棉子糖对花鲈生长、免疫抗应激及抵御嗜水气单胞菌攻毒的影响

摘要

实验研究了棉子糖对花鲈(LateolabraxJaponicus)生长、非特异性免疫、抗应激能力和嗜水气单胞菌攻毒后存活率的影响.基础饲料依据花鲈营养需求配制.实验设计5个处理,棉子糖添加量分别为:0(对照组)、200、400、800和2000 mg/kg饲料,分别命名为R0、R200、R400、R800和R2000.每个处理3个重复,每个重复30尾鱼(初始体重3 g左右).实验共持续16周,实验结束后称重并取血清样品用于测定免疫和抗氧化指标.此外还分别进行了30s空气暴露应激和嗜水气单胞菌攻毒实验.结果表明各实验组花鲈存活率和摄食率没有显著差异(P＞0.05),R800组增重率显著高于对照组、R400和R2000组(P＜0.05).R400组饲料系数显著高于R800组、蛋白质效率显著低于R800组(P＜0.05),但与其他各组没有显著差异.各组间蛋白质沉积率、肝指数没有显著差异(P＞0.05),对照组、R200和R2000肥满度显著高于R400和R800组(P＜0.05),R800组花鲈内脏比显著低于R400组(P＜0.05).各组间血清溶菌酶、超氧化物歧化酶活力和氧化产物丙二醛含量没有差异(P＞0.05).30s空气暴露应激后血清葡萄糖和皮质醇也未显示差异,但嗜水气单胞菌(Aeromonas hydrophila)攻毒后对照组累计存活率为65%,显著低于各试验组(P＜0.05).棉子糖在花鲈饲料里适宜添加量为800 mg/kg.%A 16w growth trial was conducted to study the effects of raffinose on growth performance, non-specific immunity, stress response and survival of Japanese seabass (Lateolabraxjaponicus) challenged with pathogenic bacteria,Aerornonas hydrophila in a recirculation system.Five experimental diets with 0, 200, 400, 800 and 2000 mg/kg of raffinose supplements were prepared, and named as R0, R200, R400, R800 and R2000, respectively.Each diet was fed to triplicates groups of Japanese seabass (initial body weight: average of 3g), with 30 fish in each tank.At the end of trial,fish were weighed and serum sample were collected.Besides, a 30s air-exposure stress test and a challenge test with A.hydrophila were carried out.Survival and feed intake of fish did not show significant difference among all groups (P＞0.05).Weight gain rate (WGR) of R800 group was significantly higher than that of control, R400 and R2000 groups (P ＜ 0.05).Feed Conversion Ratio (FCR) and protein efficiency rate (PER) of R800 treatment were significantly lower and higher than R400 treatment, respectively (P ＜ 0.05).Condition factor (CF) of control, R200 and R2000 treatments were significantly higher than R400 and R800 treatments (P ＜ 0.05).There were no difference on serum lysozyme, superoxide dismutase and malondialdehyde (P ＞ 0.05), and glucose and cortisol level of serum after 30s air stress were no difference (P ＞ 0.05), either.However, accumulative survival of control group significantly lower than that of groups with various level of raffinose after being challenged by Aerornonas hydrophila (P ＜ 0.05).800mg/kg of raffinose was recommended to use in diet of Japanese sea bass.