Semester

Spring

Date of Graduation

2012

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Animal and Nutritional Sciences

Committee Chair

Janet C. Tou

Committee Co-Chair

Vagner Benedito

Committee Member

Joseph Moritz

Abstract

Justification: The lungs are constantly exposed to oxidative stress and inflammation which increase the risk of lung damage. Omega-3 polyunsaturated fatty acids (n-3 PUFAs), found in different dietary sources, regulate the expression of various genes involved in eicosanoid production and oxidative stability.;Objective: to determine whether providing different sources of n-3 PUFAs will affect the fatty acid composition, inflammation and oxidation in the lungs of growing rats.;Methods: Growing (age 28 d) Sprague-Dawley rats were randomly assigned (n=10/group) to diets consisting of either corn oil (CO) or n-3 PUFA rich flaxseed (FO), krill (KO), salmon (SO) or tuna (TO) oil for 8 weeks. Diet and tissue fatty acid composition was analyzed by gas chromatography. The enzymes involved in eicosanoid synthesis, 5-lipoxygenase (5-LOX) and cyclooxygenase II (COX II), and the antioxidant enzymes, catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase 1 (SOD1), were determined using real-time polymerase chain reaction.;Results: Rats fed FO, with the highest alpha-linolenic acid (ALA, 18:2n-3) content, had the highest (P<0.001) lung ALA deposition. Rats fed KO, with the highest eicosapentaenoic acid (EPA, 20:5n3) content, had the highest (P<0.001) lung EPA deposition compared to all diet groups, except SO-fed rats. Rats fed TO, with the highest docosahexaenoic acid (DHA, 22:6n-3) content, had the highest (P<0.001) lung DHA deposition compared to rats fed CO or FO. The relative expression of 5-LOX was significantly up-regulated (P=0.007) in rats fed FO compared to CO-fed rats. Expression of the antioxidant defense enzyme, SOD1 was down-regulated (P=0.01) in TO-fed rats compared to rats fed CO. Dietary TO has an EPA/DHA ratio of 1:2 and had a higher ( P<0.001) lung DHA content compared to rats fed CO.;Significance: The fatty acid composition of the lungs reflected dietary intake. The increase in o-3 PUFAs in lung tissue may affect the risk of lung damage, and in turn, susceptibility to lung diseases by altering gene expression of inflammation and oxidative stability.

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