Probiotic Modulation of the Gut Microbiota of Fish - Aquaculture Nutrition: Gut Health, Probiotics and Prebiotics - page 200

40

60

80

100

Uncultured bacterium

Lactococcus plantarum

Streptococcus
thermophilus

alpha proteobacterium
Brevundimonas sp.

Lb. rhamnosus
Agrococcus sp.

Aeromonas sp.

Lr P3 P1 P2 C3 C1 C2

Fig. 8.2 Dendrogram and DGGE profiles of the GI bacterial populations of zebrafish. Each lane
represents replicates of the control (C1-C3) or the Lb. rhamnosus -treated (P1-P3) fish. Lane Lr represents
the migration point of the known Lb. rhamnosus culture. (Source: Adapted from Gioacchini et al . 2012.)

50% dissimilarity to one another, and trends towards reduced bacterial richness, evenness
and diversity were observed in the probiotic fed group (see Figure 8.2). Sequence analy-
sis of isolated bands revealed that the abundance of a strain of Streptococcus thermophilus ,
which was not detected in the control replicates, was clearly stimulated by the presence of
the probiotic.
The administration of Lactobacillus strains in teleosts has shown varying degrees of suc-
cess. Studies which have successfully modulated the GI microbiota of fish with Lactobacillus