Effects of the halothane genotype and slaughter weight on texture of pork

The objective of this study was to investigate the effects of the halothane (HAL) genotype, slaughter weight (SW), and the HAL x SW interaction on compositional and textural traits of raw and cooked pork. Pigs were bred to exhibit one of the three HAL genotypes (NN, Nn, and nn) with otherwise equivalent genomes. The nn halothane reactors are known to typically produce PSE pork, whereas NN pigs do not typically produce PSE pork. Pietrain x Large White gilts and boars, all with verified Nn genotype (by DNA test), were mated to obtain F2 littermates of the three HAL genotypes. These pigs were slaughtered at either 101 +/- 3 ("light") or 127 +/- 3 ("heavy") kg BW and were evaluated for longissimus muscle traits. The pH at .5 h after death (pH1) was 6.35, 6.13, and 5.68 in NN, Nn, and nn pigs, respectively. Sarcomere length was greater in nn than in NN and Nn pigs (1.94 vs 1.83 and 1.85 microm, respectively). Mechanical resistance was higher in nn than in NN pigs for both raw and cooked meat. Meat from nn pigs was judged by a trained panel to be less rough, more cohesive, harder, more fibrous, less granular, more elastic, and less easy to swallow than meat from NN pigs. For most traits under study, the heterozygotes were intermediate between the homozygotes but closer to NN than to nn pigs. Muscle from heavy pigs had longer sarcomeres and less moisture than muscle from light pigs. The n allele of the HAL gene unfavorably affects pork texture, and this effect is maintained throughout the range of 101 to 127 kg BW.     

苏钟Ⅰ系和Ⅱ系猪的氟烷基因及其对产肉性能的影响

:对 3 0 1头瘦肉型新品系苏钟 系和 系仔猪进行氟烷测验 ,阳性率为 1 .3 3 %。随机抽取氟烷阴性猪 3 4头进行基因型检测 ,有 6头为杂合子 ,由此得知 NN、Nn和 nn3种基因型的频率分别为 81 .2 6%、1 7.4 1 %和 1 .3 3 %,N和 n2种基因的频率分别为 89.97%和 1 0 .0 3 %。对 3种基因型猪的肉质进行评定结果显示 ,4头氟烷阳性猪 ( nn)肉质最差 ,出现 3头严重 PSE肉和 1头轻度 PSE肉 ,而氟烷阴性猪 ( NN或 Nn)未发生 PSE肉。2 0头苏钟 系氟烷阴性猪用阳性公猪测交 ,对产出的 2 0 8头后代进行氟烷测验 ,共检出 4窝中的 2 1头阳性猪。对测交后代进行肥育性能和肉质测定 ,发现阳性猪的日增重和饲料报酬等较低 ,屠宰率、眼肌面积和瘦肉率较高 ,肉质较差     

猪氟烷基因的检测及其对生长与肉质的影响

对中国瘦肉猪新品系ＤＩ和ＳＪ系３０１头仔猪进行氟烷测验,阳性率为１．３３％。随机抽取氟烷阴性猪３４头进行基因型检测,有６头为杂合子,由此推知ＮＮ、Ｎｎ和ｎｎ的频率分别为８１．２６％１７．４１％和１．３３％,Ｎ和ｎ的频率分别为８９．９７和１０．０３％。对三种基因型的肉质进行评定结果显示,４头氟烷阳性猪（ｎｎ）肉质最差,出现３头严重ＰＳＥ肉和一头轻度ＰＳＥ肉,而氟烷阴性猪未发生ＰＳＥ肉。２８头ＳＪ系氟烷阴性猪用阳性公猪测交,对产出的２０窝２０８头后代进行氟烷测定,共检出４窝中的２１头阳性猪,对测交后代进行肥育性能和肉质测定,结果阳性猪的日增重和饲料转化率等较低,屠宰率、眼肌面积和瘦肉率等较高,肉质较差。     

Evaluation of Duroc- vs. Pietrain-sired pigs for carcass and meat quality measures

