The Estimation of Soil Trace Elements Distribution and Soil-Plant-Animal Continuum in Relation to Trace Elements Status of Sheep in Huangcheng Area of Qilian Mountain Grassland, China

Journal of Integrative Agriculture 2014, 13(1): 140-147

January 2014

RESEARCH ARTICLE

The Estimation of Soil Trace Elements Distribution and Soil-PlantAnimal Continuum in Relation to Trace Elements Status of Sheep in Huangcheng Area of Qilian Mountain Grassland, China WANG Hui, LIU Yong-ming, QI Zhi-ming, WANG Sheng-yi, LIU Shi-xiang, LI Xia, WANG Hai-jun, WANG Xiao-li, XIA Xin-chao and ZHU Xin-qiang Key Laboratory of Veterinary Pharmaceutics Development, Ministry of Agriculture/Key Laboratory of New Animal Drug Project of Gansu Province/Engineering and Technology Research Center of Traditional Chinese Veterinary Medicine of Gansu Province/Lanzhou Institute of Husbandry and Pharmaceutics Sciences, Chinese Academy of Agricultural Sciences, Lanzhou 730050, P.R.China

Abstract The purpose of the present study was to survey contents of trace elements of Cu, Mn, Fe, and Zn in the surface layer (0-20 cm) in the soil, pasture and serum of sheep in Huangcheng area of Qilian mountain grassland, China. Also the soil-plantanimal continuum was analyzed. Soil (n=300), pasture (n=60), and blood serum samples from sheep (n=480) were collected from Huangcheng area of Qilian mountain grassland, China. The contents of trace element in the samples were analyzed by atomic absorption spectrophotometer after digestion. The soil trace elements density distribution shows a ladder-like pattern distribution. Equations developed in the present study for prediction of Fe (R2=0.943) and Zn (R2  KDGVLJQL¿FDQWR2 values. Key words: WUDFHHOHPHQWVPLQHUDOVGH¿FLHQF\VRLOW\SH4LOLDQPRXQWDLQJUDVVODQGFRUUHODWLRQ

INTRODUCTION Trace element content and distribution in soil are LPSRUWDQWIDFWRUVIRUUHÀHFWLQJHQYLURQPHQWFRQGLWLRQ in specific area, and have great significance for soil environmental quality evolution research, and reasonable development and utilization of land resources (Tao et al. 2001). Previous researches had shown that the characteristics of trace element content LQVRLOKDYHVLJQL¿FDQWUHJLRQDOGLIIHUHQFHV:HQet al. 2007). The compartment soil is considered a fundamental part of the global ecosystem, having the crucial

function of supplier of nutrients and mechanical support to plants. It is important to determine the mineral concentrations of soils and forages to estimate the mineral needs of ruminants. Trace metal levels are important for human health. Cu, Mn, Fe and Zn can be considered trace minerals with a central role in many metabolic processes throughout the body and are essential for correct growth and development of all animals. They predominantly act as catalysts in PDQ\ HQ]\PH DQG KRUPRQH V\VWHPV ZKLFK LQÀXHQFH on growth, bone development, feathering, enzyme structure and function, and appetite (Rahman et al. 2006; Stef and Gergen 2012). Fe is essential for maintaining proper cell functions and is normally

Received 5 January, 2013 Accepted 16 May, 2013 Correspondence WANG Hui, Tel: +86-931-2115263, E-mail: [email protected]; LIU Yong-ming, Tel: +86-931-2115263, E-mail: [email protected]

© 2014, CAAS. All rights reserved. Published by Elsevier Ltd. doi: 10.1016/S2095-3119(13)60504-3

