Body color is a prominent phenotypic trait and a significant economic characteristic in fish. While current research mainly examines the effects of genetic factors, less emphasis has been placed on the role of endogenous hormones in fish body color.
In this study, we investigated the changes in phenotype and pigment content in juvenile
Compared to the control group, the body color of the low-concentration L-thyroxine treatment group (20 nM) was lighter, while that of the high-concentration group (40 nM and 80 nM) was darker. Thyroid hormone treatment simultaneously affected melanophores, xanthophores, and iridophores in different ways, leading to an increase of melanin and guanine, and a reduction of pteridine and β-carotene. These findings suggest that thyroid hormone regulates fish body color pigment synthesis through both melanin-based and non-melanin-based mechanisms. Additionally, expression of genes involved in melanin-based (e.g.
Our results enhanced the understanding of the role of thyroid hormone in fish pigmentation and provide useful information for cultivating fish with desirable body colors in aquaculture.