An experimental exploration of the incorporation of hydrogen isotopes from dietary sources into avian tissues

Abstract

SUMMARYThe analysis of hydrogen stable isotopes (D) is a potentially powerful tool for studying animal ecology. Unlike other stable isotopes used in ecological research, however, we are less familiar with the physiological processes that influence the incorporation of hydrogen isotopes from dietary resources to animal tissues. Here we present the results of a controlled feeding experiment utilizing Japanese quail (Cortunix japonica) that was designed to: (1) estimate the relative contributions of diet to the D signatures of blood plasma, red blood cells, intestine, liver, muscle and feathers; (2) investigate possible differences among these same tissues in diet to tissue discrimination; and (3) explore the differences in incorporation dynamics between deuterium ( 2 H) and a well-studied isotope, 13 C, for blood plasma solids and red blood cells. Tissues differed in both the relative contribution of diet to tissue D and diet to tissue discrimination. The average residence time of both hydrogen and carbon was significantly lower in plasma solids than in red blood cells. The average residence time of hydrogen was significantly lower than that of carbon in plasma solids, but not in red blood cells. Although the average residence times of hydrogen and carbon were positively correlated, the correlation was weak. Hence the incorporation of carbon seems to be a poor predictor of that of hydrogen.

Multi‐tissue δ2H analysis reveals altitudinal migration and tissue‐specific discrimination patterns in Cinclodes

“…2) are similar in direction but of higher magnitude than those found by Wolf et al (2012) for captive quail fed diets and drinking water with consistent d 2 H compositions. Quail liver d…”

“…1E) observed in nigrofumosus to represent the non-migratory resident (marine) end-member offset for comparison to other Cinclodes species that are altitudinal migrants and switch between consuming marine resources in winter and foraging in freshwater streams at high elevation during the summer. A d 2 H feather-muscle offset of similar direction but larger magnitude (;þ30%) was observed in captive quail (Wolf et al 2012) that were fed isotopically homogenous food and drinking water. The d 2 H feather-muscle offset observed in C. nigrofumosus and previously reported for captive quail is probably primarily driven by tissue-specific d 2 H discrimination related to physiology (i.e., tissue biosynthesis) rather than ecology.…”

“…2 H values at a given altitude than feathers, a pattern similar to that found by Wolf et al (2012) H of individual amino acids, which form the building blocks of proteinaceous tissues, varies depending on how they are synthesized or routed by an organism (Fogel et al 2010). Thus, the isotopic composition of bulk tissues vary as a function of their amino acid concentration irrespective of ecologically related isotopic variation in food or water sources.…”

“…d 2 H isotopic incorporation rates have not been quantified for liver, muscle, or whole blood, but McKinnon et al (2012) found that d 2 H half-life estimates for red blood cells in two species of migratory thrushes varied from 14 to 21 days. Wolf et al (2012) and Storm-Suke et al (2012) reported similar incorporation rates for d 2 H of red blood cells in captive Japanese quail; half life estimates for plasma in quail were ;3.5 days. In addition, Wolf et al (2012) found that d 2 H and d 13 C v www.esajournals.org incorporation rates were similar for both plasma and red blood cells.…”

“…Wolf et al (2012) and Storm-Suke et al (2012) reported similar incorporation rates for d 2 H of red blood cells in captive Japanese quail; half life estimates for plasma in quail were ;3.5 days. In addition, Wolf et al (2012) found that d 2 H and d 13 C v www.esajournals.org incorporation rates were similar for both plasma and red blood cells. Hobson and Clark (1992) reported half-lives for d 13 C in liver, muscle, and whole blood of 2.6, 12.4, 11.4 days, respectively, for captive Japanese quail, which are similar to d 13 C incorporation rates for liver and muscle reported by Carleton and Martinez del Rio (2005) in house sparrows (Passer domesticus).…”