Effect of food addiction of lysine on feeding habit in fish

• Published in: Aquaculture 2025-04, Vol.599, p.742160, Article 742160
• Main Authors: Lu, Hong-Liang, Miao, Yun-Liang, Zou, Jia-Ming, Hu, Zi-Jun, Li, Ying-Cen, Liang, Xu-Fang, He, Shan
• Format: Article
• Language: English
• Subjects: Feeding habit; Fish; Food addiction; Glucose; Lysine
• ISSN: 0044-8486
• DOI: 10.1016/j.aquaculture.2025.742160

The current researches on food addiction focus on the diagnostic criteria, neurobiological theory, relationship of obesity and treatment. However, little is reported on the relationship between food addiction and feeding habit, especially in fish. In the present study, in vitro, the signaling pathway of food addiction of lysine and glucose in the brain cells of Chinese perch (Siniperca chuatsi) was determined. In vivo, the behavior experiment of food addiction was conducted on zebrafish (Danio rerio). In vitro, we found that lysine had a positive regulatory effect on food addiction signaling pathway and orexigenic factor Agrp expression, and the effect was suppressed with the inhibitors treatment of the signaling c-Fos/Mor/Drd1, whereas glucose exhibited a contrary trend. In vivo, the zebrafish were fed with the diets containing the normal lysine/carbohydrate level (Control Group1/2, CG1/2) or high lysine/carbohydrate level (Food Addiction Group1/2, FAG1/2) for 31 days during the food addiction formation. At Day 7, 12, 18, 23, 28 and 31, the food intake experiment showed that the FAG1 fish ingested the gelatin bait containing the high lysine diets more than the CG1 fish, and the increase trend was eliminated by the inhibitor of Mor (FAG1 + inhi). In the food selection experiment, the FAG1 fish preferred to ingest the gelatin bait containing the high lysine diets more than that containing the control diets, and the increase trend was eliminated in the FAG1 + inhi fish. Zebrafish existed the lysine addiction, which could modulate the food selection through the signaling pathway of food addiction and Agrp. Our data illustrated for the first time that food addiction to nutrients such as lysine exists in fish and that it is regulated by the food addiction signaling pathway c-Fos/Mor/Drd1/Agrp. •Effect of food addiction on feeding habit in fish is firstly discovered.•Lysine could cause the food addiction, but glucose could not.•Food addiction in fish is attributed to agrp transcription.•Mor/Drd1 or Drd2 signaling pathway is involved in food addiction of fish.