ARS | Publication request: Chicken bile Matrix metalloproteinase; its characterization and significance

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2012
Publication Date: N/A

Technical Abstract: Previous studies from our lab had shown that the avian bile was rich in matrix metalloproteinase (MMP), enzymes implicated in the degradation of extracellular matrices (ECM) such as collagens and proteoglycans. We hypothesized that bile MMP may be evolutionarily associated with the digestion of ECM proteins that are generally resistant to digestion by conventional proteases such as trypsin, chymotrypsin, or pepsin. Thus, the objective of our study was to characterize the chicken bile MMP and explore their relations to gastrointestinal digestion. The MMP activity was monitored by gelatin zymography, azocoll degradation assays, and confirmed by the use of specific inhibitors. Bile MMP was purified by gelatin affinity chromatography and separated by 1D electrophoresis. Bands corresponding to gelatinolytic activities were excised, and subjected to in-gel trypsin digestion, mass spectrometric characterization which identified the enzyme as 75 kDa type IV collagenase. To examine whether enrichment with feed additives would modulate bile MMP activities, we supplemented the basal diets with 4% either beef gelatin, milk powder, lard, or rice powder and fed to the chickens from 1-43 days post hatch. The results showed a significant increase in bile MMP activities in birds fed with gelatin and lard supplements. We then compared the MMP activities of bile from chicken, turkey, sheep and cow using gelatin zymography followed by densitometric quantification. The results showed although each of these species had MMP activities, the chicken and turkey showed significantly higher enzyme activities compared with herbivores such as cow and sheep. Overall, these results suggest that bile MMP may have some role in gastrointestinal physiology necessary for the digestion of ECM proteins that constitute a large part of body proteins.