The Role of Cyclooxygenase inhibitors on lipopolysaccharide-induced hypophagia in chicken

previous studies showed that cyclooxygenase 1 (COX) enzyme has important role in lipopolysaccharide (LPS) induced hypophagia in mammals but effect of COX on LPS-induce hypophagia has not been studied in avian species. Current study was designed to investigate effects of Indomethacin, a non-selective cyclooxygenase inhibitor, Aspirin (irreversible cyclooxygenase inhibitor), Piroxicam (a selective COX-1 inhibitor) and Celecoxib (a selective COX-2 inhibitor) on lipopolysaccharide (LPS)-induced hypophagia in 3-h food-deprived (FD3) cockerels. A hundred and sixty ROSS 308 chickens were randomly located in 5 experiments and 4 treatment groups within 8 replicate in each group of experiments. Guide cannula surgically implanted into the lateral ventricle of chickens. In experiment 1, birds received LPS (5, 10 and 20 ng) intracerebroventriculary (ICV). In experiment 2, chickens were intraperitoneally (i.p.) injected with Indomethacin (5 mg/kg) prior to LPS injection (20 ng; ICV). In experiment 3, birds were i.p. injected with Aspirin (50 mg/kg) followed by LPS injection (20 ng; ICV). In experiment 4, the chickens were given LPS (20 ng; ICV) after Piroxicam injection (10 mg/kg; i.p.). In experiment 5, chickens were injected with Celecoxib (10 mg/kg; i.p.) prior to LPS injection (20 ng; ICV). Cumulative food intake was determined until 8 h post-injection. According to the results, LPS significantly decreased food intake at 4 and 8 h post injection in birds (P≤0.05). Furthermore, LPS-induced hypophagia was attenuated by pre-injection with Indomethacin, Aspirin and Celecoxib (P≤0.05). However, Piroxicam had no effect on LPS-induced hypophagia (P≥0.05). These results suggest that presumably COX-2 mediates LPS-induced hypophagia in broilers.