Ceramides cause rainbow trout to eat less

Sketch of a rainbow trout from Wikimedia Commons

Ceramides are a type of sphingolipid composed of both fatty acids and sphingosine that are important in maintaining the structure of cell membranes and cell signaling pathways. Given their structure, it is perhaps not surprising that levels of ceramide are increased in the brains of mammals after eating a diet high in fats as well as in individuals who are obese.  In mammals, ceramides are also known to help regulate food intake.

Since rainbow trout (Oncorhynchus mykiss) do not rely on glucose as heavily as proteins or fats for metabolism, researchers from the Universidade de Vigo were interested in determining whether ceramides alter food intake in rainbow trout  as this had reportedly never been studied before. They administered ceramide to the brains of rainbow trout and then recorded their food intake for the following 6, 24 and 48 hours. They found that ceramide actually reduced food intake in the fish and impaired the systems that are responsible for sensing fatty acids. This means that ceramide reduced food intake in trout through a mechanism that does not require detection of fatty acids. These findings were surprising because ceramide actually increases food intake in mammals. So alas, ceramides are not the next frontier for weight loss in mammals.

Source: 

Velasco C, Librán-Pérez M, Otero-Rodiño C, López-Patiño MA, Míguez JM, Soengas JL. Ceramides are involved in the regulation of food intake in rainbow trout (Oncorhynchus mykiss). American Journal of Physiology - Regulatory, Integrative and Comparative Physiology. In press. doi:10.1152/ajpregu.00201.2016