Characterization of biliary proteins and composition of bile from sheep and goats

Higher lipid content in gall bladder bile of sheep and goats as compared with monogastric species was due to higher proportion of glycerides. The volume of bile per gall bladder was higher in sheep than in goats. Bile from sheep and goats has a higher content of proteins and lower contents of dry matter, cholesterol and phospholipids compared with monogastric species. Biliary proteins partially purified by the ammonium sulfate precipitation method were characterized and quantified by polyacrylamide gel electrophoresis (PAGE), fast protein liquid chromatography (FPLC) and immunodiffusion. FPLC and PAGE profiles indicate that biliary proteins of sheep and goats are mainly of low mol. wt. of upto 65 KDa. Proportions of immunoglobulin (Ig) like molecules in biliary proteins precipitated by ammonium sulfate of different degrees of saturation, were 10.4 to 26.7 and 21.9 to 30.7 per cent of total proteins in bile of goats and sheep. IgG and IgA like molecules were the predominant Ig and lacked carbohydrates. On immunodiffusion such Ig like molecules did not show cross reactivity with humoral Ig. It was concluded that sheep and goats appear to secrete Ig into bile after deglycosylation and partial degradation. The proteins of smaller molecular weight may be secretory fragments or degradation products of Ig.