Obtaining healthy, safe and quality food is one of the main challenges of our society. Fish undoubtedly meets these requirements as evidenced by the increase in its demand which, due to the stagnation of extractive fishing, can only be met by aquaculture (FAO, 2014). The main cost of aquaculture is feed, so developing strategies that make it more efficient to minimize the economic and environmental cost (associated with uneaten food) is a priority field of research, within which understanding the mechanisms that regulate intake stands out. The control of food intake is a complex process resulting from the integration at a central level (in the brain) of different factors that include the fish’s ability to detect circulating nutrient levels and its energy status.
The research team of Fish Physiology and its application in aquaculture (FB2) of the University of Vigo was a pioneer and is an international reference in the characterization of nutrient sensor systems and their involvement in the control of food intake in fish as can be seen in the large number of research articles published on the subject in recent years (http://fisioloxiapeixes.webs.uvigo.es/es/publicaciones.html). Among the model fish on which they focus their studies, the rainbow trout stands out (Figure), although they also carry out studies with sole, turbot or zebrafish in the facilities of the Faculty of Biology and ECIMAT.
It has been shown in fish that high levels of macronutrients in the food such as proteins, lipids and carbohydrates inhibit intake while low levels of the same stimulate it. The FB2 group confirmed the presence of a glucosensor system based on glucokinase and described its mechanism of action, its modulation by different hormones and its interaction with stress. More recently, the group characterized the presence at the central level of alternative glucose sensors systems to the glucokinase-dependent one, which are based on the hepatic X receptor, the SGLT-1 transporter, mitochondrial activity and taste receptors never detected so far in a non-mammalian vertebrate. At the level of lipid metabolism, the FB2 group demonstrated the existence and functioning of fatty acid sensor mechanisms in trout, based on the FAT/CD36 transporter, CPT-1 activity and the K+ATP channel, as well as the activation of these sensors by some polyunsaturated fatty acids in sole. In contrast to what happens in mammals, researchers demonstrate that in fish medium-chain fatty acids participate in the metabolic control of intake.
The ongoing research of the FB2 group continues to provide evidence on the mechanisms involved in the regulation of food intake in fish. The growth of the aquaculture industry has been exponential in recent years and the future prospects are excellent. Studying what limits its development and providing solutions will make it possible to fulfill these predictions. Among these limitations, the optimization of feeding stands out. In this sense, the objective of the research of the FB2 group of the University of Vigo on the control of food intake in fish will allow optimizing the availability of food in relation to the needs of the fish at different times of its production cycle, minimizing losses and maximizing the use in the form of growth. The subsequent application of the knowledge obtained at a scientific level will result in a clear economic benefit for our society by being able to produce foods of high nutritional quality in a more efficient and sustainable way.
To learn more about the fish intake control system and the mechanisms of action of these glucose sensor systems, consult our blog: https://oceanoecimat.wordpress.com/2016/05/24/como-se-obtiene-y-procesa-la-informacion-metabolica-que-determina-que-el-pez-coma-o-no-coma/
