Cholecystokinin (Cck) and peptide YY (Pyy) play important roles in digestive regulation in fish, but their function in red seabream (Pagrus major) remains obscure. Two cck complementary DNAs (cck-1 and cck-2) in red seabream were identified, and tissue distribution analysis of the genes revealed that cck and pyy were expressed throughout the digestive tract, except for stomach cck-2. After feeding, cck-1 expression significantly increased in the stomach and pyloric caeca, cck-2 expression significantly increased in the pyloric caeca and hindgut, and pyy expression increased in the pyloric caeca of red seabream. After oral administration of dietary protein, i.e., high-quality fish meal (HQFM), soy protein concentrate (SPC), or low-quality FM (LQFM), only HQFM significantly increased stomach cck-1 expression. To assess the growth of red seabream in response to different sources of dietary protein, three isonitrogenous and isoenergetic diets were formulated: HQFM, SPC with a low percentage of HQFM, and LQFM. Mean body weight was highest in the HQFM group after 6 weeks. The stomach cck-1 response to HQFM may explain the high growth in the HQFM group. Our data suggest that cck-1, cck-2, and pyy are involved in digestion. Furthermore, stomach cck-1 may be a valuable tool for evaluating the quality of dietary protein sources for red seabream.

中文翻译：

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红鲷鱼中的胆囊收缩素 1 和 2：分子克隆、对摄食的反应以及膳食蛋白质来源质量的潜在指标

胆囊收缩素 (Cck) 和肽 YY (Pyy) 在鱼类的消化调节中起重要作用，但它们在红鲷（大鲷）中的功能仍不清楚。鉴定了红鲷中的两个 cck 互补 DNA（cck-1 和 cck-2），基因的组织分布分析显示 cck 和 pyy 在整个消化道中表达，除了胃 cck-2。饲喂后，cck-1在胃和幽门盲囊中的表达显着增加，cck-2在幽门盲囊和后肠中的表达显着增加，pyy在紫鲷幽门盲囊中的表达增加。口服膳食蛋白质，即优质鱼粉 (HQFM)、大豆浓缩蛋白 (SPC) 或低质量 FM (LQFM) 后，只有 HQFM 显着增加了胃 cck-1 的表达。为了评估红鲷对不同日粮蛋白质来源的反应，制定了三种等氮和等能日粮：HQFM、具有低 HQFM 百分比的 SPC 和 LQFM。6 周后 HQFM 组的平均体重最高。胃对 HQFM 的 cck-1 反应可以解释 HQFM 组的高增长。我们的数据表明 cck-1、cck-2 和 pyy 参与消化。此外，胃 cck-1 可能是评估红鲷膳食蛋白质来源质量的宝贵工具。我们的数据表明 cck-1、cck-2 和 pyy 参与消化。此外，胃 cck-1 可能是评估红鲷膳食蛋白质来源质量的宝贵工具。我们的数据表明 cck-1、cck-2 和 pyy 参与消化。此外，胃 cck-1 可能是评估红鲷膳食蛋白质来源质量的宝贵工具。