Sorghum Grain Secondary Metabolites and Underlying Genetics to Reduce Foodborne Pathogens in Poultry

Author

• Maria A. Conti, Clemson UniversityFollow

Date of Award

5-2026

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Plant and Environmental Science

Committee Chair/Advisor

Richard E. Boyles

Committee Member

Jenna Hershberger

Committee Member

Sachin Rustgi

Committee Member

Mireille Arguelles-Ramos

Abstract

The rise in antibiotic-resistant pathogens poses a threat to the poultry industry's ability to maintain animal health, prompting growing interest in alternatives to synthetic antibiotics. The use of non-tannin sorghum [Sorghum bicolor (L.) Moench] in poultry rations offers a valuable alternative, as this cereal grain has a high bioactive profile that can provide health benefits, including antimicrobial (AM) activity. The scope of this study was to examine the AM potential of non-tannin sorghum grain against Clostridium perfringens, a major foodborne pathogen that negatively impacts poultry health and production. To that end, the inhibitory effects of a non-tannin sorghum recombinant inbred line (RIL) population against C. perfringens were evaluated, and the correlation of these effects with grain quality and field performance was investigated. Additionally, the population’s secondary metabolite profile was analyzed to identify compounds associated with AM activity that could serve as biomarkers for selection. Lastly, QTL mapping was performed to identify marker-trait associations that could be used in marker-assisted breeding to develop enhanced sorghum varieties.

Overall, the AM activity measured in this population had no negative impact on grain quality or field performance, and even showed positive associations with grain yield, thousand-grain weight (TWG), and grain mold resistance. Additionally, positive associations observed with grain gross energy, crude fat, and starch content indicate that AM activity is influenced by high-energy compounds, such as lipids or lipid-derived bioactive secondary metabolites. This was confirmed by the secondary metabolite profiling, which identified 13 compounds associated with AM activity, two of which showed higher abundance in RILs with high AM activity. One metabolite was a phosphatidic acid, a lipid molecule involved in membrane structure and signaling in response to stress, while the other was a ferulic acid amide, a phenolic compound that enhances cell wall integrity and strength.

The QTL analysis revealed a complex genetic architecture and polygenic nature of the AM activity and its underlying metabolic profile, with multiple overlapping QTL regions detected across chromosomes for the AM trait and for eight of the 13 associated metabolites. Interestingly, a major-effect locus on chromosome 1 (at 25.85 Mb) was consistently detected by the AM activity phenotype and by five of those 13 associated metabolites. Upon further exploration, this locus also significantly influenced the relative abundance of additional metabolites that were not associated with this chromosome 1 QTL, indicating that this genetic region may harbor key regulatory gene(s) that modulate different metabolite biosynthesis pathways and, thus, the resulting AM activity. Importantly, this locus was positioned in a region that was not linked to the YELLOWSEED1 (Y1) gene on chromosome 1, which influences pericarp color and is involved in the biosynthesis of phenolic compounds known to have bioactive properties.

Recommended Citation

Conti, Maria A., "Sorghum Grain Secondary Metabolites and Underlying Genetics to Reduce Foodborne Pathogens in Poultry" (2026). All Dissertations. 4256.
https://open.clemson.edu/all_dissertations/4256

Author ORCID Identifier

0009-0004-1592-6241