Relationship between liver degeneration and the production of dark firm dry meat in slaughtered pigs

Sixty-five of 77 slaughtered pigs with liver degeneration produced dark firm dry (DFD) meat. The biochemical properties of blood, liver and muscle of those pigs were examined. In the blood, the NEFA level was higher, which indicated the mobilization of lipids from adipose tissues. The serum CPK and LDH5 levels were higher, the enzymes being derived from muscle. In the degenerative liver with yellowish discoloration, the TG level was higher and the glycogen level was lower than in a normal liver. In the DFD muscle with the final pH above 6.0, both the glycogen level immediately after slaughter and the lactic acid level 24 hr after slaughter were lower than in a normal muscle with the final pH below 6.0. Five pigs exhausted experimentally by 53-hr fasting and hard exercise showed the same changes in the blood and liver as the pigs with liver degeneration. Four of the 5 exhausted pigs showed the same changes in the muscle as in DFD meat. From these data, it was confirmed that exhaustion before slaughter led to lipid accumulation in the liver and to a decrease in muscle glycogen, and consequently caused both liver degeneration and DFD meat in the same pig.     

Acid-base equilibrium in the blood in cattle in relation to the incidence of DFD (dark, firm, dry) meat

We studied changes in the parameters of the acid-base balance of the blood in cattle before animal transport to the slaughterhouses, after transport, after stunning and before bleeding. At the same time we studied the occurrence of DFD meat by measuring the pH value of the muscle and by determining the meat color. We found out that the disorder of acid-base balance was less manifest, with respect to the large capacity of the buffer systems of the blood, than the changes caused by glycogenolysis in the muscle.     

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.     

Toxoplasma gondii in Switzerland: a serosurvey based on meat juice analysis of slaughtered pigs, wild boar, sheep and cattle

Toxoplasmosis is one of the most important zoonotic diseases worldwide and is caused by the protozoan Toxoplasma gondii. Besides vertical infection during pregnancy, humans can get infected post-natally either by peroral uptake of sporulated Toxoplasma oocysts or by ingestion of tissue cysts upon consumption of raw or undercooked meat. The aim of this study was to approximate the risk of human infection via meat consumption by estimating the seroprevalence of T. gondii in slaughtered animals in Switzerland and to compare data with prevalences assessed 10 years ago. The study included pigs, cattle, sheep and wild boar of different age groups and housing conditions whenever possible and applicable. A P-30-ELISA was used to detect T. gondii-specific antibodies and to determine seroprevalences in meat juice of slaughtered animals. A total of 270 domestic pigs (120 adults, 50 finishing, 100 free-ranging animals), 150 wild boars, 250 sheep (150 adults, 100 lambs) and 406 cattle (47 calves, 129 heifers, 100 bulls, 130 adult cows) were tested. Seropositivity increased with the age of the assessed animals. Independent of the age-group, the overall seroprevalence was lowest in wild boars (6.7%), followed by pigs (23.3%), cattle (45.6%) and sheep (61.6%), respectively. Conventional fattening pigs and free-ranging pigs surprisingly had comparable seroprevalences (14.0% and 13.0%, respectively). Unlike in other European countries, where generally a decrease in the number of seropositive animals had been observed, we found that the prevalence of seropositive animals, when compared with that of 10 years ago, had increased for most species/age groups. Conclusively, the results demonstrated a high seroprevalence of T. gondii in animals slaughtered for meat production and revealed that increasing age of the animals is a more important risk factor than housing conditions in Switzerland.     

Growth performance,dry matter and nitrogen digestibilities,serum profile,and carcass and meat quality of pigs with distinct genotypes

