为研究着色虹鳟在摄食状态和饥饿状态下的虾青素降解规律,实验选用平均体质量为(101.9±1.3)g的未着色虹鳟和已着色虹鳟,对未着色虹鳟饲喂含虾青素(100 mg/kg)饲料以研究虾青素在机体的沉积规律(虾青素沉积组)；对着色虹鳟,饲喂含虾青素(100 mg/kg)饲料(正对照)、不含虾青素饲料(摄食降解组)或予以饥饿处理(饥饿降解组),实验共设4个处理组,每个处理组3个重复.实验共持续4周,每周采样一次,测定肌肉、肝脏和全鱼虾青素含量,血清类胡萝卜素含量,肌肉色差值(L*,a*,b*)和肌肉罗氏比色卡得分.结果表明,虾青素沉积组的虹鳟肌肉、肝脏虾青素含量、肌肉红度值和罗氏比色卡得分随饲养时间延长而增加(P＜0.05),在第3周时达到基本稳定,与第4周测定值无显著差异(P＞0.05)；在4周养殖期内,全鱼虾青素含量呈增加趋势,而全鱼虾青素沉积率则呈下降趋势,第1周、第4周时的全鱼虾青素含量和全鱼虾青素沉积率分别为3.71 mg/kg、8.59 mg/kg和21.31％、15.26％;饥饿降解组和摄食降解组虹鳟的全鱼、肌肉、肝脏虾青素含量、肌肉红度值和罗氏比色卡得分随养殖时间延长逐渐降低(P＜0.05),其中饥饿降解组的下降趋势更为明显,第3周后,这种降低趋势减缓.上述研究表明,在虹鳟饲料中添加100 mg/kg虾青素,经过3周饲养即可使肌肉达到着色要求,虾青素的沉积率随时间延长而下降；饥饿和投喂不含虾青素的饲料均可使已着色虹鳟肌肉虾青素含量和红色度显著下降,饥饿使虾青素的减少更加迅速,虾青素在鱼体内的减少量随时间的延长而降低.%In the present study, four treatments with triplicates were designed with colored or un-colored rainbow trouts with average initial weight of (101.9+1.3) g. Un-colored rainbow trout was fed with diet containing 100 mg/kg astaxanthin to study the deposition of astaxanthin in body (astaxanthin deposition group). Colored rainbow trout was fed with basal diet with 100 mg/kg astaxanthin addition (positive control) or without astaxanthin addition (feeding degradation group), or deprived of diet during the whole feeding period (starving degradation group) to study the degradation of astaxanthin in body. The feeding trial lasted for four weeks. Samples, including muscle, liver and serum, were collected once a week, and measured for astaxanthin contents of flesh, liver and whole fish, serum carotenoids, flesh chromatism(L*, a*, b*), and flesh Salmo Fan score. Results showed that in astaxanthin deposition group, astaxanthin contents of flesh and liver, flesh a* value, Salmo Fan score of rainbow trout increased with feeding time prolonging (P<0.05), and kept stable in the 3rd week. There were no significant difference in these indexes between 3rd week and 4th week(P>0.05). In the whole feeding period, astaxanthin content of whole fish tended to rise, but axtaxanthin retention rate of whole fish tended to decreases. In the first week and in the fourth week, astaxanthin content and axtaxanthin retention rate of whole fish were 3.71 mg/kg, 8.59 mg/kg and 21.31% 15.26%, respectively. In both starving and feeding degradation groups, astaxanthin content of tissue, flesh a* and Salmo Fan score of rainbow trouts decreased with feeding time prolonging(P<0.05), but the decreasing trend of these indexes slowed down in the 3rd week. The decreasing speed of these indexes in starving degradation group was faster than those in feeding degradation group. Results above showed that an addition of 100 mg/kg astaxanthin in diet could make the flesh of rainbow trout present ideal red colour after three weeks feeding, but astaxanthin retention rate decreased with feeding time prolonging. For rainbow trout fed diet without astaxanthin or deprived of diet, flesh astaxanthin and a* value significantly decreased during feeding period, and starving makes astaxanthin reduce more quickly than feeding diet without axtaxanthin. The degradation speed of astaxanthin in body of rainbow trout tended to slow down with time prolonging.
展开▼
