Toxic Effects Of Aflatoxin B₁on Growth Performance, Biochemical And Hepatopancreas Microstructure Of Litopanaeus Vannamei

The toxic effects of aflatoxin B1(AFB1) on Litopanaeus vannamei were examined in termsof growth indices, body composition, hepatopancreas microstructure and biochemical ofhaemolymph and hepatopancreas. A total of540shrimp (initial mean weight:0.3±0.02g)were randomly albcated in to6groups with3replicates per group and30shrimp perreplicate. Six isonitrogenous purified diets were fed to shrimp for8weeks in triplicatetanks connected to recirculating system. Diets contained different levels of AFB1(0,400,800,1200,1600,2000μg.kg-1). Crude protein of whole shrimp were no significantdifferences (P>0.05). Body lipid tended to be higher within shrimp fed diets with higherAFB1level (1600μg.kg-1and2000μg.kg-1). The lowest weight gain (304.67%) was found inshrimp fed with1200μg.kg-1diet. However the shrimp fed with2000μgAFB1.kg-1got thelowest survival rate (58.33%) and the highest weight gain. Enzyme activities generallyindicated a downward trend. Total antioxidant capacity of hepatopancreas decreasedsignificantly (P<0.05) was found in2000μg.kg-1diet. The activity of GST, Na+,K+-ATPase and SOD in hepatopancreas reached minimum in shrimp fed with1600μg.kg-1AFB1diet, but GST of haemolymph was significantly higher than others (P<0.05). Shrimpfed diets with1600μg.kg-1AFB1had a significantly lower total haemocyte count (THC)(P<0.05) compared with control group. GPT, GOT of haemolymph and GOT inhepatopancreas tended to be higher within shrimp fed diets with higher AFB1level(1600μg.kg-1and2000μg.kg-1), GPT of hepatopancreas increased significantly (P<0.05)was found in2000μg.kg-1diet. All experimental groups of glutathione peroxidase(GSH-PX) in hepatopancreas activity increased with the feed of AFB1decreased, andreached the lowest value at2000μg.kg-1. Haemolymph in all experimental groups ofmalondialdehyde (MDA) has no significant difference (P>0.05), but higher than controlgroup. MDA of hepatopancreas has no differences with control group while other groupsgenerally indicated a significant (P<0.05) upward trend. Histological study on shrimp fedmore AFB1exhibited histological changes. Besides higher AFB1residues inhepatopancreas were observed in shrimp fed with higher level AFB1. The most AFB1 residues in hepatopancreas were detected at95.49μg.kg-1in shrimp fed with2000μg.kg-1.However no AFB1residue in muscle was detected in all of groups. The overall conclusionis that antioxidant and detoxification function of hepatopancreas in shrimp reduced alongwith the feed of AFB1. No AFB1residual in muscle so that consumption of shrimp is notharmful to humans.