REDUCTION OF BACTERIAL CONTAMINATION OF COMMON CARP UNDER VARIOUS REARING CONDITIONS
Stanisław Niewolak, Stefan Tucholski
Warmia and Masuria University in Olsztyn
ABSTRACT. Numbers of bacteria identified on broth agar in 20 and 37°C, coliforms, fecal coliforms, fecal streptococci, anaerobic sulfite-reducing Clostridium perfringens, Pseudomonas aeruginosa, Aeromonas sp., and Salmonella sp. were evaluated in the muscles, skin, and digestive tract content of common carp (Cyprinus carpio). The fish were sampled: 1. from a pond supplied with biologically purified sewage from a sewage treatment plant in Jedwabno (at the age 1+), 2. after 6 months of wintering in an earthen pond supplied with clean lake water, and 3. after subsequent 6 months of rearing in the same water. Wintering and subsequent rearing took place in the Stocking Material Production Centre in Warlity. The fish were aged 2+. Muscles, skin and digestive tract contents of all fish were free from Clostridium perfringens, Pseudomonas aeruginosa. Salmonella sp. were present only in muscles and skin of fish from sewage-supplied pond. Wintering caused considerable reduction (90.0-98.8%) of coliforms, and fecal coliforms (98.7-100%) in the tissues and digestive tract contents. Numbers of Aeromonas sp. in skin were reduced by 91.1% and concentration of fecal streptococci in the guts - by 74.6%. Further reduction of bacterial contamination was observed after another 6 months of rearing in the pond supplied with clean lake water, but numbers of Aeromonas sp. in the digestive tract increased considerably.
Keywords: FISH FRY, TABLE CARP, AQUACULTURE, WASTEWATER POND, LAKE WATER, PURIFICATION, BACTERIAL INDICES