Thiamine ameliorates inflammation of the ruminal epithelium of Saanen goats suffering from subacute ruminal acidosis

摘要

This study aimed to examine the role of thiamine inthe local inflammation of ruminal epithelium caused byhigh-concentrate diets. Eighteen mid-lactating (148 ±3 d in milk; milk yield = 0.71 ± 0.0300 kg/d) Saanengoats (body weight = 36.5 ± 1.99 kg; body conditionscore = 2.73 ± 0.16, where 0 = emaciated and 5 =obese) in parity 1 or 2 were selected. The goats wererandomly divided into 3 groups (n = 6/group): (1) controldiet (concentrate: forage 30:70), (2) high-concentratediet (HC; concentrate: forage 70:30), and (3) highconcentratediet with 200 mg of thiamine/kg of drymatter intake (THC; concentrate: forage 70:30). Goatsremained on experimental diets for 8 wk. On the lastday of 8 wk, ruminal and blood samples were collectedto determine ruminal parameters, endotoxin lipopolysaccharide,and blood inflammatory cytokines. Goatswere slaughtered to collect ruminal tissue to determinegene and protein expression of toll-like receptor 4(TLR4) signaling pathways. Thiamine supplementationincreased ruminal pH (6.03 vs. 5.42) compared with theHC group. Propionate (21.08 vs. 31.61 mM), butyrate(12.08 vs. 19.39 mM), lactate (0.52 vs. 0.71 mM), andfree lipopolysaccharide (42.16 vs. 55.87 × 10~3 endotoxinunits/mL) concentrations in ruminal fluid were lower inTHC goats compared with HC goats. Similar to plasmainterleukin 1β (IL-1β) concentration (209.31 vs. 257.23pg/mL), blood CD8~+ percentage (27.57 vs. 34.07%)also decreased in response to thiamine. Compared withHC goats, THC goats had lower ruminal epitheliumactivity of the enzymes myeloperoxidase and matrixmetalloproteinase (MMP) 2 and 9. In contrast to HC,THC had downregulated mRNA expression of nuclearfactor-κB (NFKB), TLR4, IL1B, MMP2, and MMP9 inruminal epithelium. Thiamine supplementation led tolower relative protein expression of IL-1β, NF-κB unitp65, and phosphorylated NF-κB unit p65 in ruminalepithelium. Taken together, these results suggest thatthiamine supplementation mitigates HC-induced localinflammation and ruminal epithelial disruption.