Feeding Experimentation Device (FED): A flexible open-source device for measuring feeding behavior

Abstract

Background Measuring food intake in rodents is a conceptually simple yet labor-intensive and temporally-imprecise task. Most commonly, food is weighed manually, with an interval of hours or days between measurements. Commercial feeding monitors are excellent, but are costly and require specialized caging and equipment. New method We have developed the Feeding Experimentation Device (FED): a low-cost, open-source, home cage-compatible feeding system. FED utilizes an Arduino microcontroller and open-source software and hardware. FED dispenses a single food pellet into a food well where it is monitored by an infrared beam. When the mouse removes the pellet, FED logs the timestamp to a secure digital (SD) card and dispenses a new pellet into the well. Post-hoc analyses of pellet retrieval timestamps reveal high-resolution details about feeding behavior. Results FED is capable of accurately measuring food intake, identifying discrete trends during light and dark-cycle feeding. Additionally, we show the utility of FED for measuring increases in feeding resulting from optogenetic stimulation of agouti-related peptide neurons in the arcuate nucleus of the hypothalamus. Comparison to existing methods With a cost of ~$350 per device, FED is >10x cheaper than commercially available feeding systems. FED is also self-contained, battery powered, and designed to be placed in standard colony rack cages, allowing for monitoring of true home cage feeding behavior. Moreover, FED is highly adaptable and can be synchronized with emerging techniques in neuroscience, such as optogenetics, as we demonstrate here. Conclusions FED allows for accurate, precise monitoring of feeding behavior in a home cage setting.

Ventral arkypallidal neurons modulate accumbal firing to promote reward consumption

“…Optogenetic ICSS Assay. Mice were acclimated to behavioral testing chambers equipped with a device composed of two nose pokes, adapted from FED (Nguyen et al, 2016(Nguyen et al, , 2017. Pokes on the active port resulted in a tone and delivery of 2 seconds of 20 Hz stimulation through the optic fibers, pokes on the inactive nose poke had no effect; the position of the active nosepoke was counterbalanced between subjects.…”

Mice under Caloric Restriction Self-Impose a Temporal Restriction of Food Intake as Revealed by an Automated Feeder System

“…Food intake measurement is often imprecise, lacks temporal resolution, and rarely allows for long-term recording (Ellacott et al, 2010; Tschop et al, 2012). There are a few labs that have implemented automation to reduce the work load with some success, but these systems are limited in their scope and capacity to both control and measure intake (Flurkey et al, 2010; Hirao et al, 2010; Nelson et al, 1982; Nguyen et al, 2016). Although commercial automated feeders are available, these systems have various limitations (Table S2).…”

Rodent Arena Tracker (RAT): A Machine Vision Rodent Tracking Camera and Closed Loop Control System

“…In experiment 2, we synchronized the RAT input/output connection with an open-source pellet dispensing device, the Feeding Experimentation Device (FED) (Nguyen et al, 2016). We programmed the FED device to send a TTL pulse to the RAT each time a pellet was taken ( Figure 3B).…”

“…In experiment 2, four C57NL/6J mice were individually housed in 9" x 12" plexiglass boxes with a FED feeding device (Nguyen et al, 2016) attached to the side and a RAT mounted above facing the arena floor. The output of the FED was connected to the input of the RAT, enabling the RAT to log the time and position of pellet retrieval events.…”