Dietary-induced changes in the hindgut microbiome and metabolism of a marine herbivorous fish

Abstract

To advance our understanding of the factors that influence gut physiology and function, we are examining how the gut microbiome changes under varying environments and diets. We integrated the gut transcriptome and microbiome to understand how dietary changes impact Cebidichthys violaceus, an herbivorous fish native to the California coast that is known to have an active microbial community in its hindgut. Wild-caught fish from San Simeon, California were fed either herbivore, omnivore, or carnivore diets in the laboratory for six months. We expected the microbiome, as well as the hindgut and liver transcriptome, to change with dietary perturbations, with wild herbivorous fish being most similar to lab-herbivore fish. Wild fish microbial communities were indeed different from laboratory-fed fish (P<0.001, Bray-Curtis distances), but the laboratory-omnivore diet fish were the most similar to wild fish, sharing a high abundance of taxa in the Bacteroidota and Bacillota (Families Ruminococcaceae and Rikenellaceae), whereas the laboratory-herbivore and laboratory-carnivore fish shared a high abundance of taxa from the Pseudomonodota (Families Burkholderiaceae and Oxalobacteraceae). The microbial diversity patterns in multivariate space among the fish on the different diets directly resembled that of host distal intestine gene expression in multivariate space (i.e., wild and lab-omnivore diet fish were the most similar). The hindgut had 519 differentially expressed genes, and wild fish highly express genes involved in ion transport and lipid and glucose metabolism. The liver, on the other hand, presented 4650 differentially expressed genes, and wild fish highly express genes for fatty acid synthesis and proteolysis. These data show how the gut microbiome and transcriptome varies as a function of different diets in an herbivorous marine fish. Our project provides insight into what it takes for fish to deal with shifting resources, which is important for marine resource management and new potential aquaculture species development. NSF Grant IOS-1355224 and William Townsend Porter Pre-doctoral Fellowship from the American Physiological Society. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.