The Estimation of Soil Trace Elements Distribution and Soil-Plant-Animal Continuum in Relation to Trace Elements Status of Sheep

tightly controlled by transporter and storage proteins (Lieu et al. 2001). Zn is acting as a catalytic, structural, and regulatory ion. Moreover, Zn-binding protein (metallothionein) plays a key role in Zn-related cell homeostasis which, in turn, is relevant also against oxidative stress, including exposure to oxyradicals, inflammation, infection, and immune responses (Stefanidou et al. 2006). Micronutrients in the human body are mainly derived from food and thus improvements to the soilplant system are instrumental to human nutrition (Zhang et al. 2010). Increasing consumer demand for nutritional balance has led to mutton becoming more popular as a source of protein. As the leader of mutton consumption and production, two major mutton-producing groups have been formed in China, agricultural regions in southwestern and middle China and pastoral regions in northern China (Sun et al. 2011). In the eastern China, livestock production is playing an important role in agriculture, where animals are managed in traditional ways. The farmers of the region based on their traditional knowledge developed low input sheep production system that does not depend mainly on cereal grains. Soil is the primary source of a variety of elements necessary for sheep health and production because sheep obtain their nutrient needs from the fodder and feed, which in turn obtain nutrients from the soil. Trace element analysis is considered to be an effective tool, because the element compositions in the local environment (soil, drinking water, etc.) can be UHÀHFWHGLQWRDJULFXOWXUDOSURGXFWVDQGGLIIHUHQFHVLQ the distribution of these trace elements among different geographical locations can give various element signatures in the organic tissues (Schwagele 2005). The concept of soil-plant-animal interrelationship implies a coordinated understanding of how particular sequence of events may lead to imbalances in nutritional quality of a feed for animals. Geographical information system (GIS) is a system for managing, manipulating, analyzing and presenting

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geographically-related information (Hamzeh et al. 2011). GS+ is a comprehensive geostatistics program that provides all geostatistics components, from semivariance analysis through kriging and mapping. Therefore, the objective of the present study was to estimate the trace elements content of soil, plant, and sheep and establish the soil-plant-animal continuum. The Kriging method was applied to calculate the unobserved points and was used to generate the map of trace elements density spatial distribution.

RESULTS Mineral content in soil, pasture, and blood serum of sheep Using the optimized experimental conditions described above, calibration curves have been prepared when the concentrations of Cu, Mn and Zn are in the range of ȝJP/-1DQG)HLVLQWKHUDQJHRIȝJ mL-1. The linear equations are as follows: (1) A=0.1122C0.0011 r2=0.9999 (2) A=0.1581C0.0010 r2=0.9968 2 (3) A=0.0699C0.0007 r =0.9977 2 (4) A=0.2119C0.0004 r =0.9943 Where A denotes absorbance value, C denotes FRQFHQWUDWLRQȝJP/-1); eqs. (1), (2), (3) and (4) can be obtained for Cu, Mn, Fe and Zn, respectively. As can be seen, the highest sensitivity was obtained for Cu, which demonstrated the high sensitivity of the proposed procedure, allowing its application to determine the analytes at trace levels in samples. The results are shown in Table 1. The mean (±SD) values of Cu, Mn, Fe, and Zn in soil, pasture, and blood serum in sheep of Huangcheng area of Qilian Mountain grassland, China, are given in 7DEOH7KHWUDFHHOHPHQWVLQVRLOZHUHVLJQL¿FDQWO\ higher than that in pasture, and the pasture was VLJQL¿FDQWO\KLJKHUWKDQWKDWLQEORRGVHUXPLQVKHHS The mean value of the total trace elements contents in

Table 1 Trace elements concentrations in soil, pasture and blood serum in sheep (mean±SD) Samples 6RLOȝJJ-1) 3DVWXUHȝJJ-1) %ORRGVHUXPȝJP/-1)

Cu 305.58±6.0751 47.672±2.2574 0.2759±0.1336

Mn 1 690.5±116.67 99.214±2.2581 0.2015±0.0635

Fe 43 107±561.51 379.21±10.910 7.0531±1.4156

Zn 191.55±13.447 29.932±1.7020 1.9145±0.2847

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the soils followed a descending order as: Fe>Mn>Cu> Zn.

