ABSTRACT
BACKGROUND: Broilers lung mechanisms that regulate endothelin [ET] in the lung are complex and poorly understood
OBJECTIVES: METHODS: In this experiment lung ET-1 mRNA levels and lung mRNA expression for the ET[A] receptors were determined in lung tissue weekly [term = 42 days, intervals = 7 days] Serum endothelin concentration was also measured at these ages
RESULTS:The study showed that expression of endothelin in lungs of layers and broilers was similar during the first three weeks and the overall trend of ET-1 expression was increasing. However, there was a significant increase of ET-1 expression which started from the fourth week and gradually increased until the end of the commercial life of the chicken [day 42]. ET-A expression in the lungs of broilers was significantly higher than layers during the last three weeks of life. Overall, trends of serum ET-1 concentration increased in both layers and broilers, but serum ET-1 concentration in broilers was significantly higher than layers
CONCLUSIONS: The higher level of serum Endothelin and expression of ET-1 and ETAin broiler lungs may explain the higher sensitivity of broilers to the vasoconstrictions activity of endothelin and the higher sensitivity of these animals to pulmonary hypertension [PH]