Double gallbladder of swine.

In research on the reduplication of the pig gallbladder, a total of 297,531 swine from 130 breeders were surveyed at a slaughter house (Ozu Health Center, Ehime Prefecture, Japan) between October 1993 and December 1995. The swine were 6-7 months old and their body weights ranged from 95 to 120 kg. Twenty-nine swine were found to have reduplication of the gallbladder. Of these 19 were females, nine were males and the sex of one was not identified. The second sac was smaller than main one. Eleven cases were diverticulum of a cystic duct (Type I). Diverticulum of the neck of the main gallbladder of six cases also gave rise to the second gallbladder (Type II). A sac attached to the neck of the main gallbladder via a small cystic duct in seven cases was another type of reduplication (Type III). Connection of the second sac to the middle of the hepatic duct via a small cystic duct was seen in three cases (Type IV). The positions of these small sacs to the main gallbladder were right (13 cases), left (II cases) and ventral (three cases). The fundus of one gallbladder were divided and resulted in double sacs (Type V). One second sac was set apart from the main gallbladder and attached to a hepatic duct of lateral left lobe of the liver (Type VI). One specimen of the Type III gallbladder had two additional small sacs as diverticulum of the cystic duct. Compared to occurrences in humans and the Japanese monkey, the ratio of gallbladder reduplication to normal system anatomy in swine was extremely low. It was similar to the ratio of spleen reduplication in swine (1/10,000).