Madrid J A, Azzaydi M, Zamora S, Sánchez-Vázquez F J
Department of Physiology & Pharmacology, Faculty of Biology, University of Murcia, Spain.
Physiol Behav. 1997 Oct;62(4):689-95. doi: 10.1016/s0031-9384(97)00155-8.
The existence of feeding rhythms implies that fish would feed better during their preferred feeding phase but reject food at any other time. In the present paper, we tested the performance of a new device for continuously collecting and detecting uneaten food pellets. The device is basically made of two parts: a pellet collector placed just under the feeder and a decanter with a sensor attached to the bottom. When a food pellet was not eaten, it was rapidly collected and transferred to the decanter, where it was detected while dropping by an infrared sensor coupled to a microcomputer. To validate this system, five groups of fifteen sea bass, Dicentrachus labrax L., were maintained under natural conditions and subjected to a daily feeding cycle (feeding rate = 2.5% of body weight) consisting of three meals of one hour duration each (0800-0900 h, 1600-1700 h and 2400-0100 h). Uneaten pellets together with demand-feeding activity were simultaneously recorded. In addition to these test tanks, "natural" demand-feeding rhythms were also investigated in five groups of sea bass maintained under an ad lib self-feeding regime. In the test tanks, when submitted to the three meal feeding cycle, sea bass showed clear time preferences for feeding, since they fed mostly during the morning and afternoon, rejecting food at night. Consequently, the profile of uneaten pellets peaked at night butt remained very low during daytime. This diurnal preference for feeding is consistent with the almost strict diurnal feeding rhythm found in the sea bass groups under ad lib self-feeding. These results revealed the usefulness of this device in estimating food utilization and its potential application in nutritional and chronobiological studies in fish.
摄食节律的存在意味着鱼类在其偏好的摄食阶段摄食情况会更好，但在其他任何时间都会拒食。在本文中，我们测试了一种用于连续收集和检测未食用鱼食颗粒的新装置的性能。该装置主要由两部分组成：一个置于喂食器正下方的颗粒收集器，以及一个底部装有传感器的滗析器。当鱼食颗粒未被食用时，它会迅速被收集并转移到滗析器中，在那里通过与微型计算机相连的红外传感器在颗粒下落时进行检测。为验证该系统，将五组每组十五条的海鲈（Dicentrachus labrax L.）置于自然条件下，并使其接受每日投喂周期（投喂率为体重的2.5%），该周期由每餐持续一小时的三餐组成（08:00 - 09:00、16:00 - 17:00和24:00 - 01:00）。未食用的颗粒以及按需投喂活动被同时记录下来。除了这些测试水箱外，还对五组处于随意自助投喂模式下的海鲈的“自然”按需投喂节律进行了研究。在测试水箱中，当处于三餐投喂周期时，海鲈表现出明显的摄食时间偏好，因为它们大多在上午和下午摄食，夜间拒食。因此，未食用颗粒的分布在夜间达到峰值，而在白天则保持在很低的水平。这种对摄食的昼夜偏好与处于随意自助投喂模式下的海鲈组中几乎严格的昼夜摄食节律一致。这些结果揭示了该装置在估计食物利用率方面的有用性及其在鱼类营养和生物钟学研究中的潜在应用。
