Effects of exogenous porcine somatotropin administration between 30 and 60 kilograms on longissimus muscle fiber morphology and meat tenderness of pigs grown to 90 kilograms

Twenty-four barrows were used to investigate the effects of exogenous porcine somatotropin (pST) administration (0 and 100 micrograms.kg-1.d-1) between 30 and 60 kg on longissimus muscle morphology and meat tenderness of pigs grown to 90 kg. Administration of pST was by daily i.m. injection. Pigs were fed a fortified diet in restricted amounts between 30 and 60 kg and had ad libitum access to this diet from 60 to 90 kg. Excipient pigs had fewer alpha R fibers and more alpha W fibers than pST-treated pigs (P less than .05). Administration of pST increased (P less than .05) muscle fiber area for all three fiber types at both the 60 kg (34%) and 90 kg (29%) slaughter weights. Furthermore, pST administration increased shear-force (30% at 60 kg; 19% at 90 kg) of the longissimus muscle, indicating that pST administration reduced meat tenderness. All the pST-treated pigs exhibited the "giant fiber syndrome" and a high proportion (62%) of pST-treated pigs exhibited pale, soft, exudative muscle. Whether the giant fiber anomaly resulted from increased muscle protein accretion rate or fiber degeneration is unknown. Results indicated that the stimulatory effects of pST on muscle growth are sustained following cessation of hormone treatment. However, the incidence of pale, soft, exudative muscle in 62% of the pST-treated pigs indicates that pST potentially has undesirable side effects.     

Evaluation of cattle breeds for beef production in New Zealand—A review

Important differences are noted between the New Zealand and European cattle industries, in terms of both breeds and farming systems. Under pasture feeding, experimental data strongly suggest that selection and genetic evaluation for growth performance should be based on weight-for-age rather than on post-weaning weight gains. Carcass merit is more appropriately measured by the yield of trimmed boneless retail cuts than by accepted commercial grades.Relative to the nationally predominant Angus beef breed, research results demonstrate an advantage in final and carcass weight per animal of 5–10% for the Hereford and 20–30% for the Friesian, with the superiority being approximately halved in crossed with the Angus. In terms of weaning performance, the Friesian dam is greatly superior, the Hereford slightly inferior, to the Angus. Heterosis for growth traits is of the order of 5%.In crosses over Jersey cows the Charolais sire is superior to the Hereford but not to the Friesian for total meat output. Carcasses from the dairy breeds and dairy x beef crosses slaughtered at the same age contain a higher bone percentage and are less acceptable on traditional export grading standards than those of the British beef breeds, but nevertheless achieve high output and quality of lean meat.Preliminary results from current large-scale trials suggest that the larger European breeds have potential for improving growth rate and meat yield in crosses with local Angus and Hereford cattle but are more prone to difficult calvings and show later sexual maturity.     

生长激素对猪生长、胴体组成及肉质的影响

选用体重６４ ｋｇ 左右的大大二三元杂种猪１８ 头， 随机分为２ 组， 试验组和对照组各９ 头。试验组每头每天肌肉注射猪生长激素（ｐＳＴ）５ ｍｇ ，共１４ ｄ， 对照组肌注生理盐水。饲养结束时进行屠宰测定， 取背最长肌进行肉质分析。结果表明： ｐＳＴ 处理组平均日增重显著高于对照组（ Ｐ ＜ ０－０５） ， 料重比下降２１－６８ ％ ， 胴体重提高２－６２ ％ ， 三点膘厚下降７－７８ ％ ， 肝重提高１４－８６％ ， 心重提高１８－０７ ％ ， 肌肉失水率提高１２－６８ ％ ，切割力提高１－６８ ％ ， 大理石纹提高１５－０９ ％ ， 但差异均不显著（ Ｐ ＞ ０－０５） 。ｐＳＴ 对其它指标均无显著影响     

Sensory, physical, and chemical properties of pork loin chops from somatotropin-treated pigs of three stress classifications.

