饲料中添加叶黄素对金鱼体色的影响

为考察饲料中添加叶黄素对金鱼体色的影响,在基础饲料中分别添加0、50、100、150、200和300 mg·kg-1叶黄素,饲喂平均体质量(7.8±0.3)g文种金鱼10周,用色差计(WSC-S)对金鱼体表三刺激值进行测定.结果表明:饲料中添加叶黄素对金鱼增质量率无显著影响,但添加300 mg·kg-1叶黄素显著增大了饲料系数(P0.05);饲料中添加叶黄素0~150 mg·kg-1时,金鱼体表+a*值(红色)随叶黄素添加量的增加而增加,L*值(亮度)随叶黄素添加量的增加而降低;当叶黄素添加量大于150 mg·kg-1时,+a*和L*值基本保持稳定;与对照组相比,叶黄素添加量为200和300 mg·kg-1时,+b*值(黄色)显著增加(P0.05);随叶黄素添加量从0增加到150 mg·kg-1,金鱼鳞片、皮肤、肌肉和尾鳍中的叶黄素含量也增加,当添加量大于150 mg·kg-1时,上述各部位叶黄素含量达到最高并基本稳定;添加100、150、200和300 mg·kg-1叶黄素均可显著提高金鱼血清酪氨酸酶活力(P0.05).上述结果表明,在金鱼饲料中添加叶黄素150 mg·kg-1可有效改善金鱼体色.

Effect of dietary xanthophyll level on body colour of goldfish (Carassius auratus)

To investigate the effect of adding xanthophyll in diet on body colour of goldfish, six diets added with xanthophyll of 0 (control group), 50, 100, 150, 200, or 300 mg·kg~(-1) were prepared, and fed to goldfish with initial body mass of (7.8±0.3) g for 10 weeks. A colorimeter (WSC-S) was chose to determine values of three primary colours of body color of goldfish. The results showed that there was no significant effect of additional xanthophyll on growth of goldfish, but feed conversion ratio (FCR) was increased (P<0.05) by the additional xanthophyll of 300 mg·kg~(-1), compared with control group. In the respect of body colour, +a~* value (redness) was increased, and L~* value (luminance) was decreased by xanthophyll addition from 0 to 150 mg·kg~(-1). When the addition level of xanthophyll was higher than 150 mg·kg~(-1), +a~* value and L~* value kept constant. The +b~* value (yellowness) of body surface was increased by additional xanthophyll of 200 mg·kg~(-1) or 300 mg·kg~(-1). With the increase of xanthophyll addition in diet, xanthophyll contents in skin, scale, muscle and tail fin were also increased. While the additional xanthophyll content was 150 mg·kg~(-1), goldfish had the highest content of xanthophyll in these tissues. Serum tyrosinase activity was significantly increased by the additional xanthophyll of 100, 150, 200, or 300 mg·kg~(-1). Results above show that the optimal xanthophyll addition in diet for goldfish pigmentation is 150 mg·kg~(-1).