scholarly journals The critical importance of experimentation in biomarker-based trophic ecology

2020 ◽  
Vol 375 (1804) ◽  
pp. 20190638 ◽  
Author(s):  
Aaron W. E. Galloway ◽  
Suzanne M. Budge
Keyword(s):  
Fatty Acids ◽  
Trophic Ecology ◽  
Dietary Fatty Acids ◽  
Bioactive Molecules ◽  
Trophic Relationships ◽  
Dietary Biomarkers ◽  
Soil Food Webs ◽  
Physiological Constraints ◽  
Feeding Experiments ◽  
Soil Ecosystems

Fatty acids are commonly used as biomarkers for making inferences about trophic relationships in aquatic and soil food webs. However, researchers are often unaware of the physiological constraints within organisms on the trophic transfer and modification of dietary biomarkers in consumers. Fatty acids are bioactive molecules, which have diverse structures and functions that both complicate and enhance their value as trophic tracers. For instance, consumers may synthesize confounding non-dietary sourced markers from precursor molecules, and environmental conditions also affect fatty acid composition. There is a vital need for more research on the uptake and transfer of trophic biomarkers in individual organisms in order to advance the field and make meaningful use of these tools at the scale of populations or ecosystems. This special issue is focused on controlled feeding experiments on a diverse taxonomic breadth of model consumers from freshwater, marine and soil ecosystems with a goal of creating a more integrated understanding of the connection between consumer physiology and trophic ecology. This article is part of the theme issue ‘The next horizons for lipids as ‘trophic biomarkers’: evidence and significance of consumer modification of dietary fatty acids'.

scholarly journals Dietary versus nondietary fatty acid profiles of lake trout ecotypes from Lake Superior and Great Bear Lake: Are fish really what they eat?

2020 ◽  
Vol 77 (7) ◽  
pp. 1209-1220
Author(s):  
L. Chavarie ◽  
J. Hoffmann ◽  
A.M. Muir ◽  
C.C. Krueger ◽  
C.R. Bronte ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Trophic Ecology ◽  
Lake Trout ◽  
Dietary Fatty Acids ◽  
Intraspecific Diversity ◽  
Dietary Biomarkers ◽  
Bear Lake ◽  
Energy Processing ◽  
Fatty Acid Biomarkers

Fatty acids are well-established biomarkers used to characterize trophic ecology, food-web linkages, and the ecological niche of many different taxa. Most often, fatty acids that are examined include only those previously identified as “dietary” or “extended dietary” biomarkers. Fatty acids considered as nondietary biomarkers, however, represent numerous fatty acids that can be extracted. Some studies may include nondietary fatty acids (i.e., combined with dietary fatty acids), but do not specifically assess them, whereas in other studies, these data are discarded. In this study, we explored whether nondietary biomarker fatty acids can provide worthwhile information by assessing their ability to discriminate intraspecific diversity within and between lakes. Nondietary fatty acids used as biomarkers delineated variation among regions, among locations within a lake, and among ecotypes within a species. Physiological differences that arise from differences in energy processing can be adaptive and linked to habitat use by a species’ ecotype and likely explains why nondietary fatty acid biomarkers can be a relevant tool to delineate intraspecific diversity. Little is known about the nondietary-mediated differences in fatty acid composition, but our results showed that nondietary fatty acid biomarkers can be useful tool in identifying variation.

scholarly journals Shifting systems: prerequisites for the application of quantitative fatty acid signature analysis in soil food webs

2020 ◽  
Vol 375 (1804) ◽  
pp. 20190650 ◽  
Author(s):  
Jakob Kühn ◽  
Kevin Tobias ◽  
Alexander Jähngen ◽  
Liliane Ruess
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Polyunsaturated Fatty Acids ◽  
Food Webs ◽  
Food Chain ◽  
Dietary Fatty Acids ◽  
Signature Analysis ◽  
Fatty Acid Signature ◽  
Soil Food Webs ◽  
Soil Ecosystems

