猪肉品质的评价指标及其影响因素

本文对猪肉品质的评价指标及其影响因素进行探讨。     

不同硒源对肥育猪鲜肉肉色和滴水损失的影响

选用108头体重60kg左右的杜×长×大三元杂交肥育猪,按饲养试验要求分成3组,对照组不添加硒(基础日粮中Se的实测值为0.045mg/kg),亚硒酸钠和硒代蛋氨酸试验组均添加0.30mg/kg硒,进行为期40d的饲养试验,然后屠宰并取样测定,研究不同硒源对肥育猪鲜肉肉色和滴水损失的影响及机理。结果表明:(1)硒代蛋氨酸使猪宰后第0.75、8、16小时肉色Huntera值显著升高(P<0.05),而亚硒酸钠仅使第0.75小时肉色Huntera值明显提高(P<0.05);(2)硒代蛋氨酸使猪宰后第8、16小时鲜肉的滴水损失显著减少(P<0.01),而亚硒酸钠有这一作用趋势,但效果不明显(P>0.05);(3)硒代蛋氨酸和亚硒酸钠均使血清和组织中硒含量增加(P<0.01),使肝脏、肌肉中谷胱甘肽过氧化物酶活力增强(P<0.01),丙二醛含量降低(P<0.01),但硒代蛋氨酸的这一作用较亚硒酸钠明显。     

植物提取物对育肥猪生长性能、胴体性状、猪肉品质及抗氧化能力的影响

本试验旨在研究植物提取物对育肥猪生长性能、胴体性状、肉品质及猪肉抗氧化能力的影响。选用20头体重相近[(83.75±5.83 kg)]的PIC猪,随机分为对照组(基础日粮)和试验组(基础日粮中额外添加0.04%植物提取物),每个处理5个重复,每个重复2头猪。结果表明,两组间育肥猪采食量、日增重、料肉比和胴体性状差异不显著(P>0.05)。与对照组相比,试验组肉色a*45min值显著提高(P<0.05),L*96 h值极显著降低(P<0.01);4℃下储存0、3 d和7 d猪肉,试验组肉样中丙二醛(MDA)的含量显著降低,超氧化物歧化酶(SOD)活性显著提高(P<0.05)。因此,饲粮中添加植物提取物有利于储存中猪肉品质的改善。     

Slaughterline records of various postmortem pathological lesions and their influence on carcass and meat quality in slaughtered pigs

The aim of this study was to identify the prevalence of pathological lesions in pigs from small‐scale farms and to determine associations between pathological lesions and hematological parameters, and carcass and meat quality in slaughtered pigs. The study was conducted on 625 pigs (~115 kg) originating from 20 small‐scale farms. Any signs of pneumonia, pleurisy, pericarditis, and liver milk spots were recorded as present or absent. Complete blood count was investigated. The following carcass quality parameters were measured: live, hot and cold carcass weights, cooling loss, dressing percentage, backfat thickness, and meatiness. Meat pH and temperature were measured 45 min postmortem. Of the 625 examined pigs, 41.8% had pneumonia, 23.5% pleurisy, 2.7% pericarditis, and 29.9% liver milk spots. The presence of pathological lesions in slaughtered pigs adversely affected hematological parameters, reduced live, hot and cold carcass weights, and meatiness and had deleterious effects on meat quality (higher pH_45min and higher prevalence of dark, firm and dry meat). In conclusion, this study showed a high prevalence of pathological lesions in slaughtered pigs, indicating serious health problems in smallholder pig production systems. The presence of single and, especially, multiple pathological lesions in slaughtered pigs negatively affected hematological parameters, and carcass and meat quality.     

