Acta Scientiae Veterinariae, 2015. 43: 1306.

RESEARCH ARTICLE

Pub. 1306

ISSN 1679-9216

Hematologic, Serum Biochemical Parameters, Fatty Acid and Amino Acid of Longissimus dorsi Muscles in Meat Quality of Tibetan Sheep Hui Wang, Meizhou Huang, Shengkun Li, Shengyi Wang, Shuwei Dong, Dongan Cui, Zhiming Qi & Yongming Liu

ABSTRACT

Background: Reference values are very important in clinical management of diseased animal. The mutton quality characteristics not only could reflect the breed of sheep, but also allow for a selection of improved meat quality in the breed analyzed with more attractive sensory attributes. The aim of this study was to establish reference values for commonly used hematologic and biochemical parameters and evaluating the amino acid and fatty acid composition of meat quality traits of Tibetan sheep. Materials, Methods & Results: A total of 80 Tibetan sheep were randomly selected. Blood samples were collected used for hematological and biochemical analysis. The contents of mineral elements in serum were also measured. The animals were slaughtered according to commercial procedures. The mutton samples were removed from the Longissimus dorsi (LD) muscles used for amino acid and fatty acid composition analyzed. We have established a locally relevant reference parameters for commonly used hematological and biochemical tests. Most hematological and serum biochemical values were similar to those of yaks and camels, but the Hemoglobin (HGB) concentration was a little higher. The concentrations of Cu, Zn and Se were remarkably lower than critical values in the present study. LD muscle in Tibetan sheep had a higher proportion of total PUFA. We found a large amount of Glu, Lys, Asp, Leu and Arg in the LD muscle of Tibetan sheep. Discussion: Hematological and biochemical parameters are useful tools in measuring the physiological status of animals because they may provide information for diagnosis and prognosis of diseases. Tibetan sheep has survived for millions of generations in this low oxygen condition on the plateau. Tibetan sheep must have evolved exceptional mechanisms to adapt to this extremely inhospitable habitat. The study about Tibetan sheep will undoubtedly facilitate the discovery of potential molecular mechanisms of high-altitude adaptation. In the present study of the Tibetan sheep, all the hematological parameters referring to the erythrocyte and leukocyte series and also to the blood platelet counting were within the reference intervals considered as normal for the ovine species. The hematological results for Tibetan sheep were basically within the reference ranges for other ruminants, including yaks, Przewalski’s, Tibetan gazelles and camels. Trace element deficiency and unbalanced distribution is a major problem in the QTP, which has caused enormous economic loss to the herdsmen. The concentrations of Cu, Zn and Se were remarkably lower than critical values in the present study. Fatty acid composition plays an important role in meat quality, not only in the flavor quality, but also in the nutritional value of meat. Meanwhile, fatty acid analysis can be also used to evaluate the quality of animal meat. LD muscle in Tibetan sheep had a higher proportion of total PUFA, which were considered as flavor precursors of meat. This provides an evidence for that Chinese indigenous sheep show better mutton flavor intensity. Amino acids are the fundamental units of protein, and amino acid content plays an important role in meat quality by providing nutritive value and flavour characteristics. We found a large amount of Glu, Lys, Asp, Leu and Arg in the LD muscle of Tibetan sheep. The fatty acid and amino acid of LD muscles not only could reflect the character of Tibetan sheep mutton, but also allow for a selection of improved meat quality in the breed analyzed with more attractive sensory attributes. Keywords: Tibetan sheep, hematologic, biochemical parameters, meat quality traits

Received: 9 April 2015

Accepted: 18 August 2015

Published: 23 September 2015

Key Lab of New Animal Drug Project of Gansu Province, Key Lab of Veterinary Pharmaceutical Development of Ministry of Agriculture, Engineering and Technology Research Center of Traditional Chinese Veterinary Medicine of Gansu Province, Lanzhou Institute of Husbandry and Pharmaceutics Sciences of Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China. CORRESPONDENCE: Y. Liu [[email protected] - Fax: +(86) 093 1211-5263]. Lanzhou Institute of Husbandry and Pharmaceutics Sciences of Chinese Academy of Agricultural Sciences. 730050 Lanzhou. Gansu, China.

