Dietary responses of taste receptor genes to plant-based diets in farmed fish: A literature review.

Taste receptor genes, particularly those in the bitter (tas2r) and umami/sweet (tas1r) families, are critical in regulating chemosensory perception and feeding behavior, influencing fish's acceptance of plant-based diets. This review synthesizes the current research on how these genes respond to plant-based diets in farmed fish. A comprehensive search of scientific databases, including Web of Science, Scopus, PubMed, and Google Scholar, was conducted to identify relevant studies. Plant-based diets modulate gene expression, receptor activity, and signaling pathways, enabling fish to adapt to alternative feeds. The findings of the studies analyzed in this review show that plant ingredients affect fish taste receptor genes by changing gene expression, receptor activity, and signaling pathways, helping fish adapt to different feeds. Oral receptors detect feed palatability, which affects feed intake, growth, and health, whereas extraoral receptors in the gut, brain, and liver sense nutrients, regulate metabolism, and control appetite. Bitter receptors can detect antinutritional factors and trigger hormone responses that reduce feed intake, whereas umami receptors promote feeding through nutrient-related reward pathways. Functional assays, dose-response studies, and gene expression mapping are essential for identifying receptors that affect the acceptance of plant-based diets. Integrating taste receptor gene knowledge into selective breeding programs may increase feed intake, digestion, and nutrient utilization, thereby supporting sustainable aquaculture. Future research should investigate the relationships between taste receptor expression and behavior and physiology through dietary, genetic, and neurophysiological studies to clarify how interactions between diet, genetics, and neural responses influence feeding, growth, and adaptation to plant-based feeds.