壳寡糖对吉富罗非鱼幼鱼生长性能、非特异性免疫及血液学指标的影响

用添加质量分数0.00(对照组)、0.10%、0.30%、0.50%和0.70%壳寡糖的饲料饲喂初始体重(3.81±0.23)g的吉富罗非鱼幼鱼(Oreochromis niloticus)10周,研究不同浓度壳寡糖的添加对吉富罗非鱼幼鱼的生长、非特异性免疫功能以及血脂指标的影响。结果表明:与对照组相比,在4个不同浓度添加组中,添加质量分数0.50%壳寡糖能显著提高幼鱼的增重率(P<0.05)、特定生长率(P<0.05),并降低饲料系数(P<0.05);添加质量分数0.3%和0.5%壳寡糖能显著提高幼鱼抗嗜水气单胞菌感染的能力(P<0.01);添加质量分数0.10%、0.30%、0.50%壳寡糖能显著提高幼鱼血清中碱性磷酸酶活性(P<0.05)。同时,各浓度的壳寡糖均能明显提高幼鱼血清中溶菌酶和超氧化物歧化酶活性以及抗嗜水气单胞菌感染的能力(P<0.05),并降低幼鱼血清中总胆固醇和低密度脂蛋白胆固醇水平(P<0.05)。在本实验条件下,添加壳寡糖可提高吉富罗非鱼幼鱼生长性能、饲料利用率、非特异性免疫功能和调节血脂水平,添加量以质量分数0.30%~0.50%为宜。

Effect of Dietary Chitosan on Growth Performance, Non-Specific Immunity and Hematological Parameters of Juvenile GIFT Tilapia, Oreochromis niloticus

A 70-day feeding trial was conducted to investigate the effects of dietary chito-oligosaccharide(COS) supplement on growth performance,non-specific immunity and hematological parameters of juvenile GIFT tilapia,Oreochromis niloticus.COS was included at 0,1,3,5 and 7 g/kg in trial diets,and hand-fed to satiation three times daily to triplicate groups of GIFT tilapia(30 fish/group,initially weighing approximately 3.81 g) reared in 400 L aquaria with(27±2) ℃.The results are as follows: compared with the control group,weight growth rate(WGR)of fish with 5 g/kg COS diets increased significantly(P < 0.05),whereas feed conversion rate(FCR) decreased significantly(P < 0.05);the resistance with infection of Aeromonas hydrophila can be improved when fed with 3 and 5 g/kg COS diets(P < 0.01).Activity of serum alkanline phoshpatase(AKP) significantly increased in groups fed on diets with 1,3 and 5 g/kg COS(P < 0.05).All groups can significantly increase activity of serum lysozyme(LSZ) and superoxid dismutase(SOD).The resistance with infection of Aeromonas hydrophila can be improved,and TC,LDL-C will decrease when adding COS(P < 0.05).Results above show that COS can increase growth performance,nonspecific immunity and promote blood lipid metabolism.The COS supplement in diets is suggested to be 3-5 g/kg for juvenile GIFT tilapia.