Skaare J U, Roald S O
Nord Vet Med. 1977 Apr-May;29(4-5):232-6.
Salmons of two different sizes (group I; 22--30 g, group II; 600--1450 g) were tested for ethoxyquin (EMQ) residues after fed ad libitum a diet supplied with the therapeutic level of 900 ppm EMQ for 2 months. The sums of residues of EMQ and possible metabolites having similar fluorescence characteristics were determined by a fluorimetric method. The percentage of unmetabolized EMQ present was estimated using a gas chromatographic-mass spectrometric (GLC-MS) method measuring only unchanged EMQ. For both methods the detection limit was 0.1 ppm. EMQ residues were also fluorimetrically estimated in muscle tissue of small salmons fed a diet preserved with 150 ppm EMQ for 2 months. At termination of feeding the diet supplied with 900 ppm EMQ, residues measured fluorimetrically in muscle tissue of salmons in both groups were averaging 0.7 ppm. Approximately one third was unchanged EMQ. From salmons of group II blood, kidney and hepatic tissue were also analyzed at termination of feeding and residues averaging 0.3, 0.8 and 1.8 ppm respectively were estimated. The elimination of EMQ from muscle tissue is illustrated in Fig. 1. No residues could be detected 9 days following termination of feeding the therapeutic level of EMQ. In muscle tissue of salmons fed the diet preserved with 150 ppm EMQ, residues ranging from 0.1 to 0.3 ppm of EMQ and possible metabolites were found in 9 of 10 samples obtained from 20 salmons in group I. For an evaluation of EMQ used as a feed additive (150 ppm), further studies were recommended. The diets used in the experiment contained 88 and 830 ppm EMQ respectively measured fluorimetrically at the end of the experiment. Approximately 88% of the residues in the feed was unchanged EMQ. It is suggested that most information regarding the hygienic aspects of residues in muscle tissue is obtained by fluorimetry which is therefore recommended for determination of EMQ residues in tissues. The GLC-MS method, however, is recommended for estimation of EMQ levels in feed.
对两种不同大小的鲑鱼（第一组：22 - 30克，第二组：600 - 1450克）进行了测试，让它们自由采食添加了治疗水平900 ppm乙氧喹（EMQ）的饲料，持续2个月，之后检测其体内的乙氧喹残留量。通过荧光法测定乙氧喹及其具有相似荧光特性的可能代谢产物的残留总量。使用仅测量未变化乙氧喹的气相色谱 - 质谱联用（GLC - MS）方法估算未代谢乙氧喹所占的百分比。两种方法的检测限均为0.1 ppm。还用荧光法对喂食添加了150 ppm乙氧喹饲料2个月的小鲑鱼肌肉组织中的乙氧喹残留量进行了估算。在喂食添加900 ppm乙氧喹饲料结束时，两组鲑鱼肌肉组织中通过荧光法测得的残留量平均为0.7 ppm。其中约三分之一是未变化的乙氧喹。在喂食结束时，还对第二组鲑鱼的血液、肾脏和肝脏组织进行了分析，测得残留量分别平均为0.3 ppm、0.8 ppm和1.8 ppm。图1展示了乙氧喹从肌肉组织中的消除情况。在停止喂食治疗水平的乙氧喹9天后，未检测到残留。在喂食添加150 ppm乙氧喹饲料的鲑鱼肌肉组织中，从第一组20条鲑鱼获取的10个样本中有9个检测到乙氧喹及其可能代谢产物的残留量在0.1至0.3 ppm之间。为评估用作饲料添加剂（150 ppm）的乙氧喹，建议进一步开展研究。实验中使用的饲料在实验结束时通过荧光法测得分别含有88 ppm和830 ppm的乙氧喹。饲料中约88%的残留是未变化的乙氧喹。建议通过荧光法获取有关肌肉组织中残留卫生方面的大部分信息，因此推荐用荧光法测定组织中的乙氧喹残留量。然而，推荐使用GLC - MS方法来估算饲料中的乙氧喹含量。
