Decrease in mass of slow and fast tenotomized muscles of guinea pigs: role of nerve impulses and neurogenic factors

The role of nerve impulses and neurogenic factors in the decrease in muscle mass following tenotomy was investigated in 30 adult (15 males, 15 females) guinea pigs. Unilateral tenotomy, neurectomy and simultaneous tenotomy and neurectomy of slow and fast hindlimb muscles were performed in 3 groups respectively. Each group comprised 10 guinea pigs. The unoperated hindlimb of each animal in each group served as control. The weight loss occurred in both slow and fast muscles but was greater in the slow soleus muscle as compared to the fast gastrocnemius muscle. In each muscle the weight loss was least in the tenotomized group. This was followed by the weight loss in the neurectomized group. The greatest weight loss was observed in the simultaneously tenotomized and neurectomized group. These observations agree with the suggestion of other workers that a possible neurogenic factor flowing from the nerves to the muscles was very significant in maintenance of muscle fibre stability. It indicated also that simultaneous neurectomy and tenotomy did not prevent degenerative changes in slow and fast muscles and that it was not nerve impulses reaching the tenotomized muscles that were responsible for degenerative changes observed but that other factors were responsible.     

Equine laryngeal hemiplegia. Part IV. Muscle pathology

This study confirmed that neurogenic muscle pathology exists in intrinsic laryngeal muscles supplied by the recurrent laryngeal nerves in horses subclinically and clinically affected with laryngeal hemiplegia. An important additional observation was the occurrence in three out of four laryngeal hemiplegic horses of neurogenic muscle changes in a hindlimb muscle, the extensor digitorum longus, a muscle supplied by another long peripheral nerve. This finding suggests that a polynenropathy exists in laryngeal hemiplegic horses, and supports the classification of this disease as a distal axonopathy. Comparison of the degree of pathology in the intrinsic laryngeal muscles and that of the recurrent laryngeal nerves innervating them, demonstrated a strong correlation between the extent of damage in the distal left recurrent laryngeal nerve and the overall degree of muscle pathology. The muscle damage in clinically affected horses is a reflection of the nerve damage present in the most distal portion of the recurrent laryngeal nerve. The more variable pathological changes found in proximal levels of the left and right recurrent laryngeal nerves probably reflects the ongoing nature of the pathological process affecting nerve fibres. The existence of a subclinically affected group of horses, the earliest involvement of an adductor, the left cricoarytenoideus lateralis muscle, and the presence of changes in the right intrinsic laryngeal muscles all confirmed the findings of previous workers.     

Passive role of articular chondrocytes in the pathogenesis of acute meniscectomy-induced cartilage degeneration

The importance of viable articular chondrocytes and enzymes or factors from surgically traumatized synovium in the pathogenesis of acute meniscectomy-induced cartilage degeneration was examined in guinea pigs (nine groups of five animals each). Iodoacetate injected intra-articularly was used to kill articular chondrocytes of guinea pigs prior to meniscectomy to determine if they were active participants in the acute lesion induction. Lesions of similar severity to those occurring in animals with viable chondrocytes at the time of surgery were observed, suggesting that the chondrocytes were not actively involved in the pathogenesis in this group. In an additional group of guinea pigs in which chondrocytes were killed by iodoacetate, the medial collateral ligament was transected to determine if acute degenerative changes could be induced in acellular cartilage exposed to a surgical manipulation that does not by itself induce lesions but does expose cartilage to enzymes/factors from traumatized synovium. Transecting the medial collateral ligament and entering the joint space without induction of instability via meniscectomy did not result in histologic evidence of cartilage damage. This suggests that synovial trauma and mild inflammation were insufficient to induce matrix degeneration in the absence of abnormal load bearing. In further support of this, guinea pigs subjected to unilateral sciatic neurectomy at the time of meniscectomy were protected against development of acute cartilage degeneration. Results of this study suggest that articular cartilage devoid of viable chondrocytes at the time of meniscectomy responds acutely in much the same way as intact cartilage subjected to this procedure.     

