Dietary supplementation of thiamine enhances colonic integrity and modulates mucosal inflammation injury in goats challenged by lipopolysaccharide and low pH

The current study aimed to investigate the protective effects of dietary thiamine supplementation on the regulation of colonic integrity and mucosal inflammation in goats fed a high-concentrate (HC) diet. Twenty-four Boer goats (live weight of 35.62 ± 2.4 kg) were allocated to 3 groups (CON: concentrate/forage = 30:70; HC; concentrate/forage = 70:30; HCT: concentrate/forage = 70:30 with 200 mg thiamine/kg DMI) for 12 weeks. Results showed that compared with the HC treatment, the HCT group had a significantly higher ruminal pH value from 0 to 12 h after the feeding. The H&E (hematoxylin-eosin) staining showed that desquamation and severe cellular damage was observed in the colon epithelium of the HC group, whereas the HCT group exhibited more structural integrity of the epithelial cell morphology. Compared with the HC treatment, the HCT group showed a markedly increased in pyruvate dehydrogenase (PDH) and α-Ketoglutarate dehydrogenase (α-KGDH) enzymes activity and a markedly decreased in matrix metalloproteinase (MMP)-2, MMP-9, Caspase-3, Caspase-8 and lactate dehydrogenase (LDH) enzymes activity. The mRNA expression in the colonic epithelium of SLC19A2, SLC19A3, SLC25A19, Bcl-2, Occludin, Claudin-1, Claudin-4 and ZO-1 in the HCT group were significantly increased, whereas the mRNA expression of NFκB, IL-1β, IL-6, IL-10, CXCL-10, CXCL-13, MMP-9, MMP-13 and Bax were significantly decreased in comparison with the HC diet treatment. Compared with the HC treatment, the HCT diet significantly increased the protein expression of claudin-1 and significantly decreased the protein expression of NFκB-related proteins p65. The results show that dietary thiamine supplementation could improve the colon epithelial barrier function and alleviate mucosal inflammation injury in goats after LPS and low pH challenge.