Quantitative fatty acid signature analysis (QFASA) is widely used to investigate trophic interactions in marine ecosystems, as nutritionally important ω 3 long-chain polyunsaturated fatty acids at the food web base allow tracing of their trophic transfer in the food chain. By contrast, the basal resources in soil food webs comprise a wider array of trophic markers, including branched-chain, cyclopropane as well as several mono- and polyunsaturated fatty acids. These diverse markers allow distinguishing between the three dominant soil carbon and energy channels, the root, bacterial and fungal pathway. QFASA has not been applied yet to soil ecosystems owing to the lack of a priori data to fit the model. The present work investigates the transfer of absolute and relative trophic marker fatty acids into Collembola as dominant representatives of the soil mesofauna. Three different species were fed on a variety of single diets characteristic for the green and brown food chain. Calibration coefficients were calculated and diet estimation trials for mixed diet set-ups were performed, using a library comprising 50 different resources. However, estimation of Collembola diet was only partially successful, identifying the main components, but not the correct relative proportions. Adjustments by fat content or diet group exclusion did not improve the results. Nonetheless, this work provides, to our knowledge, a first comprehensive dataset to translate the application of QFASA from marine to soil ecosystems. This article is part of the theme issue ‘The next horizons for lipids as ‘trophic biomarkers’: evidence and significance of consumer modification of dietary fatty acids’.

scholarly journals Dietary vs non-dietary fatty acid profiles of lake trout ecotypes from Lake Superior and Great Bear Lake: Are fish really what they eat?

2019 ◽  
Author(s):  
L Chavarie ◽  
J. Hoffmann ◽  
A.M. Muir ◽  
C.C. Krueger ◽  
C.R. Bronte ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Trophic Ecology ◽  
Lake Trout ◽  
Dietary Fatty Acids ◽  
Intraspecific Diversity ◽  
Fatty Acid Profiles ◽  
Dietary Biomarkers ◽  
Bear Lake ◽  
Energy Processing

AbstractFatty acids are well-established biomarkers used to characterize trophic ecology, food-web linkages, and the ecological niche of many different taxa. Most often, fatty acids that are examined include only those previously identified as “dietary” or “extended dietary” biomarkers. Fatty acids considered as non-dietary biomarkers, however, represent numerous fatty acids that can be extracted. Some studies may include non-dietary fatty acids (i.e., combined with dietary fatty acids), but do not specifically assess them, whereas in other studies, these data are discarded. In this study, we explored whether non-dietary biomarkers fatty acids can provide worthwhile information by assessing their ability to discriminate intraspecific diversity within and between lakes. Non-dietary fatty acids used as biomarkers delineated variation among regions, among locations within a lake, and among ecotypes within a species. Physiological differences that arise from differences in energy processing can be adaptive and linked to habitat use by a species’ ecotypes, and likely explains why non-dietary fatty acids biomarkers can be a relevant tool to delineate intraspecific diversity. Little is known about the non-dietary-mediated differences in fatty acid composition, but our results showed that non-dietary fatty acids biomarkers can be useful tool in identifying variation.

scholarly journals Stable isotopes of fatty acids: current and future perspectives for advancing trophic ecology

2020 ◽  
Vol 375 (1804) ◽  
pp. 20190641 ◽  
Author(s):  
Cornelia W. Twining ◽  
Sami J. Taipale ◽  
Liliane Ruess ◽  
Alexandre Bec ◽  
Dominik Martin-Creuzburg ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Stable Isotope ◽  
Best Practices ◽  
Resource Use ◽  
Trophic Ecology ◽  
Isotope Analysis ◽  
Dietary Fatty Acids ◽  
Food Web Ecology ◽  
Dietary Requirements

To understand consumer dietary requirements and resource use across ecosystems, researchers have employed a variety of methods, including bulk stable isotope and fatty acid composition analyses. Compound-specific stable isotope analysis (CSIA) of fatty acids combines both of these tools into an even more powerful method with the capacity to broaden our understanding of food web ecology and nutritional dynamics. Here, we provide an overview of the potential that CSIA studies hold and their constraints. We first review the use of fatty acid CSIA in ecology at the natural abundance level as well as enriched physiological tracers, and highlight the unique insights that CSIA of fatty acids can provide. Next, we evaluate methodological best practices when generating and interpreting CSIA data. We then introduce three cutting-edge methods: hydrogen CSIA of fatty acids, and fatty acid isotopomer and isotopologue analyses, which are not yet widely used in ecological studies, but hold the potential to address some of the limitations of current techniques. Finally, we address future priorities in the field of CSIA including: generating more data across a wider range of taxa; lowering costs and increasing laboratory availability; working across disciplinary and methodological boundaries; and combining approaches to answer macroevolutionary questions. This article is part of the theme issue ‘The next horizons for lipids as ‘trophic biomarkers’: evidence and significance of consumer modification of dietary fatty acids’.