The map of trace elements density spatial distribution Based on semi-variance structure analysis and model fitting, Inverse Distance Weighting interpolation gave a continuous surface of trace elements density covering the grassland (Fig. 1), created using the geostatistical tool package of ArcGIS, GS+ and eq. (6). Fig. 1 showed that in the study area, the overall trace elements density is distributed in layers, with the spatial distribution of the density following a ladderlike pattern and patch mosaic distribution. It is easy to determine the soil trace elements storage for the studied grassland. In terms of spatial distribution, the trace elements density in the southeastern part of the Huangcheng grassland is slightly higher than that of the surrounding areas.

Soil-plant-animal relationship No significant correlation values were obtained between soil and pasture, pasture and sheep, and soil and sheep for Cu, Mn, Fe and Zn (P>0.05) (Table 2). An attempt was made to predict the mineral content in sheep keeping the soil and pasture mineral content as independent variables. Prediction equations that could fairly predict the mineral content in sheep based on the mineral content in soil and pasture were given in Table 3. Equations developed in the present study for prediction of Fe (R2=0.943) and Zn (R2=0.882) had VLJQL¿FDQW R2 values, and can be successfully used in practice.

DISCUSSION Trace elements are known to play an important role in human health, and micronutrient malnutrition is a major health problem in China (Yang et al. 2007). Micronutrients in the human body are mainly derived from food and thus improvements to the soil-plant system are instrumental to human nutrition. Trace element requirements vary with age and production

WANG Hui et al.

level-young, pregnant and lactating animals have the greatest need. The natural contents of trace elements in soils are of great interest, as background values are needed to assess the degree of soil contamination and to evaluate soil quality - the prerequisites for sustainable land use (Hamzeh et al. 2011). Qilian mountain grassland is located in the northeastern part of the Qinghai-Tibet Plateau in China, and is also China’s important base of animal husbandry. Understanding the distribution of the trace elements in Qilian mountain grassland, therefore, has both VFLHQWL¿FDQGHFRQRPLFVLJQL¿FDQFH 0LQHUDOGH¿FLHQF\FDQOHDGWRLPSDLUHGJURZWKDQG reproduction and increase in disease, due to impaired immune function, and serious deficiency may even cause death. In China, approximately 40% of the WRWDO ODQG DUHD LV GH¿FLHQW LQ )H DQG =Q 
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The Estimation of Soil Trace Elements Distribution and Soil-Plant-Animal Continuum in Relation to Trace Elements Status of Sheep

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Zn (μg g-1) 200 199 198 198 197 196 195 194 193 193 192 191 190 189 189 188

Fe (μg g-1) 44 450 44 288 44 127 43 965 43 803 43 642 43 480 43 319 43 157 42 996 42 834 42 673 42 511 42 349 42 188 42 026

Cu (μg g-1) 311 310 308 307 306 305 303 302 301 300 299 297 296 295 294 292

Mn (μg g-1) 1 797 1 775 1 752 1 730 1 708 1 686 1 663 1 641 1 619 1 597 1 574 1 552 1 530 1 508 1 485 1 463

Fig. 1 Interpolated maps of the topsoil trace elements content.

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WANG Hui et al.

Table 2 Soil-pasture-sheep relationship (correlation) in respect to trace elements status Correlation Soil-pasture Pearson correlation value Sig. (2-tailed) Pasture-sheep Pearson correlation value Sig. (2-tailed) Soil-sheep Pearson correlation value Sig. (2-tailed)