Forty-eight pigs of three known stress classifications were injected daily with porcine somatotropin (pST; 4 mg/d) or placebo. The effects of pST and stress classification on the sensory, physical and chemical characteristics of loin chops were observed. Chops from pST-treated animals were less tender and juicy than chops from control animals. Positive stress classification also significantly decreased juiciness but had no effect on tenderness and flavor. A significant interaction was observed for initial juiciness and sustained juiciness between chops from pST and stress-positive pigs. Whereas chops from carriers and normal pigs showed a reduction in juiciness traits with the pST treatment, among stress-positive animals both initial and sustained juiciness were increased with pST treatment. Treatment with pST had no effect on the fat, protein, and moisture content of the longissimus muscle. Furthermore, stress classification had no effect on the fat and moisture content of the longissimus muscle, but protein content was significantly higher in loin chops from stress-positive animals. Chops from pST-treated animals had significantly higher maximum shear force values, required more energy to break the sample, and had higher yield point values than chops from control animals, but stress classification did not affect the shear force values significantly. Treatment of stress-susceptible animals with pST does not lead to an increased incidence of pale, soft, exudative meat and may improve juiciness attributes of chops from stress-positive animals. However, pST treatment of animals, in this trial, led to a reduction of juiciness and tenderness of pork loin chops.     

贵州地方猪品种对氧磷脂酶1基因的多态性研究

本试验以欧洲猪种为参照,研究贵州地方猪对氧磷脂酶1(paraoxonase,PON1)基因的多态性,探讨基因多态性与地方猪的脂肪沉积之间是否存在相关性。研究采用锚定聚合酶链反应技术对香猪、糯谷猪、萝卜猪和可乐猪共138个贵州地方猪品种PON1基因的单核苷酸多态性(single nucleotide polymorphisms,SNP)进行研究。结果表明,猪群PON1基因的163/165位点出现A/T、G/A变异,515位点检测到C/T突变,均以3种基因型存在。经卡方(χ²)检验,贵州地方猪群PON1基因515位点的基因型频率和基因频率与欧洲猪品种间的差异不显著(P>0.05);163/165位点中,贵州地方猪种A等位基因的频率为83.7%,明显高于欧洲猪品种(25.2%)。贵州地方猪品种PON1基因的163/165位点A等位基因占优势,编码的第55位氨基酸为甲硫氨酸(Met55),与脂代谢异常人群的基因型相同;欧洲猪种以B等位基因为主(P<0.01),编码的第55位是亮氨酸(Leu55),与正常人群的基因型一致。以人PON1蛋白的晶体结构为模板,推导出香猪PON1蛋白的三维结构。地方猪PON1基因变异导致的Met55突变可能影响PON1水解酶活性中心的疏水环境,可能使蛋白的水解酶活性下降,使得地方猪品种的脂肪沉积量和肉质不同于欧洲猪种。由此推测,贵州地方猪品种PON1基因163/165位点存在多态性,可能与地方猪种的脂肪沉积和肉质有一定的相关性。     

Relationship of mode of porcine somatotropin administration and dietary fat to the growth performance and carcass characteristics of finishing pigs.

Ninety-six pigs were used to investigate the relationship of diet (control vs fat-supplemented with equal energy:protein ratios), porcine somatotropin (pST) administration (non-treated; 2 mg/d, daily injection; and 2 mg/d, 6-wk implant), and sex (barrows and gilts) to performance and carcass characteristics. Diet and pST treatments were initiated at 87 kg of BW and continued for 38 d. Both the fat-supplemented diet (P less than .001) and pST treatment (P less than .0001) improved feed efficiency. The effects of diet were accounted for by differences in energy density of the diets. Across diets, pST improved gain:feed ratio by 29 and 16% in pigs treated by daily injection and the implant, respectively; the two modes of delivery resulted in different responses (P less than .01). Circulating insulin-like growth factor I (IGF-I) levels, determined from blood samples drawn on d 35, were increased 2.5-fold above those of controls in pigs treated by either daily injection or the implant. However, the elevation of glucose and decrease in blood urea nitrogen concentrations in response to pST were of a greater magnitude in pigs treated by daily injection. Similarly, reductions in backfat thickness and the rate of backfat accretion determined by ultrasound were greater in response to the daily injection of pST than in response to the implant. Lean meat ratio, calculated from measurements with a Fat-O-Meater probe, was increased by 6 and 13% by the implant and daily injection, respectively. It is concluded that although the use of an implant that delivers pST on a continuous basis was as effective as the same dose administered as a bolus injection for increasing IGF-I levels, it was less effective in improving feed efficiency and carcass quality.     

