IRMS

This study aimed at evaluating the influence of dietary glutamine, glutamic acid and nucleotides on duodenal and jejunal carbon turnover, and on mucosa morphometry of piglets weaned at an age of 21 days. The diets were: additive-free diet – control (C); 1% of glutamine (G); 1% of glutamic acid (GA); and 1% of nucleotides (N). In intestinal mucosa morphometry trial, 65 animals were used. At day 0 (baseline), five animals were slaughtered to determine the villus height (VH), crypt depth (CD), VH : CD ratio and villi density (VD). The remaining 60 animals were allocated into a randomized block design with 4 × 3 factorial arrangement (four diets: C – control, G – glutamine, GA – glutamic acid and N – nucleotides; three slaughter ages: 7, 14 and 21 days post-weaning) with five piglets slaughtered per treatment. In carbon turnover trial, 123 animals were used. At day 0 (baseline), three animals were slaughtered to quantify the δ 13 C half-life (T50%) and the 99% carbon substitution (T99%) on intestinal mucosa. The remaining 120 animals were blocked by three weight categories (light, medium and heavy) and, randomly assigned to pen with the same four diets from the previous trial with one piglet slaughtered per weight category per treatment at days 1, 2, 4, 5, 7, 9, 13, 20, 27 and 49 after weaning. Morphometric analyses have yielded no consistent results regarding the action of the evaluated additives, and few reproducible age-related effects. The N diets determined lower T50% values (5.18 days) and T99% (17.21 days) than G and C diets (T50% = 7.29, 7.58 days and T99% = 24.22, 25.17 days, respectively) in the duodenal mucosa. In jejunum, the N, GA and G diets determined the lowest T50% means (4.9, 6.2 and 6.7 days, respectively) and T99% means (15.34, 21.10 and 21.84 days, respectively) in comparison with C diets (T50% = 7.44 and T99% = 24.72 days). The inclusion of the additives in the diets of piglets accelerated the carbon turnover in piglets during the post-weaning period. The stable isotopes technique (δ 13 C) is an important methodology in studies of additives with trophic effects on the intestinal mucosa of the piglets. Implications The inclusion of dietary glutamine, glutamic acid and nucleotides in the diets of piglets accelerated the carbon turnover during the post-weaning period.

Nitrogen (N) is an important driver of vegetation growth and its multiple transformations are closely linked with soil formation. Therefore, the understanding of the change in N transformations with advancing ecosystem development is an important prerequisite to predict, how an ecosystem may respond to possible future anthropogenically caused changes in N deposition. Considering that the bioavailability of N is regulated by the occurrence of mineral N and that most of N in soil is stored in organic bonds, the rates of transformation of organic to mineral N determine storage, loss and availability of N.
In this study, the results of the first 15N tracer experiments along a glacier retreat chronosequence on acidic mainly granitic glacial debris in the subtropics are presented. Five ecosystem succession stages deglaciated since 2-3, 24, 44, 84 and 124 years during the retreat of the Hailuogou Glacier on the eastern slope of the Gongga Mountain, Sichuan, China were chosen as study sites. At all five study sites an open-system pulse chase experiment with two different isotopic tracers (i.e. 15NH4+ and 15NO3-) and a closed-system mineralization experiment with 15NH4+ as tracer were conducted.
Despite the elevation of 3000 m above sea level, soil formation and occupation by vegetation was highly dynamic and changing rapidly within succession stage. The ecosystem age relation of gross mineralization (25-50’575 μg N kg-1 dry soil d-1) and gross nitrification rates (117-2320 μg N kg-1 dry soil d-1) could be described by an exponential function (r = 0.90, p = 0.036; r = 0.84, p = 0.073). At the initial succession stage, gross nitrification exceeded gross mineralization. But with further succession, gross mineralization became predominant, parallel to the development of an organic layer. Total tracer recovery was positively correlated with ecosystem age (15NH4+: 17-46 %, r = 0.63, p = 0.258; 15NO3-; 18-66 % r = 0.77, p = 0.124), attributable to increased immobilization and plant uptake. Maximum mean post-incubation recovery of 15NH4+ was found in the bryophyte layer at the 2-3 year-old site (13 %), in the shrub layer at 24 (17 %), 44 (23 %) and 84 year-old site (12 %) and in the mineral soil at 124 year-old site (15 %). Maximum mean post-incubation recovery of 15NO3- was found in the bryophyte layer at the 2-3 year-old site (16 %), in the Oi/Oe layer at 24 year old site (13 %), in the shrub layer at 44 (26 %) and 84 year-old site (18 %) and in the grass/herb layer at 124 year-old site (29 %). The recovery in the KCl-extractable NO3- pool decreased with ecosystem age particularly at the first day after labeling (15NH4+: 0.83-0.02 ‰, r = -0.67, p = 0.216; 15NO3-: 24.8-1.4 ‰, r = -0.32, p = 0.594).
The results of this study emphasize the importance of the development of an organic layer for the N retention and supply of the vegetation, particularly in an area, where coarse sediments are dominating like in the study area. The formation of the organic layer is favored by a fast vegetation succession under the subtropical climate initiated by N-fixing species and bryophytes.

