Microflora of Arctic charr,Salvelinus alpinus(L.): gastrointestinal microflora of free‐living fish and effect of diet and salinity on intestinal microflora

摘要

Abstract.The adherent aerobic bacterial flora present in the gastrointestinal tract and faeces of free‐living Arctic charr,Salvelinus alpinus(L.), from Lake Takvatn, Northern Norway, were identified both qualitatively and quantitatively. Approximately 105bacteria g−1were found in both the small and large intestines. The predominant bacterial species were identified asAeromonas, Enterobacteriaceae,MicrococcusandLactobacillus.Other microorganisms isolated includedAcinetobacter, Cytophaga, Flavobacterium, Moraxella, Pseudomonas, Vibrio, Coryneforms andStreptococcus.The intestinal microflora of free‐living fish was dominated byAeromonasandLactobacillus, but the intestinal bacterial flora of wild fish transferred to hatchery was affected by feeding them either a capelin roe diet or a commercial feed in fresh and sea water. Approximately 55 of the bacterial flora in intestinal contents from fish fed the capelin roe diet was Enterobacteriaceae when the fish were held in fresh and sea water. However, when the wild‐caught charr were fed a commercial diet in fresh water,AeromonasandPseudomonasdominated in faeces, whileVibrioandPseudomonaswere predominant in the diet group held in se