Caffeine causes pulmonary hypertension syndrome (ascites) in broilers

Area of Science:

• Animal Science
• Avian Physiology
• Cardiovascular Research

Background:

• Pulmonary hypertension syndrome (PHS), characterized by elevated pulmonary arterial pressure and right ventricular hypertrophy (RVH), impacts broiler health.
• Experimental models are crucial for understanding PHS pathogenesis and identifying resistant lines.
• Caffeine's effect on pulmonary circulation was previously unestablished.

Purpose of the Study:

• To investigate the impact of caffeine on PHS parameters in broiler chicks.
• To determine if cold temperatures exacerbate caffeine-induced PHS.
• To establish a reliable experimental model for PHS.

Main Methods:

• Two experiments were conducted on young broiler chicks.
• Experiment 1: Caffeine administered at doses of 0-100 mg/(kg BW·d) under standard temperatures.
• Experiment 2: Caffeine administered at doses of 0-45 mg/(kg BW·d) under cool environmental temperatures.

Main Results:

• Caffeine at ≥12.5 mg/(kg BW·d) induced severe PHS, mortality, and RVH in Exp. 1.
• Caffeine and cool temperatures significantly increased PHS incidence and RVH in Exp. 2.
• Hematocrit levels increased with caffeine supplementation, particularly under cool conditions.

Conclusions:

• Caffeine administration effectively induces PHS in broiler chickens.
• Cold environmental temperatures potentiate caffeine's detrimental effects on the pulmonary circulation.
• This study provides a validated model for PHS research in poultry.