Genetic and Physiological Characterization of the Intestinal Bacterial Microbiota of Bluegill (Lepomis macrochirus) with Three Different Feeding Habits

Abstract

Bluegill (Lepomis macrochirus) in Lake Biwa, Japan, feed on benthic invertebrates (benthivorous type), aquatic plants (herbivorous type), and zooplankton (planktivorous type). To evaluate the effect of food on intestinal bacterial microbiota, we characterized and compared the intestinal microbiota of these three types of bluegill in terms of community-level physiological profile (CLPP) and genetic structure. The CLPP was analyzed using Biolog MicroPlates (Biolog, Inc., Hayward, CA, USA), and multivariate analysis of variance revealed that the CLPP of intestinal microbiota differed significantly between any pairs of the three types of bluegill. The genetic profiles were analyzed by temperature gradient gel electrophoresis of polymerase chain reaction (PCR)-amplified 16S rDNA fragments, and multidimensional scaling indicated the existence of specific intestinal bacterial structures for both the benthivorous and the planktivorous types. These results suggest that the host's feeding habit can be one factor controlling the intestinal microbiota of fish in the natural environment.

The variation profile of intestinal microbiota in blunt snout bream (Megalobrama amblycephala) during feeding habit transition

“…However, few studies have reported the impact of dietary transition on the intestinal microbiota of teleost [38, 56]. This study presents a comprehensive survey of the gut microbiota in fish throughout the development of feeding habit, and it provides insight into the relationship among diet transition, digestive enzymes of gut content and intestinal microbiota for the first time.…”

Genetic difference but functional similarity among fish gut bacterial communities through molecular and biochemical fingerprints

“…As that fish may play a crucial role in aquatic ecosystem functioning (Vanni, 2002), more attention should be focused on their contribution to nutrient cycling and, in particular, the functional diversity of their gut bacterial communities should be estimated. Only one study has explored simultaneously the functional and genetic structure of fish intestinal bacterial communities and showed conflicting results between individuals (Uchii et al, 2006). Indeed, the literature provides contrasted results on the relationship between bacterial genetic and functional diversity: positive (de Lipthay et al, 2004;Leflaive et al, 2008), negative (Sala et al, 2005;Winter et al, 2005) or absent (Wertz et al, 2006).…”

“…Indeed, the literature provides contrasted results on the relationship between bacterial genetic and functional diversity: positive (de Lipthay et al, 2004;Leflaive et al, 2008), negative (Sala et al, 2005;Winter et al, 2005) or absent (Wertz et al, 2006). Using substrate metabolism, Uchii et al (2006) showed that the functional diversity of intestinal microbiota differs among fish of the same species (Lepomis macrochirus) inhabiting the same part of the natural environment, while the difference in carbon use is mainly related to feeding habits of host fish. Only one study has explored simultaneously the functional and genetic structure of fish intestinal bacterial communities and showed conflicting results between individuals (Uchii et al, 2006).…”

Trophic polymorphism in bluegill sunfish (Lepomis macrochirus) introduced into Lake Biwa: evidence from stable isotope analysis

“…The feeding types of the bluegill were classifi ed according to Uchii et al (2006). The stomach contents were sorted into fi ve prey items, i.e., benthic invertebrates, aquatic plants, zooplankton, terrestrial insects, and other, under a binocular microscope.…”