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H. Wang, M. Huang, S. Li et al. 2015. Hematologic, Serum Biochemical Parameters, Fatty Acid and Amino Acid of Longissimus dorsi Muscles in Meat Quality of Tibetan Sheep. Acta Scientiae Veterinariae. 43: 1306. INTRODUCTION

variation and strong adaptability to environment in morphology, structure, behavior and physiology, etc, and have contained a great number of favorable genes due to the long period of natural selection and artificial selection. Tibetan sheep is one of the most important livestock species found on the QTP, with a population of over 50 million animals; it’s also the main source of all human’s production and means of subsistence in these regions. The stable development of the Tibetan sheep industry relates our country’s economic boom in national minority area and social stability.

The Qinghai-Tibetan Plateau (QTP) is a large elevated plateau (mean elevation 4500 m) mainly across the Qinghai Province and Tibet Autonomous Region of China (Figure 1). The QTP is an important biogeographical area and has recently become a focus for biodiversity studies. Having been living in such a harsh environment for several thousand years, yak has evolved the special mechanism of nutrient digestion and metabolism in response to a lack of nutrition [22,31]; also Tibetan sheep seem to have developed some special physiological features for their survival. Tibetan sheep is one of the dominant livestock species on the QTP, with a population of over 50 million animals providing meat, milk and major source of income for most nomadic and seminomadic peoples in these regions [26]. Reference ranges of physiological parameters can be useful for the evaluation of the state of health in specimens of the species as well as diagnostics and prevention of diseases. Locally relevant reference ranges for commonly used hematologic and biochemical parameters are essential for screening and safety follow up of trial participants as well as for routine clinical management [8]. As an increased emphasis on meat quality among producers and consumers, the interest for meat quality traits and the possibility for implementing these traits into breeding programmes have attracted interest among sheep breeders and sheep breeding companies [17]. Thus, the objective of this study was aimed at establishing reference values for commonly used hematological and biochemical parameters and evaluating the amino acid and fatty acid composition of meat quality traits of Tibetan sheep.

Sampling

Two types of blood samples were collected from the jugular vein into vacutainer tubes from 80 (40 male and 40 female) Tibetan sheep (6-10 mo of age, weighing 10.0 to 20.0 kg), each of 10 mL (Figure 1); the first blood sample was collected in plain vacutainer tube and used for obtaining serum. The second blood sample was collected in vacutainer tube1 containing EDTA as anticoagulant and used for hematological analysis. Blood samples in plain tubes were centrifuged at 1008 g for 15 min, after which serum was harvested, stored at -20°C, and were used for measuring serum biochemical constituents. The animals were slaughtered according to commercial procedures. The mutton samples of Tibetan sheep were removed from the Longissimus dorsi (LD) muscle, placed in zipped plastic bags, and frozen for instrumental quality analysis. Samples for amino acid and fatty acid composition determination were stored in -80°C until analyzed. Analysis of hematologic and biochemical parameters

White blood cell (WBC), Neutrophils percentage (NEU %), Lymphocytes percentage (LYM %), Monocytes percentage (MON %), Eosinophils percentage (EOS %), Basophils percentage (BAS %), Neutrophils (NEU), Lymphocytes (LYM), Monocytes (MON), Eosinophils (EOS), Basophils (BAS), red blood cell (RBC), Hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), red cell distribution width-coefficient of variation (RDW-CV), red cell distribution width-standard deviation (RDWSD), platelets (PLT), mean platelet volume (MPV), platelet distribution width (PDW) and plateletcrit

MATERIALS AND METHODS

Study area

Rangelands of the QTP, although sparsely populated and contributing little to China’s overall economy, play an important environmental role throughout Asia. They contain high biodiversity values and can also potentially provide China with a source of cultural and geographic variety in the future. Tibetan sheep is one of the finest local sheep breeds in China. They have formed abundant

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H. Wang, M. Huang, S. Li et al. 2015. Hematologic, Serum Biochemical Parameters, Fatty Acid and Amino Acid of Longissimus dorsi Muscles in Meat Quality of Tibetan Sheep. Acta Scientiae Veterinariae. 43: 1306.

