Neural Melanocortin Receptors in Fish Offer Key Insights for Aquaculture Growth Regulation
Background
Optimizing feed conversion into healthy fish is critical for sustainable aquaculture, yet current growth enhancement relies on time-consuming selective breeding. A deeper understanding of hormonal control over energy metabolism is needed to develop innovative approaches. The melanocortin system, with its five receptors (MC1R to MC5R) and six ligands, is a key regulator of energy homeostasis, food intake, and body weight in vertebrates, making it a prime target for improving growth and feed efficiency in aquatic animals.
Study Design
This review synthesizes current knowledge on the melanocortin system in fish, focusing on the five MC1R to MC5R receptors and their six endogenous ligands, including agonists like α-MSH and antagonists like AgRP. The authors explore the system's role in energy homeostasis, food intake, and body weight regulation in aquatic animals, highlighting its potential for improving aquaculture practices. The paper aims to provide a comprehensive understanding of hormonal control over metabolism in commercially significant species, contrasting it with traditional breeding methods.
Results
The melanocortin system, comprising five receptors (MC1R to MC5R) and six ligands, is crucial for energy homeostasis in vertebrates, including fish. Agonists like α-MSH, β-MSH, γ-MSH, and ACTH are derived from tissue-specific post-translational cleavage of proopiomelanocortin (POMC). The system uniquely features two endogenous antagonists, AgRP and ASIP (agouti-signaling protein), which were long considered the only known GPCR antagonists until LEAP2 for the ghrelin receptor was identified. > MC1R is highly expressed in skin and hair follicles, regulating pigmentation, while MC2R is predominantly found in the adrenal cortex, controlling adrenal function. The review emphasizes the hypothalamic POMC/α-MSH neurons' role in food intake and body weight regulation, underscoring the system's broad influence on metabolic processes relevant to growth in aquatic species.
Key Findings
- The melanocortin system, with
MC1RtoMC5Rand six ligands, is central to energy homeostasis in fish. - Agonists like
α-MSHand antagonists likeAgRPregulate food intake and body weight. MC1Rcontrols pigmentation, whileMC2Rregulates adrenal function.- Hypothalamic
POMC/α-MSHneurons are key for food intake and body weight regulation. - Modulating melanocortin receptors holds potential for improving aquaculture growth and feed efficiency.
Why It Matters
Understanding the melanocortin system in fish offers a powerful alternative to traditional selective breeding for enhancing aquaculture productivity. Targeting these neural receptors could lead to novel strategies for improving growth rates and feed efficiency in farmed fish, directly impacting economic returns and the sustainability of the industry. This knowledge could inform the development of feed additives or genetic interventions that modulate melanocortin receptor activity, leading to faster-growing, healthier fish. The insights pave the way for more efficient resource utilization and higher-quality food production, moving beyond slow, conventional methods.
melanocortin-receptors
fish
aquaculture
growth-regulation
energy-homeostasis
food-intake