Crossbred progeny sired by either Duroc or Pietrain boars, normal for the ryanodine receptor gene, were evaluated for carcass composition and meat quality. Boars from each breed were mated to Yorkshire or F1 Yorkshire-Landrace females. A total of 162 off-spring was evaluated for carcass and meat quality traits at a common age (approximately 26 wk of age). Duroc-sired progeny had heavier (108.0 vs. 103.0 kg, P < 0.001) and longer carcasses (86.9 vs. 84.8 cm, P < 0.01), whereas Pietrain-sired pigs had less backfat at the first rib (44.6 vs. 47.7 mm, P < 0.01), last lumbar vertebrae (20.9 vs. 23.0 mm, P < 0.05), and 10th rib (23.0 vs. 25.5 mm, P < 0.01). No difference between Pietrain and Duroc progeny was detected for fat depth at the last rib (27.8 vs. 28.8 mm, respectively). Pietrain progeny had a higher percentage of lean at slaughter (52.6 vs. 50.7, P < 0.05) and higher dressing percentage (74.0 vs. 73.1, P < 0.01). Primal cut weights were collected with Pietrain progeny having a greater percentage of carcass as ham (23.0 vs. 22.4, P < 0.01) and loin (21.6 vs. 21.2, P < 0.05), whereas Duroc progeny had a higher percentage of belly weight (12.0 vs. 11.7, P < 0.05). Percentages of Boston butt (8.8 vs. 9.0) and picnic shoulder (9.9 vs. 9.9) were similar for Duroc vs. Pietrain progeny. Total weight of these five primal cuts, as a percentage of carcass weight, was higher for Pietrain progeny (75.2 vs. 74.3, P < 0.01). With heavier carcass weight, Duroc progeny had greater primal cut weights as a function of age. Subjective meat quality scores for color, marbling, and firmness (1 to 5 scale) were more favorable for Duroc-sired progeny. Furthermore, chops from Duroc progeny had higher 24-h pH (5.53 vs. 5.48, P < 0.001) and Minolta a* (17.33 vs. 17.04, P < 0.05) with less percentage drip loss (2.88 vs. 3.80, P < 0.001). No differences were detected between Duroc- and Pietrain-sired progeny for Minolta L* (54.77 vs. 55.37) or b* (7.58 vs. 7.58) objective color scores, percentage cooking loss (28.63 vs. 29.23), or Warner-Bratzler shear force (6.94 vs. 7.11 kg). Both sire breeds have beneficial traits that can be utilized in commercial pork production and merit further study.     

Effects of trailer design on animal welfare parameters and carcass and meat quality of three Pietrain crosses being transported over a long distance

This study aimed at evaluating the effects of trailer design on stress responses and meat quality traits of 3 different pig crosses: 50% Pietrain breeding with halothane (HAL)(Nn) (50Nn); 50% Pietrain breeding with HAL(NN) (50NN); and 25% Pietrain breeding with HAL(NN) genotype (25NN). Over a 6-wk period, pigs (120 pigs/crossbreed) were transported for 7 h in either a pot-belly (PB) or flat-deck (FD) trailer (10 pigs/crossbreed(-1.)trailer(-1.)wk(-1)). Temperature (T) and relative humidity (RH) were monitored in each trailer. Behaviors during loading and unloading, time to load and unload, and latency to rest in lairage were recorded, whereas a sub-population of pigs (4 pigs/crossbreed(-1.)trailer(-1.)wk(-1)) was equipped with gastro-intestinal tract (GIT) temperature monitors. Blood samples were collected at exsanguination for measurement of cortisol, creatine kinase (CK), lactate, haptoglobin, and Pig-MAP concentrations. Meat quality data were collected at 24 h postmortem from the LM and semimembranosus (SM) and adductor (AD) muscles of all 360 pigs. Greater T were recorded in the PB trailer during transportation (P = 0.006) and unloading (P < 0.001). Delta GIT temperature was greater (P = 0.01) in pigs unloaded from the PB. At loading, pigs tended to move backwards more (P = 0.06) when loaded on the FD than the PB trailer. At unloading, an interaction was found between trailer type and crossbreed type, with a greater (P < 0.01) frequency of overlaps in 50NN and 25NN pigs and slips/falls in 50Nn and 50NN pigs from the FD than the PB trailer. Cortisol concentrations at slaughter were greater (P = 0.02) in pigs transported in the PB than FD trailer. Greater lactate concentrations were found in 50Nn and 50NN pigs (P = 0.003) and greater CK concentrations (P < 0.001) in 50Nn pigs. As expected, 50Nn pigs produced leaner (P < 0.001) carcasses, with greater (P = 0.01) dressing percentages, as well as lower (P < 0.001) ultimate pH values and greater (P < 0.001) drip loss percentages in the LM and greater (P = 0.002) drip losses and a paler color (greater L* values, P = 0.02) in the SM than 50NN pigs. When used for long distance transportation under controlled conditions, the PB trailer produced no detrimental effects on animal welfare or pork quality. Pigs with 50% Pietrain crossbreeding appear to be more responsive to transport stress, having the potential to produce acceptable carcass and pork quality, provided pigs are free of the HAL gene.     

