Ileal epithelial tissue transcript profiles of steers with experimentally induced liver abscesses

Authors: Lindholm-Perry, Amanda; Keel, Brittney; HALES, KRISTIN - Texas Tech University; Wells, James - Jim; Kuehn, Larry; Keele, John; Crouse, Matthew; Nonneman, Danny - Dan; NAGARAJA, T - Kansas State University; LAWRENCE, TY - West Texas A & M University; AMACHAWADI, RAGHAVENDRA - Kansas State University; Carroll, Jeffery - Jeff Carroll; Sanchez, Nicole; Broadway, Paul

Submitted to: Applied Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2024
Publication Date: 6/1/2024
Citation: Lindholm-Perry, A.K., Keel, B.N., Hales, K.E., Wells, J.E., Kuehn, L.A., Keele, J.W., Crouse, M.S., Nonneman, D.J., Nagaraja, T.G., Lawrence, T.E., Amachawadi, R.G., Carroll, J.A., Burdick Sanchez, N.C., Broadway, P.R. 2024. Ileal epithelial tissue transcript profiles of steers with experimentally induced liver abscesses. Applied Animal Science. 40(3):414-420. https://doi.org/10.15232/aas.2023-02503.
DOI: https://doi.org/10.15232/aas.2023-02503

Interpretive Summary: Liver abscesses in cattle negatively impact cattle production and are a source of economic loss for producers across the beef cattle industry. Recently, a model has been developed to induce liver abscesses that will provide a method to better study and evaluate the mechanisms that underlie their development. Using this model, calves were fed a diet to produce acidosis and these animals were also inoculated with bacteria typically isolated from liver abscesses to promote the development of liver abscesses. Seven of the 13 animals developed liver abscesses. Ileum tissue was collected from these animals to determine if there were genes differentially expressed in the animals with liver abscesses. A total of 26 differentially expressed genes were identified. Genes involved in cellular restructuring, transport of compounds across cell membranes, and protection of RNA and protein products were also identified as differentially expressed. These functions illustrate that there are changes in the ileum that correspond with the development of liver abscesses.

Technical Abstract: Objective: Liver abscesses in cattle negatively affect production and cause economic losses across the beef cattle industry. Recently, a nutritional model has been developed to induce liver abscesses that will provide a method to evaluate the underlying mechanisms driving their development. The objective of this study was to evaluate gene expression of ileal tissue from calves challenged using the new model. Materials and Methods: In the model, calves were fed a diet to induce ruminal acidosis and were then intraruminally inoculated with bacteria typically associated with liver abscesses. On d 21, following inoculation, calves were euthanized. Seven of the 13 calves had liver abscesses. Ileal tissues were collected and total RNA was isolated for RNA-sequencing. Results and Discussion: A total of 26 genes were differentially expressed in the calves with liver abscesses compared to those without. Two genes (COX2, COX3) are components of the cytochrome c oxidase enzyme in the electron chain transport pathway, and both were down-regulated among the animals with liver abscesses. Other genes involved in cellular restructuring, transport of compounds across cell membranes, and protection of RNA, and protection of protein products were also identified. These functions illustrate that there are changes in the ileal epithelium that correspond to the development of liver abscesses. Implications and Applications: We identified several genes that were differentially expressed in the ileal tissue of calves that developed liver abscesses using the combination of an acidosis-inducing diet and intraruminal inoculation of bacteria. Our results suggests that the ileum has a role in liver abscess development, and future studies to validate the involvement of the mucosal barrier of the ileum are warranted.