scholarly journals The insectivorous bat Pipistrellus nathusii uses a mixed-fuel strategy to power autumn migration

2012 ◽  
Vol 279 (1743) ◽  
pp. 3772-3778 ◽  
Author(s):  
Christian C. Voigt ◽  
Karin Sörgel ◽  
Jurģis Šuba ◽  
Oskars Keišs ◽  
Gunārs Pētersons
Keyword(s):  
Fatty Acids ◽  
Stable Carbon Isotope ◽  
Carbon Isotope Ratio ◽  
Dietary Fatty Acids ◽  
Autumn Migration ◽  
Dietary Proteins ◽  
Mixed Fuel ◽  
Feeding Experiments ◽  
Body Reserves ◽  
Oxidized Fatty Acids

In contrast to birds, bats are possibly limited in their capacity to use body fat as an energy source for long migrations. Here, we studied the fuel choice of migratory Pipistrellus nathusii (approximate weight: 8 g) by analysing the stable carbon isotope ratio ( δ 13 C V-PDB ) of breath and potential energy sources. Breath δ 13 C V-PDB was intermediate between δ 13 C V-PDB of insect prey and adipocyte triacylglycerols, suggesting a mixed-fuel use of P. nathusii during autumn migration. To clarify the origin of oxidized fatty acids, we performed feeding experiments with captive P. nathusii . After an insect diet, bat breath was enriched in 13 C relative to the bulk and fat portion of insects, but not deviating from the non-fat portion of insects, suggesting that bats oxidized exogenous proteins and carbohydrates, but not exogenous fatty acids. A feeding experiment with 13 C-labelled substrates confirmed these findings. In conclusion, migratory P. nathusii oxidized dietary proteins directly from insects captured en route in combination with endogenous fatty acids from adipocytes, and replenished their body reserves by routing dietary fatty acids to their body reserves.

scholarly journals Juvenile Dungeness crabs ( Metacarcinus magister ) selectively integrate and modify the fatty acids of their experimental diets

2020 ◽  
Vol 375 (1804) ◽  
pp. 20200038 ◽  
Author(s):  
Michael D. Thomas ◽  
Julie B. Schram ◽  
Zade F. Clark-Henry ◽  
Bree K. Yednock ◽  
Alan L. Shanks ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Dietary Fatty Acids ◽  
Theme Issue ◽  
Natural Diet ◽  
Northeast Pacific ◽  
Feeding Experiments ◽  
Fa Composition ◽  
In The Wild ◽  
Dungeness Crabs ◽  
Juvenile Crab

Dungeness crabs ( Metacarcinus magister ) are ecologically and economically important in the coastal Northeast Pacific, yet relatively little is currently known about their feeding behaviour in the wild or their natural diet. Trophic biomarkers, such as fatty acids (FA), can be used to reveal trophic interactions. We used two feeding experiments to assess differences in FA composition of juvenile crabs fed different known foods to evaluate how they modify and integrate dietary FA into their own tissues and determine whether crab FA reflect diet changes over a six-week period. These experimental results were then compared with the FA signatures of wild caught juvenile crab with undetermined diets. We found that juvenile Dungeness crabs fed different foods assimilated dietary FA into their tissues and were distinct in their FA signatures when analysed with multivariate statistics. Experimentally fed juvenile crabs contained greater proportions of the most abundant long-chain polyunsaturated fatty acids (LCPUFA, >C20) than their foods. Crabs fed foods lacking in LCPUFA, particularly DHA (22:6 ω 3, docosahexaenoic acid), did not survive or grew slower than crabs fed other foods. This suggests that LCPUFA are physiologically important for this species and indicates biosynthesis of these FA does not occur or is not sufficient to meet their needs. This article is part of the theme issue ‘The next horizons for lipids as ‘trophic biomarkers’: evidence and significance of consumer modification of dietary fatty acids’.

scholarly journals Dietary fat concentrations influence fatty acid assimilation patterns in Atlantic pollock ( Pollachius virens )

2020 ◽  
Vol 375 (1804) ◽  
pp. 20190649 ◽  
Author(s):  
Suzanne M. Budge ◽  
Kathryn Townsend ◽  
Santosh P. Lall ◽  
Jeffrey F. Bromaghin
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Dietary Fat ◽  
Dietary Fatty Acids ◽  
Signature Analysis ◽  
Formulated Diets ◽  
Natural Prey ◽  
Feeding Experiments ◽  
Prey Items ◽  
Calibration Coefficients

