Influence of Specimen Handling on Determination of Non-Polar Lipid Content of Fish

Brittany Trushel

Department of Biological Sciences

Faculty Sponsor: Dr. Joel Snodgrass

(2004)

Lipids are the main energy storage components of many organisms. Lipids have a high caloric value and are often stored for later use when resources in the environmental are limited. The manner by which organisms store and use lipids has been the focus of ecological studies for decades. However, before studying the cycling of lipids in any species, it is important to understand how sample storage and processing affects estimates of lipid content. To examine the influence of different storage and handling techniques on gravimetric determination of non-polar lipid content of small stream fish, blacknose dace (Rhinichthys atratulus), I analyzed lipid content of dace that were stored in either formalin or frozen, and were processed by drying in an oven or freeze drying. Forty blacknose dace were collected from a local stream in Baltimore City, Maryland. Half of the fish were preserved and stored in 10% formalin and the other half were freezing at -80°C until processing. These two treatments were further divided into either freeze-drying or oven drying of the samples. Neither method of storage or processing had a significant affect on percent lipid content of fish. However, it was more difficult to dry fish preserved in formalin using a freeze-drier. My results suggest that preservation and storage of dace in formalin, followed by drying in a drying oven does not produce degradation of polar lipids to non-polar forms that would bias estimates of energy storage.

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Updated July 11, 2004