| Summary: | Investigations of the aerobic bacterial flora in the digestive tract of the following fish were carried out in 1995: European flounder (Platichhys flesus), burbot (Lota lota), Baltic herring (Clupea harengus membras), bullrout (Myoxocephalus scorpius), European pike-perch (Stizostedion lucioperca), European whitefish (Coregonus lavaretus), ruffe (Gymnocephalus cernuus), plaice (Pleuronectes platessa), Baltic cod (Gadus morhua callarias), European smelt (Osmerus eperlanus) from the Lithuanian coast (Baltic Sea). Heterotrophic bacteria predominated in the bacteriocenosis of the digestive tract of the tested fish, proteolytic and amylolytic bacteria were isolated too. Increasing environmental polution by various xenobiotics affects the bacteriocenosis of the digestive system of animals. Hydrocarbon-degrading bacteria were detected in great abundance in the digestive tract of the tested species, and counts were highest in autumn with a maximum of about 3*10 5 cells g-1 in ruffe. Hydrocarbon-degrading bacteria get into the digestive tract of fish from the environment and oil products - with food. Oil products taken up by fish may be partly degraded by enzymes of micro-organisms present in the intestines. We argue that fish with well developed intestinal microflora have a greater opportunity to assimilate food with high efficiency, and that increasing environmental pollution by xenobiotics may effect the bacteriocenosis of the digestive tract.
|
|---|