Effect of sex and exogenous porcine somatotropin on longissimus muscle fiber characteristics of growing pigs

Thirty-seven pigs with an initial live weight of 60 kg were used to investigate the effects of daily exogenous porcine somatotropin (pST) administration at two dose levels (0 and 100 micrograms.kg-1.d-1) for a 31-d period on muscle fiber characteristics and meat tenderness of boars, gilts and barrows. Excipient boars and gilts had more alpha W and fewer alpha R fibers than did those receiving pST. The percentage of muscle fiber type for barrows was not affected by pST treatment. The administration of pST resulted in an increase in muscle fiber size for all three fiber types in all three sexes, but these changes were of greater magnitude in barrows (31.8%) and gilts (27.8%) than in boars (9.3%). Somatotropin negated the intrinsic sex effect differences in fiber area of the pigs. There was no difference in tenderness among excipient boars, barrows and gilts; however, with the inclusion of pST, shear force decreased in boars and gilts and increased in barrows. A high proportion of the pST-treated pigs contained giant fibers in the longissimus muscle. Furthermore, a small proportion of the pST-treated pigs exhibited pale, soft, exudative muscle. Whether the giant fiber anomalies occurred through increased muscle activity or from fibers undergoing degenerative changes was not determined.     

Effect of recombinant porcine somatotropin on energy and protein utilization by growing pigs: interaction with capacity for lean tissue growth.

Three litters of four pigs from each of four different groups were used to evaluate the effect of porcine somatotropin (pST) on growth performance, body gain composition, energy and N metabolism, and in vitro cytochrome oxydase (final enzyme of the respiratory chain) activity of tissues. The four groups included boars from a synthetic line (SG1) or the Large White breed (SG2) and barrows from the Large White breed (SG3) or crossbred between Large White and Meishan breeds (SG4). Inherent capacity for daily lean tissue growth (LTG) decreased from SG1 to SG4. Within a litter, one pig was slaughtered and dissected at the beginning of the experiment (55 kg BW) and the three others were fed the same daily supply of protein and amino acids (26 g of lysine/d) but relative daily energy levels were either 113 (without pST: E1/0), 100 (3 mg of pST/d: E2/pST) or 87 (3 mg of pST/d: E3/pST). The 100 energy level corresponded to the ad libitum intake of E2/pST pigs. Two energy and N balances were carried out in respiration chambers during the experimental period. Pigs were slaughtered and dissected at approximately 95 kg BW and composition of gain was estimated using the comparative slaughter technique. In E1/0 pigs, daily BW, lean, and N gain were affected (P less than .01) by group; 566, 471, 374, and 315 g/d of lean tissue gain in SG1, SG2, SG3, and SG4 pigs, respectively. At high ME intake (E2/pST vs E1/0), pST increased daily BW (+14%), lean (+27%), or N (+26%) gain and reduced adipose tissue (-50%) gain, but the pST effect was inversely related to LTG: for N, the improvement was 2.8, 7.1, 7.0, and 11.1 g/d in SG1, SG2, SG3, and SG4 groups, respectively. Energy restriction (E3/pST vs E2/pST) reduced (P less than .001) adipose tissue gain in all groups but did not affect lean tissue or N gains in SG1, SG2, and SG3 pigs. In the pST-treated pigs of the SG4 group, the lean tissue or N gains were reduced (P less than .01) by energy restriction. Energy restriction combined with pST treatment (E3/pST) led to negligible amounts of fat deposited (40 g/d for SG1 + SG2 + SG3 pigs) and a gain:feed ratio higher than 500 g/kg (580 in SG1 pigs). The increased heat production measured in pST-treated pigs was due to its maintenance component: 275 vs 257 kcal of ME.kg BW-.60.d-1 (P less than .01).(ABSTRACT TRUNCATED AT 400 WORDS)     

