Study on The Digestive Ability of The Stomach and Intestine of Leiocassis longirostris and Silurus meridionalis

In the study,the stomach and intestine of Leiocassis longirostris and Silurus meridionalis were observed.The mocous surface of the stomach and intestine were observed with the scanning electron microscope.The activities of protease and diastase of the stomach and intestine were measured.The weight ratio of the stomach,intestine and liver to body weight and the length ratio of intestine length to body length expectively indicat that they are typical carnivoroas fish.The expanding and contracting ability of stomach of Silurus meridionalis is greater than that of Leiocassis longirostris.However,the diet in Silurus meridionalis stomach connt be grinded into pieces,and lacks the hydrochloric acid.The distitution density of the digestive gland in the mocous of stomach and intestine of Leiocassis longirostris is higher,and there are more fine hair on the mocous of intestine compared with Silurus meridionalis.These indicat that the ability of secreting gastric and intestine juices of Lerocassis longirostris juices is greater than that of Silurus meridionalis.The activities of protease and diastase in stomach and intestine of Leiocassis longirostris is higher,and the digestive ratios of stomach and intestin of Leiocassis lognirostris in exteral experiment for fish meat powder,pig meat powder,soya-bean powder and rapeseed powder are higher compared with Silurus meridionalis.Thus,the ability of catching food of Silurus meridionalis is strong and a relatively large volume food may be swallowed at one time by Silurus meridionalis.However,the digestive ability of Leiocassis longirostris is greater than that of Silurus meridionalis for a same food at the same condition.Thses indicat that Leiocassis longirostris is easily tamed for a rearing fish with feed in ponds or cages.