色素添加对咖啡金黄水母体色影响的初步研究

在人工繁殖水母的饵料中添加食用性人工合成色素、人工合成荧光色素、天然虾青素、铁元素和饲喂含有色素的海蜇等,测定水母采食饵料后感官指标、酪氨酸酶活力和总类胡萝卜素含量的变化,分析添加物质对水母生理机能的影响。试验结果显示,4种人工食用色素均能大大提升水母的观赏性,但颜色保持时间短,3 h后,所有水母均恢复原来的体色,水母状态未发现改变。水母注射水溶性荧光色素,10 h后才能通过水循环扩散到全身,荧光色维持时间可达30 d。水母饲喂天然虾青素、铁元素和含有色素的海蜇1个月后,肉眼观察,海蜇组的水母比对照组的水母颜色深,而虾青素组、FeSO_4组与对照组差异不明显。各组酪氨酸酶活力和总胡萝卜素含量均较低。组内个体间酪氨酸酶活力差异较大,但各组间差异均不显著(P>0.05)。总胡萝卜素在450 nm处吸收值最高。海蜇组水母的酪氨酸酶活力和总胡萝卜素含量均最高,分别为0.133 U/mL和251.01 mg/kg。虾青素组酪氨酸酶活力最低,为0.109 U/mL。食用色素组总胡萝卜素含量最低,仅为158.83 mg/kg,酪氨酸酶活力仅高于虾青素组,可能与色素并未在表皮和中胶层形成色素沉淀有关。试验结果表明,人工添加色素能获得颜色各异的水母,水溶性荧光色素能长期保存在动物体内,可作为体色调控色素。水母的色素合成与酪氨酸酶活力和总胡萝卜素含量有关。

Effect of Dietary Pigments on Body Color of Jellyfish Chrysaora melanaster

The sensory index, tyrosinase activity and total carotenoid content were studied in jellyfish Chrysaora melanaster fed diets containing synthetic pigment, synthetic fluorescent pigment, astaxanthin, iron and edible jellyfish to evaluate the effects of dietary pigments on body color of the jellyfish. The results showed that the four edible pigments led to greatly improve the ornamental value of the jellyfish, with short color retention time. It was found that all the jellyfish was recoveried to their original color in 3h, without change in the jellyfish status. The fluorescent pigments were kept in the body of jellyfish injected with the pigments for 30 days, though they were distributed all over the body in 10 h through the water cycle. The jellyfish fed natural astaxanthin, iron, and edible jellyfish for a month had deeper body color in the edible jellyfish group than the jellyfish in the control did, without significant differences between the astaxanthin group, and the FeSO 4 group and the control group ( P >0.05). There were low tyrosinase activity and total carotene content in all groups, without significant difference among groups ( P >0.05), though great variation among individuals. The maximal absorption value of total carotene was observed at 450 nm, and the maximal tyrosinase activity (0.133 U/mL) and total carotene content ( 251.01 mg/kg) in edible jellyfish group, with the minimal activity ( 0.109 U/mL) of tyrosinase in astaxanthin group, and the minimal content (only 158.83 mg/kg) of total carotene in the edible pigment group. Higher activity of tyrosinase in the edible pigment group than that in the astaxanthin group was involved in the absence of sediment of pigment in the epidermis and mesoglobin. The findings indicate that various color jellyfish is obtained through exogenous pigments which are preserved in the animals for a long time, and that the pigment synthesis of jellyfish depends on tyrosinase activity and total carotene content.