飼料中添加不同類胡蘿蔔素對橙色恆河毛足鱸增豔效果之影響

Abstract

本實驗主要探討在飼料中添加不同種類與濃度的類胡蘿蔔素(Carotenoid)對於橙色品系恆河毛足鱸(Trichogaster chuna)體表呈色之影響，及找出提升魚體呈色的最佳建議添加量，並推測其對於類胡蘿蔔素的代謝與蓄積方式。實驗進行9週，前3週餵食不含類胡蘿蔔素之飼料對魚隻進行馴養以及退色，後6週為呈色實驗，並在飼料中添加玉米黃素(Zeaxanthin，以下簡稱Z)、游離型蝦紅素(Astaxanthin-free，以下簡稱A)和酯化型蝦紅素(Astaxanthin-ester，以下簡稱E) ，共分為10組:0(Control)、Z25、Z50、Z75，A25、A50、A75，E25、E50、E75(mg/kg diet)。在投餵類胡蘿蔔素飼料前，以及開始餵食色素飼料的第0、2、4、6週分別測量各組的增重百分比(Weight gain %)、飼料效率(Feed efficiency %)並在相同條件下對魚體的呈色進行量化，測定呈色變化，並計算色差值(△E)。 本實驗結果指出在恆河毛足鱸的飼料中添加類胡蘿蔔素對於增重率及飼料效率無顯著差異。飼養6週後萃取飼料中添加的玉米黃素殘存比例約為82%，游離型蝦紅素殘存比例約為57%，而酯化型蝦紅素的殘存比例約為75%，酯化型蝦紅素較游離型蝦紅素有更佳的保存效果。而萃取魚皮中含類胡蘿蔔素含量，玉米黃素組類胡蘿蔔素含量範圍在5.86-7.11 mg/100g；游離型蝦紅素組含量範圍在5.07-7.76 mg/100g；而酯化型蝦紅素組含量範圍在6.96-7.94 mg/100g，並以酯化型蝦紅素E75為最高含量，有最多的蓄積含量。且添加不同的類胡蘿蔔素，魚皮中含類胡蘿蔔素的量皆隨著飼料中添加的量而上升。色差值(△E)表現上，腹鰭部位的色差值，在添加色素的組別當中，色差值皆大於6，達肉眼辨識標準。在腹部部位，只有添加玉米黃素及蝦紅素組別中的E75組達到肉眼辨識標準。鰓蓋部位僅有玉米黃素組達到肉眼辨識標準。依據魚皮中類胡蘿蔔素蓄積含量與色差值的表現，玉米黃素對於恆河毛足鱸比蝦紅素有更高蓄積能力及魚皮呈色表現，而酯化型蝦紅素又較游離型蝦紅素有更高的蓄積量。因此建議恆河毛足鱸以添加75mg/kg含量的玉米黃素可增加魚體呈色能力，游離型蝦紅素為75mg/kg，酯化型蝦紅素為50mg/kg。

This study focused on the different kinds and concentrations of carotenoids in diet for effects of pigmentation of Trichogaster chuna var. orange, to find out the optimal amount to enhance the skin color, and speculated that the carotenoids for the metabolism and accumulation. The experiment was conducted for 9 weeks. The first 3 weeks of feeding without carotenoids feed on the domestication of fish and fade. After 6 weeks of coloring experiments, and add zeaxanthin (Z), free-type astaxanthin (A), and ester-type astaxanthin (E) in the diet. The experiments divided into 10 groups: 0(Control)、Z25、Z50、Z75，A25、A50、A75，E25、E50、E75 (mg/kg diet). Before feeding the carotenoids diet, the percent weight gain and feed efficiency of each group was measured at weeks 0, 2, 4, and 6, respectively. The color of the fish body was quantified under the same condition, the color change was measured with color difference (△E). The results of this study indicate that the addition of carotenoids to the diet of the Trichogaster chuna var. orange was not significantly different for the percentage of weight gain and feed efficiency. The residual ratio of zeaxanthin was about 82% in the diets, about 57% in the free-type astaxanthin, and about 75% in the ester-type astaxanthin. The ester-type astaxanthin has a better preservation effect than the free-type astaxanthin. The content of carotenoids in the extracted fish skin and carotenoid content in the zeaxanthin group ranged from 5.86-7.11 mg / 100g. The content of free -type astaxanthin group ranged from 5.07-7.76 mg / 100g, while the content of ester-type astaxanthin group ranged from 6.96-7.94 mg / 100g, and the content of ester-type astaxanthin E75 was the highest. The addition of different carotenoids, fish skin with carotenoids in the amount of diet are added with the increase. The color difference value (△E) of the pelvic fin is greater than 6 in the group of pigment added, and reach the naked eye recognition standard. In the area below lateral line, only the addition of zeaxanthin group and E75 group to the naked eye recognition standards. The operculum color was identified by the naked eye with the zeaxanthin group. According to the accumulation of carotenoid in skin and color difference, zeaxanthin has higher accumulating capacity and skin coloring performance than that of astaxanthin. Ester-type astaxanthin has a higher accumulation than free-type astaxanthin. It is suggested that the addition of 75 mg / kg zeaxanthin can increase the coloring ability of Trichogaster chuna, 75mg / kg of free-type astaxanthin and 50mg / kg of ester-type astaxanthin.