Bacteriological study of freshwater giant prawn larvae

Abstract

A total of 49 isolates were obtained from diseased Macrobrachium rosenbergii larvae of marine hatchery UMT. This study was carried out to identify the bacterial genera of Macrobrachium rosenbergii larvae and their resistance to various antibiotics and heavy metals used commonly in aquaculture. Fifteen different types of antibiotic were used in antibiotic analysis. Antibiotics such as Amoxicillin (AML, 25 μg), Erythromycin (E, 15 μg), Novobiocin (NV, 30 μg), Florfenicol (FFC, 30 μg), Flumequine (UB, 30 μg), Colistin sulphate (CT, 25 μg), Ampicillin (AMP, 10 μg), Fosfomycin (FOS, 50 μg), Nitrofurantoin (F, 50 μg), Oleandomycin (OL, 15 μg), Spiramycin (SP, 100 μg), Tetracycline (TE, 30 μg), Oxolinic acid (OA, 2 μg), Doxycycline (DO, 30 μg), and Lincomycin (MY, 15 μg) were used for determination of bacterial resistant to the antibiotic. Heavy metals such as copper (Cu), cadmium (Cd), mercury (Hg) and potassium dichromate (Cr) were used for heavy metal analysis. The isolates were identify by morphological typing using selective agar: TCBS, XLD, GSP, EMB, and Mac Conkey Result showed that they are four genera of bacteria that were observed, which are genera Vibrio, Enterobacter, Aeromonas and E. coli. All the isolated bacteria were resistant to lincomycin and amoxylin. MAR index of 0.61 had shown that the UMT hatchery was frequently exposed to antibiotic. Heavy metal test against four different heavy metals with five different concentrations showed that all the isolates were resistant to heavy metals.