(PCT) were determined using an automatic hematology analyzer (UniCel DxH800)2. The serum content of total protein (TP), albumin (ALB), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatine kinase (CK–NAC), amylase (Amy), Lipase, γ-glutamyl transferase (GGT), blood glucose (GLU), total bilirubin (T.BILI), direct bilirubin (D.BILI), blood urea nitrogen (BUN), creatinine (CRE), cholesterol (CHOL) , calcium(Ca) and phosphorus (P) were determined on an automatic analyzer (UniCel DxC800)2 using commercial test kits2.

initial descriptive statistics, including mean and standard deviation (SD). RESULTS

The minimum and maximum values, arithmetic means and standard deviation of means of hematologic values and serum biochemical parameters are presented in Tables 1 and 2, respectively. The results obtained from the QTP area demonstrated that HGB (90.8-160.1 g/L) and RBC (8.636×1012/L) were a little higher than values set as standards (90.0-145.0 g/L and 8.0×1012/L, respectively) on the clinical hematology machines being used for clinical trials assessments in the study area, but there was no significant difference. Such variations are expected for animals in different geographical/ ecological locations. To investigate the relationships between blood physiological and biochemical indexes in Tibetan sheep, Pearson correlation analyses were performed for the accessions (Table 3). Among the chemical composition and trace elements, closely positive associations were recognized between the contents of HGB and TP, EOS and ALT, BAS and ALT, EOS and ALP (P < 0.01). The relationship between MON% and ALP was indicated that there was a very significantly negative association (P < 0.01). The relationships between blood physiological and biochemical indexes will provide reference date for breeding, disease prevention, feeding and management. The mean concentration of Cu, Zn and Se, observed in the present study were 0.259, 1.915 and 0.04 μg/mL, respectively (Table 4). The levels of serum Fe and Mn were in normal range. The concentrations of Cu, Zn and Se were remarkably lower than critical values in the present study. Table 5 and Figure 2 shows results of fatty acid composition of LD muscle from Tibetan sheep. The proportion of polyunsaturated fatty acids (PUFA) (C16:1, C18:1, C18:2, C18:3) was similar to saturated fatty acids (SFA) (C14:0, C16:0, C18:0); there was no significant difference. LD muscle in Tibetan sheep had a higher proportion of total PUFA. Table 6 shows the amino acid composition in LD muscle of Tibetan sheep. We found a large amount of Glu, Lys, Asp, Leu and Arg in LD muscle of Tibetan sheep.

Amino acid analysis

About 100 mg of minced muscle samples of meat used for amino acid analysis were hydrolyzed with 10 mL of HCl (6 mol/L) at 110°C for 22 h in sealed evacuated tubes [1]. Amino acid composition of the muscle powder was analyzed using ion–exchange chromatography with an automatic amino acid analyzer (L-8900)3. Fatty acid composition analysis

Fatty acid methyl esters were prepared following the direct method of O’Fallon et al. [16], and identified and quantified using gas chromatography (GC-450)4, equipped with a flame ionization detector (FID) and a fused silica capillary column (120 m×250 μm×0.25 μm)5. The temperature program was as follows: the carrier gas (helium) flow rate was 0.81 mL/min, the column was equilibrated at 45 °C for 3 min, then it was increased to 175°C at 13°C/min where it was maintained for 27 min, further it was increased to 215 °C at 4°C/min and kept for 5 min. Carrier gas was helium (2 mL/min), and the split ratio was 30:1. The identification of fatty acids was accomplished by comparison with external standards. The amount of each fatty acid was calculated as peak area percentage of total fatty acids. Analysis of trace elements

Copper (Cu), iron (Fe), zinc (Zn), manganese (Mn) were determined by atomic absorption spectrophotometry (AAS ZEEnit 700)6 [26]. The hydride generation atomic fluorescence spectrometry was used for Selenium (Se) determination [14]. Statistical Analysis

The SPSS procedure (Version 19.0)7 was used for all statistical analyses of data. We performed

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H. Wang, M. Huang, S. Li et al. 2015. Hematologic, Serum Biochemical Parameters, Fatty Acid and Amino Acid of Longissimus dorsi Muscles in Meat Quality of Tibetan Sheep. Acta Scientiae Veterinariae. 43: 1306. Table 1. Normal values for some hematological parameters in Tibetan sheep.

