Respiratory biology study reveals zebrafish use taste buds to gauge oxygen levels in water

A recent study conducted at the University of Ottawa reveals that some fish use their taste buds to measure oxygen levels in the water.

Specifically, zebrafish larvae (a freshwater fish belonging to the minnow family) can taste oxygen levels in the water using the same cells they use to taste their food. These same cells also function as oxygen sensors, playing a crucial role in regulating the fish’s respiratory response to low-oxygen conditions.

This dual functionality of taste bud cells was previously unknown and challenges our current understanding of sensory systems in aquatic animals. The study, titled “Developing zebrafish use taste signaling pathways for oxygen chemoreception,” is published in the journal Current Biology.

“We have discovered a fascinating link between taste and respiration in fish,” says Steve Perry, professor emeritus in the Department of Biology at the University of Ottawa. “Our research provides the first direct evidence of oxygen-sensitive cells linked to the control of respiration in these animals and, surprisingly, these cells are located in their taste buds.”

To reach these conclusions, the research team used innovative techniques, including imaging of intracellular calcium in living fish.

“We observed that these sensory cells are activated by low oxygen levels, or hypoxia,” said Yihang Kevin Pan, a co-author of the study and a postdoctoral researcher in Perry’s lab. “When we removed these cells, it disrupted the fish’s breathing patterns under hypoxic conditions. Conversely, activating the nerves emanating from the taste buds stimulated breathing.”

This discovery has important implications for understanding how fish adapt to changing environmental conditions. It suggests that the ability to “taste” oxygen levels in water could be a crucial survival mechanism for aquatic organisms, allowing them to detect and respond quickly to potentially dangerous low-oxygen situations.

The research also highlights the remarkable adaptability of sensory systems in nature. “This is a great example of how the same biological structure can serve multiple functions,” Pan notes. “In this case, taste buds, in addition to their well-known function of detecting taste signals, also serve a vital respiratory function.”

In the face of increasing environmental challenges, including climate change-induced alterations of aquatic ecosystems, it is becoming increasingly crucial to understand how fish perceive and respond to changes in their environment. Beyond scientific understanding, this discovery could have practical implications for the protection and cultivation of aquatic life.