Plasma Yolk Precursor Dynamics during Egg Production by Female Greater Scaup (Aythya marila): Characterization and Indices of Reproductive State

ABSTRACT We characterized dynamics of the plasma yolk precursors vitellogenin (VTG), very-low-density lipoprotein (total VLDL-TG), and VLDL particle size distribution during egg production by female greater scaup (order: Anseriformes, Aythya marila). We also evaluated VTG and total VLDL-TG as physio...

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Bibliographic Details
Main Authors: Kristen B Gorman, Daniel Esler, Rosemary L Walzem, Tony D Williams
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Published: 2009
Subjects:
Aythya marila
greater scaup
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1038.7679
http://www.sfu.ca/biology/wildberg/NewCWEPage/papers/GormanetalPhysBiochemZool09.pdf
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Summary:ABSTRACT We characterized dynamics of the plasma yolk precursors vitellogenin (VTG), very-low-density lipoprotein (total VLDL-TG), and VLDL particle size distribution during egg production by female greater scaup (order: Anseriformes, Aythya marila). We also evaluated VTG and total VLDL-TG as physiological indices of reproductive state. Mean ‫1ע(‬ SE) plasma concentrations of VTG and total VLDL-TG for females with nondeveloped ovaries were mg Zn mL Ϫ1 and 0.58 ‫ע‬ 0.05 3.75 ‫ע‬ mmol TG L Ϫ1 , respectively. Yolk precursor concentrations 0.29 increased rapidly to maximum levels in association with small increases in ovary mass during rapid follicle growth. Mean concentrations of VTG and total VLDL-TG for females with a full ovarian follicle hierarchy were mg Zn mL Ϫ1 and 3.38 ‫ע‬ 0.40 mmol TG L Ϫ1 , respectively. Concentrations of VTG 7.31 ‫ע‬ 2.56 and total VLDL remained elevated throughout the laying cycle and decreased markedly by 3 d into incubation. Individual reproductive state (non-egg producing vs. egg producing) was more accurately identified by plasma profiles of VTG (90%) than by those of total VLDL-TG (74%). Greater scaup VLDL particle sizes during egg production were within the range for predicted yolk-targeted VLDL size (25-44 nm). We conclude that plasma profiles of VTG and total VLDL-TG can be used as nonlethal, physiological indices of reproductive state in greater scaup and should be of great utility to a variety of evolutionary, ecological, and applied conservation studies of reproduction in waterfowl.

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