The Respirometry Blog

Continuous Metabolic Phenotyping - How Continuous is "Continuous"?

A continuous metabolic phenotyping system is required for tracking rapid changes in metabolic data. Such a metabolic phenotyping system must sample continuously from each cage in parallel. Because each cage gets its own gas analyzer system, the sampling rate can be greatly increased relative to multiplexed systems, which share a gas analyzer chain between several cages. This allows transient metabolic phenomena to be resolved. For example, responses to injections or other such treatments can be tracked with excellent temporal resolution.

Sex, lies, and water vapor

This blog entry deals with lies and water vapor, especially lies - oops, "differently truthful claims" - about the feasibility of using direct water vapor measurement to correct mathematically for the dilution effects of water vapor on respiratory gases. Tests establishing the validity of the technique are described, and a list of publications by leading scientists in major journals that use this technique is included.

Tiny Food Intake Events (Micro-Intakes) Can be Important!

Many food intake events (= food uptake events) are too small for legacy "food intake measurement systems" or metabolic phenotyping systems to detect. Each of these feeding events corresponds to a neurological signal to feed, even if the actual amount is small. As such, they convey important behavioral information.

Combining a metabolic cage (with urine and feces collection) and respirometry: It's easy!

Measuring metabolic rates in a stress free home cage environment is great for the experimental animal, but can't be implemented if quantitative urine and feces collection is also required. Metabolic cages exist that are specially designed for accurate collection of urine and feces, and as this blog post shows, can easily be adapted for metabolic measurement using a Promethion pull-mode metabolic phenotyping system.

Distinguishing individual food uptake in communally housed mice using RFID

Mice are communal beasts, just like rats. They live in groups, and separating them - as required for measuring food intake / food uptake or energy expenditure - stresses them, elevating cortisol levels and leading to to a host of unwanted side-effects. Using the right technology, however, obtaining separate food uptake recordings from communally housed mice is straightforward. This short article demonstrates just such an application, combining a Promethion mass measurement module (2 mg resolution) with RFID.