波尔山羊对我国本地山羊杂交改良的初步效果

目前我国山羊无论存栏数还是产肉量均居世界首位,但各地方品种众多,与世界优良肉用山羊相比普遍体重小、生长慢.从1995年以来我国引进了著名肉用山羊--波尔山羊,各地相继开展了波尔山羊对本地山羊的杂交改良,都取得了显著的效果,杂交后代在生长速度及产肉性能方面都有很大的提高,为加速我国肉用山羊业的发展开创了新的途径.     

杜泊绵羊对我国本地绵羊杂交改良的初步效果

目前我国绵羊无论存栏数还是产肉量均居世界首位,但各地方品种众多,与世界优良肉用绵羊相比普遍体重较小、生长慢。2001年以来我国引进了著名肉用绵羊—杜泊绵羊,各地相继开展了杜泊绵羊对本地绵羊的杂交改良,都取得了显著效果,杂交后代在生长速度及产肉性能方面都有很大的提高,为加速我国肉用绵羊业的发展开创了新的途径。     

Whole genome analyses revealed genomic difference between European taurine and East Asian taurine

European taurine and East Asian taurine are two main clades in Bos taurus, but their genomic differences are not clearly elucidated. Here, we sequenced 16 Mongolian cattle genomes and compared them to the 92 genomes of 10 representative breeds worldwide. We found the highest LD level in Mishima cattle and the fastest LD decay in European taurine. Phylogenetic analysis revealed that Mongolian, Hanwoo and Mishima cattle were clustered into East Asian taurine. From selective sweep, gene annotation, functional enrichment and differential expression analysis, we identified selective signals including genes and/or pathways related to rapid growth and large body size in European taurine, and superior meat quality in East Asian taurine. Our findings will help us understand the evolutionary history and formation process of the breeds and provide theoretical materials regarding the genetic mechanism underlying breed characteristics and molecular breeding programmes of the taurine clades in the future.     

Performance, plasma hormones, histochemical and biochemical muscle traits, and meat quality of pigs administered exogenous somatotropin between 30 or 60 kilograms and 100 kilograms body weight.

Forty-five Large White barrows were injected daily i.m. with either excipient from 30 to 100 kg BW (CTRL), excipient from 30 to 60 and porcine somatotropin (pST; 100 micrograms/kg BW) from 60 to 100 kg BW (pST-60), or pST (100 micrograms/kg BW) from 30 to 100 kg BW (pST-30). Somatotropin accelerated overall growth rate (+4 and +9% for pST-60 and pST-30, respectively), increased longissimus (+10.3 and +14.7%) and semitendinosus (+17 and +13%) muscle weights, and decreased backfat (-49 and -58%) and leaf fat (-49 and -53%) weights. The administration of pST resulted in a similar increase in muscle fiber size for all fiber types in both longissimus (LM) and semispinalis (SS) muscles (+21%). Somatotropin had otherwise little effect on muscle fiber types and biochemical traits of LM, whereas dramatic changes were observed in SS. The relative area occupied by Type IIB fibers was increased (+22 and +29%) and that of Type I fibers was decreased (-10 and -15%). In pST-30 animals, myosin ATPase activity (+15%) and native myosin fast isoform proportion (+10%) were augmented, and energy metabolism was more glycolytic (lactate dehydrogenase: +25%) and less oxidative (citrate synthase: -13%; beta-hydroxyacyl-CoA dehydrogenase: -21%). Compared to CTRL animals, administration of pST increased muscle water concentration (LM: +.8 and +1.1%: SS: +3.3 and +3.3%) and decreased intramuscular fat (LM: -29 and -27%; SS: -39 and -50%). The pH measured 45 min and 24 h postmortem, glycogen content, reflectance, and index of light diffusion were mostly not affected by pST treatment. In conclusion, pST had a very favorable effect on growth performance without any important effect on meat quality traits except for the reduction in intramuscular lipid content. The results indicated that the effects of pST on muscular histochemical and biochemical characteristics were different in LM and SS muscles.     

