Scientists offer 'best practices' nutrition measurement for researchers

March 30, 2014
On the verge: Drosophila yakuba sometimes lays eggs that have already hatched. Its genome may help to reveal how animals make the switch to live birth. Credit: Drosophila Species Stock Center

At first glance, measuring what the common fruit fly eats might seem like a trivial matter, but it is absolutely critical when it comes to conducting studies of aging, health, metabolism and disease. How researchers measure consumption can make all the difference in the accuracy of a study's conclusions.

Scientists from the Florida campus of The Scripps Research Institute (TSRI) have developed what amounts to a best practices guide to the most accurate way of measuring fruit fly food that could lead to more informed research and better decisions about directions in further studies.

"While our study isn't the final technical reference on measuring fly , it will help guide researchers to think more carefully about nutrition and in their own studies," said TSRI Assistant Professor William Ja, who led the study, which was published online ahead of print on March 30, 2014 by the journal Nature Methods.

Researchers, Ja said, generally haven't given sufficient thought to feeding and nutrient intake when it comes to measuring fruit fly behavior, metabolism and health.

"If you're making a huge effort to change an animal's diet and trying to draw conclusions about what nutrition and nutrients do to animal health and lifespan," he said, "then one of the most fundamental parameters is accurately measuring food intake."

TSRI Research Associate Sonali Deshpande, a first author of the study with graduate student Ariadna Amador and former TSRI Research Associate Gil Carvalho, underlined the importance of using the best measurement methods. "Drug studies, in particular, where compounds are added to fly food, are difficult to interpret without proper measurement of food and drug intake," she said.

In the study, the team determined that radioisotope labeling is the most sensitive and consistently accurate feeding method now available—levels of accumulated isotope are later measured in the animals. This method's main limitation appears to be underestimation of consumption due to excretion.

For the most accurate measurement, the study suggested pairing radioisotope labeling with a more low-tech approach, such as the capillary feeder (CAFE). The CAFE assay, introduced by Ja in 2007, is similar to a water dispenser used for pet hamsters, but on a smaller scale.

"In a significant number of studies, we found that researchers appeared indifferent to the impact feeding might have on the experiment," Ja said. "This doesn't seem like good science to me. Can you imagine doing a mouse experiment, saying that you watched mice for four hours and saw no difference in feeding, then make conclusions about total over days or longer?"

Explore further: Smaller meals more times per day may curb obesity in cats

More information: Quantifying Drosophila food intake: comparative analysis of current methodology, DOI: 10.1038/nmeth.2899

Related Stories

Smaller meals more times per day may curb obesity in cats

February 11, 2014

Just as with people, feline obesity is most often linked to excessive food intake or not enough physical activity. Attempts to cut back on calories alone often result in failed weight loss or weight regain in both people ...

Recommended for you

How cells in the developing ear 'practice' hearing

November 25, 2015

Before the fluid of the middle ear drains and sound waves penetrate for the first time, the inner ear cells of newborn rodents practice for their big debut. Researchers at Johns Hopkins report they have figured out the molecular ...

How cells 'climb' to build fruit fly tracheas

November 25, 2015

Fruit fly windpipes are much more like human blood vessels than the entryway to human lungs. To create that intricate network, fly embryonic cells must sprout "fingers" and crawl into place. Now researchers at The Johns Hopkins ...

Study suggests fish can experience 'emotional fever'

November 25, 2015

(—A small team of researchers from the U.K. and Spain has found via lab study that at least one type of fish is capable of experiencing 'emotional fever,' which suggests it may qualify as a sentient being. In their ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.