Production of low-gizzerosine fish meal

肌苷是一种由过热的鱼粉引起的鸡砂囊糜烂的致病化合物。新鲜鱼肉中不含吉泽新，而是在加工鱼肉过程中产生的。如果产品被强烈加热，例如130摄氏度，3小时，鱼粉中会产生大量的吉泽罗新。本研究旨在开发低吉泽霉素鱼粉的生产方法，首先建立了吉泽霉素的简易测定方法。在鱼粉中加入0.5%的赖氨酸或抗坏血酸，在130 ℃下加热3小时后，用离子交换高效液相色谱法测定，结果表明，该方法能较好地完成对马肉样品的分析。在对照膳食中产生了显著量的吉泽新。然而，具有0.5%赖氨酸的膳食含有较低量的吉泽罗新。添加抗坏血酸会产生不良影响，使吉泽罗新的生成量增加。采用该产品（含0.3%或0.5%游离赖氨酸的鱼粉），进行雏鸡生长试验、砂囊糜烂发生率和赖氨酸生物利用率的研究。结果清楚地表明，即使在强烈的热处理后，含有游离赖氨酸的鱼粉也远好于对照膳食，这是根据砂囊侵蚀的发生率和动物的生长速率来判断的。产品中赖氨酸的利用率也很好。经热处理后，含游离赖氨酸的鱼粉中肌苷含量显著低于对照鱼粉，为生产低肌苷鱼粉提供了可能。

Gizzerosine is a causative compound of chicken gizzard erosion induced by over-heated fish meals. Gizzerosine is not contained in fresh fish meat but is produced during processing of fish meat. If the product is heated strongly, e.g. 130ﾟC, 3 hours, significant amount of gizzerosine is produced in the fish meal. The present studies were planned to develop methods to produced low-gizzerosine fish meal.At first, a simple method of gizzerosine determination was developed. The new method, which employs ion-exchange high performance liquid chromatography, could finish mare samples compared with the former methods.We added lysine or ascorbic acid (at 0.5 %) to a fish meal and heated the product at 130ﾟC, 3 hours. A significant amount of gizzerosine was produced in the control meal. However, the meal with 0.5 % lysine contained lower amount of gizzerosine. Addition of ascorbic acid induced bad effects, producing more gizzerosine.The method to add lysine to fish meal was applied for practical fish meal production. Employing the product (fish meals with 0.3 or 0.5 % free lysine), chick growth test, the incidence of gizzard erosion, and biological lysine availability were investigated. The results clearly showed that the fish meals with free lysine are far better than the control meals even after strong heat treatment, judged by the incidence of gizzard erosion and the growth rate of animals. The lysine availability in the product was also excellent. Gizzerosine content of the meals with free lysine was significantly lower than the control meals after heat treatment.The present project made it possible to produce low-gizzerosine fish meal.