The effect of the Halothane and Rendement Napole genes on carcass and meat quality characteristics of pigs

The objective of this study was to determine the effects of the Halothane (N) and Rendement Napole (RN) genes on carcass and meat quality characteristics in pigs. Halothane and RN carrier (Nn/RN- rn+) Hampshire boars (n = 4) were mated to dams that were homozygous for the normal allele of both genes (NN/rn+ rn+) to produce progeny of four genotypes: 1, NN/rn+ rn+ (n = 31); 2, Nn/rn+ rn+ (n = 27); 3, NN/RN- rn+) (n = 30); and 4, Nn/RN- rn+ (n = 23). A DNA test was used to determine Halothane genotype, and longissimus glycolytic potential was used to predict the RN genotype. Pigs were reared under standard conditions to approximately 120 kg live weight and slaughtered at a commercial plant, and carcass characteristics and meat quality were evaluated. Halothane carriers (Nn/ _ _), in comparison to Halothane normal (NN/_ _) pigs, had shorter carcasses, lower longissimus ultimate pH, higher Minolta L* and b* values, and greater drip loss. Rendement Napole gene carriers (_ _/RN- rn+) had higher L* and b* values and drip and cooking loss and lower longissimus ultimate pH than homozygous recessive animals (_ _/rn+ rn+). There were Halothane x RN genotype interactions (P < 0.05) for subjective color, firmness, and marbling scores, and for shear force. Animals that were normal for both genes (NN/rn+ rn+) had the highest subjective scores for color (2.60, 1.88, 1.85, and 1.95, SE = 0.181, P < 0.05), firmness (2.53, 2.03, 2.10, and 1.89, SE = 0.182, P < 0 .05), and marbling (2.11, 1.44, 1.53, and 1.55, SE = 0.153, P < 0 .05) for genotypes 1, 2, 3, and 4, respectively, suggesting darker, firmer muscle with a higher level of marbling for this genotype. Shear force was highest for Nn/rn+ rn+ animals (3.83, 4.41, 3.79, and 3.70, respectively, SE = 0.172, P < 0.05). Gilts had less s.c. backfat thickness, greater longissimus muscle area, and lower subjective marbling scores than barrows. There was no effect (P > 0.05) of gender on other meat quality traits. This study illustrates the negative effects of the Halothane and RN genes on fresh pork quality and suggests that in combination the detrimental effects of the two genes are additive for ultimate pH, objective color, and water-holding capacity.     

Quantitative trait locus mapping in an F2 Duroc x Pietrain resource population: II. Carcass and meat quality traits

Pigs from the F(2) generation of a Duroc x Pietrain resource population were evaluated to discover QTL affecting carcass composition and meat quality traits. Carcass composition phenotypes included primal cut weights, skeletal characteristics, backfat thickness, and LM area. Meat quality data included LM pH, temperature, objective and subjective color information, marbling and firmness scores, and drip loss. Additionally, chops were analyzed for moisture, protein, and fat composition as well as cook yield and Warner-Bratzler shear force measurements. Palatability of chops was determined by a trained sensory panel. A total of 510 F(2) animals were genotyped for 124 microsatellite markers evenly spaced across the genome. Data were analyzed with line cross, least squares regression interval, mapping methods using sex and litter as fixed effects and carcass weight or slaughter age as covariates. Significance thresholds of the F-statistic for single QTL with additive, dominance, or imprinted effects were determined on chromosome- and genome-wise levels by permutation tests. A total of 94 QTL for 35 of the 38 traits analyzed were found to be significant at the 5% chromosome-wise level. Of these 94 QTL, 44 were significant at the 1% chromosome-wise, 28 of these 44 were also significant at the 5% genome-wise, and 14 of these 28 were also significant at the 1% genome-wise significance thresholds. Putative QTL were discovered for 45-min pH and pH decline from 45 min to 24 h on SSC 3, marbling score and carcass backfat on SSC 6, carcass length and number of ribs on SSC 7, marbling score on SSC 12, and color measurements and tenderness score on SSC 15. These results will facilitate fine mapping efforts to identify genes controlling carcass composition and meat quality traits that can be incorporated into marker-assisted selection programs to accelerate genetic improvement in pig populations.     

