Date of Graduation

12-2019

Document Type

Thesis

Degree Name

Master of Science in Poultry Science (MS)

Degree Level

Graduate

Department

Poultry Science

Advisor/Mentor

Gisela Erf

Committee Member

Sam Rochell

Second Committee Member

Nicholas Anthony

Keywords

Broilers, Immunology, Inflammation, Micronutrients, Nutrition, Poultry

Abstract

Trace minerals, particularly copper, zinc and manganese, play a role in ensuring optimal immune function. To examine the effects of diets containing different levels and sources of trace minerals on the inflammatory response, Cobb 500 broilers were fed four experimental diets containing 5 mg/kg Cu and 45 mg/kg of Zn and Mn or 10 mg/kg Cu and 90 mg/kg Zn and Mn in either the sulfate or hydroxychloride form. When the broilers were 5 weeks of age, 16 μg of lipopolysaccharide (LPS) was injected into the pulp of growing feathers (GF; 16 GF per chicken; 1 μg LPS per GF). Injected GF and blood were sampled before (0 hour) and at 6- and 24-hours post-GF-injection of LPS. Samples were used to determine leukocyte infiltration profiles in LPSinjected pulps, alterations in concentrations and proportions of blood leukocytes (WBC), concentrations of thrombocytes, red blood cells (RBC) and other RBC-related measurements, reactive oxygen species (ROS) generation, and superoxide dismutase (SOD) activity. A time effect (P ≤ 0.05) was observed for most of the aspects examined. In GF, LPS-injection into the pulp resulted in heterophil and monocyte/macrophage infiltration that reached maximal levels at 6- and 24-hours, respectively. Additionally, levels of ROS generation were greatly increased at 6 hours post-pulp injection of LPS. In the blood, GF injection of LPS increased heterophil and monocyte concentrations at 6 hours, thrombocyte concentration and plasma SOD activity at 24 hours, and decreased lymphocyte and RBC concentrations at 6 hours. While few dietary effects were observed, birds fed lower trace mineral levels had lower SOD activity in the GF pulp (but not in the plasma) than the chickens fed higher levels of trace minerals. Using the GF as a minimally invasive, cutaneous test-site, together with periodic sampling of injected GF and blood for laboratory analyses, the early phase of LPS-induced inflammatory response could be observed both at the local (GF-pulp) and systemic (peripheral blood) level in the same broiler chickens. Furthermore, inclusion of the GF-injection approach revealed effects of dietary supplementation on the inflammatory activities in the inflamed tissue that were not detected in the blood.

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