| Summary: | 碩士 === 國立臺灣大學 === 漁業科學研究所 === 100 === This study focused on the different kinds and concentrations of carotenoid in diet, for effects of pigmentaion of giant cichlid (Pentenia splendida), assessment of pigment metabolism, and raise fish pigmentaion in the suitable amount. Experimental feeds are supplemented with two kinds of different carotenoid: zeaxanthin (hereinafter referred to as Z), astaxanthin (hereinafter referred to as A). The experiment period was total 12 weeks. In the pigmentaion experiments for the first 8 weeks, were divided into seven groups: control, Z25, Z50, A25, A50, A75 and A100 (mg/kg diet). In the dispigmentaion experiments for the last 4 weeks, all the groups were fed not add carotenoids diet. Fish skin were tested with tristimulus colorimeter, and further quantified for integument pigment.
The experimental results indicate that the carotenoids have no effects on growth and feed efficiency, but improve pigmentation in the giant cichlid. In the pigmentaion experiments, 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/100 g. In the dispigmentaion experiments, 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/100 g. Although the results of the experimental group by the color difference is able to maintain with control group differences, but by the decreased content of carotenoids shows that indeed fading phenomenon fell by an average rate of about 25-32%. The ability is similar in zeaxanthin and astaxanthin to affect the pigmentation in this species. The results indicate that 32.4-35.5mg/kg is a recommended dietary level of zeaxanthin or astaxanthin to ensure good pigmentation in the giant cichlid.
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