Cu

Mn

Fe

Zn

-0.052 0.948

-0.834 0.166

-0.544 0.456

0.183 0.817

-0.198 0.802

0.760 0.240

0.521 0.479

0.760 0.240

0.649 0.351

-0.494 0.506

0.113 0.887

-0.404 0.596

concentrations of trace elements values of soils in China were as following (Zhang et al. 2010): Cu (22.6±11.4) mg kg -1 , Mn (583±363) mg kg -1 , Fe (2.94±0.95)%, Zn (74±33) mg kg-1. Results of the present study revealed that the surface soils were much higher compared with the average value of soils in China. Grass and forage varies widely in trace element content due to soil type, pH, drainage, plant species and fertilizer use (Warman and Termeer 2005). In the present study, observed that the Cu, Mn, Fe and Zn concentrations in pasture samples were higher than the recommended level (NRC 2007). Deficiencies are more accurately diagnosed from blood or tissue tests. Copper and zinc are the most important essential minerals necessary for the normal functioning of animals’ reproduction functions (Yildiz and Balikci 2004). Many investigators (Ghosal and Mathur 1992; Liu et al. 1992; Kargin et al. 2004) reported that the levels of serum Cu in sheep should be between 0.8 and 1.2 μg mL -1 , and Zn should be between 6.9 and 14.86 μg mL -1. In ruminants, DYHUDJHEORRG&XYDOXHVRIȝJP/-1 are a sign of severe Cu deficiency (Zhou et al. 2009). The mean concentration of Cu and Zn, observed in the present study were 0.28 and 1.91 μg mL-1, respectively, so remarkably lower than critical values. The results

suggested that most of the sheep were deficient in Cu and Zn. The levels of serum Fe and Mn were in normal range. The mineral content of the pasture depend upon the type of the soil and environmental conditions in which they are grown. Low concentration of particular mineral in soil will lower the mineral content in plant grown on such soil; accumulated organic matter near the soil surface can increase plant availability of Cu, Mn, Fe and Zn (Shuman 1988); however, the soil rich in a particular mineral may not result in its higher level in the plant (Kumaresan et al 6LJQL¿FDQW correlation values were not observed between the mineral levels in soil and pasture, pasture and sheep, soil and sheep in our research. Maybe due to Cu, Mn, Fe and Zn complexes with organic, which can not be utilized by plants (Dong et al. 2009), so the correlation is not significant. Our findings are agree to those of Khalili et al. (1993), who reported no correlation between soil, fodder, and blood plasma of cattle in Ethiopia. In the present study, the regression equation developed to predict the mineral concentration in sheep based on the soil and pasture mineral content showed positive relationship for Fe and Zn suggesting the possibility of prediction of mineral status in sheep.

CONCLUSION 7KLV VWXG\ SURYLGHG WKH ¿UVW VXUYH\ RI WUDFH HOHPHQWV of Cu, Mn, Fe, and Zn contents in the soil, pasture and serum of sheep in Huangcheng area of Qilian mountain grassland, China. The soil trace elements density distribution shows a ladder-like pattern distribution. Further, the present study established the trace elements relationship between soil, pasture, and sheep.

Table 3 Regression equation on soil-pasture-sheep continuum in relation to mineral status Mineral Cu Mn Fe Zn

Regression equation to predict mineral content in pasture based on the mineral status of soil1) A=52.032-0.01B A=115.991-0.01B A=645.718-0.006B A=24.672+0.028B

R2 0.003 0.696 0.273 0.034

Regression equation to predict mineral content in sheep based on the mineral status of pasture2) C=0.794-0.008D C=-2.370+0.026D C=50.516-0.116D C=-1.084+0.1D

R2 0.039 0.578 0.677 0.577

Regression equation to predict mineral content in sheep based on the mineral status of soil and pasture3) Y=-0.775-0.006X1+0.005X2 Y=-4.009+0.039X1 Y=110.847-0.001X1-0.161X2 Y=0.7-0.011X1+0.113X2

R2 0.448 0.643 0.943 0.882

1)

A, mineral content in pasture; B, mineral content in soil. C, mineral content in sheep; D, mineral content in pasture. 3) Y, mineral content in sheep; X1, mineral content in soil; X2, mineral content in pasture. 2)

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The Estimation of Soil Trace Elements Distribution and Soil-Plant-Animal Continuum in Relation to Trace Elements Status of Sheep

MATERIALS AND METHODS Characterization of study area The Huangcheng Town is representative grassland on the Qilian range, which is located at Sunan County, Gansu Province, China (longitude 101°60´19´´-101°95´92´´, latitude 37°62´88´´-38°00´15´´, 2 500-5 254 m altitude, 3 800 km2) (Fig. 2-A). The grassland of this area is more than 2 897 km2, and is the one of the famous grasslands of China.

