Phenylalanine (Phe), an essential aromatic amino acid, is emerging as a potential biomarker of metabolic and health status in animals. Altered Phe concentrations reflect changes in metabolic, inflammatory, and disease processes. In companion animals, shifts in serum or biofluid Phe have been linked to hepatopathies, inflammatory enteropathies, and neoplastic conditions. In livestock, variations in milk or serum Phe accompany mastitis, metabolic stress, lameness, and other production-related disorders. Evidence for cats, horses, poultry, and aquaculture species remains limited. Interpretation is complicated by analytical variability, small sample sizes, and confounding factors such as diet, stress, and microbiome composition.
Non-invasive sampling of milk, urine, saliva, and breath, shows promise for Phe monitoring across animal species. Advances in multi-omics, particularly metabolomics, proteomics, and microbiome analyses, can clarify mechanisms and support development of composite biomarker panels. This review evaluates current evidence on Phe as a biomarker across species, highlights gaps in research coverage and methodology, and outlines priorities for future work. Expanding studies to underrepresented species, standardizing measurement protocols, and conducting longitudinal research. Addressing these priorities is essential to establish Phe as a robust biomarker, for veterinary diagnostics, health monitoring, and the optimization of animal welfare and production systems.
Details
Title
Phenylalanine as a biomarker of disease in animals: Current evidence and future perspectives
Authors/Creators
James Mettam
Nauman Zaheer Ghumman
Bao-Tao Liu
Henry Annandale - Murdoch University, School of Veterinary Medicine
Jully Gogoi Tiwari - Murdoch University, School of Veterinary Medicine