豫西黑猪不同屠宰体重肌纤维组织学及成肌调控基因发育性变化

【目的】试验旨在揭示豫西黑猪背最长肌肌纤维组织学、肌纤维类型和成肌调控相关基因发育性变化及其相互之间的关系。【方法】选取平均体重约为60、75、90、105和120 kg共5个体重阶段的豫西黑猪，每个体重屠宰3头，共15头，公母随机。采用HE染色和免疫荧光染色分析快慢肌类型组成和纤维组织学特性，利用实时荧光定量PCR方法测定成肌调控相关基因生肌决定因子（myogenic differentiation，MyoD）、配对盒7（paired-box 7，Pax7）、肌肉生长抑制素（myostatin，MSTN）、肌细胞生成素（myogenin，MyoG）、肌细胞增强因子2C （myocyte enhancer factor 2C，MEF2C）和肌纤维肌球蛋白重链（myosin heavy chain，MyHC）亚型的mRNA表达量。【结果】随着豫西黑猪体重的增加，肌纤维密度整体呈下降趋势，在75 kg时极显著高于其他体重阶段（P<0.01），肌纤维面积和肌纤维直径整体呈上升趋势；慢肌面积占比在60和105 kg时显著或极显著低于其他体重阶段（P<0.05；P<0.01），快慢肌所占面积总百分比在90 kg时极显著低于其他体重阶段（P<0.01）。实时荧光定量PCR检测结果发现，MyHCⅠ基因mRNA表达量在75和105 kg时极显著高于其他体重阶段（P<0.01），MyHCⅡA基因mRNA表达量整体呈下降趋势，MyHCⅡX基因mRNA表达量在60 kg时达到最高，而MyHCⅡB基因mRNA表达量在75 kg时极显著低于其他体重阶段（P<0.01）；MyoD、Pax7、MSTN、MyoG、MEF2C基因mRNA表达量分别于60、75、90、120、120 kg时达到最大值。相关性分析结果表明，除MSTN基因外，MyoG、MyoD、Pax7和MEF2C基因均与肌纤维形态和MyHC基因各亚型之间有显著或极显著的相关性（P<0.05；P<0.01）；通过对120 kg的豫西黑猪和杜洛克猪比较发现，两者间肌纤维直径、肌纤维面积、肌纤维密度，以及MyHC和相关成肌调控基因mRNA表达量均有极显著差异（P<0.01）。【结论】在豫西黑猪60~120 kg生长阶段，肌纤维面积、肌纤维直径整体呈上升趋势，肌纤维密度呈下降趋势；在肌肉发育过程中，纤维类型组成的变化主要是Ⅰ、ⅡA、ⅡX型肌纤维向ⅡB型肌纤维的转化；与杜洛克猪相比，豫西黑猪肌纤维面积和肌纤维直径较大，肌纤维密度较低，MyHCⅠ与MyHCⅡA基因mRNA表达量较高。     

Factors Responsible for Smaller Pelvic Muscle Mass in Dysplastic Dogs

Pectineus muscles of 23 German shephard dogs were studied. 10 dogs had normal hips, 13 dogs had hip dysplasia. The relative weight of each pectineus muscle was determined, when the dogs were 24 months old. Cryostat sections were stained for demonstration of ATPase, thereby differentiating muscle fibres into type I (slow twitch), type II (fast twitch) and intermediate fibres. The results (Tables 1–3) shows, that the relative pectineus muscle weight was smaller in dysplastic dogs and there were significantly fewer type I muscle fibres in the pectineus muscles of dysplastic dogs.     

