饲料中添加丝兰提取物对大菱鲆幼鱼生长和生理及水环境的影响

用丝兰提取物添加量为0.00% (D0)、0.05% (D1)、0.10% (D2)、0.20% (D3)和0.40% (D4)的实验饲料投喂大菱鲆幼鱼(42.200.06) g 60d, 研究其对大菱鲆幼鱼生长性能、体组成、血清免疫代谢指标及养殖水质指标的影响。结果显示, 在饲料中添加丝兰提取物对大菱鲆幼鱼增重率(WGR)、特定生长率(SGR)、饲料系数(FCR)、脏体比(VSI)、肝体比(HSI)、肥满度(CF)均无显著影响(P 0.05)。全鱼、肌肉及肝脏中水分、粗蛋白、粗脂肪含量变化无显著性差异(P 0.05)。D3组幼鱼血清溶菌酶显著高于其他各组(P 0.05), 而D4组各免疫指标明显低于对照组(P 0.05); D3和D4组幼鱼血清的谷丙转氨酶(ALT)、谷草转氨酶(AST)活力显著低于对照组。除A1-6h组外各实验组水体氨氮含量均显著低于对照组(P 0.05), 各实验组亚硝酸盐含量均显著高于对照组(P 0.05), 各实验组总氮、总磷、磷酸盐含量均与对照组无显著性差异(P 0.05)。研究证明, 在饲料中适量添加丝兰提取物能够显著增强大菱鲆幼鱼非特异性免疫能力, 并显著降低养殖水体氨氮含量, 对大菱鲆生长及体组成无显著影响。以非特异性免疫及水体氨氮含量为综合评定指标, 大菱鲆幼鱼饲料中丝兰提取物的适宜添加量为0.20%。  

EFFECTS OF DIETARY YUCCA SCHIDIGERA EXTRACT ON THE GROWTH PERFORMANCE,BLOOD PHYSIOLOGICAL AND BIOCHEMICAL INDICES OF TURBOT (SCOPHTHALMUS MAXIMUS) AND WATER ENVIRONMENT

In order to assess the effect of Yucca extract on growth performance, nutritional composition, serum immune of juveniles and aquaculture water environment, five formula feeds contained Yucca Extract at levels of 0.00% (D0), 0.05% (D1), 0.10% (D2), 0.20% (D3) and 0.40% (D4) were fed with juvenile Turbot (Scophthalmus maximus). The result showed that, no significant difference occurred in weight gain, specific growth rate, feed conversion ratio, viscerosomatic index, hepatosomatic index and condition factor of fish among all dietary treatments (P 0.05). Water, crude protein and crude lipid content of whole fish, muscle and liver exhibited no significant difference among groups (P 0.05). Serum lysozyme was enhanced in fish fed diet D3 significantly, while all immune indices were reduced in fish fed diet D4. The activities of alanine transaminase and aspartate aminotransferase of fish fed diet D3 and D4 were lower than that of the control dietary treatment (P 0.05). Except D1-6h, Ammonia content of all dietary treatments were significantly lower than that of the control treatment (P 0.05). Nitrite content of all dietary treatments were higher than that of the control treatment (P 0.05), while total nitrogen, total phosphorus and phosphate content showed no significant difference to the control treatment (P 0.05). The optimum content of Yucca Extract for juvenile turbot was 0.20% of weight based on the consideration of non-specific immunity and ammonia nitrogen content in aquaculture water.