A Gansu Province

Qinghai Province

B

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7UDFHHOHPHQWGH¿FLHQF\LVDPDMRUSUREOHPLQJUDVVODQGRI Qilian range, which has caused enormous economic loss to the herdsmen. We participated in the investigation of the trace element content in grassland of Qilian range, in order to guide reasonable nutrition and prevent trace elements GH¿FLHQFLHV

Sampling To ensure representative of samples, the soil, pasture, and blood serum samples were collected from randomly selected smallholder sheep farms. Topsoil samples at 0-15 cm depth were collected. A portable GPS was used to locate each sample site, and a total of 300 soil samples were collected from 60 soil sampling sites (Fig. 2-B). After air-drying, the soil samples were passed through a 0.25-mm sieve for laboratory analysis. A total of 60 pasture samples were collected from each smallholder sheep farm and stored in polythene bags for transport and storage for further analysis. The blood samples were collected from sheep maintained at the sheep farms where pasture samples and soil were collected. A total of 480 blood samples (8 from each sampling sites) were collected. The breed of sheep was Gansu Alpine Merino and Tibetan sheep, at the age of 7-10 mon, and each sheep farm maintained more than 300. Approximately 8 mL blood was collected from each sheep in clean, sterilized glass test tube by jugular vein puncture (Yang et al. 2013), allowed to clot at room temperature and centrifuged for 15 min at 3 000 r min-1. The serum was frozen at -20°C prior to analysis (Zhou et al. 2012). The trace elements content was determined using the atomic absorption spectrophotometer.

Reagents and chemical standard

N Legend Sampling point 0

5

km 10

All chemical reagents were analytical reagent grade. Standard stock solutions were prepared from Chinese &HUWL¿HG5HIHUHQFH0DWHULDOPJ/-1) and were diluted to the corresponding metal solution. The working solution was freshly prepared by diluting an appropriate aliquot of the stock solutions. Ultra pure water was used for all dilutions.

Fig. 2 The location of the grassland (A) and sampling sites (B).

Processing and digestion of samples In the study area, the sheep and yaks were free ranged. All the herdsmen practiced low input production system, in which the sheep and yaks were mostly dependent on local vegetation. So the trace element deficiency was appeared over with time. In biochemistry, a trace element is a dietary mineral that is needed in very minute quantities for the proper growth, development, and physiology of the organism. Deficiency disease caused by deficiency of a particular essential nutrient (such as a micronutrient or trace element), is usually with a characteristic set of symptoms.

Soil and pasture samples were dried in an oven at 70°C for 48 h, crushed, and sieved through 0.25-mm sieve. Soil (0.2 g), pasture (1 g) and serum (1 mL) samples were placed in PTFE digestion tubes and 12 mL diacid mixture (HNO3HCl, 39) was added. The samples were analyzed after microwave digestion using microwave digestion system (MARS5, CEM Company, America). The digestion procedure is given in Table 4. The digested samples were cooled to room temperature, transferred to glass tube, 1 mL HClO4 was added, and the diacid mixture was removed until

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WANG Hui et al.

1 mL was left using intelligent temperature controller in 115°C. The digested solution was transferred to volumetric ÀDVNDQGYROXPHPDGHXSWRP/ZLWKXOWUDSXUHZDWHU 7KHVRLODQGSDVWXUHVROXWLRQVZHUH¿OWHUHGEHIRUHHVWLPDWLRQ of different minerals. A blank digest was carried out in the same way. Four elements (Cu, Mn, Fe, Zn) were measured by atomic absorption spectrophotometer (ZEEnit 700, Analytik Jena, Germany) with a deuterium background corrector. The elements were determined by using air-acetylene flame. The procedure used for measuring concentrations of trace elements has been described previously (Anan et al. 2001). Optimization of the instrument was done for higher sensitivity and lower detection limits. The optimized operation conditions for analysis of the diluted samples were as Table 5.

