Role of the Rumen Epithelium and Associated Changes Under High-Concentrate Diets

Area of Science:

• Ruminant nutrition
• Animal physiology
• Gastroenterology

Background:

• High-concentrate diets (HCD) improve ruminant production but risk subacute rumen acidosis (SARA).
• SARA, caused by rumen acidification from rapidly fermentable carbohydrates, reduces dry matter intake (DMI) and causes inflammation.
• The rumen epithelium (RE) plays crucial roles in absorption, transport, and barrier function, making it central to SARA pathogenesis.

Purpose of the Study:

• To review the structure, functions, and responses of the rumen epithelium (RE) under high-concentrate diets (HCD).
• To elucidate the cellular and molecular mechanisms of subacute rumen acidosis (SARA) pathogenesis.
• To understand the impact of HCD on RE function and integrity.

Main Methods:

• Literature review of studies on HCD, SARA, and rumen epithelium.
• Analysis of cellular and molecular changes in RE under dietary challenges.
• Synthesis of current knowledge on SARA pathogenesis.

Main Results:

• Short-term HCD feeding initially enhances RE proliferation and transporter activity.
• Prolonged HCD feeding impairs RE function and promotes inflammation.
• Accumulation of lactate and SCFAs from HCD lowers rumen pH, leading to SARA.

Conclusions:

• The rumen epithelium undergoes significant adaptive and detrimental changes under HCD, contributing to SARA.
• Understanding RE responses to HCD is critical for managing SARA and mitigating economic losses in ruminant production.
• This review provides a comprehensive analysis of RE's role in SARA pathogenesis at cellular and molecular levels.