限饲模式下宁乡花猪商品猪的生长肥育性能分析

为探索限饲模式下宁乡花猪商品猪生长肥育性能以适应品牌猪肉具备风味性、安全性需要,在初生重(0.98±0.02)kg饲养(99.69±2.48)d的基础上,相应于25~35 kg、35~60 kg、60~75 kg等3个体重阶段,采用精料重分别占90%、80%、70%,青料重分别占10%、20%、30%配制饲粮,并按8.5成饱模式饲喂。结果表明:1)试猪由体重(24.79±0.64)kg饲养至出栏日龄(243.77±2.67)d、出栏体重(78.22±1.76)kg,该生长肥育全程(144.03±0.23)d、日增重(370.50±9.50)g、料重比(3.51±0.03),充分体现出限饲模式可行性;2)在≤240 d、240~260 d、>260 d的日龄梯级下分别以初生重(1.02±0.02)kg、(0.94±0.04)kg、(0.99±0.08)kg所求取的日增体重百分率曲线与日龄梯级呈负相关态势,显现日龄低梯级明显优于高梯级,反映出生长强度与日龄负相关的必然性;3)自起运至屠宰分别间隔5 h、29 h的胴体率、白条率的相差值达5.04和5.05个百分点,屠宰间隔直接造成胴体损失。     

Distribution,quantitative load and characterization of Salmonella associated with swine farms in upper-northern Thailand

This study was conducted to analyze the prevalence and quantitative loads of Salmonella spp. on pig farms in Chiang Mai, Lamphun, Thailand to assess loading levels before slaughtering. The serotype diversity, antimicrobial-resistance pattern and pulse-field type of Salmonella spp. were also characterized to assess the dynamic propagation of the pathogen. The Salmonella-positive prevalence was 246/805 (30.56%), and the quantitative loads varied from 1.48~4.04 Log₁₀MPN/g, with a mean ± standard deviation of 2.11 ± 0.57. AMP/S/TE (ampicillin/streptomycin/tetracycline) was the highest frequency antimicrobial resistance pattern found in this study. In addition, Salmonella Rissen was the primary serotype in this region. PFGE results indicated the occurrence of infection by cross contamination among pig farms. Our study showed that pork is easily contaminated with this pathogen. Farm control programs must be based on strict biosecurity and hygienic measures, which could further reduce the contamination pressure at slaughterhouses or retail shops.     

Serum thyroxine concentrations in clinically healthy pet guinea pigs (Cavia porcellus)

Background: Guinea pigs (Cavia porcellus) are often presented as patients in veterinary practice. Nevertheless, only limited information is available about endocrine diseases or thyroxine reference values for the species. Objective: The aim of this study was to determine serum thyroxine concentrations in a well‐defined population of clinically healthy pet guinea pigs. Methods: Between October 2007 and July 2008, serum samples were collected from 40 clinically healthy guinea pigs of different sexes, ages, and breeds that were presented to our clinic for a general health check or for castration. Pregnant females were excluded from the study. Thyroxine concentration was measured using a chemiluminescence test (Immulite 2000 Canine Total T4). Results: Thyroxine concentrations ranged from 14.2 to 66.9 nmol/L (1.1–5.2 μg/dL) with a median value of 27.0 nmol/L (2.1 μg/dL). Females (n=16) had significantly (P=.039; Mann–Whitney U‐test) lower thyroxine values than castrated males (n=8), whereas no differences were found between females and intact males (n=16) or between intact and castrated males. No significant correlation was found between thyroxine concentration and age. Conclusion: This is the first report of serum thyroxine reference values for a well‐defined population of healthy pet guinea pigs as measured by a chemiluminescence assay. The results were higher than those previously reported for this species and emphasize the importance of using appropriate reference intervals for the diagnosis of hyperthyroidism.     

