Fish can detect flavors in the gut

A Spanish team of researchers describes for the first time the development of the taste system of seabream from its embryonic development to adulthood.

September 13, 2022

A Spanish research team found that fish also detect flavors in their gut. The study characterizes a system of taste receptors in seabream (Sparus aurata) from the beginning of its embryonic development to adulthood, proving that these receptors could regulate intestinal physiology as occurs in mammals. The discovery opens the door to the design of specific compounds based on the taste properties of the species to stimulate their intake and improve digestive processes.

Taste detection is carried out thanks to the presence in the oral cavity of specific receptors that detect nutritional or non-nutritional components of food. There are five tastes: sweet, salty, sour, bitter and umami, and each taste is detected by a type of receptor. The IATS-CSIC Fish Intake Control group led by José Miguel Cerdá Reverter has studied the T1R family of receptors, responsible for detecting sweet flavors (sugars and sweeteners) and umami (protein), throughout the development of sea​bream.

The results of the research are the most complete to date on the development of taste in fish, researchers said. “We show for the first time that the receptors responsible for detecting taste information originally appear in the digestive tract before in the oral cavity,” explained Cerdá. The expression of the family of T1R receptors in the oral tract starts with the opening of the mouth when seabream begins exogenous feeding.

“When they are adults, we found that these receptors are also expressed in enteroendocrine cells, that is, those responsible for hormone secretion from the gastrointestinal tract. This means that, in some way, flavors control the intestinal physiology and the hormonal secretion of the gastrointestinal tract in a process called ‘gutsensing’, something that has been proven in mammals and that we have demonstrated for the first time in fish,” Cerdá explained.

For Cerdá, this implies that, like us, fish could also detect flavors in the intestine and communicate the information either through nerve impulses from peripheral nerves or to the modulation of the synthesis and secretion of hormones. Trials on seabream showed that, indeed, these taste receptors of the T1R family are capable of modulating the secretion of hormones to improve digestive processes and the absorption of nutrients, as well as informing the brain to act accordingly, reducing or increasing intake or promoting behaviors aimed at increasing the selective intake of nutrients.

According to the researchers, knowing how farmed species, such as seabream, manage flavors, as well as the effects they have on their taste receptors, will make it possible to design specific compounds based on the taste properties of each species to stimulate their intake and improve the digestive processes by increasing nutrient absorption and feed efficiency.

The experiments have been developed and financed in collaboration with LUCTA.

Check out the study here.