Paylean alters myosin heavy chain isoform content in pig muscle

Feeding beta-adrenergic agonists promotes muscle growth. Early histological techniques failed to show precisely how feeding ractopamine-HCl (Paylean) alters muscle growth in pigs. To understand these effects, an indirect enzyme-linked immunosorbent assay (ELISA) was used to determine the abundance of each adult skeletal muscle myosin heavy chain isoform, one means of assigning muscle fiber type, in fast and slow muscles of pigs fed Paylean. Sixty growing pigs (-85 kg) were randomly assigned to three Paylean doses (0, 20, or 60 ppm). At 3, 7, 14, 28, and 42 d of treatment, four pigs per dose were harvested and white (WST) and red (RST) semitendinosus and longissimus (LM) muscles were removed and processed, and myosin heavy chain was quantified by ELISA. Feeding Paylean enhanced (P < 0.05) pigs' average daily gain. Muscle myosin heavy chain (slow, 2A, 2AX, and 2B) composition differed (P < 0.05) across muscles. Compared with LM, RST contained approximately five times more (P < 0.0001) slow and type 2A myosin heavy chain and three times more 2AX myosin heavy chain but nearly undetectable amounts of 2B myosin heavy chain. Myosin heavy chain composition of the WST closely resembled that of the LM (i.e., greater 2AX and 2B and less slow and 2A). After 42d of 60 ppm Paylean, the amount of slow, 2A, and 2AX myosin heavy chain decreased (P < 0.05) across the three muscles whereas the amount of 2B myosin heavy chain increased (P < 0.05). In contrast, relative amounts of 2A and 2AX myosin heavy chain increased (P < 0.05) in muscle of control pigs at 42d. Changes associated with the 20-ppm dose were intermediate to and different from (P < 0.05) control and 60 ppm treatments. Correlations (P < 0.05) among various myosin heavy chain within muscles suggest that slow, type 2A, and 2X decrease with increases in 2B myosin heavy chain. These data show that administration of Paylean affects myosin heavy chain isoform composition in a time- and dose-dependent manner and provides a mechanism of action for Paylean altering animal growth.     

Free-range rearing of pigs during the winter: adaptations in muscle fiber characteristics and effects on adipose tissue composition and meat quality traits

This research aimed to determine whether outdoor free-range rearing during the winter (average ambient temperature of 5 degrees C) vs. indoor housing (22 degrees C) affects meat quality, muscle metabolic traits, and muscle fiber characteristics. Forty Large White gilts and barrows were blocked by weight within each gender (20 per gender) and allotted randomly into two groups of pigs, with one reared indoors (IN) in individual pens (2.6 m2) and the other reared outdoors (OUT) from December to March in a 0.92-ha pasture. Both groups had free access to the same grower-finisher diet from 23 to 105 kg. At slaughter, adipose (backfat [BF] and omental fat [OF]) and muscle tissues (longissimus muscle [LM], rectus femoris [RF], and semitendinosus [ST]) were obtained from the right side of each carcass. Muscle fibers were stained and classified on the basis of stain reaction as slow-oxidative (SO), fast oxidative-glycolytic (FOG), and fast glycolytic (FG); fiber area and distribution were determined. Also assessed were carcass characteristics, initial and ultimate pH, L*a*b* values, drip loss percent, glycolytic potential (GP), and intramuscular lipid content, as well as the fatty acid profile of each muscle and adipose tissue. The OUT pigs had lower (P < 0.05) ADG and leaner (P < 0.05) carcasses than IN pigs. Rearing environment did not (P > 0.63) affect the intramuscular lipid content of the ST, but intramuscular lipid content was lower (P < 0.01) in the LM and tended to be higher (P = 0.06) in the RF of OUT than in those of IN pigs. In the BF outer layer of the OUT pigs, the higher PUFA content was compensated by both a lower (P < 0.01) saturated and monounsaturated fatty acid (MUFA) content, whereas in the OF, LM, and dark portion of the ST, only the percentage of MUFA was decreased (P < 0.01). In all tissues of the OUT pigs, the linolenic acid content was higher (P < 0.01) and the n-6:n-3 ratio was lower (P < 0.01). The GP of all muscles was higher (P < 0.01), and the ultimate pH of the RF and ST was lower (P < 0.01), in OUT compared with IN pigs. Lightness (L*) values were lower (P < 0.01) in the LM. Percentages of drip loss were higher (P < 0.05) in the LM and light portion of the ST of OUT than in those of IN pigs. The LM and RF of OUT pigs had more (P < 0.01) FOG and fewer (P < 0.01) FG fibers than muscles of IN pigs. Results suggest that rearing pigs outdoors increases aerobic capacity of glycolytic muscles but has little concomitant influence on meat quality traits.     

