Date of Graduation

12-2016

Document Type

Thesis

Degree Name

Master of Science in Poultry Science (MS)

Degree Level

Graduate

Department

Poultry Science

Advisor/Mentor

Sami Dridi

Committee Member

Michael Kidd

Second Committee Member

Walter G. Bottje

Third Committee Member

Douglas D. Rhoads

Fourth Committee Member

Mike Vayda

Keywords

Biological sciences, Heat stress, Liver, Orexin, Oxidative stress

Abstract

It is widely known that orexin A and B peptides as well as their receptors are expressed in the hypothalamus and distributed throughout the central nervous system, but there have been few studies regarding its presences in other parts of the body. There is now evidence that orexin (ORX) and its receptors (ORXR1/2) are present in the avian liver; however, their regulation under different environmental conditions is still unknown. In the current study, we sought to determine the effects of heat and oxidative stress using hydrogen peroxide (H2O2) and 4-hydroxynonenal (4-HNE) on the hepatic expression of ORX and ORXR1/2 in the avian species. Overall, heat stress significantly down regulated the expression of ORX, and ORXR1/2 mRNA and pro1tein in quail liver and LMH cells. LMH cells treated with H2O2 had decreased ORX protein and increased ORX mRNA levels (P < 0.05). There was a biphasic effect of 4-HNE on the expression of ORX and ORXR1/2 in LMH cells. There was a significant upregulation at low doses (10 and 20 μM) and significant down-regulation at a high dose (30μM) of 4-HNE. In light of the current data, the hepatic expression of orexin could serve as a molecular signature in the heat and oxidative stress response.

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