微卫星DNA标记与鸡肉品质性状的相关分析

本研究测定了隐性白羽和仙居鸡参考家系F2代500羽个体的26个微卫星座位的多态性,分析微卫星标记与鸡肉品质性状之间的相关性,结果发现:位于2号染色体上的标记ADL212分别与pH值和嫩度显著相关;位于3号和5号染色体上的微卫星标记MCW 004和MCW 223与肉色显著相关;与胸肌失水率显著相关的微卫星标记分别为:位于2号染色体的MCW 264和ADL212以及5号染色体的MCW 223和9号染色体的ADL211。     

猪肉质性状评定方法及其研究进展

随着生活水平的不断提高,人们对猪肉产品的消费已经从注重数量而转变到优质肉品质上来,因此如何对猪肉品质进行有效评定已经变得愈发重要。21世纪以来,在诸如光谱分析和高通量测序等技术飞速发展的时代背景下,新的猪肉质评定方法和手段层出不穷。为了能更好地了解猪肉质性状形成的分子基础及其评定方法,文章回顾了近年来猪肉质性状评定中广泛应用的研究方法与技术,同时全面地阐述了这些方法的研究进展。     

Associations of the variation in the porcine myogenin gene with muscle fibre characteristics, lean meat production and meat quality traits

Pig breeding is aimed at improving lean meat production ability as well as meat quality, and muscle fibre characteristics may be important for enhancing these traits. Therefore, new molecular markers have been demanded for selecting lean meat production ability and meat quality in live animals. Myogenin belongs to the MyoD gene family, and is a candidate gene responsible for muscle fibre characteristics. We identified a new single nucleotide polymorphism (SNP) site in the 5' upstream region of the myogenin gene (nucleotides C and T). A total of 252 pigs of three breeds were genotyped by polymerase chain reaction–restriction fragment length polymorphism using BspCNI . Additionally, they were genotyped for the previously detected Msp I site in the 3'-flanking region (alleles A and B). The CCBB diplotype had the highest frequency over breeds, followed by TCBB and CCAB. The other diplotypes were not found in studied pigs. Association analysis performed for the markers found that the TCBB diplotype has desirable effects on the total number of fibres (p   < 0.002), fibre cross-sectional area (p   < 0.06), and loin eye area (p   < 0.001) than the other diplotypes. Moreover, the diplotype had the highest muscle pH value (p   < 0.07) and all meat quality traits were near the upper limit of the normal range as a reddish pink, firm and non-exudative (RFN) pork. Therefore, we suggest that selection for the myogenin diplotypes could improve total muscle fibre number, size and lean meat production ability with good meat quality.     

Ob基因对松辽黑猪肉质和胴体性状的影响

以松辽黑猪为研究对象,分析Ob基因对其肉质和胴体性状的影响。测定30头松辽黑猪的9个肉质性状和6个胴体性状,用PCR-RFLP方法检测Ob基因型。结果显示,松辽黑猪TT基因型平均膘厚比CT基因型低,而肌内脂肪含量、瘦肉率则显著高于后者(P<0.05),其他肉质和胴体性状在Ob基因型间没有显著差异(P>0.05)。结果表明,Ob基因的TT基因型对猪的肉质和胴体性状具有显著的正遗传效应。     

西门塔尔牛CS基因多态性与肉质性状的相关性分析

以柠檬酸合成酶基因（citrate synthetase,CS）为候选基因,分析了该基因外显子3的遗传多态性与西门塔尔牛肉质性状的相关关系。选用95头西门塔尔牛为试验材料,采用PCR-RFLP的方法对该基因的外显子多态性进行检测,并利用SPSS软件对该外显子多态性与肉质性状的相关性进行分析。结果表明：CS基因第三外显子第206bp处存在G/A突变,该基因多态性与脂肪颜色呈显著相关,AA型显著高于BB型。对其他性状的影响差异不显著。通过研究CS基因外显子的多态性,为西门塔尔牛利用该基因的多态性进行分子育种提供了试验依据。     

Improving growth performance and blood profile by feeding autolyzed yeast to improve pork carcass and meat quality

