Systemic immune responses to intestinal-derived lipopolysaccharide (LPS) during subacute ruminal acidosis (SARA) and their possible role in innate immunity
The effects of induced subacute ruminal acidosis (SARA) using grain pellet-based (GPI) and alfalfa pellet-based diet models on systemic immunological parameters were evaluated in nonlactating Holstein cows. The systemic immunological parameters analysed in this study included rectal temperature, blood cell leukogram, expression of lipopolysaccharide (LPS) recognition receptors on leukocytic cells, and plasma and serum proteins. Also, blood biochemistry was analysed. There were no significant differences in rectal temperature, blood cell leukogram, expression of LPS recognition receptors and fibrinogen or haptoglobin concentrations between control and SARA induction treatments. Concentrations of serum amyloid A and lipopolysaccharide-binding protein increased while total protein concentrations decreased in response to GPI SARA compared to control. Blood glucose and urea concentrations increased and decreased, respectively, with GPI SARA treatment. Grain pellet-induced SARA resulted in changes to serum proteins and acute phase proteins but did not affect other systemic immunological parameters suggesting a localized inflammatory response was initiated.
Subacute ruminal acidosis, Lipopolysaccharide, CD14