Reflux of duodenal bile acids and abomasal ulcerations in experimental abomasal displacement in sheep

Abstract

Fourteen healthy Iranian crossbred rams with the same age and weight were used to study the relationship between the reflux of duodenal bile acids and abomasal ulcerations in sheep. Rams were fed upon the same ration. The animals were randomly assigned into two equal groups of left abomasal displacement and right abomasal displacement. Before induction of abomasal displacement, ruminal and abomasal fluid samples were taken by paracentesis and the pH was recorded. Samples were centrifuged and supernatants were collected and frozen for later analysis (control samples). In each group, six sheep underwent induced abomasal displacement, and one sheep underwent exploratory laparotomy without induced abomasal displacement to provide a control for the effect of surgical stress on abomasal ulcer formation. After 4–6 days, abomasally displaced sheep showed clinical signs of abomasal displacement. After 2 weeks, the condition of animals in both groups got worse and then slaughtered. At necropsy, abomasal and ruminal fluid samples were taken and centrifuged and stored like controls. The abomasum was opened, its mucosa was examined, and the lesions and the type of ulcers were recorded. Tissue samples were also collected from each type of the lesion for histological examination. Bile acids in abomasum and rumen fluids and chloride in ruminal fluid were measured. The increase in pH and bile acids concentrations in abomasal fluid samples was well associated with abomasal ulcer formation and their severity. Significant increase in abomasal bile acids occurred after abomasal displacement in both groups (P < 0.05). This increase was significantly greater in cases which had ulcers in abomasum. Chloride concentration increased in ruminal fluid samples of both groups, which indicated the reflux of abomasal contents into the rumen (P < 0.05). It is concluded that there is a clear relationship between the increase in abomasal bile acids and ulcer formation in the abomasum.