Role of gastrointestinal microbiota in fish

Abstract

The gastrointestinal (GI) tract of an animal consists of a very complex and dynamic microbial ecosystem that is very important from a nutritional, physiological and pathological point of view. A wide range of microbes derived from the surrounding aquatic environment, soil/sediment and feed are found to colonize in the GI tract of fish. Among the microbial groups, bacteria (aerobic, facultative anaerobic and obligate aneraobic forms) are the principal colonizers in the GI tract of fish, and in some fish, yeasts are also reported. The common bacterial colonizers in the GI tract of freshwater and marine fish include Vibrio, Aeromonas, Flavobacterium, Plesiomonas, Pseudomonas, Enterobacteriaceae, Micrococcus, Acinetobacter, Clostridium, Fusarium and Bacteroides, which may vary from species to species as well as environmental conditions. Besides, several unknown bacteria belonging to Mycoplasma, Arthrobacter, Brochothrix, Jeotgailbacillus, Ochrobactrum, Psychrobacter and Sejongia species in the GI tract of different fish species have now been identified successfully using culture‐independent techniques. Gnotobiotic and conventional studies indicate the involvement of GI microbiota in fish nutrition, epithelial development, immunity as well as disease outbreak. This review also highlights the need for manipulating the gut microbiota with useful beneficial microbes through probiotic, prebiotic and synbiotic concepts for better fish health management.

Diversity of autochthonous bacterial communities in the intestinal mucosa of grass carp (Ctenopharyngodon idellus) (Valenciennes) determined by culture-dependent and culture-independent techniques

“…One goal of long-term efforts to promote and sustain the health of aquaculture fish is to develop effective strategies for manipulating gut microbial communities (Nayak 2010). To achieve this goal, we must first understand gut microbial composition, especially the mucosal microbiota in freshwater fish.…”

“…The identification and comparison of the mucosa-associated autochthonous microbiota is undoubtedly significant for understanding functional mechanisms between the microbes and host (G omez & Balc azar 2008). An in-depth study of autochthonous bacteria may help to develop new aquaculture probiotics (Nayak 2010).…”

Gut content microbiota of introduced bigheaded carps ( Hypophthalmichthys spp.) inhabiting the largest shallow lake in Central Europe

“…During the past three decades, an increasing attention was paid to studying the versatile role of microbes in the nutrition of fishes Nayak, 2010;Ray et al, 2012;Ghanbari et al, 2015). Microorganisms may contribute to fish nutrition either directly as part of the ingested and digested food Matĕna et al, 1995;Kamjunke and Mehner, 2001) or indirectly by colonizing their digestive tracts and participating in digestion processes, influencing absorption and synthesis of important nutrients (Ray et al, 2012;Li et al, 2013;Clements et al, 2014).…”

Characterization of bacterial community in the stomach of yellow catfish (Pelteobagrus fulvidraco)

“…The gastrointestinal (GI) tract of fish consists of a very complex microbial ecosystem that plays important roles in host immunity and nutrition (Nayak 2010). Investigation on GI microbiota of fish may reveal potential probiotics and pathogenic bacteria, and elucidate the characterization of microbiota of digestive tract, which are useful in manipulation of GI microbiota (Verschuere et al 2000;Ringø et al 2003).…”