Intra-muscular and inter-muscular variation in carbon turnover of ovine muscles as recorded by stable isotope ratios

Research progress on mutton origin tracing and authenticity

With the globalization of the food market and the convenience of food transportation between countries, consumers are increasingly worried about the source and safety of the food they eat. Traceability has been identified as an important tool for ensuring food safety and quality. This review mainly introduces the principles of five food traceability technologies, summarizes the progress in mutton application, comprehensively compares and analyzes the five traceability technologies, and discusses their application prospects, advantages and disadvantages. It is aimed at promoting research and application of traceability technology in mutton safety, promoting establishment and improvement of food traceability system.

Characteristics of Paprika samples of different geographical origin

This study investigated 11 different kinds of ground paprika of different geographical origin and tried to find some correlations between their measured chemical composition and country of origin. The parameters examined in ground paprika were as follows: sample moisture, total content of ash, total content of lipids, total content of nitrogen, content of saccharides (glucose, fructose, sucrose), elemental analysis (selected elements were Ca, K, Mg, Na, Cu, Fe, P a Zn), ASTA color value and pH value of water extract. Average content of moisture in paprika was 10.7 ±1.7 %. Average content of ash in the paprika samples was 5.8 ±0.6. Average total lipid content in paprika was 10.6 ±3.3 %. Total content of nitrogen in paprika was 1.93 ±0.17 % in average. Content of fructose (316 ±92 mg·g-1 ), glucose (215 ±119 mg·g-1 ) and sucrose (92 ±41 mg·g-1 ) in ground paprika was measured by HPLC-ELSD. Elemental analysis has been performed by ICP-OES. Average content of individual elements was: Ca 27 ±7 mg·g-1 , K 198 ±23 mg·g-1 , Mg 23 ±4 mg·g-1 , Na 20 ±4 mg·g-1 , Cu 0.155 ±0.015 mg·g-1 , Fe 1.2 ±0.4 mg·g-1 , P 33 ±6 mg·g-1 and Zn 0.17 ±0.04 mg·g-1 . Average ASTA color value of paprika samples was 119 ±31 ASTA. The pH value of paprika water extract was 5.13 ±0.12 in average. Obtained data were statistically processed with Analysis of Variance (ANOVA) on p <0.05 and with Principal Component Analysis (PCA). Statistical analysis of the data confirmed, that samples from more distant regions (Hungary, Spain, Turkey, Bulgaria) can be differentiated according to their different chemical composition, while samples from similar regions (Hungary, Slovakia, Romania) is more difficult to differentiate

Dietary Effects on Stable Carbon Isotope Composition of Fatty Acids in Polar and Neutral Fractions of Intramuscular Fat of Lambs

In this study we measured δ¹³C values of the main fatty acids (FA) present in neutral and polar intramuscular lipids of meat samples from 24 lambs, fed with four different diets supplemented with sunflower and linseed oil and the tanniferous shrub Cistus ladanifer L. The objective was to understand if the increase in intramuscular fat observed in lambs fed simultaneously C. ladanifer and oil was explained mostly by incorporation of diet derived FA or by increased de novo FA synthesis. De novo FA synthesis was evaluated by ¹³C enrichment (‰) of 16:0 in intramuscular lipids compared to bulk diet or compared to dietary 16:0. Oil reduced ¹³C enrichment of 16:0 in muscle lipid but had no effect when the diet included C. ladanifer (P value <0.01). Thus, dietary C. ladanifer blocked the inhibitory effects of lipid supplementation on de novo FA synthesis.

Stable Isotope Ratio Analysis for Assessing the Authenticity of Food of Animal Origin

The main elemental constituents (H, C, N, O, and S) of bio-organic material have different stable isotopes (² H, ¹ H; ¹³ C,¹² C; ¹⁵ N,¹⁴ N; ¹⁸ O,¹⁷ O,¹⁶ O; ³⁶ S, ³⁴ S, ³³ S, and ³² S). Isotopic ratios can be measured precisely and accurately using dedicated analytical techniques such as isotope ratio mass spectrometry (IRMS). Analysis of these ratios shows potential for assessing the authenticity of food of animal origin. In this review, IRMS analysis of food of animal origin and variability factors related to stable isotope ratios in animals are described. The study also lists examples of application of stable isotope ratio analysis to meat, dairy products, fish, and shellfish and emphasizes the strengths and weaknesses of the technique. Geographical, climatic, pedological, geological, botanical, and agricultural factors affect the stable isotope ratios (SIR) of bio-elements, and SIR variations are ultimately incorporated into animal tissue through eating, drinking, breathing, and exchange with the environment, being recorded in the resulting foods. SIR analysis was capable of determining geographical origin, animal diet, and the production system (such as organic/conventional or wild/farmed) for pork, beef, lamb, poultry, milk, butter, cheese, fish, and shellfish. In the case of the hard PDO (protected designations of origin) cheeses Grana Padano and Parmigiano Reggiano it is also used in real-life situations to assess the authenticity of grated and shredded cheese on the market.