Evaluation of associations between prion haplotypes and growth, carcass, and meat quality traits in a Dorset x Romanov sheep population

There is concern about potential antagonistic correlated responses due to intensive selection for scrapie-resistant haplotypes of the prion (PRNP) gene in sheep. The objective of the present research was to test for associations of PRNP haplotypes for codons 136, 154, and 171 with growth, carcass, and meat quality traits in an F2 Dorset x Romanov population (n = 415) segregating the 2 callipyge alleles. Haplotypes of the 3 PRNP codons were determined for each sheep, and breed of origin of each gamete was predicted by genotyping 6 microsatellite markers flanking the PRNP locus. Twenty-five growth, carcass, and meat quality traits were evaluated. Data were analyzed using a basic model consisting of fixed effects of year, sex, and callipyge genotype, the random effect of sire, and 7 covariates corresponding to the probability that a lamb inherited a specific PRNP haplotype of either Dorset or Romanov origin. A fixed effect of litter size was added to the model for growth traits. The model for carcass traits contained the linear and quadratic effects of chilled carcass weight and the interactions among callipyge genotype and linear and quadratic terms. For meat quality traits, the model contained chilled carcass weight as a covariate and the interaction between callipyge genotype and chilled carcass weight. A contrast between the resistant ARR haplotype and the average effect of other PRNP haplotypes was tested to investigate the effects of potential selection for ARR within each breed of origin (Dorset, ARR vs. ARQ, VRQ, and AHQ; Romanov, ARR vs. ARQ and VRQ). There was limited evidence that selecting for scrapie resistance would cause correlated responses due to linkage disequilibrium. Associations of only 3 traits with PRNP haplotypes were detected in either breed of origin. In Romanov, the ARR haplotype was associated with longer carcasses (P < 0.013), narrower rumps (P = 0.038), and less marbling (P = 0.022) than the average of ARQ and VRQ haplotypes. No significant contrasts were detected for Dorset. This study is the first to account for breed of origin while investigating haplotype associations in an F2 population. This study provided limited evidence of associations between PRNP haplotypes and growth, carcass, and meat quality traits.     

Effect of two dietary concentrate levels on tenderness, calpain and calpastatin activities, and carcass merit in Waguli and Brahman steers

The objective of this study was to compare carcass characteristics of a newly introduced breed, the Waguli (Wagyu x Tuli), with the carcass characteristics of the Brahman breed. Brahman cattle are used extensively in the Southwest of the United States because of their tolerance to adverse environmental conditions. However, Brahman carcasses are discounted according to the height of their humps because of meat tenderness issues. The Waguli was developed in an attempt to obtain a breed that retained the heat tolerance of the Brahman but had meat quality attributes similar to the Wagyu. Twenty-four animals were used. Six steers from each breed were fed a 94% concentrate diet and 6 steers from each breed were fed an 86% concentrate diet. Eight steers, 2 from each group, were harvested after 128 d, after 142 d, and after 156 d on feed. Waguli steers had larger LM, greater backfat thickness, greater marbling scores, and greater quality grades than the Brahman steers (P < 0.05). The Japanese Wagyu breed is well known for its highly marbled and tender meat, and these traits are also present in the Waguli. The Waguli had significantly lower Warner-Bratzler shear force values than the Brahman steers after 7 and 10 d of postmortem aging (P < 0.05); this difference decreased after 14 d postmortem (P = 0.2), when tenderness of the slower aging Brahman had increased to acceptable levels. Toughness of the Brahman has been associated with high levels of calpastatin in Brahman muscle, and the Waguli LM had significantly less calpastatin activity (P = 0.02) at 0 h postmortem than the Brahman LM. At 0-h postmortem, the total LM calpain activity did not differ between the Brahman and Waguli (P = 0.57). Neither diet nor days on feed had any significant effect on the 0-h postmortem calpain or at 0-h postmortem calpastatin activity, nor an effect on Warner-Bratzler shear-force values. In conclusion, LM muscle from the Waguli steers had a high degree of marbling, lower shear force values, and low calpastatin activity, all of which are related to more tender meat.     

