Effects of background adaptation on the skin color of Malaysian red tilapia

Abstract The effects of changes in background color, between white and black, on the apparent body color, the skin L*, a* and b* values, the MSH levels in the serum and the melanin-concentrating hormone (mch), proopiomelanocortin (pomc), melanocortin 1 receptor (mc1r) and tyrosinase (tyr) gene mRNA expressions of Malaysia red tilapia were investigated. After rearing in black (B) or white (W) background tanks for 27 days, the rest fishes were transferred to the same (WW and BB) or opposite (WB and BW) background tanks for another 27 days. The apparent body color of fish was paler in white background and darker in black background, and the body color was reversibly variable in response to transfer to the opposite background color. Correspondingly, the L* and b* values were higher and a* values were lower in white background groups than that in black background groups in the skin of fish (P   .05) and peaked in WW group (P   .05). However, BB fish showed significantly higher skin mc1r mRNA expressions than WW and BW fish (P