中文摘要：

旨在探讨低分子质量壳聚糖（low molecular weight chitosan，LMWC）对鲤鱼（Cyprinuscarpio）生长和消化酶活性的影响。采用单因子浓度梯度法，设基础饲料组和质节分数分别为0．25％、0．50％、0．75％、1．0％LMWC细：分别件30、45、60d对不同绀鲤鱼质量增加率、投饵系数以及肝胰脏和肠道淀粉酶、脂肪酶、胰蛋白酶的活性进行动态分析。结果农明：随着LMWC添加量增加和时间延长，与对照组相比，鲤鱼质量增加率、淀粉酶、脂肪酶和胰蛋白酶活性郁毕现逐渐升高的趋势，投饵系数早．现逐渐下降的趋势。任45、60d时0．75％LMWC组鲤鱼的质量增加率，淀粉酶、脂肪酶、胰蛋白酶活件相对于对照、0．25％、0．50％、1．0％LMWC组，升高趋势最为明显。1．0％LMWC组鲤鱼随着时间延长，质量增加率和消化酶（淀粉酶、脂肪酶、胰蛋白酶）活性的升高趋势逐渐变缓；饲料中添加不同质量分数的LMWC对鲤鱼消化酶活性的影响不同，0．75％为LMWC的最适添加量。

英文摘要：

This study aimed to examine the effect of dietary supplementation with low molecular weight chitosan （LMWC） on common carp growth and digestive enzyme activities. Basal diet group was used as control and LMWC groups at increasing gradient concentrations （0.25%, 0.50%, 0.75% and 1.0%） were established. Body weight gain, feed coefficient and the activities of amylase, lipase and trypsin in the hepatopancreas and gut were analyzed after feeding for 30, 45 d and 60 d. When compared with control group, body weight gain and the activities of amylase, lipase and trypsin showed a gradual upward trend, whereas an opposite trend was observed for feed coefficient with increasing dietary LMWC supplementation and feeding time. After 45 d and 60 d of feeding, a more striking increase in body weight gain and the activities of amylase, lipase and trypsin was found for 0.75% LMWC group compared with control group and 0.25%, 0.50% and 1.0% LMWC groups. For 1.0% LMWC group, the increasing trend of body weight gain and digestive enzyme activities gradually slowed down with increasing feeding time. Dietary LMWC supplementation in different proportions had different effects on digestive enzyme activities in common carps and the optimal dosage was 0.75%.