Replacing Dietary Roughage with Barley Hay Affects Rumen Fermentation, Microbial Community, Serum Immune and...

Area of Science:

• Animal Nutrition and Metabolism
• Ruminant Physiology
• Immunology

Background:

• Barley hay (BH) is rich in protein and fiber, with bioactive compounds.
• Hypothesized to positively influence ruminal microbiota and systemic immunity in sheep.
• Need to understand the effects of graded BH substitution for optimal sheep nutrition.

Purpose of the Study:

• To evaluate the impact of replacing traditional forage with graded levels of BH on sheep.
• Assessed effects on ruminal fermentation, microbial composition, and blood immune/antioxidant status.
• Determined optimal BH substitution level for sheep health and performance.

Main Methods:

• Forty-five lambs were divided into five groups: control and four BH substitution levels (25%, 50%, 75%, 100%).
• Ruminal fermentation, microbiota, and blood parameters (immune and antioxidant markers) were analyzed at 30 and 60 days.
• Statistical analysis and correlation analysis were performed to link microbial changes with host responses.

Main Results:

• BH supplementation increased ruminal acetate and the acetate-to-propionate ratio, while reducing ammonia-nitrogen.
• BH enriched fiber-degrading bacteria (e.g., Clostridia, Prevotella) without altering alpha diversity.
• BH modulated immune markers (IgA, IgG, IL-6, TNF-α) and antioxidant status (reduced CAT, increased MDA), with BH100 showing the most favorable profile.

Conclusions:

• Barley hay substitution modulates ruminal fermentation and immune responses by promoting fiber-degrading bacteria.
• BH supplementation can enhance beneficial microbial populations and systemic immunity.
• Complete replacement (BH100) appears superior, optimizing acetate and immunoglobulin production while mitigating oxidative stress.