# Cryptosporidium spp. infection drives distinct alterations in the faecal extracellular vesicles metaproteome of calves

## TL;DR

This study shows that Cryptosporidium infection in calves changes the proteins in their fecal extracellular vesicles, offering a non-invasive way to monitor gut health and disease.

## Contribution

The study introduces faecal extracellular vesicles as a novel non-invasive tool for monitoring gut health and pathogen effects in calves.

## Key findings

- Cryptosporidium spp. infection alters the faecal extracellular vesicles proteome, reducing host and microbial defense proteins.
- fEVs contain host and microbial proteins that reflect gut physiology and pathophysiology.
- Lyophilisation significantly changes the protein profiles of fEVs.

## Abstract

The gut is primarily responsible for digestion and nutrient absorption, plays essential roles in immune regulation and metabolic balance, and is supported by a diverse microbiome essential for digestion, absorption, and defence from pathogens. Understanding gut physiology and pathophysiology in pre-weaned calves is essential, as infections like cryptosporidiosis can lead to gut dysbiosis, impair growth, and negatively affect long-term productivity. Faeces are considered easily accessible biological specimens that can be used to monitor gastrointestinal disorders. The methods employed in this study aimed to investigate the potential use of faecal extracellular vesicles (fEVs) as a non-invasive tool for assessing gut health and infections in calves. Particularly, considering Cryptosporidiosis as a model for gut infectious disease.

The analysis using a hybrid reference-based metaproteomic approach revealed that the proteomic profiles of fEVs significantly differed from that of faecal crude (FC) suspensions. Both sample types contained microbial and host proteins, which are important for maintaining gut defence and microbial homeostasis. However, Cryptosporidium spp. infection significantly shifted the fEV proteome, reducing both host and microbial proteins involved in gut defence. It also reduced proteins from microbes that are important for maintaining microbial homeostasis, while increasing stress-related proteins. Further, lyophilisation of fEVs significantly altered the protein profiles.

These findings underscore that fEVs contain host and microbial proteins that are a valuable resource for studying gut physiology, pathophysiology, host-microbe-pathogen interactions, and microbiome dynamics. Changes in the proteomic profile of fEVs during Cryptosporidium spp. infection demonstrates the pathogen’s ability to manipulate host immune defences and microbiome composition for its survival and replication. Overall, these findings support the utility of fEV proteomics as a non-invasive platform for biomarker discovery and advancing research in gastrointestinal health and disease in livestock.

The online version contains supplementary material available at 10.1186/s40104-025-01332-4.