TÓM TẮT NỘI DUNG:

Several common aerobic bacteria were isolated from selected tissues of healthy major carps (Labeo rohita) kept in ponds, lakes and lagoons in the Red River Delta. Ten samples each of muscle, liver, spleen, kidneys, gills, and intestine of healthy major carp were investigated for common bacteria. Seven kinds of bacteria, viz. Salmonella sp., Aeromonassp., Pseudomonas sp., Bacillus subtilis, Staphylococcus sp., Streptococcus sp., and Proteus vulgaris were found. All of the found bacteria were detected in the intestine, whereas only two to five kinds were found in the other tissues. Aeromonas sp. was found in all of the six selected tissues; Salmonella sp. and Proteus vulgaris were detected only in the intestine; Streptococcus sp. was found in all the tissues, except muscle. The total number of colony forming units (CFU) per gram was highest in the intestine and lowest in muscle, being 142,800*10 2 and 0.6*10 2 , respectively.