We investigated the effect of distinct genotypes on growth performance, DM and N digestibilities, serum metabolite and hormonal profiles, and carcass and meat quality of pigs. Eight control-line and eight select-line pigs with an equal number of gilts and castrated males per genotype were chosen from the group of pigs subjected to selection for lean growth efficiency. Pigs were housed individually and allowed ad libitum access to common grower, finisher 1, and finisher 2 diets when they reached approximately 20, 50, and 80 kg, respectively, and water throughout the study. Although genotype had no effect on growth performance during the finisher 2 phase and overall, select-line pigs grew faster and more efficiently (P < 0.05) during the grower and finisher 1 phases than did control-line pigs. Dry matter and N digestibilities during the grower phase were lower (P < 0.05) in select-line pigs compared with control-line pigs. Select-line pigs had less ultrasound backfat (P < 0.05) at the end of the grower and finisher 2 phases. Serum urea N (P < 0.05) and leptin concentrations were lower in select-line pigs than in control-line pigs, but the effect of genotype on serum glucose, triglyceride, or insulin concentration was rather inconsistent. Select-line pigs had heavier heart (P < 0.05), liver (P = 0.08), and kidneys (P < 0.01), implying a higher metabolic activity. Less 10th-rib carcass backfat (P < 0.01) and a trend for larger carcass longissimus muscle area (P = 0.10) were reflected in the greater (P < 0.01) rate and efficiency of lean accretion in select-line pigs. Select-line pigs had lower subjective meat color (P < 0.01), marbling (P < 0.05), and firmness (P < 0.01) scores. Final serum leptin concentration was correlated positively with carcass backfat thickness (r = 0.73; P < 0.01) and negatively with overall feed intake (r = -0.77; P < 0.01). These results indicate that pigs with distinct genotypes exhibited differences in the growth rate, metabolite and hormonal profiles, and body composition. Further research is necessary to determine whether pigs with distinct genotypes respond differently to dietary manipulations, which would have an effect on developing optimal feeding strategies for efficient and sustainable pig production.     

Relationship of osteomyelitis and associated soft-tissue lesions with green liver discoloration in tom turkeys

Tom turkey carcasses with partial green discolored livers (n = 191) or normal livers (n = 198) were examined for osteomyelitis and/or associated soft-tissue lesions. Seventy-nine turkeys with green discolored livers had osteomyelitis and/or associated soft-tissue lesions (41.4%), including 53 with just osteomyelitis (27.7%), while 112 (59.6%) had no osteomyelitis and/or soft-tissue lesions. Only five turkeys (2.5%) with normal livers had osteomyelitis. Discolored livers were significantly heavier, but carcasses with discolored livers weighed significantly less than carcasses with normal livers. Bacteria were isolated from 54 of 61 osteomyelitis lesions (88.5%); most frequently staphylococci (50.8%) followed by Escherichia coli (14.8%), Streptococcus sp. (13.1%), and occasional other organisms. Most associated soft-tissue lesions and livers were sterile (74.7%). These finding indicate that although turkey carcasses with green discolored livers are more likely to have osteomyelitis and/or associated soft-tissue lesions than turkey carcasses with normal livers, there is also an approximately equal chance they will not have these lesions.     

Slaughter value, meat quality, creatine kinase activity and cortisol levels in the blood serum of growing-finishing pigs slaughtered immediately after transport and after a rest period

The experimental materials comprised 44 hybrid [female (Polish Large White x Polish Landrace) x male Duroc] growing-finishing pigs. The animals were randomly divided into two groups: 24 pigs were slaughtered immediately after transport and 20 pigs were slaughtered after a 24-hour rest period in the lairage. The meat content of pork carcasses, carcass dressing percentage, the proximate chemical composition, physicochemical and sensory properties of meat and shear force values were determined. Serum creatine kinase activity and cortisol levels were determined in blood samples collected before transport and during carcass bleeding. Pigs slaughtered immediately after transport, compared with those slaughtered after a 24-hour rest period, were characterized by a higher meat content of the carcass and a higher carcass dressing percentage. Pre-slaughter handling had no effect on pork quality. The incidence of normal-quality meat, partially PSE (pale, soft, exudative) meat and PSE meat was similar in both groups. Chemical analysis showed that the content of dry matter, total protein, fat and minerals in meat was comparable in both groups. As regards the functional properties of the pork, samples from the carcasses of pigs that had rested before slaughter had a higher contribution of the red color component. Meat from pigs slaughtered immediately after transport had more desirable sensory properties. Pre-slaughter resting had a significant effect on those analyzed physiological parameters which were found to be good indicators of pre-slaughter stress. Serum creatine kinase activity and cortisol levels were higher in blood samples collected after transport (during carcass bleeding) than in samples collected before transport, pointing to a strong stress response of animals to pre-slaughter treatment. The decrease in serum cortisol levels in blood samples collected during bleeding from the carcasses of pigs slaughtered after a 24-hour rest period, compared with samples collected from animals slaughtered immediately after transport, suggests that rest before slaughter alleviated stress induced by pre-slaughter handling operations.     

