Cellular Transport and Metabolism of Nutrients, Natural Toxins, Pollutants, and Drugs in the Digestive System of Fish and Aquatic Invertebrates

In addition to absorbing nutrients, the intestine is the main (and in some cases, the only) entry path for xenobiotics, including natural toxins, pollutants, and drugs. In particular, xenobiotics enter the enterocytes through various transporters, such as bile salt or nutrient transporters, and are subsequently metabolized and excreted. In addition to direct entry into the intestine, xenobiotics can be transported from other organs to the liver for metabolization and/or excretion in the bile to the gastrointestinal tract during digestion. Thus, the detoxifying functions of the intestine and liver are intimately tied to the organism’s nutrition physiology. Uniquely, aquatic organisms are exposed to water borne substances, however, the underlying transport and metabolization processes are largely unknown. Comparative information on this subject is critical for understanding the ecophysiology of aquatic organisms and the ecotoxicological consequences of water quality, as well as for directing studies to improve nutrition in aquaculture.

In this Research Topic, we aim to gather comparative information and to build an integrative view of the cellular transport and metabolization of nutrients, metabolites and xenobiotics, as well as the regulation of these functions, in the digestive systems of aquatic organisms. This physiological view includes ecotoxicological and fishery perspectives, for conservation, aquaculture, and environmental applications. Further, while this collection will provide a unique perspective on the challenges faced by fish and aquatic invertebrates, by exploring the physiology of these organisms we can ultimately offer comparisons and insights for human physiology. Hence the goal of this Research Topic is to provide a breadth of knowledge on the handling of nutrients, natural toxins, pollutants, and drugs in fish and invertebrates for ecological, toxicological, and conservation applications. This knowledge can be used in a variety of industries, from aquaculture to medicine.

We welcome studies about the function and regulation of membrane transporters, metabolic pathways related to biotransformation of physiological substrates and xenobiotics, intracellular effects of xenobiotics and nutrients, and detection of and cellular response to substances (both nutrient and toxic) in the digestive system of aquatic vertebrates and invertebrates. As an integrative topic, this call will consider studies spanning histological, immunohistochemical, molecular, and biochemical approaches along with any other approach that contributes to the knowledge of the digestive physiology of aquatic animals.