Comparing dietary intake of free-feeding to feeding in restrained imaging chamber environments using seven days post fertilization larvae.

Abstract

Heart disease and diabetes are both in the top ten for leading causes of death in the United States with both being linked to obesity. Studying human metabolism can prove difficult due to ethical concerns with human subjects but zebrafish larvae (Danio rerio) are optically transparent. Zebrafish larvae at seven days post fertilization also have fully formed digestive tracts and are actively seeking new food due to exhausting their supply of egg yolk. Free feeding environments are typically the standard when introducing new food to the larvae but lack versatility in their imaging. The Walters lab microfluidic chip can image larvae before, during, and after their introduction to the diet. To prove the two types of feeding environments were compared by using fluorescent digestive markers mixed into high fat diets. The free fed larvae were put into a well filled with diet and allowed to feed for three hours while sat on a orbital shaker inside of a 28 degrees Celsius incubator. After three hours, these larvae were rinsed out and imaged. The microfluidic chip larvae were mounted into the chip and fed the diet while inside and under the same Zeiss Discovery V8 microscope the freely fed larvae were imaged under. Future predictions for this data were that the larvae would consume slightly less diet inside of the microfluidic chip than the larvae in free feed. Results for this are still ongoing but seem to lead towards supporting the hypothesis.