Dietary energy levels regulate feed intake of broilers through the brain-gut axis

Area of Science:

• Animal Nutrition
• Gut-Brain Axis Research
• Broiler Physiology

Background:

• Dietary energy levels significantly impact broiler feed intake (FI) and growth performance.
• The brain-gut axis (BGA) is a key mediator, but mechanisms linking energy intake, FI, and gut health are not fully understood.

Purpose of the Study:

• To investigate the effects of low-, medium-, and high-energy diets on broiler BGA function over 21 days.
• To elucidate how dietary energy modulates feed intake, growth, and intestinal health via BGA signaling.

Main Methods:

• Broilers were fed low- (2,900 kcal/kg), medium- (3,200 kcal/kg), or high-energy diets (3,500 kcal/kg).
• Feed intake, body weight gain, and feed conversion ratio were measured.
• Hormonal profiles (CCK, POMC, orexin, AgRP, NPY, PYY), hypothalamic signaling pathways (Rac1/PI3K/SF1), cecal microbiota, and intestinal barrier integrity (ZO-1) were analyzed.

Main Results:

• Increasing dietary energy reduced FI but improved weight gain and feed conversion.
• Medium-energy diets favorably modulated appetite hormones and promoted cecal microbiota balance.
• High-energy diets further enhanced satiety signals but impaired intestinal barrier function and induced inflammation, despite activating hypothalamic pathways.

Conclusions:

• Dietary energy levels remodel the BGA, integrating appetite hormones, hypothalamic signaling, and gut health.
• High-energy diets promote growth at the expense of intestinal integrity.
• Further research should explore interventions to optimize broiler growth while preserving gut health.