Blood index WBC (109/L) NEU % LYM % MON % EOS % BAS % NEU (109/L) LYM (109/L) MON (109/L) EOS (109/L) BAS (109/L) RBC (1012/L) HGB (g/L) HCT (%) MCV (fL) MCH (pg) MCHC (g/L) RDW–CV (%) RDW–SD (fL) PLT (109/L) MPV (fL) PDW (fl) PCT (%)

Mean±SD 9.395±4.418 49.59±11.60 46.61±10.19 2.115±1.056 2.933±1.757 0.071±0.085 4.758±1.824 3.761±1.908 0.168±0.118 0.565±0.819 0.016±0.026 8.636±2.484 117.0±16.70 36.88±9.548 43.39±8.186 14.58±4.638 311.2±38.72 18.20±3.098 31.46±6.166 407.6±285.1 5.453±1.327 15.25±0.768 0.230±0.141

let radiation [9]. Non-native animals such as humans that visit such high-altitude regions may experience life-threatening acute mountain sickness. In contrast, the Tibetan sheep, which has survived for millions of generations in this low oxygen condition on the plateau. Tibetan sheep must have evolved exceptional mechanisms to adapt to this extremely inhospitable habitat. The study about Tibetan sheep will undoubtedly facilitate the discovery of potential molecular mechanisms of high-altitude adaptation. In the present study of the Tibetan sheep, all the hematological parameters referring to the erythrocyte and leukocyte series and also to the blood platelet counting were within the reference intervals considered as normal for the ovine species [5]. Biochemical tests commonly used during screening/enrollment and safety monitoring of trial participants in animal study area are ALT, AST, Bilirubin (Total and Direct), Urea and Creatinine. Liver damage induces an increase in the serum total bilirubin, and the

Range 3.50–18.0 26.3–70.1 35.2–71.0 0.20–4.50 0.90–5.10 0–0.40 2.42–6.92 2.10–8.35 0.01–0.49 0.02–2.9 0–0.10 3.75–12.6 90.8–160.1 16.6–53.2 33.2–70.4 10.0–27.2 250.0–456.2 15.0–25.6 21.6–43.2 72.4–840.0 4.59–17.2 13.30–17.20 0.04–0.50

Table 2. Normal values for some biochemical parameters in Tibetan sheep serum.

WBC,White blood cell; NEU %, Neutrophils percentage; LYM %, Lymphocytes percentage; MON %, Monocytes percentage; EOS %, Eosinophils percentage; BAS %, Basophils percentage; NEU, Neutrophils; LYM, Lymphocytes; MON, Monocytes; EOS, Eosinophils; BAS, Basophils; RBC, red blood cell; HGB, Hemoglobin; HCT, hematocrit; MCV, mean corpuscular volume; MCH, mean corpuscular hemoglobin; MCHC, mean corpuscular hemoglobin concentration; RDW–CV, red cell distribution width–coefficient of variation; RDW–SD, red cell distribution width–standard deviation ; PLT, platelets; MPV, mean platelet volume; PDW, platelet distribution width; PCT, plateletcrit. SD: Standard deviation.

