Response of layer breeders to dietary acetylsalicylic acid. 1. Effects on hen performance and eggshell quality

ABSTRACT White Leghorn breeder hens were fed 0,.05, or.40 % acetylsali-cylic acid (ASA) for either 1 wk or 1 mo. Blood samples were collected 4 h postentrance of an egg into the uterus (baseline) and at oviposition of a hard-shelled (HS) egg. Plasma samples were analyzed for prostaglandin (PG) F2 « by radioimmunoassay. Peripheral PGF2a concentrations peaked upon oviposition of a HS egg in both ASA-fed hens as well as the controls (0 % ASA). The levels of dietary ASA and the duration of time the ASA was administered did not affect baseline or peak PGF2a concentrations. It was concluded that either the timing or route of administration of ASA resulted in the failure of ASA to effectivel