Amino acid sequences of multiple fast and slow troponin T isoforms expressed in adult bovine skeletal muscles

Multiple nucleotide sequences of complementary DNA (cDNA) of bovine troponin T (TnT) isoforms expressed in the adult skeletal muscles were determined to facilitate the elucidation of the TnT degradation progress during postmortem aging of muscles. Fresh muscle samples were excised from the lingual, masseter, pectoralis, diaphragm, psoas major, longissimus thoracis, spinnalis, semitendinosus, semimembranosus, and biceps femoris muscles of three Holstein cows within 1 h of slaughter. Complementary DNA fragments of fast and slow TnT isoforms expressed in each muscle were amplified by reverse-transcribed PCR. Consequently, four major fragments of fast TnT and two fragments of slow TnT, all of which contained the complete coding region, were obtained. The sequence determination of these fragments revealed that at least eight and two isoforms were generated by the alternative splicing from bovine fast and slow TnT messenger RNA, respectively. In the fast TnT isoforms, five small variable exons were observed; three of these five exons were in the amino (N)-terminal region. The calculated molecular weight of fast and slow TnT isoforms ranged from 29,816 to 32,125 and from 30,166 to 31,284, respectively. The deduced amino acid sequences revealed that the N-terminal region of all the TnT isoforms was extremely glutamic acid-rich. Reverse-transcribed PCR analysis revealed that expression of each of these isoforms was distributed in a fast or slow muscle-specific manner. Given that TnT degradation has been reported to accompany a decrease in glutamic acid content in the conventional 30-kDa degradation product, the sequence data suggested that the 30-kDa fragment seem to be generated by the proteolytic removal of the glutamic acid-rich N-terminal ends. The multiplicity of TnT isoforms may result in a complicated pattern of TnT degradation on SDS-PAGE gel during beef aging.     

大白猪不同部位肌肉肌纤维表达特点

取3头本地大白猪4个不同部位的肌肉组织,运用免疫组化方法,测定快肌纤维和慢肌纤维的表达情况。免疫组化结果表明在猪的不同部位肌肉组织中,快肌纤维与慢肌纤维含量之间存在极显著差异(P<0.01)。快肌纤维的表达在股二头肌中最多,其次为背最长肌和内脊肌,头半棘肌最少。慢肌纤维的表达在头半棘肌中最多,其次为内脊肌和股二头肌,在背最长肌中表达最少。通过对猪4种骨骼肌中快肌纤维和慢肌纤维的免疫组化分析显示,二者的表达在猪不同部位的肌肉存在显著差异。     

非常规饲料原料对生长育肥猪屠宰性能和肉品质的影响

文章旨在评估日粮添加非常规饲料原料对生长育肥猪屠宰性能和肉品质的影响。试验将12周龄平均初始体重为(33.15±1.23)kg的450头(公母各半)生长猪随机分为3组,每组5个重复,每个重复30头猪。对照组饲喂常规玉米-豆粕-小麦型日粮,处理1组饲喂含有30%马铃薯茎叶和10%苜蓿草的日粮,处理2组饲喂含有30%马铃薯茎叶、10%苜蓿草及0.5%中草药提取物的日粮,试验共开展10周。结果:处理1和2组较对照组显著提高生长猪屠宰率和背膘厚度(P<0.05),但瘦肉率和眼肌面积显著降低(P<0.05)。日粮处理与性别对屠宰率、胴体长度、眼肌面积及背膘厚度的影响具有显著交互作用(P<0.05)。处理组较对照组显著提高了肌肉系水力(P<0.05),处理2组肌肉的适口性显著高于对照组(P<0.05)。此外,处理组肌肉粗蛋白质含量显著高于对照组(P<0.05),而脂肪含量显著降低(P<0.05)。结论:与常规饲料相比,非常规饲料对生长育肥猪肌肉感官特性表现出积极影响,特别是改善了适口性和嫩度。     

不同梯度发酵豆粕对育肥猪生长性能、胴体性状及肉品质的影响

试验旨在研究不同梯度发酵豆粕等量替代普通豆粕对育肥猪生长性能、胴体性状及肉品质的影响.采用单因素完全随机试验设计,选择240头初始体重(61.25±2.31) kg的"杜×长×大"育肥猪,随机分为6组,每组8个重复,每个重复5头猪.对照组育肥猪饲喂玉米-豆粕型基础日粮,5个试验组依次采用5％、7％、9％、11％、13％...     