DISCUSSION

Hematological and biochemical parameters are useful tools in measuring the physiological status of animals because they may provide information for diagnosis and prognosis of diseases [25,15]. This study aimed at establishing hematologic and biochemical reference values to serve as standards for the interpretation of laboratory results during screening and follow-ups in clinical trials and routine healthcare in the Tibetan plateau area. Tibetan plateau has a low partial pressure of oxygen and a high level of ultravio-

Parameter

Mean±SD

Range

TP (g/L)

63.50±9.49

42.0–74.0

ALB (g/L)

31.78±7.24

17.1–45.0

ALT (U/L)

31.19±21.50

10.0–85.2

AST (U/L)

541.6±728.9

40.2–2160.0

ALP (U/L)

299.1±181.4

100.1–480.1

CK–NAC (U/L)

57.89±46.51

10.2–140.5

Amy (U/L)

119.0±63.57

40.4–200.4

Lipase (U/L)

150.1±31.23

105.1–195.0

GGT (U/L)

10.05±6.16

1.20–20.6

GLU (mmol/L)

3.353±1.64

1.51–7.00

T.BILI (μmol/L)

6.433±5.03

0.41–16.2

D.BILI (μmol/L)

1.657±1.21

0.10–3.00

BUN (mmol/L)

26.64±22.10

6.9–84.7

CRE (μmol/L)

111.5±65.23

31.2–210.0

CHOL (mmol/L)

6.140±1.369

3.1–8.0

Ca (mmol/L)

2.944±0.553

1.9–3.6

P (mmol/L)

2.375±1.174

1.0–4.3

TP, total protein; ALB, albumin; ALT, alanine aminotransferase; AST, aspartate aminotransferase; ALP, alkaline phosphatase; CK–NAC, creatine kinase; Amy, amylase; GGT, γ–glutamyl transferase; GLU, blood glucose; T.BILI, total bilirubin; D.BILI, direct bilirubin; BUN, blood urea nitrogen; CRE, creatinine; CHOL, cholesterol; Ca, calcium; P, phosphorus. SD: Standard deviation.

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H. Wang, M. Huang, S. Li et al. 2015. Hematologic, Serum Biochemical Parameters, Fatty Acid and Amino Acid of Longissimus dorsi Muscles in Meat Quality of Tibetan Sheep. Acta Scientiae Veterinariae. 43: 1306.

LYM

NEU

BAS%

EOS%

MON%

LYM%

NEU%

WBC

Index

0.086

–0.108

0.128

0.233

0.210

–0.037

–0.296

–0.171

0.103

0.381

TP

0.131

0.000

0.061

0.176

0.173

0.070

–0.090

0.016

0.222

0.140

ALB

0.742**

–0.192

–0.391

–0.131

0.446*

0.491*

–0.162

0.225

0.220

–0.171

ALT

0.239

–0.092

0.223

0.030

–0.067

–0.390

–0.308

–0.380

–0.036

0.331

AST

0.517**

–0.241

–0.131

–0.120

0.226

0.032

–0.550**

–0.134

–0.172

–0.019

ALP

0.127

0.421*

0.180

0.354

0.102

0.137

0.347

0.305

0.289

–0.002

CK–NAC

0.094

0.193

0.129

0.122

0.037

–0.017

0.107

0.011

0.141

–0.006

Amy

–0.097

0.449*

0.002

0.104

–0.028

0.033

0.385

0.248

0.301

–0.200

Lipase

–0.228

0.355

0.501*

0.263

–0.287

–0.232

0.156

0.306

0.166

0.207

GGT

0.129

–0.100

0.018

–0.144

0.033

0.008

–0.020

–0.081

0.220

–0.045

GLU

0.077

–0.262

0.106

–0.180

–0.242

–0.185

–0.123

–0.240

0.072

0.040

T.BILI

0.106

0.279

0.150

–0.011

–0.198

0.061

0.042

0.060

–0.060

–0.177

D.BILI

–0.013

0.045

0.220

0.213

–0.016

–0.023

–0.204

0.264

0.061

0.000

BUN

–0.104

0.441*

–0.149

0.018

0.182

0.117

0.312

0.188

0.029

–0.260

CRE

0.089

0.259

0.153

0.040

0.186

0.287

0.288

0.201

0.320

–0.087

CHOL

0.137

0.144

–0.179

–0.285

–0.083

–0.169

0.082

–0.362

–0.042

–0.177

Ca

–0.143

–0.313

–0.057

–0.318

0.100

0.154

–0.170

–0.192

–0.238

–0.360

P

Table 3. Pearson phenotypic correlations between blood physiological and biochemical indexes in Tibetan sheep.

