Use of urinary 13,14, dihydro-15-keto-prostaglandin F2α (PGFM) concentrations to diagnose pregnancy and predict parturition in the giant panda (Ailuropoda melanolecua).

Beth M Roberts,Janine L Brown,Barbara S Durrant,David C Kersey,Rebecca J Snyder,Andrew J Kouba,Bi-Song Yue

doi:10.1371/journal.pone.0195599

Abstract

Pregnancy determination is difficult in the giant panda (Ailuropoda melanolecua), representing a challenge for ex situ conservation efforts. Research in other species experiencing pseudopregnancy indicates that urinary/fecal concentrations of 13,14, dihydro-15-keto-prostaglandin F2α (PGFM) can accurately determine pregnancy status. Our objective was to determine if urinary PGFM concentrations are associated with pregnancy status in the giant panda. Urinary PGFM concentrations were measured in female giant pandas (n = 4) throughout gestation (n = 6) and pseudopregnancy (n = 4) using a commercial enzyme immunoassay. Regardless of pregnancy status, PGFM excretion followed a predictable pattern: 1) baseline concentrations for 11–19 weeks following ovulation; 2) a modest, initial peak 14–36 days after the start of the secondary urinary progestagen rise; 3) a subsequent period of relatively low concentrations; and 4) a large, terminal peak at the end of the luteal phase. Pregnant profiles were distinguished by an earlier initial peak (P = 0.024), higher inter-peak concentrations (P < 0.001), and a larger terminal peak (P = 0.003) compared to pseudopregnancy profiles. Parturition occurred 23 to 25 days from the initial PGFM surge and within 24 hours of the start of the terminal increase. These pattern differences indicate that urinary PGFM monitoring can be used to predict pregnancy status and time parturition in the giant panda. Furthermore, this is the only species known to exhibit a significant PGFM increase during pseudopregnancy, suggesting a unique physiological mechanism for regulating the end of the luteal phase in the giant panda.

Highlights

Once widespread throughout southern China, only ~2,000 giant pandas remain in the wild [1], and these populations are distributed across a highly fragmented habitat [2]
Serially-diluted urine samples demonstrated displacement curves parallel (R2 = 0.999, P < 0.001) to those obtained for the PGFM standards (Fig 1A)
Interassay coefficients of variation (CV) of high (800 pg/ml) and low (100 pg/ml) PGFM controls run on each plate were 13% and 16%, respectively (n = 59), and intra-assay CV was

Summary

Introduction

Once widespread throughout southern China, only ~2,000 giant pandas remain in the wild [1], and these populations are distributed across a highly fragmented habitat [2]. Captive giant pandas represent ~20% of the global population and are a major resource for the species’ survival [3]. Intensive research over the last 30 years has improved giant panda husbandry and assisted breeding techniques, resulting in a sustainable captive population [3,4,5,6]. The lack of reproductive success in some captive individuals remains a challenge for preserving longterm genetic diversity [3, 7]. Considerable research has been conducted on the biology of giant pandas (Ailuropoda melanolecua), but many aspects of this species’ reproductive physiology remain poorly understood, including biomarkers of pregnancy and pregnancy loss. The lack of a definitive pregnancy diagnosis tool presents a major challenge for ex situ species management. A better understanding of the unusual and complex reproductive physiology of this species would benefit conservation efforts

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Conclusion