ACCUMULATION, TRANSFORMATION AND ELIMINATIONOF PSP IN MYTILUS EDULIS
YAN Tian, FU Meng, LI Jun, YU Ren-Cheng, ZHOU Ming-Jiang(Institute of Oceanology, The Chinese Academy of Sciences, Qingdao, 266071)
Using a PSP (Paralytic Shellfish Poisoning) producing strain Alexandrium tamarense (ATHK), we studied toxin accumulation, transformation and elimination of PSP in mussels Mytilus edulis. The results show that the PSP content increased with time both in visceral and muscle during an 8-day accumulation period when mussels were feeding with A. tamarense. At the end of the accumulation period, the mean toxin amount and accumulation efficiency in each mussel were 13.40nmol, 12.45% (comparing to the total PSP amount from algae), respectively. The toxicity level was 12.24μgSTX Eq/100g, which did not reach the sanitation standard (80μgSTX Eq/100g). The accumulation of visceral was more intense than that of muscles. The toxin amount in visceral of average each mussel was 13.07nmol, with its accumulation efficiency being 12.14% at the end of accumulation period, whilst those of muscles were only 0.33nmol and 0.31%, respectively. The percentage of toxin accumulated in visceral was 97.5% of total, indicating that visceral was the main part for toxin accumulation in shellfish. There are also different toxin profiles of the alga and mussel, indicating that the toxins may have transformed in mussels. During the eight-day elimination period, the a mount of total PSP decreased with an elimination rate of about 9% per day. Except GTX1,4, the main PSP composition in muscle which decreased too, GTX2, GTX3, NEO and dsSTX did show decrease, but STX increased during the elimination period. This was probably caused by complicated transformation among PSP compositions. Further studies will focus on PSP depuration of shellfish to provide techniques for developing sanitary shellfish industry in China.