不同脂肪源饲料对中华绒螯蟹幼蟹生长、消化酶活力和脂肪酸组成的影响

选用初始体重为(2.15±0.10)g的中华绒螯蟹(Eriocheir sinensis)雄性幼蟹,随机分为5组(每组12只幼蟹),饲喂100%鱼油组(简称F1组)、100%豆油组(F2组)、100%亚麻油组(F3组)、50%鱼油+50%豆油组(F4组)、50%鱼油+50%亚麻油组(F5组)不同脂肪源配制的5种等氮等能饲料。实验蟹单个体养殖,实验周期为112 d。结果表明,F5组体重、增重率和特定生长率都显著高于其他饲料组(P0.05),各组的蜕壳间隔和肝胰腺指数没有显著差异(P0.05)。肝胰腺组织消化酶活力测定结果表明,F1组幼蟹肝胰腺的类胰蛋白酶活力显著高于其他各组(P0.05);F3组的胃蛋白酶活力显著高于其他各组(P0.05);F1组、F2组和F4组的脂肪酶活力显著高于其他两组(P0.05);各组的淀粉酶活力差异不显著(P0.05)。脂肪酸测定结果表明,肝胰腺和肌肉中的亚油酸(LOA)(C18:2n-6)、亚麻酸(LNA)(C18:3n-3)、EPA(C20:5n-3)和DHA(C22:6n-3)等主要脂肪酸含量与饲料脂肪酸组成呈正相关关系,F1组的高度不饱和脂肪酸(HUFA)含量显著高于其余各组(P0.05),F2组的LOA含量显著高于其余各组(P0.05),F3组的LNA含量显著高于其余各组(P0.05)。本研究结果表明,以50%的豆油或亚麻油替代鱼油能促进中华绒螯蟹幼蟹的生长,但可能使幼蟹的成活率降低。以豆油或亚麻油替代鱼油会影响幼蟹胰蛋白酶、胃蛋白酶和脂肪酶的活力和肝胰腺、肌肉脂肪酸组成。

Effects of different lipid sources on growth, digestive enzyme activity, and fatty acid composition in juvenile Chinese mitten crab, Eriocheir sinensis

This study determined the effects of different sources of dietary lipid on survival rate, weight gain, molting, digestive enzyme activity, and fatty acid composition in male juvenile Chinese mitten crab, Eriocheir sinensis. Five diets were formulated to contain different amounts of fish oil, soybean oil, and linseed oil. The con-trol feed (Group F1) was formulated with 6% fish oil, whereas the other 4 experimental diets were formulated with 6% soybean oil (Group F2), 6% linseed oil (Group F3), 3% fish oil and 3% soybean oil (Group F4), and 3% fish oil and 3% linseed oil (Group F5). Juvenile crabs (with initial body weight 2.15 g±0.10 g) were randomly allo-cated to one of the diet groups. Twelve juvenile crabs per diet group were individually stocked in plastic tanks. After 112 d, weight gain and specific growth rate of Group F5 was significantly higher than that of the other groups (P<0.05). No significant difference was observed in molting interval or hepatosomatic index. Analysis of digestive enzyme profiles from the hepatopancreas revealed positive correlations between enzyme activity and lipid sources: tryptase activity in Group F1 was significantly higher than that in the other groups (P<0.05); pepsin activity in Group F3 was significantly higher than that in the other groups (P<0.05); lipase activity in Groups F1, F2, and F4 was significantly higher than that in the other two groups (P<0.05). Different diets had no significant effects on amylase activity. Fatty acid composition of the hepatopancreas and muscles followed the fatty acid composition of the diet. Eicosapentaenoic acid (C20:5n3) and docosahexaenoic acid (C22:6n3) in Group F1 was sig-nificantly higher than that in the other groups (P<0.05); linoleic acid (C18:2n6) in Group F2 was significantly higher than that in the other groups (P<0.05); linolenic acid (C18:3n3) in Group F3 was significantly higher than that in the other groups (P<0.05). These results suggested that replacing 50% fish oil with soybean or linseed oil had a posi-tive effect on growth, but a negative effect on survival rate in juvenile Chinese mitten crab, E. sinensis. Both soy-bean oil and linseed oil had a significant effect on tryptase activity, pepsin activity, lipase activity, and fatty acid of the hepatopancreas and muscles in juvenile Chinese mitten crab, E. sinensis.