Feeding Experimentation Device (FED): Construction and Validation of an Open-source Device for Measuring Food Intake in Rodents

Abstract

Food intake measurements are essential for many research studies. Here, we provide a detailed description of a novel solution for measuring food intake in mice: the Feeding Experimentation Device (FED). FED is an open-source system that was designed to facilitate flexibility in food intake studies. Due to its compact and battery powered design, FED can be placed within standard home cages or other experimental equipment. Food intake measurements can also be synchronized with other equipment in real-time via FED's transistor-transistor logic (TTL) digital output, or in post-acquisition processing as FED timestamps every event with a real-time clock. When in use, a food pellet sits within FED's food well where it is monitored via an infrared beam. When the pellet is removed by the mouse, FED logs the timestamp onto its internal secure digital (SD) card and dispenses another pellet. FED can run for up to 5 days before it is necessary to charge the battery and refill the pellet hopper, minimizing human interference in data collection. Assembly of FED requires minimal engineering background, and off-the-shelf materials and electronics were prioritized in its construction. We also provide scripts for analysis of food intake and meal patterns. Finally, FED is open-source and all design and construction files are online, to facilitate modifications and improvements by other researchers.

Ventral arkypallidal neurons inhibit 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.…”

Challenges in quantifying food intake in rodents

“…Time-stamp analyses of pellet retrieval events allow for calculation of caloric intake with high temporal precision. Pellet dispensing devices can be small enough to be placed in standard vivarium housing, and open source versions exist that are cheap to build (Nguyen et al, 2016; Nguyen et al, 2017; Oh et al, 2017). Dispensers can be programmed to restrict food based on caloric or temporal requirements (Acosta-Rodriguez et al, 2017), or based on the animal performing an operant task (Rainwater et al, 2017).…”

Differential control of intestine function by genetically defined enteric neurons

“…Feeding studies were performed using a custom-built food pellet dispensing system with ad libitum access to drinking water. The specifications of the food pellet dispenser were constructed as described by the Feeding Experimentation Device (FED) 2.0 specifications 127,128 (see https://hackaday.io/project/72964-feeding-experimentation-device-fed-20). Briefly, the housing of the dispenser was created using Stereolithography (SLA) 3D-printing in-house on a Formlabs Form 3+.…”