Serum proteome of the Egyptian rousette bat (Rousettus aegyptiacus) reveals signatures of immunity, proteostasis, and metabolism.

Bats are increasingly studied for their ability to coexist with diverse viruses of human health importance. While this focus has yielded insights into host–pathogen dynamics, baseline physiological data from healthy bats remain limited, constraining comparative and mechanistic understanding. Serum proteomics offers a direct window into circulating proteins that underpin immune regulation, cellular maintenance, and metabolism. Here, we characterize the serum proteome of clinically healthy, captive Egyptian rousette bats (Rousettus aegyptiacus), the only known natural reservoir host species of Marburg virus. Using untargeted proteomic profiling, we identified and ranked over 400 proteins across major functional categories. Prominent findings included extensive representation of complement components spanning all activation pathways, high levels of interferon-responsive proteins, and abundant proteasome subunits, including immunoproteasome components. The dataset further revealed a robust profile of oxidoreductases and antioxidant enzymes, consistent with mechanisms of redox balance and iron regulation, alongside an apolipoprotein profile suggestive of dietary specialization. An unexpected finding was the unusually high abundance of type XX collagen, potentially linked to tissue remodeling demands of flight. Exploratory sex-based analyses suggested trends in stress response and immune-related proteins, although sample size limited statistical resolution. This work provides the first-look of the Egyptian rousette bat serum proteome, providing a reference point for cross-species comparisons and future studies of bat immunity, metabolism, and longevity. By identifying constitutive molecular features in healthy individuals, these findings expand the use of proteomics for understanding non-traditional model organisms and set the stage for future targeted functional investigations.