Intraruminal infusion of oligofructose alters ruminal microbiota and induces acute laminitis in sheep.

The objectives of this study were to examine the clinical response, changes in ruminal bacterial microbiota, and inflammatory response in lamellar tissues during oligofructose-induced laminitis. Ten fistulated sheep were randomly assigned into a control group ( = 5) and a treatment group ( = 5). The treatment group was infused with oligofructose (21 g/kg BW) by rumen cannula, and the control group was sham-treated with saline. Results showed that all 5 sheep treated with oligofructose developed anorexia and diarrhea 8 to 12 h after the administration of oligofructose. By 12 to 24 h after treatment, the treatment group developed lameness and roach back. Compared with the control group, oligofructose administration decreased ( < 0.001) the rumen pH and concentrations of total VFA and increased ( < 0.001) the level of lactic acid in the rumen. Microbial data analysis revealed that oligofructose infusion increased the abundance of ( = 0.009) and ( = 0.008) and decreased the percentage of unclassified Christensenellaceae ( = 0.028), unclassified Ruminococcaceae ( = 0.009), ( = 0.016), unclassified Lachnospiraceae ( = 0.009), and ( = 0.009) compared with the control group. Oligofructose infusion decreased the ACE ( = 0.047) and Shannon ( = 0.009) indices compared with the control group. The histomorphology analysis revealed that oligofructose overload resulted in damage to the dermoepidermal junction in the lamellar tissue of sheep. Quantitative real-time PCR results showed that compared with the control group, the mRNA expression of membrane-type metalloproteinase-1 ( = 0.049) was downregulated whereas the expression of proinflammatory IL-6 ( = 0.004) and matrix metalloprotease-9 ( = 0.037) was upregulated in the lamellar tissues of the oligofructose treatment group. In general, the present study provides the foundation for a sheep model of oligofructose-overload-induced acute laminitis that could be used in later experiments. Our findings suggest that intraruminal infusion of oligofructose altered ruminal microbiota and resulted in acute laminitis and that the inflammatory damage to the lamellae tissue may be related to the upregulation of matrix metalloprotease-9. The information generated will provide more insight into the systemic effects of lameness caused by oligofructose overload in sheep.