The effects of different terrestrial feeds on the growth performance and bacteriological analysis of Asian clam, Corbicula fluminea.

This paper studies the effect of terrestrial feeds on the growth performance and bacteriological analysis of Asian clam, Corbicula fluminea. Smoked Asian clam which is famous among Kelantanese has been recognized as a Kelantan traditional food heritage. However, Asian clam population is gradually declining in their natural habitat due to over-exploitation, excessive sand dredging activity, deforestation and freshwater pollution. Thus, an effort to culture Asian clam must be conducted in order to fulfil the market demand and at the same time prevent this clam from diminishing in their natural habitat. Therefore, in the present study the effect of three feeding treatments namely fermented soy pulp (FSP), treated quail dung (TQD) and nitrogen-phosphorus-potassium fertilizer (NPK) on growth performance of Asian clam restricted to pedal-feeding mode were conducted. Each treatment (n=30) was carried out in three replicates and the growth performance of Asian clam was monitored for 60 days. Control treatment was also included where no food was given to the clams. Growth parameters such as clams’ shell length and body dry weight were recorded. At the end of the experiment, treatment that gave high growth performance of Asian clam was proceeded with bacteriological analysis through method of total plate count (TPC) and Most Probable Number (MPN) before continued with antibiotic sensitivity test. The findings indicate that FSP showed the highest growth performance based on body dry weight and shell length of Asian clam (mean±SD) (10±0.4 μg/d and 17.0±3.00 μm/d) followed by NPK (8.0±0.30 μg/d and 21.0±3.00 μm/d) which are significantly different at p≤0.05 to TQD (3.0±0.10 μg/d and 6.0±1.80 μm/d) and control (-5.0±0.50 μg/d and 3.0±0.10 μm/d) respectively. Bacteriological analysis result on Asian clam tissue sample taken from FSP treatment shows the total plate counts for E. coli, Salmonella spp., Vibrio spp. and total bacteria are 6.18 x 104 Cfu/g, 5.26 x 104 Cfu/g, 4.23 x 103 Cfu/g and 6.28 x 105 Cfu/g respectively. Meanwhile, the MPN value for the Asian clam tissue sample is 274±38 MPN/100g. The bacteriological analysis result indicates that the clams are not safe for consumption as it exceeded standard safe level. Moreover, only six antibiotics are effective to inhibit growth of more than 70% of all bacteria isolated, namely Tetracycline, Doxycycline, Flumequine, Florfenicol, Tetracycline and Chloramphenicol. Furthermore, multiple antibiotic resistances (MAR) index for E. coli, Salmonella spp. and Vibrio spp. are 0.58, 0.43 and 0.50. This indicates the bacteria isolated from Asian clam in the culturing system are highly exposed to antibiotics residue. In conclusion, the findings suggest that FSP is a potential feed for Asian clam but the clams must be depurated and cooked thoroughly before consumption.