长吻和南方大口鲶胃肠道消化能力的研究

通过对长吻（Ｌｅｉｏｃａｓｉｓｌｏｎｇｉｒｏｓｔｒｉｓ）、南方大口鲶（Ｓｉｌｕｒｕｓｍｅｒｉｄｉｏｎａｌｉｓ）胃、肠道所作大体解剖观察对比、粘膜扫描电镜观察、蛋白酶和淀粉酶活力测定等的研究结果表明，南方大口鲶的胃壁和胃粘膜皱褶非常发达，其伸缩能力远强于长吻。但长吻的胃、肠粘膜的分泌功能较南方大口鲶强，其蛋白酶和淀粉酶活力强于相近体重的南方大口鲶。南方大口鲶的发达的胃壁作用可能在于有较强的伸张能力以便一次性地食贮较多或较大个体食物，并在胃内进行初步消化。总体评价，长吻一次性的摄食能力不如南方大口鲶，但对同种食物的消化能力强于相近或相同体重的南方大口鲶。南方大口鲶胃、肠道消化生理特点适于一次捕食较大个体食物，具间歇性摄食的消化生理特点。而长吻则适于以较高摄食频率和对食物较强的消化利用率以适应营养的需要。

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 meri-dionalis 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 conn't 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