Abstract
Digestive disorder is one of the main causes of calves’ high mortality rate. Thus, it is important to understand the precise mechanism of intestinal epithelial barrier function which comprises innate and adaptive immunity. In our previous study, a secreted protein called “chemerin”, which is formerly revealed to possess antimicrobial property on epidermis, was shown to be abundantly produced in epithelial crypt of small intestine in calves. Here, we aimed to elucidate the functionality of this host-derived protein in epithelial chemical barrier against intestinal microbiota.
The effect of chemerin on small intestinal microbiota was investigated by batch culture method. Jejunal content was collected from male Holstein calves (n=2) at 2 weeks of age and was mixed with equal volume of McDougal’s buffer. 10 mL of this mixture was aliquoted in Hungate tubes, supplemented with vehicle or recombinant bovine chemerin (at final concentrations of 100 or 500 ng/mL), and incubated at 37°C for 16h. Incubation was performed in triplicate. Bacterial fermentation products in the culture were measured by metabolites assay and change in microbiota was analyzed by DGGE. Experimental values were statistically analyzed by Tukey’s HSD test.
Propionate concentration in the culture was significantly decreased by chemerin supplementation at both dose levels (P < 0.05), which led to lower concentration of total SCFA (P < 0.05). D/L-lactate production was not different between control and supplemented groups. Chemerin supplementation did not affect the levels of ammonium-N, indole and skatole. However, chemerin affected bacterial community in the culture to form independent clusters for each experimental group shown by DGGE. Thus, this study indicated a significant effect of chemerin on intestinal microbiota which might be attributed to its antimicrobial property on certain groups of bacterial species.
Keywords: Calf, Antimicrobial peptide, Gut microbiota