The 63 commercial pigs were divided into three groups consisting of seven replicates of three piglets each. The experimental diets were (1) control diet, (2) diet with autolyzed yeast (AY) 0.5%, and (3) diet with AY 1.0%. Compared to the control group, using AY 0.5% in the diet reduced average daily feed intake (ADFI) and improved feed conversion ratio (FCR) (p < 0.05). The blood urea nitrogen (BUN) and neutrophil/lymphocyte ratio (N/L) in blood decreased with the addition of AY 0.5% (p < 0.05). The pH at 6-h postmortem of meat in the 0.5% AY diet group was higher than for the control group (p < 0.05). Backfat thickness (p = 0.09) and P2-backfat thickness (p = 0.07) tended to decrease, while the fat free index (FFI; p = 0.07) tended to increase with 0.5% AY supplementation. The protein percentage (p = 0.07) and the a* value (redness) (p = 0.08) in the meat tended to increase, and the springiness increased with 0.5% AY supplementation (p < 0.05). An appropriate level of AY supplementation can impact positively on the physiological functions in swine with a consequent seems to improve in qualitative traits of the meat quality.     

Genetic correlations between ewe reproduction and carcass and meat quality traits in Merino sheep

Genetic correlations between reproduction traits in ewes and carcass and meat quality traits in Merino rams were obtained using restricted maximum likelihood procedures. The carcass data were from 5870 Merino rams slaughtered at approximately 18 months of age that were the progeny of 543 sires from three research resource flocks over 7 years. The carcass traits included ultrasound scan fat and eye muscle depth (EMDUS) measured on live animals, dressing percentage and carcass tissue depth (at the GR site FATGR and C site FATC), eye muscle depth, width and area and the meat quality indicator traits of muscle final pH and colour (L*, a*, b*). The reproduction data consisted of 13 464 ewe joining records for number of lambs born and weaned and 9015 records for LS. The genetic correlations between reproduction and fat measurements were negative (range ?0.06 ± 0.12 to ?0.37 ± 0.12), with smaller correlations for live measurement than carcass traits. There were small favourable genetic correlations between reproduction traits and muscle depth in live rams (EMDUS, 0.10 ± 0.12 to 0.20 ± 0.12), although those with carcass muscle traits were close to zero. The reproduction traits were independent of meat colour L* (relative brightness), but tended to be favourably correlated with meat colour a* (relative redness, 0.12 ± 0.17 to 0.19 ± 0.16). There was a tendency for meat final pH to have small negative favourable genetic correlations with reproduction traits (0.05 ± 0.11 to ?0.17 ± 0.12). This study indicates that there is no antagonism between reproduction traits and carcass and meat quality indicator traits, with scope for joint improvement of reproduction, carcass and meat quality traits in Merino sheep.     

Genetic parameters for carcass and meat quality traits and their relationships to liveweight and wool production in hogget Merino rams.

