Abstract: This experiment was conducted to study the effects of lutein and lutein ester on the growth and body color of Koi, Yamabaki ogon. 200 mg/kg lutein and lutein ester were supplemented to the basal diet, and 270 golden Koi with an average weight of 26.03±0.07 g were divided into three groups. Each group had three replicates. There were 30 fish in each tank. The culture experiment lasted for 42 d. The results showed that the addition of lutein and lutein ester had no significant effect on the growth of fish compared with the control group（P>0.05）, but the addition of lutein ester significantly improved the body indexes（body length/body height）of Koi（P<0.05）. After adding lutein, the body moisture content of fish decreased significantly, but the lipid content was significantly higher than that of the control group（P<0.05）. There was no significant difference in protein content among the treatment groups. The addition of lutein and lutein ester had no significant effect on the redness（a *）and brightness （L *）of Koi（P>0.05）, but significantly improved the yellowness（b *）, the yellowness of each group increased gradually with the extension of the experiment period（P<0.05）. Generally, after adding lutein and lutein ester for 14 d, the yellowness value of fish could reach a similar effect as that of 42 d. Compared to the lutein, lutein ester had a faster and more significant coloring effect on golden koi.

Key words: lutein, lutein esters, Koi, Yamabaki ogon, growth, body color