Stable carbon and nitrogen isotopic fractionation between diet and tissues of captive seals: implications for dietary reconstructions involving marine mammals

The amount of isotopic fractionation (change in isotope ratios) between diet and animal tissues is generally poorly known and may be affected by trophic position. Diet-tissue fractionation of stable-carbon and -nitrogen isotopes was measured in several tissues of red foxes (Vulpes vulpes) raised on a commercial pellet feed. Stable carbon isotopic fractionation in red fox was positive for all tissues and was greatest in fur (2.6), intermediate in muscle (1.1), and least in liver and blood fractions (0.4-0.6). These carbon isotope fractionation values were greater than those previously measured for mammalian herbivores but were similar to values for marine mammals in most tissues. Little variation in stable nitrogen isotopic fractionation occurred among tissues, except in the blood fractions. Nitrogen isotopic fractionation was much higher in blood serum (4.2) than in liver, muscle, and fur (3.3-3.5). Cellular fractions of blood had the lowest fractionation values (2.6). There was a significant age effect in nitrogen- but not in carbon-isotopic fractionation. Subadult foxes (<1 year) were significantly enriched in 15N compared with adult foxes for fur, muscle, and liver (no blood was collected from adults). The cause of this enrichment is unclear, but it may be related to the higher rate of protein synthesis and catabolism in growing animals. This study is the first to report isotopic fractionation values for a terrestrial mammalian carnivore. Such estimates are necessary to interpret stable-isotope patterns in wild carnivores.

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Reconstructing Avian Diets Using Stable-Carbon and Nitrogen Isotope Analysis of Egg Components: Patterns of Isotopic Fractionation and Turnover

The Condor ◽

10.2307/1369183 ◽

1995 ◽

Vol 97 (3) ◽

pp. 752-762 ◽

Cited By ~ 158

Author(s):

Keith A. Hobson

Keyword(s):

Isotope Analysis ◽

Isotopic Fractionation ◽

Nitrogen Isotope ◽

Stable Carbon ◽

Carbon And Nitrogen ◽

Nitrogen Isotope Analysis ◽

Egg Components

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DIETARY STUDIES OF MARINE MAMMALS USING STABLE CARBON AND NITROGEN ISOTOPIC RATIOS OF TEETH

Marine Mammal Science ◽

10.1111/j.1748-7692.1999.tb00804.x ◽

1999 ◽

Vol 15 (2) ◽

pp. 314-334 ◽

Cited By ~ 56

Author(s):

Jane L. Walker ◽

Stephen A. Macko

Keyword(s):

Marine Mammals ◽

Isotopic Ratios ◽

Stable Carbon ◽

Carbon And Nitrogen

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Stable carbon and nitrogen isotopic fractionation between diet and swine tissues

Scientia Agricola ◽

10.1590/s0103-90162006000600012 ◽

2006 ◽

Vol 63 (6) ◽

pp. 579-582 ◽

Cited By ~ 23

Author(s):

Gabriela Bielefeld Nardoto ◽

Patricia Barboza de Godoy ◽

Epaminondas Sansigolo de Barros Ferraz ◽

Jean Pierre Henry Balbaud Ometto ◽

Luiz Antonio Martinelli

Keyword(s):

Stable Isotope ◽

Isotopic Fractionation ◽

Isotope Ratios ◽

Animal Nutrition ◽

Stable Carbon ◽

Carbon And Nitrogen ◽

Dietary Reconstruction ◽

Naturally Occurring ◽

C And N ◽

The One

Naturally occurring stable isotope ratios can be a powerful tool in studies of animal nutrition, provided that the assumptions required for dietary reconstruction are validated by studies such as the one presented here. The objective of this study was to document the magnitude of isotopic fractionation between swine diet and their different tissues. For this, the isotopic ratios of carbon and nitrogen of the diet and selected tissues (hair, nail, liver, muscle, fat and cartilage) were determined. The delta13C and delta15N of the diet were -15.9‰ and 1.3‰, respectively, and all delta15N of swine tissues were 2.2 to 3.0‰ enriched in 15N in relation to the diet. Little variation in delta15N occurred among tissues, with exception to liver that was less enriched in 15N than the nail. Nail and hair presented no 13C enrichment relative to diet. Cartilage was ~1.0‰ enriched in 13C as compared to diet. Liver and muscle were on average 2.1‰ more depleted in 13C in relation to diet as well as fat tissues. Some of the C and N isotope ratios of swine tissues differed in organs, but the isotopic fractionation trends among tissues appears to be similar to other mammals. Therefore our data provide a good baseline to interpret stable isotope patterns in domestic mammals (such as swine) in controlled or semi-controlled experiments.

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