Production characteristics of Dutch Landrace and Dutch Yorkshire pigs as related to their susceptibility for the halothane-induced malignant hyperthermia syndrome

During a one-year survey a total of 1034 Dutch Yorkshire and 1640 Dutch Landrace pigs were subjected to the halothane-test after their arrival at one of the national pig testing stations. The average percentage reactors was 3% in the Dutch Yorkshire breed and 22% in the Dutch Landrace breed. Death losses during the fattening period and during the transport of the gilts to the slaughter-house were almost ten times higher in reacting as in non-reacting Dutch Landrace pigs (5.27% vs 0.56%). In the Dutch Landrace breed significant differences were found between reactors and non-reactors in the growth traits of the boars and in all carcass and meat quality characteristics of the gilts, which confirm previous observations. However, in the Yorkshire breed no significant differences were found in these traits between reacting and non-reacting animals. The conflicting results obtained in this breed are discussed. It is suggested that the halothane-test will be most effective for minimization of stress-susceptibility and abnormal meat quality when used as a selection criterion in commercial breeding and selection of Dutch Landrace pigs.     

猪氟烷基因型的PCR检测及杂合子氟烷阳性猪的发现

对１４７头猪进行了氟烷测验,测得氟烷阳性猪３头,阳性率为２．０４％。运用ＰＣＲ－ＲＦＬＰ分析法对氟烷阳性猪及其同胞进行了基因型检测,结果４头被测猪中有２头为隐性纯合子,２头为杂合子。结合氟烷测验结果,２头隐性纯合子表现为氟烷阳性,符合一般规律;而２头杂合子中发现１头为氟烷阳性,此前尚未见报道,这一结果证明了氟烷表现与基因型并非完全对应     

Genetic and phenotypic relationships of serum leptin concentration with performance, efficiency of gain, and carcass merit of feedlot cattle

Leptin is the hormone product of the obese gene that is synthesized and predominantly expressed by adipocytes. This study estimated the genetic variation in serum leptin concentration and evaluated the genetic and phenotypic relationships of serum leptin concentration with performance, efficiency of gain, and carcass merit. There were 464 steers with records for serum leptin concentration, performance, and efficiency of gain and 381 steers with records for carcass traits. The analyses included a total of 813 steers, including those without phenotypic records. Phenotypic and genetic parameter estimates were obtained using SAS and ASREML, respectively. Serum leptin concentration was moderately heritable (h2 = 0.34 +/- 0.13) and averaged 13.91 (SD = 5.74) ng/mL. Sire breed differences in serum leptin concentration correlated well with breed differences in body composition. Specifically, the serum leptin concentration was 20% greater in Angus-sired steers compared with Charolais-sired steers (P < 0.001). Consequently, ultrasound backfat (27%), carcass 12th-rib fat (31%), ultrasound marbling (14%), and carcass marbling (15%) were less in Charolais- than Angus-sired steers (P < 0.001). Conversely, carcass LM area (P = 0.05) and carcass lean meat yield (P < 0.001) were greater in Charolais- compared with Angus-sired steers. Steers with greater serum leptin concentration also had greater DMI (P < 0.001), greater residual feed intake (P = 0.04), and partial efficiency of growth (P = 0.01), but did not differ in feed conversion ratio (P > 0.10). Serum leptin concentration was correlated phenotypically with ultrasound backfat (r = 0.41; P < 0.001), carcass 12th-rib fat (r = 0.42; P < 0.001), ultrasound marbling (r = 0.25; P < 0.01), carcass marbling (r = 0.28; P < 0.01), ultrasound LM area (r = -0.19; P < 0.01), carcass LM area (r = -0.17; P < 0.05), lean meat yield (r = -0.38; P < 0.001), and yield grade (r = 0.32; P < 0.001). The corresponding genetic correlations were generally greater than the phenotypic correlations and included ultrasound backfat (r = 0.76 +/- 0.19), carcass 12th-rib fat (r = 0.54 +/- 0.23), ultrasound marbling (r = 0.27 +/- 0.22), carcass marbling (r = 0.76 +/- 0.21), ultrasound LM area (r = -0.71 +/- 0.19), carcass LM area (r = -0.75 +/- 0.20), lean meat yield (r = -0.59 +/- 0.22), and yield grade (r = 0.39 +/- 0.26). Serum leptin concentration can be a valuable tool that can be incorporated into appropriate selection programs to favorably improve the carcass merit of cattle.     