The use of stable isotope analysis as a tool for characterization of carbon turnover (d 13 C) in piglet's tissues by tracing its feeding system has drawn attention. Thus, this study aimed at evaluating the influence of dietary glutamine, glutamic acid and nucleotides supplementation on carbon turnover in fundic-stomach region of weaned piglets at an average age of 21 days. The diets consisted of additive-free diet e control (C); 1% glutamine (G); 1% glutamic acid (GA) and 1% nucleotides (Nu). At weaning day (day 0: baseline), 3 piglets were slaughtered to quantify the d 13 C of stomach. The remaining 120 piglets were blocked by weight and sex, randomly assigned to pens with 3 piglets slaughtered per treatment at days 1, 2, 4, 5, 7, 9, 13, 20, 27 and 49 after weaning in order to verify the fundic-stomach isotopic composition by treatments. Samples were analyzed in terms of 13 C/ 12 C ratio by mass spectrometry and converted to relative isotopic enrichment values (d 13 C ‰) used to plot the first order exponential curves over time using OriginPro 8.0 software. The inclusion of glutamine, glutamate and nucleotides in piglet's diets has accelerated the carbon turnover in stomach during the post-weaning period, demonstrating also that glutamate has guaranteed fastest 13 C incorporation rate on fundic-stomach region and pH-lowering. Besides that, stable isotopes technique (d 13 C) has proved to be an important methodology to determine the timescales at which piglets shift among diets with different isotopic values, characterizing the trophic effects of additives and the phenotypic flexibility of stomach.

Determination of the geographical origin of agricultural products has been a growing issue over the past decade mostly due to ,the increased concern of consumers about food authenticity. Isotope-Ratio Mass spectrometry (IRMS), utilized to determine the isotopic relationship of stable isotopes, is considered as an extremely useful analytical technique for differentiation between the different geographic origins of various agricultural products. The isotopes and their ratio most commonly used in origin assessments are those of the light elements. In our study a comparative analysis of stable isotope ratios 13C/12C, 15N/14N and 34S/32S was performed in dry beans (Phaseolus vulgaris L.) originated from different regions in Greece (Prespes and Kastoria), China and Kirgistan using an IRMS coupling elemental analyzer. All isotope ratios were expressed as 6 0/00 against international standards. Results indicated significant differences in 615N and 6 34S while no significant differences in 613C between samples were obtained. In partricular, China originated beans exhibited lower values of 615N followed by those from Kirgistan. As far as 6 34S is concerned, Prespa's beans exhibited the lowest values Results suggested that combining the isotopic ratios of 6 34S and 615N a good discrimination between dry beans from the regions sudied could be achieved.

Abstract Current approaches in diet-related bioarchaeological research focus on establishing major developments in ancient societies, whilst small-scale and high-resolution studies of social constituents of past food consumption have gained far less attention. We conducted a multiproxy study of ancient diet in the 12th–13th century AD cemetery at Kukruse, NE-Estonia, in order to address the question of socially constrained food in the past. Two different food related archaeological sources – ceramic vessels and human bones – were investigated by applying organic residue (gas chromatography-mass spectrometry (GC-MS), bulk isotope ratio mass spectrometry (IRMS), gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS)), and plant microfossil analysis for the first, and human bone stable isotope (IRMS) analysis for the latter. Results show that there was a gender and to some extent also age-specific food consumption by different community members at Kukruse: male (and some older female) diet was based on more aquatic and higher trophic level organisms, whilst younger females tend to feed on lower trophic level and potentially more herbivorous animals and their products. The paper emphasises the concept of past diet as a social phenomenon, the aspects of which can be best revealed with the help of multiproxy bioarchaeological analysis.