The influence of diurnal and nocturnal feeding on daily rhythms of gut levels of cholecystokinin (CCK) and the activity of two key pancreatic proteases, trypsin and chymotrypsin, were examined in juveniles of Senegalese sole (Solea senegalensis), a species with nocturnal habits. Four feeding protocols were performed: P1) One morning meal; P2) Six meals during the light period; P3) Six meals during the dark period; and P4) 12 meals during 24 h. Daily activity patterns of both proteases were remarkably similar and showed a high correlation in all the experimental protocols. In P1, daily patterns of CCK and digestive enzymes showed a single maximum. In P2, CCK levels exhibited two peaks. Digestive enzymes activities showed slightly delayed peaks compared to CCK, although their daily fluctuations were not significant. In P3, intestinal CCK concentration exhibited two peaks at the end of light and dark periods, but only the second one was significant. The first maximum level of chymotrypsin activity occurred 4 h after the first CCK peak, while the second one coincided with the second CCK peak. Fluctuations of trypsin activity were not significant. In P4, CCK concentration showed three small peaks. Digestive enzymes daily fluctuations were not significant, although they showed an inverted trend with respect to CCK. The daily pattern of the gut CCK content in our study is in agreement with the anorexigenic function of this hormone. Our results support the existence of a negative feedback regulatory loop between CCK and pancreatic proteolytic enzymes in Senegalese sole juveniles.

在塞内加尔鳎 ( Solea senegalensis)幼鱼中检查了昼夜进食对胆囊收缩素 (CCK) 肠道水平的日常节律和两种关键胰蛋白酶、胰蛋白酶和胰凝乳蛋白酶的活性的影响)，一种具有夜间习性的物种。执行了四种喂养方案：P1) 一顿早餐；P2) 清淡期六餐；P3) 黑暗时期六餐；和 P4) 24 小时内 12 餐。两种蛋白酶的日常活动模式非常相似，并且在所有实验方案中都显示出高度相关性。在 P1 中，CCK 和消化酶的每日模式显示出单一最大值。在 P2 中，CCK 水平表现出两个峰值。与 CCK 相比，消化酶活性的峰值略有延迟，尽管它们的每日波动并不显着。在 P3 中，肠道 CCK 浓度在明暗期结束时出现两个峰值，但只有第二个峰值显着。糜蛋白酶活性的第一个最大水平出现在第一个 CCK 峰值后 4 小时，而第二个与第二个 CCK 峰值重合。胰蛋白酶活性的波动不显着。在 P4 中，CCK 浓度显示出三个小峰。消化酶的每日波动并不显着，尽管它们相对于 CCK 显示出反向趋势。我们研究中肠道 CCK 含量的日常模式与这种激素的厌食功能一致。我们的研究结果支持塞内加尔鳎幼鱼 CCK 和胰蛋白水解酶之间存在负反馈调节回路。我们研究中肠道 CCK 含量的日常模式与这种激素的厌食功能一致。我们的研究结果支持塞内加尔鳎幼鱼 CCK 和胰蛋白水解酶之间存在负反馈调节回路。我们研究中肠道 CCK 含量的日常模式与这种激素的厌食功能一致。我们的研究结果支持塞内加尔鳎幼鱼 CCK 和胰蛋白水解酶之间存在负反馈调节回路。