired Crohn's samples from 52 participants, the primary pathway has positive community RNA in 205 samples but named-species RNA in only 25. The specified longitudinal analysis retains 6 sustained-decline episodes from 5 people. Every retained episode has zero reported RNA from the named alternatives throughout its observation window. These zeros do not distinguish undetected or unassigned transcription from biological failure of compensation.