STUDIES OF THE DIGESTIVE TRACTS AND THE DIGESTIVE ENZYMES OF THE GOLDFISH, CARASSIUS AURATUS (LINNAEUS) AND THE LARGEMOUTH BLACK BASS, MICROPTERUS SALMOIDES (LACÉPÈDE)

Abstract

The digestive tract in goldfish, unlike that of largemouth black bass, is an elongated, relatively undifferentiated tube, which could be separated into several divisions by the character of the epithelial lining. A true stomach is absent; its place is taken by an enlargement of the intestine, the intestinal bulb. The bile and pancreatic ducts open on the roof of the bulb and a short distance behind the valve-like structure separating the bulb from the esophagus. Of the 3 proteinases studied, trypsin was the only enzyme found in extracts from hepato-pancreas, intestinal bulb, anterior intestine, and posterior intestine of goldfish. It was active in a greater part of the tract. In largemouth black bass, both pepsin and trypsin were found, the former in extracts from the stomach, and the latter in extracts from the liver, pancreas, and pyloric caeca. The action of pepsin was limited to the lumen of stomach; trypsin was active in the stomach, duodenum, and small intestine. Amylase, maltase, and invertase were found in extracts from hepato-pancreas, oesophagus, intestinal bulb, anterior intestine, and posterior intestine of goldfish. These were active in the intestinal bulb, anterior intestine, and posterior intestine. Carbohydrases were absent in largemouth black bass. Lipase was found in extract from the hepato-pancreas, and it was active in the intestinal bulb and the anterior intestine of goldfish. In largemouth black bass, lipase was found in extracts from liver and pyloric caeca, and it was active in the duodenum and small intestime.