Relationships between the H and A-O blood types, phosphohexose isomerase and 6-phosphogluconate dehydrogenase red cell enzyme systems and halothane sensitivity, and economic traits in a superior and an inferior selection line of swiss landrace pigs

Associations between production traits and the genes for halothane sensitivity (HAL), S, A and H blood group systems and phosphohexose isomerase (PHI) and 6-phosphogluconate dehydrogenase (6-PGD) enzyme systems were investigated in two lines of pigs selected for an index. The phenotypic variance-covariance matrix of the index included backfat thickness and daily gain, whereas the genetic variance-covariance matrix included daily gain, feed conversion and percentage of lean meat. The experiment was conducted at the experimental station of the Institute of Animal Production and has been underway since 1973. The same index was applied but in two opposite directions to give a superior and inferior line in relation to the production traits. One hundred twenty-nine animals of the superior line in the seventh generation and 88 animals of the inferior line in the sixth generation were studied. Forty-two percent (54/129) of the animals of the superior line were halothane-positive. No animals in the inferior line were halothane reactors. Of the halothane-positive pigs, 70.4% (38/54) in the superior line had the HaHa and 94.4% (51/54) had the SsSs genotype, whereas only 4% (3/75) of the HaHa and 12% (9/75) of the SsSs pigs were halothane-negative. By practicing selection at the H and S loci, it seems possible to efficiently reduce halothane sensitivity in Swiss Landrace pigs. In pigs of the superior line, there were significant differences in percentage of lean meat, carcass length, pH1 (pH value at 45 min to 1 h postmortem, M. longissimus) and reflectance values among genotypes of the HAL, S and H systems and among some genotypes of the 6-PGD system. Poorest meat quality, highest percentage of lean meat and shortest carcass length were observed in pigs homozygous for the alleles HALn, Ss, Ha, PHIB and 6-PGDA. In the inferior line, these associations were absent. As the HAL locus is associated with the above mentioned production traits, linkage disequilibria may explain the observed associations among the H, S, PHI and 6-PGD types and production traits.     

长×大×通、大×长×通杂交猪及其亲本的生长性能、胴体性状和肉品质比较研究

试验以通城猪为母本,长白猪（瑞典）、大白猪（英国）为父本进行三元杂交,对两个三元杂交猪（长×（大×通）、大×（长×通）,简称为长×大×通、大×长×通）及亲本分别从生长性能、胴体性状及肉品质方面进行了比较。结果显示,长×大×通和大×长×通三元杂交猪的生长性能、胴体性状及肉品质均表现出较好的杂种优势。长×大×通三元杂交猪的测定期平均日增重、料重比、活体背膘厚、剪切力、大理石纹和肌内脂肪含量的杂种优势率分别为12.54%、-13.89%、10.39%、-8.71%、-8.33%和8.57%,大×长×通的杂种优势率分别为10.81%、-11.05%、10.55%、-6.50%、6.67%和2.44%。长×大×通和大×长×通两者比较,长×大×通三元杂交猪的试验期平均日增重、眼肌面积及腿臀肉骨率分别为843.4 g/d、34.51 cm²和73.54%,大×长×通三元杂交猪分别为808.6 g/d、31.45 cm²和70.67%,二者差异均显著（P<0.05）。综上所述,以通城猪为母本进行的两个三元杂交猪的生长和胴体性状显著优于亲本通城猪,肉质显著优于亲本长白猪和大白猪,且长×大×通组合优于大×长×通组合。     

