Indigenous Lactic Acid Bacteria in Fish and Crustaceans - Aquaculture Nutrition: Gut Health, Probiotics and Prebiotics - page 133

heavily focused on rainbow trout and Atlantic salmon ( Salmo salar L.) and most studies have
used only a general purpose medium. Recently, however, molecular based investigations of the
GI microbiota of salmonids reveal a more diverse LAB population composed of members from
the Carnobacterium , Lactobacillus , Lactococcus , Leuconostoc , Streptococcus and Weissella
genera (Table 6.1).
6.3.1 Carnobacteria
Carnobacteria are ubiquitous LAB and have been isolated from both cold and temperate envi-
ronments, and they are frequently isolated from foods, meat, some dairy products and fish.
A range of Carnobacterium species have been identified as components of the microbiota of
the GI tract of salmonids (Table 6.1). To our knowledge the first study to isolate carnobacteria
from fish was carried out by Strøm (1988). Strøm isolated a strain (Lab01), initially identi-
ied as Lactobacillus plantarum but later reclassified as Carnobacterium divergens (Ringø
et al . 2001), from the GI tract of wild Atlantic salmon. This bacterium has subsequently
been shown to have antagonistic activity against several fish pathogens (Ringø 2008) and has
been used in ex vivo studies evaluating its ability to adhere to the intestine and to study the
interactions between C . divergens and fish pathogens (Ringø et al . 2007; Kristiansen et al .
2011). Figure 6.1 shows the typical morphology of C . divergens Lab01 (Ringø et al . 2001).
C. divergens , Carnobacterium maltaromaticum (previously characterized as Carnobacterium
piscicola ), Carnobacterium alterfunitum -like, and Carnobacterium spp. have all been iden-
tified from the GI tract of rainbow trout (Spanggaard et al . 2000; 2001; Huber et al . 2004;
Pond et al . 2006; Kim and Austin 2006a; Balcázar et al . 2007a; Kim et al . 2007; Mansfield
et al . 2010; Desai et al . 2012; Abid et al . 2014). C. maltaromaticum , C. mobile , C. diver-
gens , Carnobacterium inhibens and Carnobacterium spp. have been identified from Atlantic
Fig. 6.1 Scanning electron microscopy of Carnobacterium divergens Lab01 isolated from the
gastrointestinal tract of Atlantic salmon ( Salmo salar L.). (Source: After Ringø et al . 2001.)