Microplastic ingestion affects the lateralised processing of predator stimuli in fish

Area of Science:

• Environmental toxicology
• Neuroscience
• Animal behaviour

Background:

• Microplastic pollution is a growing environmental concern.
• Previous research indicates microplastics affect fish at the molecular level.
• The impact of microplastics on fish cognitive phenotypes is not well understood.

Purpose of the Study:

• To investigate the effects of microplastic ingestion on the cognitive phenotype of zebrafish (Danio rerio).
• To assess if microplastics alter brain lateralisation, a measure of information processing.
• To determine the phenotypic consequences of microplastic exposure in fish.

Main Methods:

• Zebrafish were fed diets containing polyethylene or poly(butylene-adipate-co-terephthalate) microplastics for 20 days.
• Cognitive function was assessed using behavioural tests, including rotational, mirror, and detour tests.
• Lateralisation, reflecting brain hemisphere specialisation, was evaluated in response to a predator model.

Main Results:

• No significant changes in rotational or mirror test performance were observed.
• Microplastic ingestion led to disrupted lateralisation in the detour test when zebrafish encountered a predator model.
• These findings indicate a specific impairment of cognitive traits at the phenotypic level.

Conclusions:

• Microplastic ingestion can negatively impact specific cognitive abilities in fish.
• The disruption of lateralisation suggests potential consequences for predator avoidance and survival.
• This study highlights the phenotypic effects of microplastics on fish cognition, extending beyond molecular changes.