Glyphosate Herbicide Alters Brain Oxidative Stress and Metabolic Reserve in Pacú Fish

A 14-day laboratory exposure to a commercial glyphosate-based herbicide has altered key physiological markers in pacú (Piaractus mesopotamicus), an economically important South American fish, according to a study published in Archives of Environmental Contamination and Toxicology. Researchers tested two concentrations of Roundup Control Max® — 0.7 mg/L, described as environmentally relevant, and 7 mg/L — against an unexposed control group. The work focused on three biological fronts: aerobic metabolism, oxidative stress, and the fatty acid composition of the exposed animals.

The metabolic results were nuanced. Neither basal metabolism nor post-exercise metabolism showed significant variation between herbicide-exposed fish and controls. However, the delta between these two parameters — the difference that reflects an animal's metabolic scope, or its capacity to ramp up energy production under demand — did differ significantly among treatments.

This suggests that while the herbicide did not change resting energy expenditure or peak exertion levels on their own, it influenced the relationship between them, a parameter the authors describe as a key metabolic indicator. Oxidative stress told a clearer story. In the brains of exposed fish, markers of oxidative stress were elevated relative to controls, indicating that the herbicide formulation triggered damaging reactive processes in neural tissue within the two-week exposure window.

The liver, by contrast, showed no significant elevation in oxidative stress, pointing to a tissue-specific pattern of effect rather than a whole-body response. The third measured dimension — the fatty acid profile — showed no significant differences among exposed and control individuals. This matters beyond toxicology: pacú is a commercially relevant species, and the study also contributes to its biological and nutritional characterization.

The stability of lipid profiles under the tested conditions suggests that short-term herbicide exposure did not reshape the fish's lipid composition, though the authors note this does not rule out effects under longer or repeated exposures. The study's context is regional as well as experimental. The authors frame their findings as evidence of this specific formulation's influence on a key metabolic parameter and on oxidative stress in neural tissue, while cautioning that the observed effects were selective: metabolism shifted in its scope rather than its absolute levels, the liver was spared, and lipids were unchanged.

They recommend that further studies continue to evaluate the effects of chronic herbicide exposure on the aerobic metabolism of pacú and other species, since the present experiment covered 14 days and two concentrations, leaving longer-term and population-level consequences open questions.

Subject of Research: Effects of a glyphosate-based herbicide on aerobic metabolism, oxidative stress, and fatty acid profiles in pacú fish

Article Title: Does Exposure to Glyphosate-Based Herbicide Affect the Aerobic Metabolism, Oxidative Stress and Fatty Acid Profile of Pacú (Piaractus mesopotamicus)?

Article References: Bonifacio, A. F., Marón, C. F., Ballesteros, M. L., Labuckas, D., Labaque, M. C., Zambrano, M., Filippi, I., & Hued, A. C. (2026). Does Exposure to Glyphosate-Based Herbicide Affect the Aerobic Metabolism, Oxidative Stress and Fatty Acid Profile of Pacú (Piaractus mesopotamicus)?. Archives of Environmental Contamination and Toxicology, 91(3), Article 29. https://doi.org/10.1007/s00244-026-01228-y

Image Credits: AI Generated

DOI: 10.1007/s00244-026-01228-y

Keywords: glyphosate, Roundup, pacú, Piaractus mesopotamicus, aerobic metabolism, oxidative stress, fatty acid profile, aquatic toxicology, fish physiology, environmental contamination, Does, Exposure