LPS is a component of the outer membrane of Gram-negative bacteria. When it is released by cell lysis, it becomes soluble and becomes a potent inflammatory molecule. Soluble LPS resulting from bacterial lysis in the rumen has been implicated in SARA.
Source: Plaizier et al. (2012) Anim. Feed Sci. Tech. 172:9-21.
Preliminary findings, soluble LPS on different farms
Abattoir sampling indicates that Caecum LPS >> Rumen LPS
Is it actually soluble LPS from bacterial lysis in the caecum, rather than the rumen, that causes the inflammation associated with SARA?
Changes in the ruminal microbiome in SARA: E. coli
LPS from E. coli is particularly potent in systemic inflammation. In the SARA project, we are investigating the strains of E. coli that are present in SARA-resistant cattle and comparing them with E. coli from SARA-susceptible cattle. If we can identify causative strains of E. coli, we will be able to design probiotics that suppress these strains.
PFGE pattern of genomic DNA extracted from SARA strains