Carotenoid supplementation during adulthood, but not development, decreases testis size in mallards

Michael W. Butler, Briette Karanfilian, Melissa Homsher, Kevin McGraw

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Nutritional constraints on reproduction are well-characterized in female animals, but rarely have particular nutrients been linked to male reproductive investments. Carotenoid pigments promote egg-laying and fertility in several animals, and are displayed externally within secondary sex traits by males of many colorful species to attract mates, but it is unclear if or how carotenoids affect male primary sex traits. We manipulated carotenoid availability in the diet of male mallards (Anas platyrhynchos) during both development and adulthood to determine effects on size and carotenoid content of the testes. We found that developmental carotenoid manipulations did not affect testis size or carotenoid concentration, but that increased carotenoid dietary levels at adulthood resulted in more carotenoid-rich, but smaller, testes. This latter result was surprising, given positive correlations in mammals between testicle size and carotenoid concentration. We also found negative correlations between testis size and carotenoid concentration for individual ducks, regardless of dietary treatment. These results suggest that carotenoid deposition into testis tissue can reduce investment in gonad size (and thus overall sperm count), although the functional consequences of this relationship remain to be tested.

Original languageEnglish (US)
Pages (from-to)465-469
Number of pages5
JournalComparative Biochemistry and Physiology - A Molecular and Integrative Physiology
Issue number3
StatePublished - Nov 2013


  • Anas platyrhynchos
  • Developmental plasticity
  • Dietary carotenoids
  • Lutein
  • Supplementation
  • Testes

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Aquatic Science
  • Animal Science and Zoology
  • Molecular Biology


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