Effects of Alcohol Extract from Soybean Meal on Pancreatic Digestive Enzyme and Bile Acid Secretion in Yellowtail Seriola quinqueradiata

摘要

A feeding experiment was conducted to investigate effects of alcohol extract from defatted soybean meal (SBM) on secretion of pancreatic digestive enzymes and bile acids in yellowtail. Four diets which were designated as SBM, ExSBM (alcohol extractedSBM) and ExSBM+Ext (ExSBM supplemented with alcohol extract) and FM (fish meal) were fed to yellowtail for 3 weeks. Total bile acid level in anterior intestinal digesta was significantly lower in fish fed ExSBM+Ext and SBM than in fish fed ExSBM and FM,despite similar levels in gallbladder among the treatments. Fish fed ExSBM+Ext and SBM showed lower lipase and trypsin activities in anterior intestinal digesta than fish fed ExSBM which presented comparable values to those fed FM. The activities of these enzymes in pyloric caeca of the former fish were slightly higher than those in the later fish. Growth performance tended to be higher in fish fed ExSBM and FM compared to those fed ExSBM+Ext and SBM though no significant differences were observed after3-week feeding. These findings indicate that alcohol extract from soybean meal inhibits the secretion of bile acids and pancreatic enzymes in yellowtail. This negative effect on digestive physiology might impair growth in along-term feeding period.