EOS

MON

–0.183

0.165

0.364

–0.358

–0.432*

–0.167

0.106

–0.127

0.117

0.202

0.126

0.128

–0.199

–0.083

–0.275

–0.150

–0.341

–0.173

–0.142

–0.282

–0.242

0.194 –0.293

0.079

0.054

–0.326

0.220

0.137

–0.320

–0.221 –0.426*

–0.317

–0.423*

0.084

–0.183

0.173

–0.250

0.081 0.103

–0.284

–0.291

0.213

–0.022

–0.132

0.169

0.353

–0.428*

–0.014 0.168

0.157

–0.389

0.242

0.342

0.267

–0.343

–0.197

0.199 0.231

0.114

–0.164

–0.182

0.206

0.123

0.424*

–0.411

–0.029 0.117

0.340

–0.124

0.062

–0.151

–0.300

0.144

0.294

–0.149

0.511*

–0.034

0.233

0.128

–0.096

–0.183

–0.040

–0.233

–0.004

0.225 0.276

–0.108

–0.098

0.271

0.098

–0.368

–0.211

–0.341

0.439* 0.175

0.289

0.028

0.049

0.096

0.261

–0.252

–0.098

0.167 0.115 0.291

0.355

0.269

0.224

0.163

0.269

–0.031

0.260 –0.079 0.247 0.320

0.078

0.090

0.027

0.144

0.070

RBC 0.684** 0.006 –0.215

0.123

0.301

0.179

–0.067

0.338

HGB 0.511* 0.328 –0.286

0.125

0.429*

–0.207

–0.126

HCT 0.417* 0.191 0.297

0.301

–0.084

0.587**

MCV 0.361 0.203 0.118

–0.019

0.035

MCH 0.460* 0.186

–0.018

0.086

MCHC 0.344

–0.274

BAS

RDW–CV

0.068

0.132

0.428*

–0.112

–0.356

0.305

0.001

0.135

0.516*

–0.188

–0.208

0.154

–0.484

0.178

0.270

–0.219

–0.546*

–0.438*

0.133

–0.060

–0.325

0.229

–0.261

0.346

0.258

–0.317

–0.304

0.064

–0.168

0.061

0.099

–0.120

0.296

0.140

–0.035

–0.369

–0.022

0.116

0.082

0.184

–0.089

0.037

–0.139

0.269

–0.462

0.136

0.507*

0.252

–0.546*

–0.222

–0.057

0.193

–0.343

0.155

0.319

0.120

0.119

0.263 –0.049

0.112

0.115

0.378 0.159

–0.199

–0.514*

0.292

MPV 0.312

0.364

PLT PDW

0.325

RDW–SD

PCT

** Significant at 0.01 probability level. * Significant at 0.05 probability level.

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H. Wang, M. Huang, S. Li et al. 2015. Hematologic, Serum Biochemical Parameters, Fatty Acid and Amino Acid of Longissimus dorsi Muscles in Meat Quality of Tibetan Sheep. Acta Scientiae Veterinariae. 43: 1306. Table 4. The concentrations of mineral elements in the serum of Tibetan sheep.

Element

Mean ± SD

Range

Se (μg/mL)

0.040±0.013

0.018–0.064

Cu (μg/mL)

0.259±0.207

0.038–0.555

Mn (μg/mL)

0.193±0.066

0.100–0.301

Fe (μg/mL)

9.678±4.794

4.10–20.1

Zn (μg/mL)

