兴凯湖红鳍原鲔消化酶活力和肌肉氨基酸组成的季节变化

研究了不同季节体质量为107．824-22．97g的兴凯湖野生红鳍原鲐（Cultrichthys erythropterus）肝胰脏、肠道消化酶活力及夏季昼夜变化和肌肉氨基酸种类组成、含量及其变化，探讨其营养生态特性及变化规律。结果显示：不同季节红鳍原铂的蛋白酶、淀粉酶和脂肪酶的比活性显著不同（P〈0．05），夏、秋季高于春、冬季，同一季节蛋白酶比活均显著高于淀粉酶比活（P〈0．05）；红鳍原鲐蛋白酶、淀粉酶和脂肪酶比活的昼夜变化为：19：00～21：00、19：00和16：00～19：00时值最高，7：00、7：00和21：00值最低。红鳍原鲴肌肉由18种氨基酸组成，冬季缬氨酸、蛋氨酸、异亮氨酸、苯丙氨酸和赖氨酸五种必需氨基酸的含量显著低于春、秋季（P〈0．05），而非必需氨基酸的含量无明显的季节变化；不同季节谷氨酸含量均最高，最低为胱氨酸。春、夏季氨基酸总量和必需氨基酸总量较高，秋、冬季较低；秋季鲜味氨基酸含量最低。研究表明，野生红鳍原鲐消化生理具有不同季节和日变化特点，氨基酸组成的季节变化提示：冬季鱼体代谢活动对肌肉组织中必需氨基酸的依赖。

Seasonal Changes in Digestive Enzyme Activities and Amino Acid Levels and Composition in Muscle in redfin culter Cultrichthys erythropterus

The activities of digestive enzymes in intestine and hepatopancreas and muscular composition of amino acids were moni- tored in redfin culter （Cultrichthys erythropterus Culter erythropteru／／／） weighing 107.82g collected in January, May, July and September, and the daily changes in muscular composition of amino acids were studied in summer. The results showed that there were significantly higher activities of digestive enzyme in summer and autumn than those in spring and winter, the activity ofprotease higher than amylase in the same season （P〈0.05）. The maximum activities ofprotease, amylase and lipase were observed from 19：00 to 21：00, at 19：00 and from 16：00 to 19：00, and the minimum activities were found at 7：00, 7：00 and 21：00. The muscular composition of amino acids was shown to be comprised of 18 kinds of amino acid, glutamic acid being the most abundant and cysine the least. The contents of five essential amino acid （valine, methionine, isoleucine, phenylanine and lysine） were significantly lower in winter than in other seasons （P〈0.05）, without seasonal changes in the non-essential amino acids. Both total amino acid and total essential amino acids were found to be the climax in spring and summer and to fall into zenith in autumn and winter, the minimal contents of delicious amino acids in autumn. The findings indicates that wild redfin culter digestive physiology has season and day revolution, and amino content changes in different seasons imply that the metabolism in winter relies on the essential amino acid in the muscle.