Semester

Summer

Date of Graduation

2013

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Animal and Nutritional Sciences

Committee Chair

Kimberly M. Barnes.

Abstract

Docosahexaenoic acid (DHA) from algae oil has been incorporated into tissues at a lower level and has been less effective than fish oil (FO) at reducing body fat. Our objective was to determine fecal excretion of eicosapentaenoic acid (EPA) and DHA from different dietary sources. Male mice (n=100) were fed a 12% lipid diet containing soy oil (SO), FO, yeast oil (YO) algae oil (AO), or AO+YO. The AO diet was fed to contain amounts of DHA equal to the FO diet, and the YO diet was fed to contain amounts of EPA equal to the FO diet. To measure absorption, fecal samples were collected over night once per week for 4 weeks, and fatty acid composition was analyzed. Muscle and adipose tissue were collected and analyzed for fatty acid composition. There were no differences in feed intake, body weight, or body fat (P>0.05). FO-fed mice did have heavier livers (P<0.05). AO+YO-fed mice had greater fecal DHA content than AO- and FO-fed mice for the first 3 weeks (P<0.05), and AO-fed mice had greater (P<0.05) fecal DHA content than FO-fed mice in weeks 2-4. FO-fed mice had greater fecal EPA than YO- and AO+YOfed mice at week one (P<0.05). FO- and YO-fed mice had greater fecal EPA at week 1 than at weeks 2-4 (P<0.05). FO-fed mice had the greatest muscle tissue EPA content (P<0.05) at weeks 2 and 4. FO-fed mice had the greatest adipose tissue EPA and DHA content at week 4 (P<0.05). At week 2, adipose tissue of FO-fed mice contained more EPA than adipose tissue of YO-fed mice (P<0.05), and more DHA than adipose tissue of AO-fed mice (P<0.05). Thin layer chromatography was performed and verified that the oil sources were primarily composed of triglycerides. Positional analysis of the oils was performed with a lipase and showed enrichment of DHA in FO at the sn-2 position. In conclusion DHA in FO is more available than in AO, because of the position of DHA on the triglyceride structure, and EPA and DHA from FO is more highly incorporated than from YO or AO.

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