Statistical analysis 6XPPDU\ VWDWLVWLFV RI WKH GDWDVHW ZHUH ¿UVWO\ FDOFXODWHG WR evaluate the distributions. Frequency distribution for each of the elements analyzed was examined based on histograms, background normality tests and calculation of skewness. The data were log-transformed before further statistical analysis to improve normal distribution and to reduce the LQÀXHQFHRIKLJKYDOXHV&RUUHODWLRQFRHI¿FLHQWRIPLQHUDO content in soil, plant, and animal was determined from the data for mineral levels of soil, pasture, and blood serum, and the correlation between the assessed elements was estimated E\ 3HDUVRQ¶V SURGXFWPRPHQW FRUUHODWLRQ FRHI¿FLHQW  7KH regression equations on the relationship among soil-plant, plant-animal, and soil-plant-animal were determined using linear regression model. Statistical analysis was performed

Table 4 Operating conditions for samples in microwave digestion system Working step 1 2 3

Temperature (°C) 100 150 160

Heating up time (min) 4 5 5

Holding time (min) 5 10 15

Power (W) 400 800 1 200

Power utilization rate (%) 100 100 100

Table 5 Working conditions of the atomic absorption spectrometer Element Cu Mn Fe Zn

Absorption line (nm) 324.8 279.5 248.3 213.9

Slit (nm) 1.2 0.8 0.2 0.5

Lamp current (mA) 3.0 6.5 6.0 4.0

Gas consumption (L h-1) 50 60 65 60

using the SPSS 17.0 package for windows. The area of the grassland was calculated using spatial statistics tools of GS + and ArcGIS. Inverse distance weighting (IDW) was used to predict a value for any unmeasured location and it gives greater weights to points closest to the prediction location. This technique is exact deterministic interpolator that requires very few decisions regarding model parameters, because it accounts for distance relationships only. This method assigned values to unknown points are calculated with a weighted average of the values available at the known points. The interpolating function is as follows (Romic et al. 2012): n n 1 1 Z(x) ¦ Z(x)= ¦ k (6) i 1 (D )k i 1 (D ) i i Where Z(x 0) is the predicted value at an interpolated point, Z(xi) is at a known point, n is the total number of known points used in interpolation, D i is the distance between point i and the prediction point and k is the weighting power that decides how the weight decreases as the distance increases. An interpolated map for each element was generated in the ArcGIS extension of the Geostatistical Analyst.

Burner height (mm) 6 6 6 6

Flame type C2H2-air C2H2-air C2H2-air C2H2-air

Input dosage (mL min-1) 5.0 5.0 5.0 5.0

Acknowledgements The financial supports are greatly appreciated from the &HQWUDO 3XEOLFLQWHUHVW 6FLHQWL¿F ,QVWLWXWLRQ %DVDO 5HVHDUFK Fund of China (1610322013003), and the Agriculture Achievements Transformation Fund Project of the Ministry of Science and Technology of China (2010GB23260564).

References Anan Y, Kunito T, Watanable I, Sakai H, Tanabe S. 2001. Trace elements accumulation in hawksbill turtles (Eretmochelys imbricate) and green turtles (Chelonia mydas) from Yaeyama island, Japan. Environmental Toxicology and Chemistry, 20, 2802-2814. Dong G T, Zhang A J, Luo G P, Xu W Q, Dai L. 2009. Study on contents of available trace elements in oasis soil of Sangong river watershed. Soils, 41, 726-732. Ghosal A K, Mathur G N. 1992. Zinc, copper and iron contents of blood serum of cattle, sheep in semiarid tract of Rjasthan. The Indian Journal of Animal Sciences, 62, 441-442. Hamzeh M A, Aftabi A, Mirzaee M. 2011. Assessing geochemical influence of traffic and other vehiclerelated activities on heavy metal contamination in urban

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The Estimation of Soil Trace Elements Distribution and Soil-Plant-Animal Continuum in Relation to Trace Elements Status of Sheep