肉碱与甜菜碱对育肥猪胴体、肉品质及肝脏营养成分的影响

本试验采用两因素3×3析因设计,研究了日粮中添加3个内碱水平(0、50、100 mg/kg)和3个甜菜碱水平(0、1000、1500 mg/kg)对杜长大三元杂交育肥猪胴体品质、肉品质和肝脏营养成分的影响.选择90头体重约为100kg的杜长大三元杂交肥育猪,按体重相近、性别比例相同原则,随机分为9处理组,每组10头.其中第1组为对照组,喂基础日粮;第2～9组为试验组,喂试验日粮.试验期为30 d.结果表明:肉碱添加水平对育肥猪背膘厚、眼肌面积、大理石纹和肝脏蛋白质含量影响显著(P＜0.05).甜菜碱添加水平对育肥猪背膘厚、肉色评分和肝脏粗脂肪含量影响显著(P＜0.05),并证实了肉碱与甜菜碱时育肥猪的胴体组成、肉质和肝脏营养成分的影响不存在交互效应.     

Total lipid and triacylglycerol contents in the liver of broiler and layer chickens at embryonic stages and hatching

To compare the hepatic function of broiler and layer chickens (Gallus gallus domesticus) at various embryonic stages and hatching, the total lipid and triacylglycerol (TG) content were determined. The chicken embryos accumulated a large amount of lipids in the liver and the total lipid content gradually increased toward hatching, though no significant difference was observed between broilers and layers. The TG contents in the liver increased considerably with developmental stage. At embryonic day 14 the TG content in the liver was similar between broilers and layers; thereafter, it was 1.3 and 2.2 times higher in broilers than in layers at embryonic day 18 and for newly hatched chicks, respectively. Chick embryos accumulate an excessive amount of cholesterol ester in the liver, but cholesterol ester is replaced by TG after hatching. The results of hepatic TG contents in the present study suggest that the development of the hepatic function between broilers and layers may already differ at embryonic stages.     

Leptospira in slaughtered fattening pigs in southern Vietnam: presence of the bacteria in the kidneys and association with morphological findings

One kidney was collected from each of 32 fattening pigs at an abattoir in southern Vietnam in 2001 in order to demonstrate infecting Leptospira serovar and to associate renal macro- and microscopic findings with the presence of renal leptospires. Leptospires were demonstrated in 22 (69%) of the investigated kidneys by immunofluorescence. Multifocal interstitial nephritis (MFIN) and gross renal lesions (white spots) were each demonstrated in 24 (75%) kidneys. Leptospira interrogans serovar bratislava was isolated from one kidney. There was no association between presence of leptospires and MFIN (P=0.19), respectively and white spots (P=0.98), respectively. These data suggest that Leptospira infection is common among fattening pigs in the study area and that these animals may be considered as an occupational human health hazard. It is also suggested that the presence of white spots is an unreliable indicator of the presence of renal leptospires.     

Influence of exogenous application of n-3 fatty acids on meat quality, lipid composition, and oxidative stability in pigs.

The effect of dietary n-3 fatty acids on the fatty acid composition and lipid peroxidation of different tissues in pigs were studied. 20 castrated male pigs were included in this investigation, one half was fed daily a diet containing 1.3 g n-3 fatty acids/kg diet (control) and 10 pigs were fed a diet containing 14 g n-3 fatty acids/kg diet (n-3 diet) at the growing-finishing period. The intake of dietary n-3 fatty acids increased the concentration of these fatty acids in backfat, and the neutral and polar fractions of skeletal muscle and heart homogenates. The polar fraction showed an increased relative concentration of n-3 fatty acids in comparison to control, while the n-6 fatty acid content was reduced. In heart homogenates there was an enlargement of n-3 fatty acids both in polar lipids and in neutral lipids whilst n-6 fatty acids were decreased. Feeding n-3 fatty acid enriched diet had no influence on meat quality parameters drip loss, meat colour or pH value. The lipid peroxidation (measured as malondialdehyde equivalents) was in the order liver > heart > skeletal muscle with higher values in the n-3 group. However, by stimulation of oxidation by Fe2+/ascorbate for 3 hours the order of oxidative products in the n-3 group was muscle > liver > heart, whereas in the control group the order was liver > heart = muscle. Summarized, feeding a highly n-3 fatty acid enriched diet caused an incorporation of these fatty acids and increased the susceptibility to peroxidation in all investigated tissues.     