Creatine monohydrate supplementation and the quality of fresh pork in normal and halothane carrier pigs

The objective of this research was to examine the impact of supplementation with creatine monohydrate (CMH) on the quality of various muscles from normal and heterozygous halothane carrier pigs. Twenty-nine crossbred pigs, 16 normal (NN) and 13 halothane carrier (Nn) genotypes, were supplemented with 0 or 25 g x pig(-1) x d(-1) of CMH for 5 d before slaughter. Supplemented pigs gained 2.26 kg more weight (P < 0.05) during 5 d of supplementation. There were trends (P < 0.10) toward higher objective marbling scores and lower cooking loss for supplemented pigs. The 45-min pH was 0.27 units higher (P < 0.05) for supplemented pigs in the semimembranosus; CMH supplementation did not influence (P > 0.05) drip loss or muscle composition. Supplementation with CMH also resulted in lower L* values in two ham muscles, semitendinosus (5.15 units) (P < 0.05) and semimembranosus (1.95 units) (P < 0.10) for Nn carcasses. Genotype had significant effects on most quality indicators, with Nn carcasses producing lower-quality lean as evidenced by less desirable subjective and objective color and higher drip losses. Genotype also affected the composition of several muscles, with the NN carcasses having more fat and less moisture.     

Effects of trailer design on animal welfare parameters and carcass and meat quality of three Pietrain crosses being transported over a short distance

The objective of this study was to evaluate the effects of trailer design on the stress responses and meat quality traits of 3 different pig crosses: 50% Pietrain breeding with HAL^Nn (50Nn), 50% Pietrain breeding with HAL^NN (50NN) and 25% Pietrain breeding with HAL^NN genotype (25NN). Market barrows (n=360), as a subset of 12 trailer loads of pigs, were transported from farm to slaughter on 6 dates in 2009 for 45 min in either a pot-belly (PB) or flat-deck (FD) trailer, with 120 pigs/genetic group being represented. Temperature (T) and relative humidity (RH) were recorded by data loggers mounted in both trailers. Behaviours and handler interventions were video-taped at loading, unloading and in lairage. At exsanguination, blood samples were collected for the assessment of lactate, cortisol, creatine kinase (CK), haptoglobin and Pig-MAP concentrations. Meat quality was measured in the longissimus dorsi (LD), semimembranosus (SM) and adductor (AD) muscles of all pigs. Temperatures were warmer in compartments 6 and 11 at loading (P<0.001), compartment 11 during travelling (P=0.05), and in compartment 5 at unloading (P=0.01) of the PB trailer. Pigs unloaded from the FD trailer overlapped more (P<0.001), whereas (P<0.001) the frequency of jamming was noted for pigs unloaded from the PB trailer. Pigs with 50% Pietrain genetics overlapped and jammed more (P<0.001) than pigs with 25% Pietrain genetics, regardless of HAL status. Greater (P=0.03) CK levels were found in 50Nn pigs transported in the PB trailer, while 50Nn and 50NN pigs had greater (P=0.028) lactate levels than 25NN pigs. Carcasses from 50Nn and 50NN pigs were leaner (P=0.04), and the skin damage score was lower (P=0.04) in 25NN carcasses. Overlap-type bruises were greater (P=0.02) in pigs transported in the FD trailer. Pigs transported in the PB trailer had greater (P=0.05) pHu in the SM and AD muscles (P=0.013). Except for pHu in the SM muscle, all meat quality parameters were affected by the Hal gene (P=0.04). The use of a PB trailer for short distance transportation of pigs to slaughter negatively affected stress responses and meat quality. The greater proportion of Pietrain genetics in the selection resulted in leaner carcasses, but also in pigs being more difficult to handle. Crossbreeding appeared to have a greater impact on animal welfare and meat quality than vehicle type, but trailer type may emphasize these negative genotype-related defects.     