世界山羊选育的现状及展望

保护动物品种的多样性,不仅对维护家畜的环境适应能力来说是非常关键的,还关系到未来动物生产模式的建立和完善。调查结果表明,现在世界山羊育种形势呈现一个矛盾的现象:一方面,发达国家通过完善的选育组织对山羊的乳用、肉用及毛用性能进行改进;另一方面,在一些落后的地方,山羊的产品还都用于农牧民的自身消耗。当前山羊育种情况如下,少数山羊经过了充分的选育过程并具有某些特点和特性;而大多数山羊尚未经过系统、完善的选育。通过分析山羊选育的现状,作者提出了一些建议,可以更有效的开发这一物种的遗传潜质。     

Effects of exogenous porcine somatotropin (pST) administration on growth performance, carcass traits, and pork meat quality of Meishan, Pietrain, and crossbred gilts

Seventeen to twenty-three females of lean (Pietrain, PI), fat (Meishan, MS), or intermediate genotype (PI x [3/4 Large White x 1/4 MS]), referred to as crossbred (CR), were injected between 60 and 100 kg live weight with 6 mg/d of porcine somatotropin (pST) and compared to similar numbers of control females receiving the vehicle only. Average daily gain increased similarly in the three genotypes (125 g/d). Feed conversion ratio tended to decrease to a higher extent in MS (-2.0 kg of feed/kg of gain) than in the other two genotypes (-1.1 and -.9 kg of feed/kg of gain for CR and PI, respectively). A significant genotype x treatment interaction was also observed for backfat thickness (BF) and fat, muscle, and bone development. Effects of pST in PI, CR, and MS pigs were, respectively, -6.2, -9.6, and -16.1 mm for BF and 3.0, 6.8, and 11.8% carcass muscle. The influence of pST on physical measurements of meat quality was rather low, although desirable effects (P less than .05) were obtained on the reflectance and water-holding capacity of PI and CR. Intramuscular fat content was reduced by approximately 1% in MS and CR but not in PI. The metatarsals of pST-treated animals had a higher water content (except in PI), a lower mineralization, and a lower breaking strength (except in MS). The existence of breed variations in the response to pST might result in changes of the relative merit of crossbreeding schemes.     

Trait values of growth,carcass and meat quality in Wild Boar,Meishan and Pietrain pigs as well as their crossbred generations

The genetic diversity between European Wild Boar, Pietrain and Meishan and their crossbred generations are described on the basis of performance traits for growth, carcass composition and meat quality. Using the results of 1333 pigs, the highest growth rates were found in crossbred generations, indicating positive heterosis effects. In carcass composition, high meat content is associated with Pietrain and high fat content with Meishan alleles. Weights of organs were greatest in Wild Boar, the weight of the head was greatest in Meishan. Meat quality and stress resistance parameters point to superior gene effects in Wild Boar and Meishan. Crossbred animals of these genetically diverse pig sources generate the maximum variability for all traits, help to demonstrate the range of values for the specified breeds of pig and allow an efficient analysis of the genes influencing performance traits.     

Genetic analysis of live weight of local kids to promote genetic evaluations in the arid areas of Tunisia

Tropical Animal Health and Production - Goat meat production, a widely extended activity in the more arid areas of Tunisia, relies on local breeds. These breeds are well adapted to produce under...     