Infusion of short chain fatty acids in the ileum improves the carcass traits,meat quality and lipid metabolism of growing pigs

Short chain fatty acids (SCFA) are the main products of indigestible carbohydrates undergoing bacterial fermentation in the hindgut, which are related to some physiological functions. This study was designed to investigate the effects of SCFA infusion by ileum on the carcass traits, meat quality and lipid metabolism of growing pigs. In a 28-day study, 24 growing barrows fitted with a T-cannula in distal ileum were divided into 4 treatments: 1) Control, 2) antibiotics (AB), 3) AB + 300 mL of SCFA1 solution (ABS1), 4) AB + 300 mL of SCFA2 solution (ABS2). The concentrations of acetate, propionate and butyrate in SCFA1 solution were respectively 61.84, 18.62 and 12.55 mmol/L, and in SCFA2 were respectively 40.08, 15.41 and 9.78 mmol/L. The results showed that the SCFA infusion increased the average daily feed intake and average daily gain of pigs (P < 0.05). Meanwhile, the SCFA treatments increased longissimus dorsi area (P < 0.05) and carcass weight (P = 0.058), decreased the drip loss of longissimus dorsi (P = 0.059), and reduced serum concentrations of triglyceride, total cholesterol and urea nitrogen (P < 0.05). Besides, the SCFA administration inhibited the mRNA expressions of fatty acid synthase (FAS) and acetyl-CoA carboxylase in longissimus dorsi (P < 0.05), the mRNA expression of FAS in the liver (P < 0.05), and the mRNA expression of hormone-sensitive lipase in abdominal fat (P < 0.05). Short chain fatty acid infusion also enhanced the mRNA expression of carnitine palmitoyltransferase-1α in the liver (P < 0.05), the mRNA expressions of peroxisome proliferator activated receptor gamma and lipoprotein lipase in abdominal fat (P < 0.05), and the mRNA expressions of free fatty acid receptor 2, glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the colon (P < 0.05). These results suggested that SCFA administration in the ileum could improve the carcass traits and meat quality of growing pigs, which was possibly due to the fact that SCFA modulated lipid metabolism.     

高铜对肉鸡肝线粒体膜通透性、脂类代谢及肝和肌肉铜含量的影响

选用1日龄健康AA肉鸡120只随机均分成4组,使用硫酸铜作为铜源,饲喂玉米-豆粕型基础日粮,对照组饲料铜含量为11mg/kg,3个试验高铜组饲料铜含量分别为110,220,330mg/kg,试验至60日龄结束,来探讨高铜日粮对肉鸡肝线粒体膜通透性、脂类代谢及肝和肌肉铜含量的影响。结果显示:(1)随着铜浓度的增加和/或饲养日龄的延长,线粒体膜通透性转换孔(Mitochondrial permeability transition pore,MPTP)逐渐扩大(P0.05);(2)血清总胆固醇(T-Ch)含量110,220mg/kg铜添加组低于对照组(P0.05),330mg/kg铜添加组极显著低于对照组(P0.01),而甘油三酯(TG)的含量在各高铜组均极显著低于对照组(P0.01);(3)与对照组相比,肝脏铜含量110,220mg/kg铜添加组有所增加(P0.05),330mg/kg铜添加组极显著增加(P0.01),肌肉中铜含量在各高铜组均极显著高于对照组(P0.01)。这说明高铜可造成肝线粒体不同程度的肿胀和损伤,改变肉鸡脂类的新陈代谢,明显增加肝和肌肉组织的铜含量。     

不同高精料耐受时间对泌乳期山羊肝脏糖脂代谢的影响

为了研究饲喂高精料日粮对泌乳期山羊肝脏糖脂代谢的影响,试验选用16只健康经产泌乳中期关中奶山羊,随机分为3组,低精料组(LC, n=5)、长期高精料组(HL, n=7)和短期高精料组(HS, n=4)。实验结束后采集血液和肝脏组织。结果显示,与LC组相比,HL和HS组奶山羊血糖和肝糖原水平显著升高(P<0.05),血液中甘油三酯(TG)水平显著降低(P<0.05),胆固醇(Tch)含量没有显著变化(P>0.05);HS组山羊肝脏TG和Tch水平显著增加(P<0.05),HL组无显著变化 (P>0.05)。HL组肝脏中丙酮酸羧化酶(PC)和葡萄糖转运蛋白2(GLUT2)mRNA表达水平显著上调;HS组肝脏PC、固醇调节元件结合蛋白1(SREBP1)、硬脂酰辅酶A去饱和酶(SCD)、二酰基甘油酰基转移酶(DGAT)和3-羟基-3-甲基戊二酰辅酶A还原酶(HMGCR) mRNA表达水平显著升高(P<0.05),SREBP-2有升高的趋势(P=0.76),肉碱棕榈酰转移酶-1(CPT-1)和胆固醇7α-羟化酶(CYP7α1)mRNA表达显著下降(P<0.05);线粒体型磷酸烯醇式丙酮酸羧激酶(PCK2)蛋白表达水平显著升高(P<0.05)。以上结果表明,短期饲喂高精料日粮能增强肝脏糖异生能力,促进肝脏胆固醇和脂肪合成;而长期饲喂高精料日粮能增强肝脏糖异生作用,但对胆固醇和脂肪代谢相关基因的表达没有影响。     