Influence of halothane genotype and body-weight on myosin heavy chain composition in pig muscle as related to meat quality

In an effort to understand the relationship between muscle fiber type, live weight, genotype, and PSE development, enzyme-linked immunosorbent analyses were used to evaluate myosin heavy chain (MyHC) isoform content in the longissimus muscle of pigs differing in halothane gene status (nn, homozygous mutant; Nn, heterozygous; NN, homozygous normal) that were slaughtered at three different weights (100, 120 and 140 kg). Pigs carrying the n gene (Nn and nn) exhibited more IIB MyHC and less slow type I MyHC than those pigs free of the n gene, while NN pigs had greater amounts of IIAX MyHC. The relative abundance of IIB and IIAX MyHC in muscle of all pigs studied was strongly negatively correlated (r=−0.834). Heavier pigs (140 kg) had the greatest amounts of slow and IIA MyHC. Across all genotypes, the relative abundance of IIB MyHC and muscle pH at 45 min postexsanguination (pH45) was negatively correlated (r=−0.418). In addition, the relative amount of slow was positively correlated with pH45 (r=0.386). Because muscle of homozygous nn positive pigs exhibited similar IIB/slow MyHC ratios to that of heterozygous Nn pigs, yet less desirable pH45 values and ultimate meat quality scores argues against a role of MyHC content per se in contributing to PSE development. However, these data do not preclude that those pigs with greater amounts of IIB MyHC are more ‘susceptible’ to adverse pork quality development than those pigs with less IIB MyHC.     

A Comparative Study on the Carcass and Meat Quality Traits of Jiangquan Black Pig and DLY Pig

To further understand the germplasm characteristics of Jiangquan Black pig,100 kg Jiangquan Black pigs (10 barrows, 10 sows) and 10 Duroc×Landrace×Yorkshire (DLY) pigs under the same conditions were randomly selected to analyse the slaughter performance and meat quality according to related rules. After slaughtered,the carcass index (carcass weight, loin muscle area, carcass length and backfat thickness etc), meat quality physical indicators (pH, meat color, marbling, drip loss etc), gerneral chemical index (the contents of crude protein, intramuscular fat, moisture and ash etc) and the proportion of amino acids in Jiangquan Black pig were analyzed. The results showed that, Jiangquan Black pig carcass lean meat rate was relatively low, the loin muscle area was reduced by about 30% (P<0.05) compared with DLY pig, while the backfat thickness was higher than that of DLY pig (P<0.05). The meat color, marbling, drip loss, cooking loss, water loss rate index and intramuscular fat content of Jiangquan Black pig were significantly better than that of DLY pigs (P<0.05), the rate of water loss and drip loss and cooking loss were decreased by 4.0%, 3.1% and 2.7%, intramuscular fat content increased by 150.0%. Therefore, The lean yield of Jiangquan Black pig was less than DLY pig, but water retention property, intramuscular fat content, meat color, marbling, meat quality indexes were significantly better than that of DLY pig. In conclusion, Jiangquan Black pig could provide good quality pork for consumers.     

江泉黑猪与杜长大三元杂交猪屠宰性能及肉质性状比较分析

为了解江泉黑猪的产肉和肉质特性,本试验选取在相同条件下饲养的100 kg左右的江泉黑猪阉公猪、母猪和杜长大三元杂交猪各10头按照相关规定进行屠宰和肉品质测定。对两种猪胴体指标（胴体重、胴体长、眼肌面积、背膘厚等）、肉质的物理指标（pH、肉色、大理石纹、滴水损失等）、常规化学指标（粗蛋白质、肌内脂肪、水分、灰分含量等）及江泉黑猪氨基酸含量进行了测定。结果表明,与杜长大三元杂交猪相比,江泉黑猪胴体瘦肉率较低,眼肌面积降低了30%左右（P<0.05）,而胴体背膘厚较高（P<0.05）。江泉黑猪在肉色、大理石纹、滴水损失、失水率、烹饪损失和肌内脂肪含量等指标上均显著优于杜长大三元杂交猪（P<0.05）,其中滴水损失、失水率和烹饪损失分别降低了约4.0%、3.1%和2.7%,肌内脂肪含量提高了约150.0%。由此可见,江泉黑猪在瘦肉产量上低于杜长大三元杂交猪,但在保水性、肌内脂肪含量、肉色、大理石纹等肉质指标上明显优于杜长大三元杂交猪,可为消费者提供品质优良的猪肉。