soils of Kerman city, using a GIS-based approach. Environmental Geochemistry and Health, 33, 577-594. Kargin F, Seyrek K, Bulduk A, Aypak S. 2004. Determination of the levels of zinc, copper, calcium, phosphorus and magnesium of Chios ewes in the Aydin region. Turkish Journal of Veterinary and Animal Sciences, 28, 609-612. Khalili M, Lindgren E, Varvikko T. 1993. A survey of mineral status of soil, feeds and cattle in the Seale Ethiopian highlands. Tropical Animal Health and Production, 25, 193-201. Kumaresan A, Bujarbaruah K M, Pathak K A, Brajendra Ramesh T. 2010. Soil-plant-animal continuum in relation to macro and micro mineral status of dairy cattle in subtropical hill agro ecosystem. Tropical Animal Health and Production, 42, 569-577. Lieu P T, Heiskala M, Peterson P A, Yang Y. 2001. The roles of iron in health and disease. Molecular Aspects of Medicine, 22, 1-87. Liu Z P, Ma Z, Zhang Y J. 1992. The research about blood and hair trace element of healthy sheep and goats. Journal of Gansu Agricultural University, 27, 190-195. (in Chinese) NRC. 2007. Nutrient Requirements of Small Ruminants: Sheep, Goats, Cervids, and New World Camelids. National Research Council of the National Academies, National Academies Press, Washington, D.C., USA. Rahman I, Biswa S K, Kirkham P A. 2006. Regulation of inflammation and redox signalling by dietary polyphenols. Biochemical Pharmacology, 72, 14391452. Romic D, Romic M, Zovko M, Bakic H, Ondrasek G. 2012. Trace metals in the coastal soils developed from estuarine floodplain sediments in the Croatian Mediterranean region. Environmental Geochemistry and Health, 34, 399-416. Schwagele F. 2005. Traceability from a European perspective. Meat Science, 71, 164-173. Shen X Y, Du G Z, Li H. 2006. Studies of a naturally RFFXUULQJPRO\EGHQXPLQGXFHGFRSSHUGH¿FLHQF\LQWKH yak. The Veterinary Journal, 171, 352-357. Shuman L M. 1988. Effect of organic matter on the distribution of manganese, copper, iron, and zinc in soil fractions. Soil Science, 146, 192-198. Stef D S, Gergen I. 2012. Effect of mineral-enriched diet and medicinal herbs on Fe, Mn, Zn, and Cu uptake in chicken. Chemistry Central Journal, 6, 19. Stefanidou M, Maravelias C, Dona A, Spiliopoulou C.

147

2006. Zinc: a multipurpose trace element. Archives of Toxicology, 80, 1-9. Sun S, Guo B, Wei Y, Fan M. 2011. Multi-element analysis for determining the geographical origin of mutton from different regions of China. Food Chemistry, 124, 11511156. Tao S, Cao J, Li B G, Xu F L, Chen W Y. 2001. Distribution pattern of trace elements in soil from Shenzhen area. Acta Pedologica Sinica, 38, 248-255. (in Chinese) Warman P R, Termeer W C. 2005. Evaluation of sewage sludge, septic waste and sludge compost applications to corn and forage: yields and N, P and K content of crops and soils. Bioresource Technology, 96, 955-961. Wen Y L, Li H, Li X W, Yang X, Wang H Z, Zhu G. 2007. Research on caparison of the content of trace element in soil and forage in Northwest Sichuan Grassland. Acta Ecologica Sinica, 27, 2837-2846. (in Chinese) Xin G S, Long R J, Guo X S, Irvine J, Ding L M, Ding L L, Shang Z H. 2011. Blood mineral status of grazing Tibetan sheep in the Northeast of the Qinghai-Tibetan Plateau. Livestock Science, 136, 102-107. Yang H S, Li F N, Xiong X, Kong X F, Zhang B, Yuan X X, Fan J X, Duan Y F, Geng M M, Li L L, et al. 2013. Soy isoflavones modulate adipokines and myokines to regulate lipid metabolism in adipose tissue, skeletal muscle and liver of male Huanjiang mini-pigs. Molecular and Cellular Endocrinology, 365, 44-51. Yang X, Chen W, Feng Y. 2007. Improving human micronutrient nutrition through biofortification in the soil-plant system: China as a case study. Environmental Geochemistry and Health, 29, 413-428. Yildiz A, Balikci E. 2004. Association between some mineral and embryonic mortality in the sera of cows. Journal of the Faculty of Veterinary Medicine, 15, 11-15. =KDQJ%
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