γ-aminobutyric acid improves gut-brain axis function and behavioral adaptation in broilers under low-protein diet

Area of Science:

• Animal Science
• Poultry Nutrition
• Gut Health

Background:

• Low crude protein (CP) diets enhance feed efficiency and reduce ammonia emissions in broiler production.
• However, reduced CP can negatively impact broiler productivity, immune function, and gut integrity.
• γ-aminobutyric acid (GABA) is a non-protein amino acid with potential benefits for animal health and metabolism.

Purpose of the Study:

• To evaluate the effects of GABA supplementation in low CP diets on broiler productivity, enzyme activity, neuropeptidergic gene expression, and behavior.
• To investigate the potential of GABA to mitigate negative effects associated with reduced dietary CP.
• To understand the molecular mechanisms underlying GABA's influence on broiler physiology and behavior.

Main Methods:

• A factorial experiment involving 360 male Ross 308 broilers was conducted using two CP levels (19.5% and 18.0%) and three GABA levels (0, 100, and 200 mg/kg).
• Productivity, enzyme activities (amylase, protease), neuropeptidergic and inflammatory gene expression (RT-qPCR), and broiler behavior were assessed.
• Statistical analysis was performed to determine the effects of CP, GABA, and their interaction on the measured parameters.

Main Results:

• Dietary CP and GABA levels did not significantly affect overall broiler productivity.
• Reducing CP downregulated anti-inflammatory and tight junction gene expression while altering broiler behavior.
• GABA supplementation upregulated orexigenic genes, downregulated anorexigenic genes, enhanced anti-inflammatory and tight junction gene expression, and modulated broiler behavior, promoting feeding and drinking.

Conclusions:

• A 1.5% reduction in dietary CP is feasible without compromising broiler production but impacts gut barrier and inflammatory gene expression.
• GABA supplementation in low CP diets effectively promotes homeostatic regulation, improves immune and gut barrier functions, and positively modulates broiler behavior.
• GABA shows promise as a feed additive to support broiler health and performance under low protein feeding strategies.