Developmental temperature has persistent, sexually dimorphic effects on zebrafish cardiac anatomy.

Area of Science:

• Environmental Science
• Developmental Biology
• Cardiovascular Physiology

Background:

• Anthropogenic climate change poses a significant threat to global biodiversity.
• Early-life environmental conditions can have long-lasting effects on organismal physiology and performance.
• Understanding the impact of temperature on aquatic species is crucial for predicting responses to climate change.

Purpose of the Study:

• To investigate the long-term effects of developmental temperature on zebrafish cardiac anatomy and aerobic exercise performance.
• To determine if thermal imprinting during early development influences cardiovascular structure and function later in life.
• To explore the molecular underpinnings of temperature-induced cardiac modifications.

Main Methods:

• Zebrafish embryos were exposed to three different developmental temperatures (24°C, 28°C, 32°C) until metamorphosis.
• Post-metamorphosis, all fish were maintained under common conditions (28°C) to adulthood.
• Cardiac anatomy was assessed, and aerobic exercise performance was measured in adult fish.
• Gene expression analysis of cardiac-related genes (nppa, myh7, mybpc3) was performed.

Main Results:

• Developmental temperature significantly affected cardiac anatomy, with increased ventricle roundness observed in juveniles and adult males exposed to higher temperatures.
• Aerobic exercise performance in adult zebrafish decreased significantly with increasing developmental temperature.
• Gene expression analysis revealed significant upregulation of nppa, myh7, and mybpc3 at colder developmental temperatures.
• These cardiac and performance alterations persisted for at least eight months after the thermal treatments concluded.

Conclusions:

• Developmental temperature has a direct and lasting impact on zebrafish cardiac form and function.
• Elevated developmental temperatures can impair cardiovascular performance in adult zebrafish.
• Findings highlight the potential consequences of rising global temperatures on fish populations and their ecological roles.