Gram-negative intestinal indigenous microbiota from two Siluriform fishes in a tropical reservoir

Abstract

The Gram-negative intestinal microbiota of Hypostomus auroguttatus and Pimelodus maculatus, a detritivorous and an omnivorous fish species, respectively, were compared between fishes from the reservoir and the stretch of the river below the dam of the Funil hydroelectric plant, Rio de Janeiro, Brazil. Four selective culture media were used under aerobic and two under anaerobic conditions. The omnivorous species had microbiota with higher population levels compared to the detritivorous species. The number of morphotypes and population levels of total bacteria, vibrio and Bacteroides tended to be higher in summer and autumn in the reservoir, and not different in the river. The number of morphotypes of enterobacteria and total bacteria were higher in the lotic environment compared with the lentic one. The bacteria Aeromonas hydrophila and Plesiomonas shigelloides and the obligate anaerobic Fusobacterium mortiferum were the most frequently identified microorganisms in the intestine of both H. auroguttatus and P. maculatus. Both season and habitat influenced the Gram-negative intestinal microbiota of H. auroguttatus and P. maculatus. Environmental factors influenced the Gram-negative intestinal microbiota of both species with possible impact on the interrelationship between the fishes and their digestive ecosystem, although the gut microbiota composition of fishes may result from host-specific selective pressures within the gut.

Under control: how a dietary additive can restore the gut microbiome and proteomic profile, and improve disease resilience in a marine teleostean fish fed vegetable diets

“…This group has been recognised to produce butyric acid as a major product of fermentation [ 85 ], and some species have been associated with diseases in mammals [ 86 ]. Fusobacteria are the most abundant phylum of the autochthonous normal gut microbiota in common carp [ 37 ], and are also well represented in the gut microbiota of some lab reared zebrafish [ 78 ] and tropical siluriform fish [ 87 ]. Other authors have reported the presence of Fusobacterium spp.…”

Plesiomonas shigelloides Revisited

“…In addition to those fish cited in a previous review (28), recent investigations have isolated Plesiomonas from rainbow trout (53,54), carp (55), and tilapia (44,56,57). Studies of the intestinal tracts of a number of freshwater fish suggest that the genus Plesiomonas is one of the most common species composing the bacterial microbiota of these vertebrates, in addition to Fusobacterium and Aeromonas (58,59). An Auburn University study pooled DNA samples from the intestinal contents of three commercial freshwater species and subjected these samples to 16S rRNA gene pyrosequencing (58).…”

Tetrodotoxin-Producing Bacteria: Detection, Distribution and Migration of the Toxin in Aquatic Systems

“…Changing the diet of puffer fish from the natural habitat to non-typical food led to a loss of animal toxicity, and returning to a natural diet restored toxicity [ 101 ]. As shown for many animals, including fish, a diet change to non-typical food causes changes in the qualitative and quantitative composition of intestinal microflora [ 105 , 106 ]. Diet normalization causes recovery of intestinal microflora [ 107 ].…”