Summary: | Microbiological studies of the digestive tracts of flounder (Platichthys flesus), burbot (Lota lota), herring (Clupea harengus), cod (Gadus morhua), smelt (Osmerus eperlanus), black sculpin (Myoxocephalus scorpius), pike-perch (Lucioperca lucioperca), whitefish (Coregonus lavaretus), ruff (Acerina cernua), and plaice (Pleuronectes platessa) from the Lithuanian coast (Baltic Sea) were carried out in 1995. Although heterotrophic bacteria predominated in the bacteriocoenosis of the tested fish, proteolytic and amylolytic bacteria were isolated. Hydrocarbon-degrading bacteria were detected in high abundance in all tested species, but counts were highest in autumn with a maximum of about 3 x 10(5) g(-1) in ruff. Oil products taken up by fish with their food may be partly degraded by enzymes of micro-organisms present in the intestines. We argue that fish with a well-developed intestinal microflora have greater opportunity to adapt to changing nutritional substrates and to assimilate food with high efficiency, and that increasing environmental pollution by xenobiotics may affect the bacteriocoenosis of the digestive system.
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