Abstract

Programs based on antibiotics are failing to control diseases due to increase in resistance of pathogens to antibiotics. Food safety, animal welfare and public health concerns have fueled interest in the use of plant-based alternatives. This study was conducted to evaluate the effect of a plant (Sericea Lespedeza, SL), and pathogen associated molecular patterns (PAMPs) (Lipopolysaccharide (LPS) and peptidoglycan (PGN)) on gene activation in ruminant blood. A water extract of SL, was used as a source of plant-derived tannins. Blood was collected from Holstein-Friesian cows (N = 4), Spanish × Boer goats (N = 4), St Croix sheep (N = 4) and incubated with 100 ng/mL of SL in the presence or absence of LPS or PGN. Samples maintained in Phosphate-buffered saline (PBS) served as negative control. The total protein concentration, WNT5a, and prostaglandin E2 in plasma were determined. Total RNA was isolated, reverse transcribed and Real time-PCR was performed using gene specific primers for TLR2, TLR4, WNT5a, and FZD. TLR2 and FZD were up-regulated in response to PAMPs. WNT5a and TLR4 genes were undetected in PAMP treated blood. SL regulated protein and prostaglandin concentration in all species. SL reduced PGE2 in sheep and cow blood. WNT5a was only secreted in LPS treated cow blood. Transcription and translation of genes involved in innate and adaptive immunity and the WNT signaling pathway in ruminant blood were responsive to diverse PAMPS, and can be modulated by SL. This suggests that dietary tannins may promote the health of ruminants. Further studies are needed to determine the significance of these changes in immune gene expression on ruminant health.

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