Understanding how birds rebuild fat stores during migration: insights from an experimental study

• Published in: Scientific reports Vol. 9; no. 1; pp. 10065 - 11
• Main Authors: Araújo, Pedro M., Viegas, Ivan, Rocha, Afonso D., Villegas, Auxiliadora, Jones, John G., Mendonça, Liliana, Ramos, Jaime A., Masero, José A., Alves, José A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11-07-2019; Nature Publishing Group; Nature Portfolio
• Subjects: 101/6; 631/158/2039; 631/158/2455; Abundance; Adipose Tissue - physiology; Animal Migration - physiology; Animals; Aquatic birds; Birds - physiology; Diet; Diet Therapy; Ecosystem; Fasting; Feeding; Food sources; Humanities and Social Sciences; Larvae; Lipogenesis; Migration; Migratory birds; Migratory species; multidisciplinary; Oryza; Science; Science (multidisciplinary); Seasons; Seeds
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-46487-z

Mechanisms underlying fat accumulation for long-distance migration are not fully understood. This is especially relevant in the context of global change, as many migrants are dealing with changes in natural habitats and associated food sources and energy stores. The continental Black-tailed godwit
Limosa limosa limosa
is a long-distance migratory bird that has undergone a considerable dietary shift over the past few decades. Historically, godwits fed on an animal-based diet, but currently, during the non-breeding period godwits feed almost exclusively on rice seeds. The latter diet may allow building up of their fuel stores for migration by significantly increasing
de novo
lipogenesis (
DNL
) activity. Here, we performed an experiment to investigate lipid flux and the abundance of key enzymes involved in
DNL
in godwits, during fasting and refueling periods at the staging site, while feeding on rice seeds or fly larvae. Despite no significant differences found in enzymatic abundance (
FASN
,
ME1
,
ACC
and
LPL
) in stored fat, experimental godwits feeding on rice seeds presented high rates of
DNL
when compared to fly-larvae fed birds (~35 times more) and fasted godwits (no
DNL
activity). The increase of fractional
DNL
in godwits feeding on a carbohydrate-rich diet can potentially be enhanced by the fasting period that stimulates lipogenesis. Although requiring further testing, these recent findings provide new insights into the mechanisms of avian fat accumulation during a fasting and refueling cycle and associated responses to habitat and dietary changes in a migratory species.