A key aspect in the use of fatty acids (FA) to estimate predator diets using quantitative FA signature analysis (QFASA) is the ability to account for FA assimilation through the use of calibration coefficients (CC). Here, we tested the assumption that CC are independent of dietary fat concentrations by feeding Atlantic pollock ( Pollachius virens ) three formulated diets with very similar FA proportions but different fat concentrations (5–9% of diet) for 20 weeks. CC calculated using FA profiles of diet and triacylglycerols in pollock liver were significantly different for the three diets. To test the robustness of diet estimates to these differences, we used the CC set derived from feeding the diet with the lowest fat concentration, published prey FA profiles and realistic diet estimates of pollock to construct ‘pseudo-predators'. Application of QFASA to each pseudo-predator using the three sets of CC and the same prey FA profiles resulted in diet estimate biases of twofold for major prey items and approximately fivefold for minor prey items. This work illustrates the importance of incorporating diets with fat concentrations that are similar to natural prey when conducting feeding experiments to calculate CC. This article is part of the theme ‘The next horizons for lipids as ‘trophic biomarkers': evidence and significance of consumer modification of dietary fatty acids'.

Postprandial Activation of Coagulant Factor VII by Long-chain Dietary Fatty Acids

1996 ◽  
Vol 76 (03) ◽  
pp. 369-371 ◽  
Author(s):  
T A B Sanders ◽  
G J Miller ◽  
Tamara de Grassi ◽  
Najat Yahia
Keyword(s):  
Fatty Acids ◽  
Dietary Fatty Acids ◽  
Factor Vii ◽  
Fat Intake ◽  
Long Chain Fatty Acids ◽  
Postprandial Lipaemia ◽  
Increased Risk ◽  
Coagulant Activity ◽  
Long Chain Triglycerides ◽  
Long Chain

SummaryFactor VII coagulant activity (FVIIc) is associated with an increased risk of fatal ischaemic heart disease (IHD). Several reports have suggested that dietary fat intake or hypertriglyceridaemia are associated with elevated levels of FVII. This study demonstrates that an intake of long-chain fatty acids sufficient to induce postprandial lipaemia in healthy subjects leads to a substantial elevation in both FVIIc and the concentration of FVII circulating in the activated form. Such an increase in FVIIc could not be induced by medium-chain triglycerides. These results suggest that the consumption of a sufficient amount of long-chain triglycerides to induce postprandial lipaemia induces the activation of FVII.

Neonatal nutritional strategy of a viviparous elasmobranch with extremely low reproductive output

2020 ◽  
Vol 638 ◽  
pp. 107-121 ◽  
Author(s):  
BS Rangel ◽  
NE Hussey ◽  
Y Niella ◽  
LA Martinelli ◽  
AD Gomes ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Reproductive Strategies ◽  
Trophic Ecology ◽  
Essential Fatty Acids ◽  
Physiological State ◽  
Maternal Investment ◽  
Early Life History ◽  
Nutritional State ◽  
Disc Width ◽  
Biomarker Analysis

Throughout evolutionary history, elasmobranchs have developed diverse reproductive strategies. Little focused work, however, has addressed how neonatal nutritional state is affected by differing degrees of maternal investment associated with these markedly different reproductive strategies. To investigate the effect of maternal investment on the nutritional quality of pups during the early life history of an extremely viviparous elasmobranch, quantitative biomarker analysis including lipids, fatty acids and stable isotopes was conducted. Using the cownose ray Rhinoptera bonasus (histotrophic viviparous) as a model, we found that pups were initially born in a positive nutritional state, enriched in physiologically important essential fatty acids and nitrogen and carbon stable isotope values (δ15N and δ13C), a result of maternal intrauterine transfer. A systematic decrease in some fatty acids and δ15N values, as well as a decrease in cholesterol with growth, confirmed that these substrates were derived from maternal resources and used in initial metabolic processes following birth. An observed increase in condition factor, plasma essential fatty acids and triglyceride:cholesterol ratio with increasing body size identified a progression towards successful independent foraging with pups not displaying marked nutritional deficiency or fasting phases. Our multi-tracer approach allowed the identification of 2 size classes of young rays (<50 and <70 cm disc width) that displayed distinct physiological states. Since prenatal maternal investment is critical for offspring condition and to promote successful foraging post birth, understanding the trophic ecology and physiological state of pups during their first year is critical to guide management and conservation within nursery grounds.

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