Growth and carcass quality of offspring in response to porcine somatotropin (pST) treatment of sows during early pregnancy

The effects of maternal treatment with porcine somatotropin (pST) during early gestation on offspring growth, carcass quality, and immunological characteristics were determined. Thirty-two sows received daily injections of either a placebo (n=16) or 6 mg of pST (n=16) from day 10 to 27 of gestation with gradual withdrawal until day 37. In neonatal piglets, a birth weight group (BWG) by treatment interaction (P<0.01) revealed decreases in the 25% heavy and 50% middle weight groups and an increase in the 25% low weight group within litters. Similar interactions were observed for muscle tissue (P=0.03) and, in opposite direction, for fat (P=0.05) percentages. The average percentage of muscle tissue was reduced (P=0.03) by pST treatment, whereas percentages of internal organs (P=0.05) and skin (P=0.04) were enhanced. The susceptibility of piglets to infections at 2 days after weaning (day 30 of age) was not altered by pST treatment. Carcasses of slaughter pigs (day 182 of age) from pST-treated sows tended to deposit less meat than controls (P=0.10) and to exhibit the same BWG by treatment interaction found at birth (P=0.08). Meat quality at slaughter was changed towards higher intramuscular fat content (P=0.01) and drip loss (P=0.01). The results suggest that pST treatment during early gestation results in more balanced litters, but, on average, is not of advantage for carcass quality.     

云南主要地方牛种肉质特性研究

对大额牛,云南瘤牛,中甸牦牛,迪庆黄牛和中甸犏牛的肉质特性作了系统测试。分析和对比。结果表明：５个牛种在肌肉ＰＨ值,系水率,嫩度,贮藏损失,熟肉率,肉色评分和大理石评分以及品偿鉴定等肉质特性指标上均有差异。     

An international panorama of goat selection and breeds

The preservation of the biodiversity of animal breeds is an important condition to maintain the ability of animal production to adapt to the changing conditions of breeding and production systems in the future. The decrease of the number of animal breeds has been observed both for sheep, cattle and goats in relation with the standardisation and intensification of animal production systems.Goats are mainly concerned by the situation as they have the biggest increase in livestock numbers in 20 years. A global overlook of goats worldwide is showing a contradictory situation: On one hand, small but well organised sectors have developed in a few countries for milk and cheese, meat and fibre production. On the other hand, most of the goats are mostly still used for auto consumption of milk meat and skin or fibres in village herds. The present goat genetic situation is the direct consequence of this evolution with the high specialisation of a small number of selected and well characterised breeds for milk, meat and fibres and a majority of not well defined populations and local breeds, generally without selection schemes and organisation.A global panorama of the main families and breeds is presented. A special consideration is then pointed on the necessary financial and logistic conditions to achieve successively these selection objectives. After having observed that in many cases these conditions are not present, this report concludes by some proposals to control better the possibilities of success and express with more efficiency the genetic potentiality of this interesting species.     

鸡SH3RF2插入/缺失等位基因在中国地方鸡种中频率分布研究

中国地方鸡种资源丰富,风味较优,但存在生长速度慢、饲料效率低等缺点,因此为了加速我国地方鸡种和肉鸡品种的遗传改良,分子标记技术得到了广泛应用。已知SH3RF2基因的插入/缺失突变与肉鸡生长和体重密切相关,因此本试验对分布在我国各地的15个地方鸡品种进行了SH3RF2基因的等位基因频率检测,以确定SH3RF2基因在我国地方鸡种中的等位基因分布情况,继而将SH3RF2基因用于鸡生长性状的选择的分子育种标记。研究结果发现所检测地方鸡种和肉鸡品种均是非缺失的纯合子,没有发现缺失的等位基因。要利用SH3RF2基因对中国地方鸡种进行选择,可能需要通过杂交等手段将缺失型等位基因导入我国地方鸡种的群体之中。