Protective Effects of Niacin on Rumen Epithelial Cell Barrier Integrity in Heat-Stressed Beef Cattle

Area of Science:

• Animal Science
• Physiology
• Nutrition

Background:

• Heat stress negatively impacts beef cattle health and productivity.
• Rumen epithelial barrier integrity is crucial for maintaining physiological functions.
• Intestinal permeability is a key indicator of gut health.

Purpose of the Study:

• To investigate the effects of niacin supplementation on rumen epithelial barrier function in heat-stressed beef cattle.
• To elucidate the role of niacin in mitigating heat stress-induced intestinal permeability.
• To analyze the impact of niacin on tight junction protein expression and inflammatory responses.

Main Methods:

• 12 Jinjiang bulls were divided into thermoneutral (TN), heat-stressed (HS), and heat-stressed niacin-supplemented (HN) groups.
• Plasma concentrations of D-lactic acid, DAO, LPSs, and cytokines were measured.
• Gene expression of tight junction proteins (ZO-1, claudins, occludin) was assessed.

Main Results:

• Heat stress increased D-lactic acid, LPS, and inflammatory cytokine levels while decreasing IL-4.
• Niacin supplementation reduced LPS and inflammatory markers and increased IL-4.
• Heat stress downregulated tight junction protein mRNA expression; niacin upregulated ZO-1 and occludin.

Conclusions:

• Heat stress impairs rumen barrier function and increases intestinal permeability by downregulating tight junction proteins.
• Niacin supplementation mitigates these negative effects, protecting the rumen barrier in heat-stressed cattle.
• Niacin shows potential as a dietary strategy to maintain intestinal integrity in beef cattle under heat stress.