Myotrophic effects of anabolic steroids

An anabolic steroid, nandrolone decanoate, was shown to produce increases in the weight, cross-sectional area, tension-generating capacity and mean fibre diameter of a limb muscle, tibialis anterior (TA), in female rabbits. Despite suggestions in the literature of an exerciserelated effect of such drugs, hypertrophy was not observed in TA muscles subjected to chronic electrical stimulation, but was seen in the contralateral control muscles and in the muscles of both hind limbs in unoperated sedentary animals. The effect was confirmed in the TA of female guinea pigs, rats and mice, and could not be explained in terms of an increase in body weight. Compared to TA some other muscles, like EDL, plantaris and soleus in the rabbit, were less sensitive to treatment; others, like pubocaudalis in the rat and mouse, and temporalis in the guinea pig, were more responsive. The myotrophic effects were undiminished in adrenalectomised female rats, and could not therefore have been mediated by interference with the catabolic actions of circulating glucocorticoids, as had been proposed in an earlier hypothesis.     

Adult Stem Cells: Perspectives for Therapeutic Applications

The right and left cranial cervical ganglia in the heads of 10 adult guinea pigs (5 male, 5 female) were dissected in detail. The cranial cervical ganglion (CCG) was located on the caudo-ventral aspect of the distal ganglion of the vagus nerve, and medial to the digastric and styloglossal muscles. It was present also ventral to the tympanic bulla, ventro-lateral to the longus capitis muscle, and between the ascending pharyngeal and the internal carotid arteries. The branches of the CCG included the internal and external carotid nerves, the jugular nerve and connecting branches to the pharynx, vagus, glossopharyngeal, accessory, cranial laryngeal, first and second cervical nerves, and vessels in the carotid body region. The number of nerves ramifying from the CCG of the guinea pig varied among cases. Compared to other species, there are also differences in the number of nerve branches and the course patterns. No sex differences are present as far as the guinea pig CCG is concerned.     

乙基纤维素包被VC对SPF级豚鼠繁殖影响的初步研究

为评价乙基纤维素包被VC对SPF级豚鼠繁殖性能的影响,选取SPF级繁育适龄雄性豚鼠24只,雌性豚鼠72只,按性别随机分成对照组、试验组Ⅰ、试验组Ⅱ、试验组Ⅲ,每组24只,其中雄性6只,雌性18只。试验组Ⅰ、试验组Ⅱ、试验组Ⅲ豚鼠饲料中分别添加500、1 000、1 500 mg/kg的乙基纤维素包被VC,对照组饲料中添加1 800 mg/kg的单体VC。使母鼠完成2胎的生产,期间观察母鼠妊娠期情况、有无脱毛、流产情况和生产仔鼠的健康状况,计算各组母鼠受孕率、产仔率、仔鼠出生重、离乳率。结果表明,当乙基纤维素包被VC添加量为500 mg/kg时,可获得与添加单体VC一致的饲养效果;当乙基纤维素包被VC添加量为1 000 mg/kg时,SPF级豚鼠繁育指标达到最优,可满足繁殖状态下SPF级豚鼠对VC的需求;当乙基纤维素包被VC添加量为1 500 mg/kg时,SPF级豚鼠繁育指标并无显著变化。综上提示,饲料中添加乙基纤维素包被VC代替单体VC进行SPF级豚鼠饲养切实可行,且乙基纤维素包被VC最优添加量为1 000 mg/kg。     

The role of quantitative electromyography (EMG) in horses suspected of acute and chronic grass sickness

