HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal My Folders Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ahn, J. Articles by El Halawani, M. Search for Related Content PubMed PubMed Citation Articles by Ahn, J. Articles by El Halawani, M. Agricola Articles by Ahn, J. Articles by El Halawani, M.

Effects of Active Immunization with Inhibin Subunit on Reproductive Characteristics of Turkey Hens¹

^a Department of Animal Science, University of Minnesota, St. Paul, Minnesota 55108 ^b School of Agricultural Biotechnology, Seoul National University, Suwon 441-744, Korea ^c School of Biology, Institute of Science, Suranaree University of Technology, Nakornrachasima 3000, Thailand

ABSTRACT

The hypothesis for the present study is that the active immunization of female turkeys with inhibin (INH) would neutralize endogenous INH, and increase levels of circulating follicle stimulating hormone (FSH) and the number of preovulatory follicles, and subsequently enhance egg production. Two experiments were conducted with female turkeys in their first (30 wk of age) and second (62 wk of age) laying cycles. Treatment groups included control turkeys immunized with keyhole limpet hemocyanine (KLH) and experimental turkeys immunized with recombinant turkey inhibin conjugated to KLH (rtINH), vasoactive intestinal peptide (VIP) conjugated to KLH or rtINH+VIP. Egg production increased (P < 0.05) in VIP and rtINH+VIP immunized birds, but not in rtINH immunized hens in comparison with a control group. A similar number of ovarian follicles, arranged in the follicular hierarchy of laying hens, was observed in all experimental groups. However, there was a larger number of nongraded yellow follicles in rtINH-immunized (62.5%) and rtINH+VIP-immunized (73.5%) groups compared with that of controls, suggesting overstimulation by FSH. Anterior pituitary FSHß subunit, LHß subunit, and prolactin (PRL) mRNA contents were determined by Northern blot analysis and reverse transcriptase-polymerase chain reaction (RT-PCR) in laying hens at the end of the experimental period. Hens immunized with rtINH showed increased FSHß subunit mRNA content, but no change in the content of LHß subunit or PRL mRNA. Hens immunized with VIP or rtINH+VIP had significant increases in both pituitary LHß subunit and FSHß subunit mRNA contents, accompanied by a decline in PRL mRNA abundance. The magnitude of the increase in FSHß subunit to INH immunoneutralization was greater in first-cycle hens than in second-cycle hens. These data suggest that active immunization of female turkeys with INH neutralizes endogenous INH and increases both circulating FSH and the number of preovulatory follicles. However, no significant increase in egg production was observed in INH-immunized hens. The data confirm previous reports that VIP immunoneutralization increases egg production in turkey hens and shows for the first time that it also increases FSHß subunit and LHß subunit gene expression.

FOOTNOTES

First decision: 6 June 2001.

¹ Supported by grant US-2846-97 from BARD.

² Correspondence: Mohamed El Halawani, 495 Animal Science, Veterinary Medicine, 1988 Fitch Avenue, University of Minnesota, St. Paul, MN 55108. FAX: 612 625 2743;elhal001{at}tc.umn.edu

This article has been cited by other articles:

				Y. Chaiseha, O. M. Youngren, and M. E. El Halawani Expression of Vasoactive Intestinal Peptide Receptor Messenger RNA in the Hypothalamus and Pituitary Throughout the Turkey Reproductive Cycle Biol Reprod, March 1, 2004; 70(3): 593 - 599. [Abstract] [Full Text] [PDF]