LIS-MSCA

Summary of the context and overall objectives of LIS

High-yielding dairy cows are often fed diets high in starch and low in fiber to boost energy intake and increase milk yield. However, such diets heighten the risk of subacute ruminal acidosis (SARA), a prevalent digestive disorder that negatively impacts animal health and herd profitability. SARA leads to reduced feed intake, decreased milk production, impaired rumen digestion, and severe health issues such as diarrhea, rumen mucosal damage, laminitis, inflammation, and liver abscesses. Studies have shown that high levels of fermentable starch in diets, such as corn silage and corn meal, are linked to increased SARA risk and reduced feed efficiency. Due to the high prevalence of SARA in Europe, which has resulted in substantial economic losses estimated at 994.4 million euros annually. Given the significant economic impact, understanding the causes of SARA and developing effective solutions to mitigate its occurrence is crucial.

Our project addresses this critical issue by focusing on the role of ruminal lipopolysaccharide (LPS) in SARA pathogenesis. Ruminal LPS, a major component of the outer membrane of gram-negative bacteria, is found in higher concentrations in SARA-affected cows due to bacterial lysis.  Dosing LPS from E. coli into culture systems changes the bacterial community and increases certain bacteria.  However, the potency of LPS from ruminal bacteria differs from that of E. coli, suggesting distinct impacts on the rumen environment. Meanwhile, the specific mechanisms underlying its involvement in SARA development remain unclear. By isolating and studying LPS from ruminal bacteria under SARA conditions, we aim to gain deeper insights into its mechanisms of action and its impact on rumen health.

The objectives of this project are to: 1. Isolate LPS from rumen bacteria by inducing SARA in a batch culture system;2. Compare the effects of ruminal bacterial LPS (LPS-R) with E. coli LPS (LPS-E) on ruminal fermentation, bacterial community composition (BCC), and function using 16S rRNA and RNA sequencing.

In conclusion, by elucidating these mechanisms, we can develop targeted interventions to mitigate SARA risk without compromising milk yield. This has the potential to not only improve animal welfare but also enhance the sustainability and profitability of dairy farming operations. Ultimately, our research has the power to transform dairy farming practices, reducing the prevalence of SARA and its associated economic losses while ensuring the continued supply of high-quality dairy products to meet global demand. Through collaboration with industry stakeholders, our findings can be translated into practical solutions that benefit both dairy farmers and society as a whole.