Effect of administering two prostaglandin synthetase inhibitors (indomethacin and aspirin) on egg production in the domestic fowl (Gallus domesticus).

The injection of 50 mg/kg bodyweight of a prostaglandin synthetase inhibitor (indomethacin) brought about a delayed oviposition time in birds of three breeds of layers, whereas the injection of 5 mg indomethacin had no effect. The daily ingestion of up to 400 mg aspirin or up to 10 mg indomethacin for three weeks, or 750 mg aspirin or 200 mg indomethacin for two weeks had no effect on egg production, oviposition time, egg-shell water conductance, oviducal prostaglandin synthetase activity or bird behaviour. Prostaglandin synthetase activity was demonstrable in both control and treated birds only in the tubular glands of the shell gland. These observations suggest that prostaglandins play a minor role in normal reproductive activity in the female domestic fowl.