Social effects on AVT and CRF systems.

Area of Science:

• Aquatic animal science
• Neuroendocrinology
• Fish behavior

Background:

• Stress and aggression negatively impact fish welfare and aquaculture productivity.
• Arginine-vasotocin (AVT) and corticotropin-releasing factor (CRF) are key neuropeptides regulating stress and aggression.

Purpose of the Study:

• To investigate the effects of social interactions on AVT, CRF, and their receptor gene expression in juvenile rainbow trout (Oncorhynchus mykiss).
• To understand the neuroendocrine mechanisms underlying stress and aggression in farmed fish.

Main Methods:

• Induction of agonistic interactions to establish dominant-subordinate relationships in juvenile rainbow trout.
• Measurement of gene expression for AVT, CRF, and their receptors.
• Quantification of plasma cortisol levels.

Main Results:

• Dominant fish displayed more aggressive behavior and increased feeding.
• Subordinate fish showed significant upregulation of the AVT receptor (AVT-R) and CRF mRNA levels.
• Subordinate fish exhibited elevated plasma cortisol levels.

Conclusions:

• Social hierarchy influences neuroendocrine pathways related to stress and aggression in rainbow trout.
• The AVT system, potentially via AVT-R, and the CRF system may mediate the attenuation of aggression in fish.
• Findings provide insights into managing stress and aggression for improved fish welfare in aquaculture.