Production of transgenic and non-transgenic clones in miniature pigs by somatic cell nuclear transfer

Miniature pigs have been recognized as valuable experimental animals in various fields such as medical and pharmaceutical research. However, the amount of information on somatic cell cloning in miniature pigs, as well as genetically modified miniature pigs, is much less than that available for common domestic pigs. The objective of the present study was to establish an efficient technique of cloning miniature pigs by somatic cell nuclear transfer. A high pregnancy rate was achieved following transfer of parthenogenetic (3/3) and cloned (5/6) embryos using female miniature pigs in the early pregnancy period as recipients after estrus synchronization with prostaglandin F2 alpha analog and gonadotrophins. The production efficiency of the cloned miniature pigs using male and female fetal fibroblasts as nucleus donors was 0.9% (2/215 and 3/331, respectively). Cloned miniature pigs were also produced efficiently (7.8%, 5/64) by transferring reconstructed embryos into the uteri of common domestic pigs. When donor cells transfected with the green fluorescent protein (GFP) gene were used in nuclear transfer, the production efficiency of the reconstructed embryos and rate of blastocyst development were comparable to those obtained by non-transfected cells. When transfected cell-derived reconstructed embryos were transferred to three common domestic pig recipients, all became pregnant, and a total of ten transgenic cloned miniature pigs were obtained (piglet production efficiency: 2.7%, 10/365). Hence, we were able to establish a practical system for producing cloned and transgenic-cloned miniature pigs with a syngeneic background.     

饲喂高含量花青素-3-糖苷的黑米糠对猪营养物质消化率、血液成分、生长性能和肉质的影响

两个试验用来评定饲喂富含花青素-3-糖苷（C3G）的黑米糠对猪营养物质消化率、血液成分、生长性能和肉质的影响。试验1,15头猪随机分为5个组,每组3个重复．做营养消化率和血液成分的试验。各试验组间血清中总胆固醇,甘油三酸酯．高密度脂蛋白胆固醇含量基本无显著性差异。但是．试验结束时．C3G组总胆固醇的量有降低趋势．与饲喂褐色米糠组相比．C3G组总胆固醇的量显著降低（P〈0．03）。在日粮中提高黑米糠含量．血清中胆固醇含量会降低。各试验组中．谷草转氨酶（GOT）和谷丙转氨酶（GPT）含量无显著差异,CRB-4组GOT含量最低。试验2,16头肥育猪（平均体重89．96±0．35kg）随机分为4组．检测饲喂高C3G黑米糠对猪生长性能和肉质的影响。各组的平均日增重、平均日采食量、饲料转化率差异不显著,C3G组平均日增重有所降低。采食量无变化．饲料转化率低于对照组。各组间体重、胴体重、屠宰率、背膘厚、肉质等级无显著差异。但是,与对照组相比,C3G组的背膘厚有降低的趋势。总之。各组间营养物质消化率、血液成分、生长性能和肉质差异不显著,但是,高C3G黑米糠可能有降低血清中总胆固醇的作用．这可能与高C3G黑米糠中高含量的抗氧化物质的影响有关。     

Establishment of serological herd profiles for zoonoses and production diseases in pigs by “meat juice multi-serology”

