Developent of Asian clam (Corbicula fluminea) depuration system

In the present study, an Asian clam, Corbicula fluminea, depuration system was developed in order to purify and enhance the quality of Asian clam in term of bacterial coliform exposure. In the meantime, antibiogram of the isolated Escherichia coli from the sampled Asian clam was also characterised. Bacterial analysis on Asian clam revealed that the level of bacterial coliform contamination in their tissue is high and proven to be non-suitable for human consumption in general. Therefore, a depuration system was developed in the present study to improve the quality of Asian clam. Antibiogram profile of the isolated E. coli colonising the Asian clam could be used as a guideline for medical purposes in the case of infections due to the consumption of Asian clam in the future. The depuration system is comprised of a glass aquarium equipped with a sponge filter system and water pump. In the depuration system, there were two containers in which one container possessed 40 individual Asian clams which was used for the study of growth performance in the system; whereas the other container consisted another 100 individuals which was used for bacterial analysis on a weekly basis for 4 weeks consecutively. Each container was filled with 2 cm thick sand as the substrate. There were two treatments namely the control treatment (T1), and fermented soy pulp (FSP) treatment (T2); where 1% FSP was mixed homogenously with the sand to serve as feed for the clams. Each treatment was made in triplicates. In the end of the experiment, E. coli isolated from the tissue of Asian clam was subjected to antibiotic sensitivity test using disc diffusion method for 17 antibiotics. The study revealed that the Asian clam from T2 showed a significantly (p < 0.05) higher weight gain (3.73 ± 1.67%) compared to T1 (−0.35 ± 0.65%). In contrast, Asian clam from T1 performed better in term of survival rate; where the recorded result was significantly (p < 0.05) higher (75.83 ± 7.22%) compared to the Asian clam from T2 (67.50 ± 0.00%). The depuration system in the present study was found to be capable in enhancing the quality of Asian clam from Class B to Class A within 2 weeks period. Antibiogram of the bacteria isolated from Asian clam showed that erythromycin is the most effective antibiotics in controlling E. coli where it has successfully inhibited all of the present bacterial isolates. The findings of the present study were the first to be reported in scientific literature concerning the development of Asian clam depuration system in enhancing the clam quality with regard to growth size and total colonizing bacteria to meet the safety standard for human consumption.