Date of Graduation

5-2013

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Cell & Molecular Biology (PhD)

Degree Level

Graduate

Department

Biological Sciences

Advisor

Douglas Rhoads

Committee Member

Robert F. Wideman, Jr.

Second Committee Member

Yuchun Du

Third Committee Member

Daniel Lessner

Fourth Committee Member

Danny Davis

Keywords

Biological sciences; Broilers; Lameness; Pulmonary hypertension syndrome; Rapid growth

Abstract

Pulmonary Hypertension Syndrome (PHS) and lameness are important metabolic diseases that affect rapidly growing broilers. The research reported in the first section of this dissertation focused on developing qPCR assays to identify differences in the expression levels of four candidate genes possibly associated with PHS: angiotensin II type 1 receptor (AGTR1): urotensin receptor 2D (UTS2D); serotonin receptor/transporter type 2Bn (HTR2B); and angiotensinogen cleaving enzyme (ACE). Expression levels of these candidate genes were examined in four different tissues. We established ribosomal protein S14 (RPS14) and RNA polymerase subunit 2B (RP2B) as suitable reference genes because they showed the most consistent deltaCt values as compared to TAT-Box binding protein (TBP) and β2-microglobulin (β2M). We found a wide range of expression variation of HTR2B and AGTR1 in blood compared to lung, liver, and kidney, indicating that blood expression levels of these candidate genes potentially will provide a minimally invasive assessment of susceptibility to PHS. Lameness attributable to Bacterial Chondronecrosis and Osteomyelitis (BCO) has been associated with a wide range of bacterial species. In the second section of this thesis 16S ribosomal RNA was used to identify bacteria causing BCO in broilers. Staphylococcus species were the main bacterial species isolated from BCO lesions and the blood. Staphylococcus agnetis was the principal species isolated from the majority of the bone and blood samples collected from lame broilers that had been hatched in two different hatcheries in two independent experiments. Staphylococcus species also were isolated from the blood of several apparently healthy birds.

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