壳聚糖对异育银鲫生长和消化酶的影响

Effects of chitosan on growth and digestive emzyme in allogynogenetic silver crucian carp

以基础饲料为对照,以在基础饲料中分别添加0.125%、0.25%、0.5%、0.75%、1%的壳聚糖为实验饲料,饲养异育银鲫(Carassius auratus gibelio)60 d,与对照组比较生长、成活、饲料系数、蛋白质效率、鱼体营养成分、白肌RNA/DNA比值及肝胰脏、肠道的蛋白酶、淀粉酶活性。结果表明,本次实验所添加壳聚糖对异育银鲫的成活率、鱼体营养成分和白肌的RNA/DNA比值均无显著影响(P>0.05)。添加0.5%、0.75%和1%壳聚糖可以显著提高异育银鲫的特定生长率和蛋白质效率,显著降低异育银鲫的饲料系数。添加0.5%壳聚糖可以显著提高异育银鲫肠道的淀粉酶活性;添加0.75%和1%壳聚糖可以显著提高肠道和肝胰脏的蛋白酶活性和肠道的淀粉酶活性。

Chitosan is rich in natural resource, but it is often thrown away as waste. The latest studies show that chitosan could affect the growth of aquatic animals. Allogynogenetic silver crucian carp were fed with control diet and test diets which were control diet containing chitosan at contents of 0. 125%, 0.25%, 0.5 %, 0.75 % and 1%, respectively. Specific growth ratio in wet weight, feed coefficient and protein efficiency ratio, nutrient ingredients in the muscle, RNA/DNA ratio in white muscle, protease activity, amylase activity in intestine and hepatopancreas were determined after 60 days feeding period. The results show that the supplement of chitosan at 0.5 %, 0.75 % and 1% could significantly improve specific growth rate （SGR） and protein effeciency ratio （PER）, and significantly decrease feed coeffeciency （FC） of the fish. Their SG-R were 0.07 %·d^-1, 0.12 %·d^-1 and 0.1%·d^-1 more than those of control respectively. Their PER were 20.37%, 35.15% and 29.38% more than that of the control respectively. Their FC were 0.21, 0.33 and 0.28 less than that of the control respectively. The supplement of 0.5% chitosan could significantly enhance amylase activity in intestine. The supplement of chitosan at the content of 0.75 % and 1.0 96 could significantly advance protease activity in intestine and hepatopancreas, amylase activity in intestine of the fish. The supplement of chitosan in the test had no significant effect on survival ratio, nutrient ingredients in the muscle and RNA/DNA ratio in white muscle of the fish. The mesult showed that 0.75 % of chitosan is optimum additive dose in the fish diet for growth. Suitable additive dose of chitosan could not only improve growth of the fish but also make RNA/DNA ratio the same tendency with growth. The mechanism that chitosan could improve growth of the fish may be that chitosan could advance protease activity in intestine and hepatopancreas, amylase activity in intestine of the fish and abilities of protein synthesis in the fish.