REASONS FOR PERFORMING THE STUDY: Clinical evidence of motor neuron involvement in equine grass sickness (EGS) has not been reported. HYPOTHESIS: Quantitative electromyography (EMG) analysis can elucidate subtle changes of the lower motor neuron system present in horses with EGS, performed ante mortem. METHODS: Fourteen horses diagnosed clinically with acute, subacute or chronic EGS were examined and quantitative EMG performed. Previously published data on healthy horses and horses with proven lower motor neuron disease (LMND) were used as controls. In 8 horses post mortem examination was performed, and in 7 muscle biopsies of the lateral vastus muscle underwent histopathology and morphometry. RESULTS: Clinical electrophysiological evidence of neuropathy was present in 12 horses. Analysis of data from the first 4 horses resulted in 95% confidence intervals (CI) of nontransformed data for motor unit action potential (MUP) duration in subclavian, triceps and lateral vastus muscle of 11.0-13.7, 14.8-20.3 and 12.2-17.2 msecs, respectively, and for MUP amplitude 291-453, 1026-1892 and 957-1736 microV, respectively. For number of phases the 95% CI was 3.6-4.4, 2.9-3.6 and 2.9-3.4, respectively, and for number of turns 5.0-6.5, 4.3-5.3 and 3.7-4.6, respectively. No changes in duration of insertional activity were measured. Pathological spontaneous activity was observed in all horses. EGS as evidenced by degenerative changes in the autonomic ganglia in combination with minor degenerative changes of the spinal lower motor neurons was observed on post mortem examination in all 8 available autopsies. In muscle biopsies of 4 out of 7 horses changes consistent with slight neurogenic atrophy were found. CONCLUSIONS AND POTENTIAL RELEVANCE: EMG results demonstrated the presence of a neuropathy of skeletal muscles in all horses suspected to have EGS. The combination of clinical and electrophysiological evidence may aid differential diagnosis of neurogenic disease in cases of weight loss and colic.     

The effects of selection of pigs on growth rate vs leanness on histochemical characteristics of different muscles

The microstructure of two type of muscles was studied in a selection experiment conducted with Dutch Large White pigs (boars and gilts) selected for either low backfat thickness (L-line) or fast growth (F-line). Second- and fourth-generation pigs were used to determine effects of selection on fiber type composition, fiber area, and capillary density in the longissimus lumborum (LL) and biceps femoris (BF) muscles. Immediately after slaughter samples were taken from the LL and BF muscles. The latter was divided into an inside (BFi) and outside (BFo) portion, which refer to the red and white portions of the biceps femoris. Serial sections were stained for ATPase (pH 4.60), succinate dehydrogenase (SDH), and alpha-amylase-periodic acid shiff (PAS) to determine fiber type and capillary density. The LL and BFo muscles had predominantly type IIBw fibers, whereas the BFi muscle had a 2 to 4 times higher amount of type I fibers. In most muscles there were more type I and fewer type IIBw fibers in F- than in L-line pigs (P < .05), except in the LL muscle of second-generation pigs and in the red part of the BF muscle of fourth-generation pigs. In both selection lines lower type I and higher type IIBw percentages were found in muscles from gilts than in those from boars (P < .05). Capillary density and fiber area of L- and F-lines showed minor differences, which could be explained by differences in weight and age of the pigs of both lines. The results suggest that selection for low backfat thickness in pig breeding compared with increased growth rate resulted in fewer oxidative and more glycolytic muscle fibers. The magnitude of the effect depended on muscle type and duration of the selection period.     

Effect of rearing and slaughter conditions on behaviour, physiology and meat quality of Large White and Duroc-sired pigs

The present study investigated the effect of outdoor rearing and genetic background on behaviour and meat quality traits in heavyweight pigs. Large White and Duroc-sired pigs were reared in groups of 3 castrated males and 3 females, conventionally or in fields, from April to October, in a study with two replicates. Compared to indoor pigs, outdoor pigs were more active and showed a larger range of behaviour suggesting improved welfare from a behavioural point of view. During 5 h of isolation, outdoor pigs were less active and had lower heart rates, and in another test, they reacted less to a non-familiar object (traffic cone). Pigs were slaughtered at 150 kg live weight, half of each treatment group after mixing, short transport, and overnight lairage and half immediately following short transport. Outdoor pigs were less aggressive during pre-slaughter mixing. Ante- and post-mortem glycogen content of the Longissimus lumborum (LL), Semimembranonus (SM) and Semispinalis capitis (SC) muscles depended on slaughter conditions, sire breed, rearing conditions, gender and year of experimentation, sometimes influencing ultimate pH. Effects of rearing on muscle glycogen content and post-mortem pH were stronger during the second year of rearing. Effect of slaughter conditions on glycogen content and ultimate pH depended on fighting levels during pre-slaughter mixing. Outdoor rearing increased muscle redness. Drip and cooking loss were higher in Large White than Duroc-sired pigs. Drip and cooking loss were correlated with early post-mortem and ultimate pH. Thawing loss was correlated with early post-mortem temperature and ultimate pH. Finally, reactivity to isolation had a predictive value as pigs more active during isolation had less skin damage due to fighting during pre-slaughter mixing. In conclusion, despite large effects of year of experimentation, outdoor rearing, sire breed, and slaughter conditions influenced behaviour and muscle characteristics.     

