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Researchers developed a new method called the Complete-or-Partial (CoP) assay to quantitatively measure food intake in planarian flatworms by evaluating whether individual animals completely or partially consume offered food volumes. Using this assay, they demonstrated that planarians adjust their consumption based on food quality, eating more of high-density liver homogenate compared to a minimal basal diet, and that animals showing partial consumption had reached satiety and would not immediately feed again. The method provides a robust, scalable tool for studying neural regulation of feeding behavior in this model organism.
Why it matters
This standardized quantitative feeding assay addresses a significant methodological gap in planarian research and could accelerate molecular studies of appetite regulation and satiety mechanisms. Since planarians are increasingly used as models for neurobehavioral research due to their regenerative abilities and relatively simple nervous systems, improved feeding assays may help identify conserved neural circuits controlling food intake across species.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Planarians exhibit a variety of behaviors in response to external stimuli and have emerged as a promising animal model for studying the neural regulation of behavior. Although their feeding behavior has been well documented, robust experimental methods for quantifying their food intake remain limited. In this study, we developed a novel methodology for the quantitative assessment of feeding termed the Complete-or-Partial (CoP) assay. This assay evaluates feeding responses as a binary outcome (complete consumption versus partial ingestion) in a volume-dependent manner at the individual level. Using this method, we examined the effects of food quality on feeding responses by comparing two distinct diets: a basal diet containing the minimum concentration of liver homogenate necessary to induce ingestion and support growth, and a high-density diet with a ten-fold higher concentration. The CoP assay enabled the robust estimation of food intake volume and successfully detected a significant overconsumption of the high-density diet compared to the basal diet, demonstrating that planarians regulate their food intake in a quality-dependent manner. Furthermore, individuals exhibiting partial ingestion did not immediately feed again even when presented with the same diet freshly prepared, indicating that they had reached satiety. Thus, we propose that the CoP assay offers a robust and scalable platform for evaluating both food intake volume and satiety status, providing a powerful tool to facilitate future molecular analyses of feeding regulation in planarians.