The role of prostaglandins in the premature oviposition of chicken eggs

Janice Marie Balog, Purdue University

Abstract

Indomethacin injections delayed oviposition in hens laying a high incidence of soft-shelled (SS) and shell-less (SL) eggs as well as hens laying exclusively hard-shelled (HS) eggs. Indomethacin was more effective in delaying oviposition when injected 16 hours post-entrance of the egg into the uterus as compared with 4 hour post-entrance injections. Shell thickness of the first egg laid following indomethacin injection was increased in the SS/SL groups but not in the HS groups. The indomethacin-induced delay in oviposition resulted in an improvement in shell quality of the first egg laid post-injection. Aged layer breeders were divided into high and low incidence groups of SS/SL egg layers and fed either control or.05% aspirin rations for 4 weeks. A decrease in SL egg production occurred in the high incidence group of SS/SL egg layers fed aspirin as compared to controls. This reduction in SL egg production resulted in a slight, but nonsignificant, increase in SS egg production. It appeared that the aspirin fed hens of the high incidence group of SS/SL egg layers were attempting to utilize more calcium for shell formation (fewer SL eggs and more SS eggs), but at the expense of producing thinner shells for the HS eggs. It was concluded that aspirin can reduce the production of SL eggs, but perhaps due to the physiological limitations in calcium mobilization, these aged breeders were not able to convert SL eggs to HS eggs. White Leghorn breeder hens were fed 0%,.05%, or.40% aspirin for either one week or one month. Blood samples were collected 4 hours post-entrance of an egg into the uterus and at oviposition of a HS egg. Plasma samples were subjected to radioimmunoassay. Peripheral PGF$\sb{2\alpha}$ levels peaked upon oviposition of a HS egg in both aspirin and control groups. The levels of dietary aspirin and length of time administered did not affect basal or peak PGF$\sb{2\alpha}$ levels. It was concluded that either the timing or mode of delivery of aspirin resulted in an insufficient level of inhibition to effectively reduce peak peripheral prostaglandin concentrations.

Degree

Ph.D.

Advisors

Hester, Purdue University.

Subject Area

Livestock|Anatomy & physiology|Animals|Veterinary services

COinS