The most important pork-borne zoonotic diseases in humans such as Salmonelloses and Yersinioses cause only latent infections in pigs. Thus, the infection of pigs does not result in apparent or palpable alterations in the pig carcasses. This is the major reason, why the traditional meat inspection with adspection, palpation and incision is not able to control the food safety risks of today. The objective of this paper is to evaluate a set of serological tests, which provides a classification of pig herds into “zoonoses risk categories” as demanded by EU law and into “herd health risk categories” by using meat juice as diagnostic specimen for ELISA tests. Serological data that were obtained by testing meat juice samples from various pig herds were analyzed as proof of the “meat juice multi-serology” concept. For that, at least 60 meat juice samples from 49 pig herds each were taken between September 2010 and March 2011 and tested for antibodies against zoonotic pathogens (Salmonella spp., Trichinella spp., Yersinia enterocolitica and Toxoplasma gondii) and against pathogens causing production diseases (Mycoplasma hyopneumoniae, influenza A virus subtype H1N1, influenza A virus subtype H3N2 and PRRSV). Apparent and true animal prevalence, herd prevalence values and intra-herd seroprevalence values as well as the predictive values for the herd and the animal prevalence values were calculated for each pathogen and each of the 49 randomly selected herds. The herd seroprevalence values (one seropositive sample per herd determined a “positive herd”) for Y. enterocolitica, Salmonella spp., T. gondii, M. hyopneumoniae and PRRSV were higher than 80%, respectively, for the influenza A viruses between 60% and 14% and for Trichinella spp. 0%. Although all herds were located in the same area in the Northwest of Germany within a radius of 250 km, the intra-herd seroprevalence values for all tested pathogens, except for Trichinella spp., varied remarkably from herd to herd. In the case of Y. enterocolitica and T. gondii the intra-herd seroprevalence values varied even from zero to 100%. This shows that a serological risk categorization of pig herds regarding zoonoses and production diseases is meaningful if used for risk-based decisions in the framework of the new meat inspection concept and as part of the herd health management system. Thus, the development of a cost-efficient, time- and labour-saving test system for simultaneously detecting various antibodies should be the next step for an extensive implementation of the meat juice multi-serology concept.     

Immunohistochemical distribution of antigens in liver of infected and immunized pigs with Ascaris suum

In the present work, we carry out an immunopathological study of the swine ascariosis, under different conditions (control, infection and immunization). Twenty-one Iberian pigs were used and divided in seven groups. Groups 1 and 2 were the uninfected and challenged controls, respectively. Groups 3 and 4 were weakly infected with increasing doses of Ascaris suum eggs and treated with pyrantel (Group 4). Groups 5-7 were immunized with 14, 42 and 97 kDa proteins from the parasite, respectively. Groups 2-7 were challenged with 10,000 infective eggs 7 days before the sacrifice. The focal parasitic granulomata with eosinophils and lymphocytes were the main histopathological lesions in the liver of reinfected pigs, while more marked cellular infiltrate and abundant connective tissue were seen in the livers of immunized animals. There were important deposits of antigens in the livers of immunized and infected pigs. Antigens were mainly located in the connective tissue, with positive staining detection of the somatic larvae antigen, the body wall from the adult worms and the 14-, 42- and 97-kDa proteins. However, cholangiols, biliary ducts and macrophages presented an immunohistochemical positive stain against excretory-secretory and somatic antigens from the larvae and the body fluid antigen from the adult parasite. The detection of A. suum antigens in the liver of infected pigs improves the diagnosis of swine ascariosis. It may be possible to apply these procedures for diagnosis of human ascariosis in liver biopsies since A. suum from swine have been previously used as a substitute for the study of the human parasite Ascaris lumbricoides.     

微粒蒙脱石对猪组织铅水平、红细胞生成和肝脏ALA-D酶活性及铅诱导的脂质过氧化的影响

选60头体质量约33kg的“杜长大”杂交猪，随机分成2组，每组3个重复，一组饲以基础日粮＋10mg/kg铅＋0.5％微粒蒙脱石，另一组饲以基础日粮＋10mg／kg铅作为对照。研究结果表明：添加微粒蒙脱石组与对照组相比，明显降低了猪全血、脑、肝、肾、骨和毛等组织中铅含量：通过血细胞计数、血红素和血球容积测定表明，添加微粒蒙脱石组的红细胞生成显著增高，且肝脏中ALA—D酶活性显著提高。铅对肝脏的损伤作用明显。表现为丙二醛（MDA）含量显著升高（17．08％），过氧化氢酶（CAT）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GPx）含量分别降低85．73％、52．17％、47．56％，而在日粮中添加微粒蒙脱石可以显著改善铅诱导的上述损伤。结果提示，微粒蒙脱石对铅中毒有潜在的治疗作用。