Date Available

9-21-2021

Year of Publication

2021

Document Type

Master's Thesis

Degree Name

Master of Science (MS)

College

Agriculture, Food and Environment

Department/School/Program

Animal and Food Sciences

Advisor

Dr. James C. Matthews

Abstract

Experiment 1 tested the hypothesis that ad libitum consumption of a 1:1 blend (MIX) of sodium selenite (ISe) and SELPLEX vs solely ISe as selenium (Se) supplements (27 ppm) in a vitamin-mineral mix (V-M) by steers subjected to summer-long grazing of toxic endophyte-infected tall fescue (TE) would ameliorate the negative effects of TE by positively affecting the expression pattern of prolactin (PRL) and NF-kB pathway genes by circulating leukocytes (WBC). Experiment 2 tested the hypothesis that the MIX form of supplemental Se also would ameliorate the negative effects of in vitro blood lipopolysaccharide challenge (LPS) on WBC gene expression. The MIX form of Se increased whole blood Se, serum PRL, and red blood cell concentrations; decreased monocyte abundance; but did not affect WBC gene expression in either pathway or experiment. However, Experiment 1 revealed that TE consumption altered expression of 5 PRL pathway genes, and 7 NF-kB genes, suggesting a reduced adaptive immune response in cattle consuming TE. Experiment 2 found that LPS challenge differentially affected expression of WBC PRL receptor (PRLR) isoforms, and altered expression of 4 PRL, and 4 NF-kB pathway genes, indicating an increased inflammatory response in cattle consuming TE with exposure to LPS.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2021.388

Funding Information

This study was supported by the United States Department of Agriculture-Agricultural Research Service (Dr. James C. Matthews and Dr. Phillip J. Bridges) Grant (no.:201602041509) in 2018.

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