1.915±0.285

1.41–2.47

haemic compound is considered as a sensitive indicator for liver injury. As bilirubin concentrations, high serum activities of some enzymes highly expressed in liver in ruminants such as AST, GGT and LDH are observed in liver injury and highly contribute to evaluate the degree of tissue damage [13]. The values of the general clinical biochemistry parameters that were selected to help in the characterization of the metabolic and nutrition state and renal, hepatic, and thyroid functions, also situated within the reference intervals published for the ovine species [7]. As far as the characterization of the energetic state of the ruminants is concerned, the glucose and the total cholesterol were evaluated. The level of glycaemia could contribute to the assessment of energy status diagnosis in association with insulin which has a close relationship with the nutritional state of the animal and with respect to the free fatty acids, high levels generally indicate a negative energy balance, conversely low levels indicate a positive balance [2]. The protein state and the kidney function can be estimated in ewes by the simultaneous determination of the total protein and urea, associated with HCT and HGB, and to the serum creatinine in the kidney function. Creatinine is mainly filtered by the kidney and there is little-to-no tubular reabsorption of creatinine [7]. The hematological results for Tibetan sheep were basically within the reference ranges for other ruminants, including yaks [18], Przewalski’s [19], Tibetan gazelles [19] and camels [11]. Some physical adaptations have induced specific changes in HGB with increasing altitude. The HGB concentration was a little higher than the value for yaks (108 ± 6.51 g/L) [18] and camel (109 ± 24 g/L) [11], so Tibetan sheep have an improved capability for accommodating the low-oxygen circumstances without having an increased concentration of hemoglobin. However, most of the non-Tibetans in the region were immigrants whom from low-lying provinces and their physiological adaptation for environment of high altitude might be different from the Tibetan, which could contribute to the ethnic differences in HGB level [28]. Trace elements are integral components of certain enzymes and of other biologically important compounds that have major physiological and bio-chemical roles, and micronutrient malnutrition is a major health problem in China [29]. Trace element requirements

Table 5. Fatty acid composition in LD muscle of Tibetan sheep.

Fatty acid

Mean

SD

Myristic (%)

C14:0

0.064

0.044

Palmitic (%)

C16:0

0.278

0.148

palmitoleic acid (%)

C16:1

0.018

0.011

Stearic (%)

C18:0

0.212

0.065

Oleic (%)

C18:1

0.386

0.187

Linoleic (%)

C18:2

0.117

0.036

α–Linolenic (%)

C18:3

0.014

0.005

Table 6. Amino acids content from protein expressed as percentage of total amino acids in Longissimus dorsi muscle of Tibetan sheep.

Hydrolyzed amino acids Amino acids (% of total amino acids) Mean SD Aspartic acid

15.086

1.232

Threonine

7.078

0.722

Serine

6.173

0.458

Glutamin acid

28.016

2.568

Glycine

9.040

1.935

Alanine

9.486

0.670

Cystine

5.067

0.463

Valine

8.186

0.494

Methionine

1.496

1.583

Isoleucine

7.083

0.795

Leucine

12.930

1.170

Tyrosine

6.377

0.368

Phenylalanine

7.421

0.726

Lysine

16.243

2.435

Histidine

4.122

0.608

Arginine

10.499

0.734

Proline

6.691

1.010

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H. Wang, M. Huang, S. Li et al. 2015. Hematologic, Serum Biochemical Parameters, Fatty Acid and Amino Acid of Longissimus dorsi Muscles in Meat Quality of Tibetan Sheep. Acta Scientiae Veterinariae. 43: 1306.

Figure 1. The location of the sampling sites (A, blank triangle). The rangelands of Qinghai-Tibetan plateau (B). The Tibetan sheep (C).

Figure 2. Gas chromatograms of fatty acid for standard (a) and Longissimus dorsi muscle of Tibetan sheep (b).

vary with age and production level-young, pregnant and lactating animals have the greatest need. QTP is also China’s important base of animal husbandry. Every year a great number of sheep died in the area, which is attributed to malnourishment and mineral deficiency [23]. Trace element deficiency and unbalanced distribution is a major problem in the region [18,27], which has caused enormous economic loss to the herdsmen.

