Eggshell biliverdin and protoporphyrin pigments in a songbird: Are they derived from erythrocytes, blood plasma, or the shell gland?

Rita Hargitai, Nóra Boross, Susanne Hámori, Eszter Neuberger, Zoltán Nyiri

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Biliverdin and protoporphyrin pigments are deposited into the eggshell when the developing egg is in the shell gland. However, the site of synthesis of eggshell pigments is still uncertain, although it may influence the possible costs and potential functions of eggshell coloration in avian species. Eggshell pigments may be derived from red blood cells or be produced in other organs and then transferred to the shell gland, or they may be synthesized de novo in the shell gland. We studied in the canary (Serinus canaria) whether eggshell blue-green and brown pigmentations are associated with experimentally elevated anemia, female hematocrit level, immature erythrocyte percentage, and feces and plasma pigment levels during egg laying to find out the possible origin of eggshell pigments. We found no significant effects of hematocrit level or experimentally elevated anemia on intensity of eggshell blue-green and brown pigmentations; therefore, we consider it less likely that eggshell pigments are derived from erythrocytes. In addition, we found no significant associations between female feces biliverdin concentration during egg laying and intensity of eggshell blue-green pigmentation, suggesting that eggshell biliverdin may not originate from the spleen or liver. We found a negative association between plasma and feces protoporphyrin concentrations during egg laying and eggshell brown chroma. This result suggests that an increased production of protoporphyrin in the liver, which could have elevated plasma and feces protoporphyrin concentrations, could inhibit eggshell protoporphyrin pigmentation, probably through affecting enzymatic activities. We suggest that both pigments are produced de novo in the shell gland in the canary, but circulating pigment levels may influence shell gland pigment synthesis, thus connecting the physiological status of the female to eggshell coloration.

Original languageEnglish
Pages (from-to)613-626
Number of pages14
JournalPhysiological and Biochemical Zoology
Volume90
Issue number6
DOIs
Publication statusPublished - Nov 1 2017

Keywords

  • Anemia
  • Antioxidants
  • Bile pigments
  • Eggshell coloration
  • Oxidative stress
  • Sexually selected eggshell coloration hypothesis
  • Shell gland

ASJC Scopus subject areas

  • Physiology
  • Biochemistry
  • Animal Science and Zoology

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