Effect of dietary components on the gut microbiota of aquatic animals. A never‐ending story?

Abstract

It is well known that healthy gut microbiota is essential to\npromote host health and well-being. The intestinal microbiota of endothermic animals as well as fish are classified as\nautochthonous or indigenous, when they are able to colonize\nthe host’s epithelial surface or are associated with the microvilli, or as allochthonous or transient (associated with digesta\nor are present in the lumen). Furthermore, the gut microbiota of aquatic animals is more fluidic than that of terrestrial vertebrates and is highly sensitive to dietary changes. In\nfish, it is demonstrated that [a] dietary form (live feeds or pelleted diets), [b] dietary lipid (lipid levels, lipid sources and\npolyunsaturated fatty acids), [c] protein sources (soybean\nmeal, krill meal and other meal products), [d] functional glycomic ingredients (chitin and cellulose), [e] nutraceuticals\n(probiotics, prebiotics, synbiotics and immunostimulants), [f]\nantibiotics, [g] dietary iron and [h] chromic oxide affect the\ngut microbiota. Furthermore, some information is available\non bacterial colonization of the gut enterocyte surface as a\nresult of dietary manipulation which indicates that changes\nin indigenous microbial populations may have repercussion\non secondary host–microbe interactions. The effect of dietary components on the gut microbiota is important to investigate, as the gastrointestinal tract has been suggested as one\nof the major routes of infection in fish. Possible interactions\nbetween dietary components and the protective microbiota\ncolonizing the digestive tract are discussed.