罗非鱼饲料添加α-硫辛酸对藻毒素的解毒作用

摘要

A 56 d growth trial was conduced to investigate the effect of dietary supplemental α-lipoic acid ( LA) on the toxicity of microcystins from oral administration of cyanobacteria on hybrid tilapia ( Oreochromis niloticus ×O.aureus).Six isonitrogenous and isocaloric experimental diets were formulated.Cyanobacteria free and LA free diet was used as the posi-tive control.Another five diets were formulated to contain 9.0% algae meal ( dietary microcystin content was 80 μg/kg) supplemented with LA at 0 ( Negative control ) , 150 , 300 , 600 and 1200 mg LA/kg diet respectively.The results showed that: weight gain ( WG) and specific growth rate ( SGR) of fish fed with negative control and all LA containing diets were significantly lower than that of positive control ( P<0.05 ).However , a significant increase in WG and SGR was observed in hybrid tilapia fed with 600 and 1200 mgLA/kg diets ( P<0.05 ) , compared to negative control and the other LA groups (P<0.05).All fish fed with LA containing diets had lower serum glutathione peroxidase (GSH-Px) than that of the posi-tive control(P<0.05), but all fish fed 600 and 1200 LA containing diets had higher serum GSH -Px than that of the neg-ative control and the other LA groups ( P<0.05 ).Serum MDA contents of the fish fed with positive control were significant-ly lower than that of the negative control and all LA containing diets , Serum MDA contents of the fish fed with LA diets were significantly lower than that of the negative control (P<0.05).Microcystins (MCs) contents in fish liver and muscle of all LA containing diets were significantly lower than that of the negative control ( P<0.05 ) , and the lowest was in the group of LA containing diets at 600 mgLA/kg diets.Based on WG, SGR, Serum GSH-Px and MDA contents and tissues MCs concentration , it suggested that 600 mg LA/kg in diet could be helpful to reduce the toxicity of MCs on hybrid tilapia.%通过56 d 的生长实验研究饲料中不同含量的α－硫辛酸（ LA）对奥尼罗非鱼（ Oreochromis niloticus × O.aureus）摄食含蓝藻粉饲料后的解毒作用。以不添加蓝藻粉和LA的饲料组作为正对照，其他5种饲料均添加9.0％的藻粉（含80 mg/kg的微囊藻毒素）， LA添加量分别为：0、150、300、600和1200 mg/kg（分别为负对照、LA150、 LA300、 LA600和LA1200），共配制6种近似等氮等能的实验饲料。结果显示：负对照和各LA添加组实验鱼的增重率和特定生长率均显著低于正对照组， LA600和LA1200组实验鱼增重率和特定生长率均显著高于负对照组和其它LA添加组。各实验组和负对照组鱼体血清中GSH－Px含量均显著低于正对照组， LA600和LA1200组实验鱼血清中GSH－Px含量显著高于负对照组和其他LA添加组。正对照组鱼体血清中MDA含量显著低于各实验组和负对照组， LA添加组鱼体血清中MDA含量显著低于负对照组。 LA添加组实验鱼肝脏和肌肉微囊藻毒素（ MCs）含量显著低于负对照组，其中LA600组实验鱼肝脏和肌肉MCs含量最低。根据以上结果，在本实验条件下，在饲料中添加600 mg/kg LA可以有效缓解奥尼罗非鱼饲料中MCs的毒性。