Date of Graduation

12-2016

Document Type

Thesis

Degree Name

Master of Science in Cell & Molecular Biology (MS)

Degree Level

Graduate

Department

Biological Sciences

Advisor

Walter Bottje

Committee Member

Sami Dridi

Second Committee Member

Byung-Whi Kong

Third Committee Member

Mack Ivey

Abstract

Oxidative stress may play a role in the phenotypic expression of feed efficiency (FE). The transcription factor NFE2L2 (nuclear factor erythroid-derived 2-like 2) coordinates antioxidant response to oxidative stress and its activity is tightly regulated in part by KEAP1 (Kelch like-ECH protein 1) and the E3 ligase CUL3 (Cullin3). Thus, one objective was to determine mRNA expression of NFE2L2, KEAP1, and CUL3 as well as three antioxidant targets [glutathione peroxidase (GPx-1), superoxide dismutase 1 (SOD1), and superoxide dismutase 2 (SOD2)] in breast muscle of immature pedigree broiler males (8 wk), immature Japanese quail males (4 wk) divergently selected for high or low susceptibility to restraint stress, and mature Japanese quail (30 wk) exhibiting high or low FE. The second objective was to determine effects of 4-hydroxy 2-nonenal (4-HNE, a secondary lipid peroxide), on NFE2L2, KEAP1, CUL3, SOD1, SOD2, and GPx-1 mRNA expression in an avian muscle cell line (Quail Muscle 7, QM7). High FE pedigree broiler males exhibited increased KEAP1 and SOD1 mRNA expression in breast muscle compared to the low FE phenotype Quail from the HS (high stress) with low FE exhibited increased mRNA expression in all the genes except SOD1. In contrast, the immature high FE quail from the LS (low stress) line had higher levels of NFE2L2, SOD2, and GPx-1. The mature high FE Japanese quail had higher mRNA expression of SOD1, SOD2 and GPx-1 compared to the low FE phenotype, but there were no differences in mRNA expression of NFE2L2, KEAP1 and CUL3 between the high and low FE mature quail. The effects of 4-hydroxynonenal (4-HNE) (0, 10, and 20 µM) on mRNA expression in QM7 cells was determined at 30, 120, and 240 min post 4-HNE treatment. After 30 min, NFE2L2, SOD1, and GPx1 mRNA expression was lower and KEAP1 levels higher (P < 0.07) in 20 µM compared to 0 M 4-HNE. At 120 min, CUL3 was higher in 10 µM compared to 0 and 20 µM 4-HNE treated cells; SOD1 expression was lower and GPx-1 expression higher in 20 µM treated compared to controls. There were no differences in mRNA expression at 240 min of treatment with the exception that 20 µM 4-HNE raised CUL3 mRNA expression compared to the 10 µM 4-HNE treated cells.

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