Experimental evidence that dietary antioxidants induce an antiviral transcriptomic signature in a wild seabird.

Infectious disease emergence in natural systems is driven by complex host-pathogen-environment interactions. Nutritional factors, particularly dietary antioxidants, can modulate physiological states by enhancing immune function and mitigating oxidative damage, but the underlying molecular mechanisms in wildlife remain poorly understood. To bridge this gap, we conducted a transcriptomic analysis of blood samples from both healthy and clinically affected Magnificent frigatebirds Fregata magnificens chicks treated with either resveratrol (a plant-derived polyphenol with known antiviral and antioxidant properties) or a placebo. Resveratrol supplementation induced significant gene expression changes, particularly in diseased individuals, where we identified the upregulation of ten key genes in treated sick chicks, of which two are unannotated novel transcripts, including the interferon-stimulated genes (IFI6, OASL2) and immune regulators (SOCS1, PLAC8). Furthermore, resveratrol treatment was associated with increased expression of DDX60, a potent antiviral factor, and CYGB1, which supports cytoprotection. In contrast, healthy chicks showed fewer differentially expressed genes, primarily associated with metabolism and cellular organization. Collectively, our results reveal a transcriptional signature consistent with dietary antioxidants such as resveratrol acting as active molecular modulators of host defence, rather than simple passive antioxidants, although direct evidence of enhanced antiviral protection (e.g. reduced viral load) remains to be established. This study highlights the utility of transcriptomic approaches to link nutritional ecology with disease dynamics, offering a framework for understanding how dietary quality shapes host defence strategies and population resilience under increasing pathogen pressure.