2025/04/04 by Marissa Mueller, Selma Tir, Carina A. Pothecary +6 · 1 voice
Medicine · Neuroscience · Psychology · #Adipose Tissue and Metabolism #Circadian rhythm and melatonin #Neuroendocrine regulation and behavior
paper · doi:10.12688/wellcomeopenres.23850.1
openalex publication_date 2025/04/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/22
<ns3:p> Background Accurately measuring activity and feeding is important in laboratory animal research, whether for welfare-monitoring or experimental recording. Quantification commonly involves manual pellet-weighing; however, this can physically disturb animals and cannot continuously assess both the amount and pattern of feeding over time. Improved means of food-intake measurement have been developed but can be costly and incompatible with many cage configurations. Methods We developed the <ns3:italic>SnackerTracker—</ns3:italic> a novel home-cage monitoring system which continuously records food-intake, food-seeking activity, and ambient light conditions in laboratory mice. After benchtop validations, we tested this device by recording from C57BL/6J control mice under 12:12h light:dark (LD) and constant darkness (DD) to measure circadian rhythms in feeding behaviour. We then recorded from mice having disturbed circadian rhythms (cryptochrome 1 and 2 double-knockouts, <ns3:italic> Cry1 <ns3:sup>-/-</ns3:sup> ,Cry2 <ns3:sup>-/-</ns3:sup> </ns3:italic> ), where irregular activity and feeding patterns were expected. Animals were individually housed with <ns3:italic>SnackerTrackers</ns3:italic> in Digital Ventilated Cages <ns3:sup>®</ns3:sup> (DVC, Tecniplast) to measure home cage activity. After habituation, 48-hour <ns3:italic>SnackerTracker</ns3:italic> and DVC recordings were collected and compared. Results The <ns3:italic>SnackerTracker</ns3:italic> accurately measured food-masses throughout benchtop and <ns3:italic>in vivo</ns3:italic> validation tests. Time-course <ns3:italic>SnackerTracker</ns3:italic> feeding traces correlated well with DVC activity recordings, indicating that feeding reflects general cage locomotion in control and cryptochrome-deficient animals. In LD, <ns3:italic>SnackerTracker</ns3:italic> data showed expected feeding/fasting cycles in control and cryptochrome-deficient animals yet reduced dark-phase feeding in cryptochrome-deficient mice. In DD, increased feeding during the subjective nighttime was maintained in control animals but abolished in cryptochrome-deficient mice. Surprisingly, cryptochrome-deficient animals exhibited ultradian feeding rhythms. Conclusions We validate the performance and value of monitoring home cage feeding using the <ns3:italic>SnackerTracker</ns3:italic> . Here we show that cryptochrome-deficient animals have decreased food-intake in LD, diurnal arrhythmicity in DD, and ultradian rhythms in feeding behaviour. The <ns3:italic>SnackerTracker</ns3:italic> provides a cost-effective, open-source, and user-friendly method of animal food intake and activity measurement. </ns3:p>