Relationships between behavioral and meat quality characteristics of pigs raised under barren and enriched housing conditions.

In this study the effects of barren vs enriched housing conditions of pigs on their behavior during the lairage period (2-h holding period before slaughter), carcass characteristics, postmortem muscle metabolism, and meat quality were studied. The barren housing system was defined by common intensive housing conditions (i.e., with slatted floors and recommended space allowances), whereas the enriched environment incorporated extra space and straw for manipulation. Salivary cortisol concentrations were measured before transport and at the end of the lairage period. During the lairage period the percentage of time spent walking and fighting by the pigs was registered. Carcass characteristics such as weight, meat percentage, and backfat thickness were determined. At 5 min, 45 min, 4 h, and 24 h postmortem, pH, temperature, and lactate concentrations were determined in the longissimus lumborum (LL) and biceps femoris (BF) muscles. Capillarization of the muscle, mean muscle fiber area, and color and drip loss after 2 and 5 d of storage were determined for both muscle types. Pigs from the barren environment had a significantly higher increase in cortisol from farm to slaughter, but no differences in behavior were observed during the lairage period. Carcass characteristics did not differ between pigs from barren and those from enriched housing conditions. Postmortem lactate formation was significantly lower in LL muscles of enriched pigs at 4 and 24 h postmortem. Capillary density and mean muscle fiber area did not differ between the groups of pigs. The percentage of drip loss at 2 and 5 d after storage of LL muscle samples from enriched-housed pigs was significantly lower than that of the barren-housed pigs. Similar tendencies were found for the BF muscle from pigs kept in an enriched environment, but these were not statistically significant. The housing system did not affect meat color. It is concluded that on-farm improvement of animal welfare by environmental enrichment can also lead to beneficial economic effects after slaughter by improving the water-holding capacity of pork.     

Studies on vertical transmission of Trichinella spp. in experimentally infected ferrets (Mustela putorius furo), foxes (Vulpes vulpes), pigs, guinea pigs and mice

Vertical transmission of Trichinella spiralis was evaluated in ferrets (n = 21), foxes (n = 11), pigs (n = 12), guinea pigs (n = 16), and mice (n = 41). The placental barrier to be crossed by migratory Trichinella larvae varies structurally in different animal species. Ferrets and foxes have an endotheliochorial placenta structure, guinea pigs and mice a haemochorial, and pigs an epitheliochorial placenta. The non-encapsulating Trichinella pseudospiralis larvae have an extended muscle migration prior to entering a muscle cell. To evaluate if T. pseudospiralis was more likely to be transmitted to offspring, an additional group of foxes (n = 11) infected with T. pseudospiralis was included. Two different dose levels were used for ferrets, pigs, guinea pigs, and mice. In pigs and guinea pigs, infection was given at different times of the gestation period. Vertical transmission, measured as recovery of muscle larvae in the offspring, was demonstrated in both ferrets groups, in all four guinea pig groups, and in the high dose mouse group, but not in any fox or pig groups.     

花椒籽替代不同比例玉米对育肥猪生长性能和肉品质的影响

本试验旨在探讨饲粮中用花椒籽部分代替玉米对育肥猪的生长性能、肉品质、背最长肌脂肪酸组成的影响.选择90日龄、体重为33 kg的健康杜× 长× 大三元猪288头,随机分为4组,每组4个重复,每个重复18头.对照组饲喂基础日粮,试验组分别用花椒籽代替饲粮中2.5％、5％、7.5％的玉米,预试验7d,正试期100 d.结果 ...