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. Investigators [10,32] reported that the levels of serum Cu in sheep should be between 0.8 and 1.2 μg/mL, Zn should be between 6.9 and 14.86 μg/mL, and Se should be between 0.06 and 0.20 μg/mL. In ruminants, average blood Cu values of < 0.5 μg/mL are a sign of

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H. Wang, M. Huang, S. Li et al. 2015. Hematologic, Serum Biochemical Parameters, Fatty Acid and Amino Acid of Longissimus dorsi Muscles in Meat Quality of Tibetan Sheep. Acta Scientiae Veterinariae. 43: 1306.

severe Cu deficiency [33]. The concentrations of Cu, Zn and Se were remarkably lower than critical values in the present study. The results indicated that most of the sheep were deficient in Cu, Zn and Se. Tibetan sheep have some physiological peculiarities in trace element metabolism maybe due to geographic (altitude, latitude, climate) and dietary factors. Fatty acid composition plays an important role in meat quality, not only in the flavor quality, but also in the nutritional value of meat [30]. Meanwhile, fatty acid analysis can be also used to evaluate the quality of animal meat [20]. Fatty acids, especially polyunsaturated fatty acids (PUFA), are major flavor precursors of meat. C18:2 was one of polyunsaturated fatty acids, which were a positive correlation with flavor of meat [3]. Furthermore, the amount and composition of fatty acids in the food are also associated with human health. The percentage and total amount of saturated fatty acids (SFA) have been identified as dietary risk factors [16], which may related to various cancers and especially coronary heart disease. PUFA are required for the normal composition of sperm, retina and brain lipids and for the optimal maturation of visual and cortical function in preterm infants [21]. Therefore, increasing PUFA content and reducing SFA content of meat has become a tendency of meat quality improvement. LD muscle in Tibetan sheep had a higher proportion of total PUFA, which were considered as flavor precursors of meat. This provides an evidence for that Chinese indigenous sheep show better mutton flavor intensity. On the other hand, meat of Tibetan sheep is good for human health because these PUFA are essential to the human body, involved in many biological functions. Protein is important resources for human with essential amino acids as one of the most important nutritional qualities [4]. Amino acids are the fundamental units of protein, and amino acid content plays an important role in meat quality by providing nutritive value and flavour characteristics [1]. We found a

large amount of Glu, Lys, Asp, Leu and Arg in the LD muscle of Tibetan sheep. Analyses of the amino acid compositions of some red meats showed that glutamic acid was present at the highest concentration in camel meat [6] and buffalo meat [34], which were similar to our study. The results from those studies found that the glutamic acid contents of camel and buffalo were 16.35-17.25 (g/16 g N) and 12.32-12.69 (g/100 g protein), respectively. In conclusion, the Tibetan sheep in the study were selected and management strictly. The results of hematologic and serum biochemical parameters of Tibetan sheep have important reference value for researchers, veterinarians and herdsman. The fatty acid and amino acid of Longissimus dorsi muscles of Tibetan sheep not only could reflect the character of Tibetan sheep mutton, but also allow for a selection of improved meat quality in the breed analyzed with more attractive sensory attributes. MANUFACTURERS 1 Becton Dickinson vacutainer. Franklin Lakes, NJ, USA. 2 Beckman Coulter. Brea, CA, USA. 3 Hitachi High-Technologies Corporation. Tokyo, Japan. 4 Varian. Palo Alto. CA, USA. 5 SGE-FFAP. Melbourne, Australia. 6 Analytik Jena. Jena, Germany. 7 SPSS Inc. Chicago, IL,USA. Funding. Financial assistance for this research was provided by Central Public-interest Scientific Institution Basal Research Fund (NO.1610322013003), National Key Technology Research and Development Program of the Ministry of Science and Technology of China (NO. 2012BAD12B03), and Special Fund for Agroscientific Research in the Public Interest (NO. 201303040-17). Ethical approval. All animal protocols have been reviewed and approved by the Institutional Animal Care and Use Committee of Lanzhou Institute of Husbandry and Pharmaceutics Sciences of Chinese Academy of Agricultural Sciences (Animal use permit: SCXK20008–0003). Declaration of interest. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

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