Genetic parameters for carcass and meat quality traits of about 18-month-old Merino rams (n = 5870), the progeny of 543 sires from three research resource flocks, were estimated. The estimates of heritability for hot carcass weight (HCW) and the various fat and muscle dimension measurements were moderate and ranged from 0.20 to 0.37. The brightness of meat (colour L*, 0.18 +/- 0.03 standard error) and meat pH (0.22 +/- 0.03) also had moderate estimates of heritability, although meat relative redness (colour a*, 0.10 +/- 0.03) and relative yellowness (colour b*, 0.10 +/- 0.03) were lower. Heritability estimates for live weights were moderate and ranged from 0.29 to 0.41 with significant permanent maternal environmental effects (0.13 to 0.10). The heritability estimates for the hogget wool traits were moderate to high and ranged from 0.27 to 0.60. The ultrasound measurements of fat depth (FATUS) and eye muscle depth (EMDUS) on live animals were highly genetically correlated with the corresponding carcass measurements (0.69 +/- 0.09 FATC and 0.77 +/- 0.07 EMD). Carcass tissue depth (FATGR) had moderate to low genetic correlations with carcass muscle measurements [0.18 +/- 0.10 EMD and 0.05 +/- 0.10 eye muscle area (EMA)], while those with FATC were negative. The genetic correlation between EMD and eye muscle width (EMW) was 0.41 +/- 0.08, while EMA was highly correlated with EMD (0.89 +/- 0.0) and EMW (0.78 +/- 0.04). The genetic correlations for muscle colour with muscle measurements were moderately negative, while those with fat measurements were close to zero. Meat pH was positively correlated with muscle measurements (0.14 to 0.17) and negatively correlated with fat measurements (-0.06 to -0.18). EMDUS also showed a similar pattern of correlations to EMD with meat quality indicator traits, although FATUS had positive correlations with these traits which were generally smaller than their standard error. The genetic correlations among the meat colour traits were high and positive while those with meat pH were high and negative, which were all in the favourable direction. Generally, phenotypic correlations were similar or slightly lower than the corresponding genetic correlations. There were generally small to moderate negative genetic correlations between clean fleece weight (CFW) and carcass fat traits while those with muscle traits were close to zero. As the Merino is already a relatively lean breed, this implies that particular attention should be given to this relationship in Merino breeding programmes to prevent the reduction of fat reserves as a correlated response to selection for increased fleece weight. The ultrasound scan traits generally showed a similar pattern to the corresponding carcass fat and muscle traits. There was a small unfavourable genetic correlation between CFW and meat pH (0.19 +/- 0.07).     

谷胱甘肽对肉羊生长性能、屠宰性能及肉品质的影响

选择东北细毛羊×德国肉用美利奴的杂交一代肉羊12只,分成对照组、试验Ⅰ组和Ⅱ组,每组4只,研究谷胱甘肽对肉羊生长性能、屠宰性能及肉品质的影响。试验期60 d。结果表明:与对照组相比,谷胱甘肽显著提高了肉羊的日增重(P<0.05),试验Ⅰ组、Ⅱ组分别提高了14.6%和11.4%;降低了肉羊的料重比(P<0.05),试验Ⅰ组、Ⅱ组分别降低了11.0%和8.1%。试验Ⅰ组的净肉率和GR值显著高于对照组(P<0.05),Ⅱ组的宰前活重显著高于对照组(P<0.05);试验Ⅰ组肉的剪切力显著低于对照组(P<0.05);试验Ⅰ组、Ⅱ组的滴水损失显著低于对照组(P<0.05),而熟肉率显著高于对照组(P<0.05),且两试验组间差异不显著(P>0.05);各试验组宰后45 min内肉的pH没有显著差异(P>0.05),但试验Ⅰ组24 h的pH极显著地高于其他2组(P<0.01)。     

牛CAPN3基因多态性及与肉质性状相关性分析

以中国草原红牛、西门塔尔牛、利木赞牛、天一冈山黑牛为试验对象,利用PCR-SSCP结合测序的方法进行SNPs检测,并采用SPSS软件分析CAPN3基因的遗传多态性与肉质性状的关系。结果表明,仅在草原红牛及天一冈山黑牛中发现第46 414处（NC_007308）发生G→T的突变,且发生G→T突变的位点所对应不同基因型的个体,其大理石花纹、失水率、滴水损失和剪切力这些肉质性状存在显著差异,而西门塔尔牛和利木赞牛中未发现此突变。     

Genetic relationships between meat quality traits and fatty acid composition in Japanese black cattle

Genetic parameters were estimated to investigate the relationships between meat quality traits and fatty acid composition from 11 855 Japanese Black cattle. The meat quality traits included beef marbling score (BMS), beef color score, firmness of beef (FIR), texture of beef (TEX) and beef fat color score (BFS). The data on fatty acid composition included oleic acid and monounsaturated fatty acids (MUFA) contents, the ratio of MUFA to saturated fatty acids (MUS) and the ratio of elongation. The heritability estimates for meat quality traits ranged from moderate (0.30) to high (0.72). The strong genetic correlations between them were useful for simultaneous genetic improvement. In addition, high heritability estimates of fatty acid composition, ranging from 0.60 to 0.63, indicated that they could also be improved genetically. The genetic correlations of fatty acid composition with BMS, FIR and TEX were weak and negative. In contrast, positive and stronger genetic correlations were found between BFS and fatty acid composition, in particular, related to the level of unsaturation (0.77 and 0.79 for MUFA and MUS, respectively). This implies that improving the level of unsaturation makes fat darker (more yellow) and thus requires balancing with BFS.     

