A survey of the relationship between bile staining and oesophagogastric lesions in slaughter pigs

In 280 slaughter pigs, the oesophageal region of the stomach was examined to test the hypothesis that there is a (causal) relationship between the intensity of bile staining of oesophagogastric tissue due to bile regurgitation and the severity of oesophagogastric lesions. When the stomachs were opened, almost all stomachs contained bile and 99.6% of stomachs showed bile staining of the pars oesophagea. A total of 14.3% of the stomachs showed distinct erosions and/or ulceration. A considerable proportion of the stomachs (58.5%) had hyperkeratosis as the only lesion. Only two animals showed a completely intact epithelium. There was no evidence for an increased proportion of oesophagogastric lesions with an increased intensity of bile staining. No dark yellow to green staining was observed; a just detectable to an obvious yellow was seen. This is an indication for bile regurgitation of recent origin. Therefore, there is no evidence for the hypothesis that the regurgitation of bile into the stomach is positively linked to the occurrence of oesophagogastric lesions in fattening pigs. It is suggested that various factors associated with slaughter, such as fasting and slaughter procedure, are primarily responsible for the presence of bile and the staining of the pars oesophagea in the stomachs.