Effect of Dietary Carotenoids, Body Color, and Illumination Variety on Growth, Pigmentation, Tail Wound Healing, and Mate Selection of Guppy Poecilia reticulate

• Main Authors: Chong-Jing Huang, 黃重景
• Other Authors: Yew-Hu Chien
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/76469496531840988064

碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 96 === Color and integrity of tail fin of guppy (Poecilia reticulate) affects not only its market price but also mate selection and breeding within a population. Two experiments were therefore conducted: I. Effects of dietary carotenoids on pigmentation, wound healing and growth of tail fin of male guppy and II. Effects of illumination color and timing on guppy’s mate selection. Experiment I was to find out the effects of 4 diets supplemented with 200 mg/kg carotenoids (astaxanthin, β-carotene, lutein, or zeaxanthin) and a control diet on pigmentation, wound healing and growth of tail fin of male guppy of 3 tail colors (red, yellow, and blue) combined with 2 tail status (sheared and intact). The results indicated that fish fed diets supplemented with carotenoids had better growth, wound healing and feed conversion than control fish. The pigmentation effects of dietary carotenoids varied with fish with different tail colors. Astaxanthin effectively enhanced pigmentation of red color and β-carotene on yellow. Tail shearing resulted in reduction of redness, yellowness, and chroma but increase of lightness. Dietary carotenoids level at 200 mg/kg and 4 weeks’ feeding were not sufficient to increase fish color. Morphological parameters of the regenerate chromatophores post shearing were not affected by any treatment. Dietary lutein and β-carotene had no contribution to blue body color, which maybe affected by phycobiliprotein and structure of iridophores, remaining to be studied. Since female guppy may have mating preference towards different color male, Experiment II was conducted to observe the frequency of female guppy attracted by males of 4 tail colors (red, yellow, blue, and black) under 3 florence light colors (red, white, and blue) at 3 durations of illumination (dawn, noon, and dusk). Only cultured single and pure color males were used. The attraction frequency was determined by the ratio of the number of female guppy entered the trap accommodated with certain color male to the total number of female turned loose. The females were turned loose either individually or by batch of total 10 fish. The results showed females’ preferences towards male color were red tail 48%, yellow tail 31%, blue tail 10%, black tail 6%, and undetermined 5%. Disregard fluorescent light color, red-tail male had higher chance being chosen at noon than at dawn and dusk. However, under white fluorescent light, there was no difference in frequency among 3 durations when red-tail male was chosen. Among 3 fluorescent light colors, red-tail male had the highest frequency being chosen under white fluorescent light. There was no difference in frequency of being chosen for yellow-tail male under 3 fluorescent light colors. Blue-tail male had the highest chosen frequency under blue fluorescent light. The frequency of black-tail being chosen was not affected by fluorescent light color. Female could not make decision the most under red fluorescent light. The frequency that female did not make choice was higher when they had been turned loose individually than by batch. Since it has been showed in this study that mate selection was affected by male tail color, illumination color and duration, and making decision by individual self or by group, which can be applied to breeding technology to promote natural mating frequency to acquire desired breeding by environment manipulation.