Effects of feeding frequency on meat quality traits and Longissimus muscle proteome in finishing pigs

Sixty‐four barrows with an initial body weight of 59.8 ± 2.1 kg were allocated to one of the two feeding frequency regimes (had free access to diet and fed two meals per day). Pigs had free access (FA) to feed were fed on an ad libitum basis during the 8‐week experimental period. Pigs fed twice daily (M2) were allowed to consume their meals in 2 h. Pigs fed twice daily had lower average daily feed intake (p < 0.01) and average daily gain (p < 0.1), but a greater G:F (p < 0.05) than FA pigs. Lower perirenal fat deposition, hot carcass weight, intramuscular fat content (p < 0.05) and dressing percentage (p < 0.1) were found in M2 pigs compared with FA pigs. Activities of citrate synthase, β‐hydroxylacyl‐CoA dehydrogenase and lactate dehydrogenase were greater in the Longissimus muscle (LM) of M2 pigs compared with FA pigs (p < 0.05). Proteomic analysis revealed that expression abundances of proteins involved in glucose metabolism, energy production and lipid utilization were upregulated, but expression levels of proteins participating in protein and amino acid metabolism, stress response and redox homeostasis were downregulated in the LM of M2 pigs than those in FA pigs (p < 0.05). In conclusion, the less meal frequency impairs growth rate, has marginal effects on carcass and meat quality traits and affects expression abundances of proteins in the LM of finishing pigs.     

Genetic parameter estimation and gene association analyses for meat quality traits in open-air free-range Iberian pigs

Meat quality of Iberian pigs is defined by the combination of their genetic characteristics and the particular production system. To carry out a genetic analysis of the main meat quality traits, we estimated their heritabilities, genetic correlations and the association effects of 32 selected SNPs of 12 candidate genes. A total of ten traits were measured in longissimus dorsi samples from 1,199 Iberian pigs fattened in the traditional free-range system: water holding capacity (thawing, cooking and centrifuge force water losses), instrumental colour (lightness L*, redness a* and yellowness b*), myoglobin content, shear force on cooked meat, and shear force and maximum compression force on dry-cured loin. Estimated heritability values were low to moderate (0.01 to 0.43) being the lowest for L* and the highest for cooking loss. Strong genetic correlations between water holding capacity traits (0.93 to 0.96) and between myoglobin content and a* (0.94) were observed. The association analyses revealed 19 SNPs significantly associated with different traits. Consistent and strong effects were observed between PRKAG3 SNPs (rs319678464G > C and rs330427832C > T), MYH3_rs81437544T > C, CASP3_rs319658214G > T and CTSL_rs332171512A > G and water losses. Also for CAPN1_rs81358667G > A and CASP3_rs319658214G > T and shear force. The SNPs mapping on PRKAG3 showed the highest effects on Minolta colour traits. Genotyping of these SNPs could be useful for the selection of Iberian young boars with similar estimated breeding values for productive traits.     

