Detection and localization of alkaline and acid phosphatases in the digestive system of the adult Catla catla (Hamilton), an Indian freshwater major carp by histochemical methods.

The localization and distribution of alkaline phosphatase (ALPase) and acid phosphatase (ACPase) in the various regions of the alimentary canal viz., buccopharynx, oesophagus, intestine, rectum and hepatopancreas of adult Catla catla have been studied by employing various histochemical techniques. ALPase activity was recorded in the various regions of the alimentary canal in the present study although its intensity of localization and distribution varies greatly. The highest ALPase activity was detected in the columnar epithelial cells of the intestine including their brush border, sub-mucosal layer as well as in the basement membrane while intense activity of the same was observed in the epithelial cells (stratified and columnar) of the buccopharynx and oesophagus, hepatic and pancreatic acinar cells. The intense localization of ALPase was also found in the nuclei of the epithelial cells (stratified and columnar), sub-mucosal connective tissue nuclei, hepatic cell nuclei, and sub-mucosal polysaccharide granules of the intestine. The moderate ALPase activity was detected in the neuroepithelial cells of the taste buds in the buccopharynx, cytoplasm of the epithelial cells (stratified and columnar) and muscularis layers. The blood vessels of the intestine and rectum also furnished moderate ALPase activity. The weak ALPase activity was noticed in the brush border of the rectum and also in the basement membrane. Intense ACPase activity was recorded in the striated border of the intestinal villi, while moderate activity of the same was detected in the nuclei of the stratified and columnar epithelial cells of the various regions of the alimentary canal as well as in the hepatic and pancreatic acinar cells. Very weak ACPase activity was localized in the cytoplasm of the stratified epithelial cells of the buccopharynx and oesophagus.