Microplastics Change the Food Utilization of Filter-Feeding Fish via Gut Microbiota

Area of Science:

• Environmental Science
• Aquatic Ecology
• Microbiome Research

Background:

• Microplastics (MPs) are widespread pollutants in aquatic environments.
• The impact of MPs on the feeding behavior of filter-feeding fish remains largely unknown.
• Silver carp, a planktivorous fish, are a key species in many aquatic food webs.

Purpose of the Study:

• To investigate how microplastic exposure affects the feeding efficiency of silver carp.
• To understand the role of gut microbiota in mediating these effects.
• To assess the ecological implications for aquatic ecosystems.

Main Methods:

• Silver carp were exposed to microplastics.
• Feeding efficiency, gut microbiota composition (gene abundance), and gut metabolomics were analyzed.
• Germ-free zebrafish and silver carp were used for fecal microbiota transplantation experiments.

Main Results:

• Microplastic exposure increased zooplankton utilization efficiency (28.45% to 38.63-40.20%) and decreased phytoplankton utilization efficiency (50.64% to 40.47-43.32%).
• Microplastics altered gut microbiota, increasing protease gene abundance and decreasing carbohydrase gene abundance.
• Metabolomic analysis revealed changes in amino acids and organic acids, linked to gut microbiota function and fish diet.

Conclusions:

• Microplastics significantly alter the feeding strategy of silver carp by modulating their gut microbiota.
• Gut microbiota plays a crucial role in mediating the effects of microplastics on fish food utilization.
• These findings highlight the ecological risks of microplastics to planktivorous fish and potential cascading effects in aquatic ecosystems.