Rabbit metabolic response and selected meat quality traits: Evaluation of dietary PLX®23 and LycoBeads® feed supplement

Effects of dietary supplementation of verbascoside and lycopene, alone and in combination, on some blood parameters, plasma oxidative status and meat quality traits in intensively reared rabbits were investigated. The test lasted 60 days and was conducted on 200 weaned‐rabbits, divided into four groups of 50 animals each (5 animals each cage × 10 repetitions). The control group (CON) received a fattening feed without any feed supplements, whereas the experimental groups received the following: the first, an integration in 22 g of PLX^®23 (Lippia citriodora extract; VB group) per ton of feed; the second, an integration in 100 g of LycoBeads^® (Solanum lycopersicum extract; LIC group) per ton of feed; and the third, an integration of both feed supplements in combination at the same doses (LIC+VB group). The dietary supplementation with Lippia citriodora and Solanum lycopersicum resulted in an improvement of the blood lipid profile, oxidative plasma markers, and hepatic and renal activity of treated growing rabbits. Feed additives also produced meat with a lower content in SFA and an increased PUFA content, and inhibited the lipid oxidation improving the oxidative stability of rabbit meat. The dietary supplementation, even reporting no effects on productive parameters and carcass yield, showed an improvement on several blood parameters, as indicator of animal welfare, and on quality and healthy meat markers.     

Dietary mulberry leaf powder affects growth performance,carcass traits and meat quality in finishing pigs

This study was conducted to evaluate the effect of mulberry leaves as an alternative source of protein on growth performance, carcass traits and meat quality in finishing pigs. A total of 180 Xiangcun Black pigs were randomly assigned to five treatment groups with six pens of six pigs per pen. The pigs were provided with a basal diet or a diet contained 3%, 6%, 9% or 12% of mulberry leaf powder during a 50‐day experiment period. The results showed that dietary mulberry leaf powder had no negative effect on growth performance in Xiangcun Black pigs, except in the 12% mulberry group, where final body weight and average daily gain decreased (p < .05) and feed to gain ratio of the pigs increased (p < .05). Dietary mulberry inclusion decreased (quadratic, p < .05) the back fat thickness, fibre mean cross‐sectional area (CSA) in the longissimus dorsi (LD) muscle and mRNA expression levels of myosin heavy chain (MyHC) IIb in LD and biceps femoris (BF) muscles, while increased (linear or quadratic, p < .05) the plasma concentration of albumin, levels of crude protein (CP), inosine monophosphate (IMP) and several amino acids in muscle tissues. When compared with the other groups, the 9% mulberry diet increased (p < .05) loin‐eye area and contents of CP and IMP in muscles, while decreased (p < .05) plasma activity of cholinesterase and concentrations of uric acid and urea. The 6% mulberry diet had the lowest fibre mean CSA and shear force and increased total fibre number of the LD muscle, when compared with the other groups. These results suggest that including mulberry in the diet at <12% is an effective feed crop to improve meat quality and the chemical composition of muscle without negatively affecting growth performance.     

The effect of inulin supply to high‐fat diet rich in saturated fatty acids on pork quality and profile of sarcoplasmic protein in meat exudate

The aim of the study was to evaluate the influence of inulin supply to high‐fat diet rich in saturated fatty acids (SFA) on pork quality and profile of sarcoplasmic protein in drip loss. At 50 days of age, twenty cross‐bred pigs (gilts) were randomly allotted to four groups: the control (C) group fed a standard diet, and three experimental (D1, D2 and D3) groups fed a high‐fat diet rich in SFA. Moreover, pigs from the groups D2 and D3 consumed an extra inulin supply (7% of daily feed intake) from 85 to 120 days of age (for 5 weeks) and from 50 to 120 days of age (for 10 weeks) respectively. The addition of inulin to the diet reduced meaty odour and flavour significantly, improved tenderness and overall sensory quality of pork and additionally influenced ultimate pH, L* colour parameter, lactate level and protein content in meat. The diets also affected the profile of sarcoplasmic proteins. Significant effects were observed for the following enzymes—PK/PGI (pyruvate kinase/phosphoglucose isomerase) and ALD (aldolase), which are related to the intensity of post‐mortem glycolysis. Presented data indicate that long‐term inulin supply to high‐fat diet has a positive effect on technological and sensory quality as well as protein profile of pork.