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ARS Home » Research » Publications at this Location » Publication #113513
Title: COMPARISON OF REPRODUCTIVE HORMONE LEVELS IN TURKEY EMBRYOS INCUBATED IN LONG-TERM SHELL-LESS CULTURE AND IN OVO

Author
item ABDELNABI, M. - UNIVERSITY OF MARYLAND
item RICHARDS, MARK
item OTTINGER, M. - UNIVERSITY OF MARYLAND

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: We have developed and employed an experimental procedure called long-term shell-less culture in which turkey embryos are incubated outside of the eggshell for extended periods of time. This technique is particularly useful to study various aspects of avian embryonic growth and development under defined conditions. In this study, we measured the levels of reproductive hormones(estrogen and androgen)to determine the course of development of both male and female embryos. The results indicated that reproductive development occurred normally in embryos incubated outside of the eggshell. Further, in embryos incubated in the eggshell, key hormonal changes (estrogen levels) were observed during the late phases of embryonic development that were important to determining the sex of the hatchling. This is the first report of such changes in developing turkeys. Our findings highlight the potential usefulness of long-term shell-less culture ein studying the role of hormones in the development of avian embryos.

Technical Abstract: Changes in concentrations of 17á estradiol (E2) and androgen hormones were measured in turkey embryos incubated in long-term shell-less culture (ex ovo) and in ovo. Blood samples were obtained from both sets of embryos on days 14, 16, 18, 20, and 22 then from embryos incubated in ovo on days 24, 26 and 28. Cultured embryos showed no differences for both hormones between males and females at all ages, with one exception. On day 14 of incubation the ex ovo females had higher(P<0.01)E2 levels (55.6ñ5.1 pg/ml) than the in ovo females (32.2ñ2.3 pg/ml). No significant differences were found in androgen concentrations between sexes in ovo on days 24, 26 and 28 of incubation. However, on days 24, 26 and 28 in ovo females showed highly significant differences (P<0.01) in E2 compared to males of the same age. These results indicate a similar developmental pattern for the endocrine system in ovo and ex ovo through day 22 of incubation. Further, distinct sex differences in E2 emerge late in embryonic development, which are likely to be critical for sexual differentiation.