Vitamin D modulates gene expression in four major muscle tissues in Atlantic salmon

Vitamin D is essential to muscle health but could affect different muscle tissues in distinct ways. In humans, vitamin D is primarily synthesized in the skin via sun exposure but can also be obtained through ingesting foods that are fortified (e.g., milk) or naturally high in vitamin D (e.g., salmon). Like humans, salmon vitamin D content can vary considerably and can be altered through dietary consumption of vitamin D. We experimentally determined how vitamin D manipulation alters gene expression in four salmon muscle tissues: skeletal, craniofacial, smooth, and cardiac. Vitamin D induced changes in expression were exceptionally profound in the heart, where there were also several gene duplicates expressed unidirectionally. Five genes were differentially expressed in multiple muscles and many genes impacted by our vitamin D treatments in salmon show extensive evolutionary conservation as they are influenced by vitamin D titers in mammals, including humans. Salmon could provide a powerful model for understanding how variation in vitamin D impacts all vertebrates.