Analysis of metabolic pools in broilers chicks

This paper shows the possibility of obtaining new parameters for the mathematical modelling of data on stable isotopes in biological systems and its application in obtaining data on metabolic pools of blood plasma, blood serum, liver and muscle of broilers. This theory states that the modelling of turnover used for studies of isotopic incorporation when the metabolism has a single metabolic pool is feasible by the technique of setting an exponential. However, when the metabolism has more than one metabolic pool, it is necessary to apply the linearization technique, linear regression adjustment and evaluation of the assumptions of regression to obtain the kinetic parameters such as half-life (T1/2) and isotope exchange rate (k). The application of this technique on carbon-13 data from 100 one-day-old chicks, with the change of diet composed of grains of the photosynthetic cycle of plants from C4 to C3, in broilers has enabled the discovery that the liver, blood plasma and blood serum have a single metabolic pool; however, the pectoral muscle has two metabolic pools. For the liver, blood plasma and blood serum, the half-life values were found by the exponential fit being T1/2 = 1.4 days with the rate of exchange of k = 0.502, T1/2 = 2.4 days with k = 0.293 and T1/2 = 2.0 days with k = 0.348, respectively. For the pectoral muscle, after linearization, the half-life values were found for T1/2(1) = 1.7 and T1/2(2) = 3 days, with exchange rates of k1 = 0.405 and k2 = 0.235, representing approximately 66 and 34%, respectively.

Isotopic turnover of carbon and nitrogen in bovine blood fractions and inner organs

RATIONALE

Isotope ratio analysis of bovine tissues is a tool for inferring aspects of the dietary history of cattle. The objective of this experiment was to quantify the carbon (C) and nitrogen (N) isotopic turnover in blood (serum and residue) and inner organs (liver, kidney, heart and brain) of beef cattle.

METHODS

Growing beef cattle (n = 70 in total) were either switched from a control diet containing barley and urea to an experimental diet containing maize and (15)N-enriched urea, for various intervals prior to slaughter or maintained on the control diet for 168 days pre-slaughter. Samples of blood, liver, kidney, heart and brain were collected at 0, 14, 28, 56, 112 and 168 days and analysed using Isotope Ratio Mass Spectrometry.

RESULTS

After 168 days, C- and N-isotopic equilibrium was reached in the blood serum, liver and kidney, approached in the heart and brain, but not reached in the non-serum component of blood. The estimated C and N half-lives were 16.5 and 20.7 days for liver, 19.2 and 25.5 days for kidney, 29.2 and 35.6 days for blood serum, 37.6 and 49.9 days for heart, 53.3 and 52.2 days for brain and 113.3 and 115.0 days for the non-serum blood residue, respectively. Modelling the C and N turnover in the different tissue combinations revealed that a combined analysis of liver and heart as well as brain and kidney can provide the most accurate estimation of the timing of the diet switch.

CONCLUSIONS

Based on the difference in turnover rates, bovine soft tissues can provide isotopic information on short- and long-term dietary changes, which in turn may be linked to the geographic or production origin of beef cattle. This study also provides basic biological data on organ C and N turnover in a large herbivorous mammal.

Sex and strain differences in isotope turnover rates and metabolism in house mice (Mus musculus)

The rate of nutrient incorporation into most organisms is an unknown but important factor in temporally variable systems. We investigate within-species variation in tissue turnover and metabolic rate among house mice ( Mus musculus L., 1758). By establishing a predictive relationship between tissue turnover rate and metabolic rate, field-based studies could more easily estimate tissue turnover rates using metabolic rate as a surrogate. Here, a diet change was administered using male and female mice of two strains (BALB/c and CBA/J) to test whether a predictive relationship was detectable within a species. Resting metabolic rate (mean values of 1.50–3.64 mL O2·h–1·g–1) and metabolic tissue turnover m (0.02–0.07), were significantly different between sexes, but not between strains. Females of both strains exhibited a nitrogen turnover rate significantly faster than males. Females had less mass than males, which could account for the differences in tissue replacement rates between sexes. The difference in metabolic rate within a species (between strains) may not be large enough to affect the rate of tissue turnover, suggesting that field researchers may be able to assume similar turnover rates among same-sex individuals of the same species. However, it may be important to account for sexual dimorphism when studying tissue turnover and metabolism.

Isotopic turnover of a submersed macrophyte following transplant: the roles of growth and metabolism in eutrophic conditions

Stable isotopic turnover with isotopic change due to growth and metabolic tissue replacement associated with a change in environmental conditions is a critical aspect of the use of stable isotope analyses as time-integrating tracers of resource-consumer interactions. However, stable isotopic turnover in plants remains poorly understood compared with those of animals, and here we used continuous flow elemental analyzer-isotopic ratio mass spectrometry (EA-IRMS) to analyse the turnover of stable carbon and nitrogen isotopes in a submersed macrophyte (Vallisneria natans) after transplantation to hypereutrophic and mesoeutrophic treatments in a field mesocosm experiment. The direction and magnitude of the isotopic shifts of V. natans were suggested to be determined by the inorganic nutrient availability and its isotopic content in the different treatments. Based on the modelling results of turnover, the contribution of growth to the isotopic turnover was as high as those observed in various aquatic ectotherms. However, the contribution of metabolism was also considerable, especially for nitrogen in the hypereutrophic treatment, which was argued to be a response, co-occurring with growth inhabitation and biochemical disorder of V. natans, to the stress induced by the eutrophication. Our results indicated that isotope turnover in a macrophyte is a feasible technique for estimating its ecophysiological conditions in the natural environment, and that it may facilitate understanding of isotopic data in field studies of food web and habitat restoration under eutrophic conditions.