FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

This study focused on the effects of different kinds and concentrations of carotenoids in diet on the pigmentation of giant cichlid (Pentenia splendida). Experimental feeds were supplemented with two different kinds of carotenoids: zeaxanthin (hereafter referred to as Z) and astaxanthin (hereafter referred to as A). The experimental period lasted a total of 12 weeks. The fish used in the pigmentation experiment during the first 8 weeks were divided into seven groups: control, Z25, Z50, A25, A50, A75 and A100 (mg/kg diet) groups. For the dispigmentation experiment during the last 4 weeks, all of those groups were fed without adding carotenoids being added to the diet. The skin colors of the fish were measured with a tristimulus colorimeter, and further quantified for integument pigment. The experimental results indicated that the carotenoid supplements had no effects on growth and feed efficiency, but did improve pigmentation in this species. For the pigmentation experiment, the average color difference value (?E) varied from 8.4-10.1, while the content of carotenoids in integument varied from 4.9-12.3mg/100g tissue. For the dispigmentation experiment, the average color difference value (?E) varied from 8.5-11.2, while the content of carotenoids in integument varied from 2.8-8.4mg/100g tissue. After carotenoid supplementation was stopped, the content of carotenoids decreased about 25-32%. The effects of astaxanthin and zeaxanthin on the pigmentation level of this species were similar. The results indicated that 32.4-35.5mg/kg diet is the recommended dietary level of astaxanthin or zeaxanthin needed to ensure good pigmentation in the giant cichlid.