Effects of dietary additives (potassium diformate/organic acids) as well as influences of grinding intensity (coarse/fine) of diets for weaned piglets experimentally infected with Salmonella Derby or Escherichia coli

The aim of this study was to examine whether and to what extent the addition of potassium diformate (pdf) or free organic acids (fpa) to the diet and the grinding intensity might affect the course of infection and the passage of orally applied Salmonella and Escherichia coli in pigs. Experiments were carried out using 80 reared piglets allotted to four groups. Pigs were fed pelleted diets ad libitum (except during a 15 h feed‐withholding‐period before infection). The control diet contained finely ground cereals (2 mm screen). To two test diets (also finely ground) 1.2% pdf, 0.9% organic acids (75% formic and 25% propionic acid, fpa) respectively were added. The fourth diet (without acids) was based on coarsely ground cereals (6‐mm screen). After experimental infection alternately with S. Derby or E. coli, the course of infection was examined (rectal swab technique). Pigs were sacrificed 4–5 h after a further oral application of ～10⁹–10¹⁰ CFU S. Derby or E. coli to determine the counts of Salmonella or E. coli in chyme (classical culture methods). Adding pdf or fpa to the diet led to reduced Salmonella shedding and resulted in significantly lower counts of Salmonella and E. coli in the stomach content indicating an improved efficacy of the stomach barrier. In the distal parts of the digestive tract, the effect was less obvious concerning counts of E. coli, whereas counts of Salmonella were reduced markedly as well. The diet based on coarsely ground cereals failed to demonstrate positive effects concerning infection and passage of orally applied bacteria as well, but this diet was also pelleted and showed unintentionally, comparable amounts of fine particles. Results obtained in this study allow the recommendation of using pdf or organic acids as additives when dietary measures against Salmonella or E. coli in pigs are required.     

Spatiotemporal heterogeneity of PPARγ expression in porcine uteroplacenta for regulating of placental angiogenesis through VEGF-mediated signalling

Non-infectious prenatal mortality severely affects the porcine industry, with pathological placentation as a likely key reason. Previous studies have demonstrated that peroxisome proliferator-activated receptor gamma (PPARγ) deficiency causes defects in the uteroplacental vasculature and induces embryonic losses in mice. However, its role in porcine placental angiogenesis remains unclear. In the present study, PPARγ expression was investigated in porcine uteroplacental tissues at gestational day (GD) 25, GD40 and GD70 via quantitative polymerase chain reaction (qPCR), Western blot and immunohistochemistry (IHC). Moreover, the roles of PPARγ in porcine placental angiogenesis were investigated using a cell model of porcine umbilical vein endothelial cells (PUVECs) to conduct proliferation, migration and tube formation assays in vitro and a mouse xenograft model to assess capillary formation in vivo. The results showed that PPARγ was mainly located in the glandular epithelium, trophoblast, amniotic chorion epithelium and vascular endothelium, as indicated by the higher expression levels at GD25 and GD40 than at GD70 in endometrium and by higher expression levels at GD40 and GD70 than at GD25 in placenta. Moreover, PPARγ expression was significantly downregulated in placenta with dead foetus. In PUVECs, knocking out PPARγ significantly inhibited proliferation, migration and tube formation in vitro and inhibited capillary formation in mouse xenografts in vivo by blocking S-phase, promoting apoptosis and downregulating the angiogenic factors of VEGF and its receptors. Overall, the spatiotemporal heterogeneity of PPARγ expression in porcine uteroplacental tissue suggests its vital role in endometrial remodelling and placental angiogenesis, and PPARγ regulates placental angiogenesis through VEGF-mediated signalling.     

单宁酸对生长猪胃-小肠仿生消化中消化酶活性及饲粮粗蛋白消化率的影响

本试验旨在探讨单宁酸对生长猪胃、小肠仿生消化中消化酶活性及玉米-豆粕型饲粮干物质和粗蛋白消化率的影响，为评价单宁酸的生物学效应提供参考。试验一采用单因素完全随机设计，考察在无饲粮下2种单宁酸对猪模拟胃液、模拟小肠液消化酶活性的影响。设5个处理，单宁酸添加量分别为0 mg （胃液体积为20 mL，小肠液体积为22 mL）；单宁酸1，10 mg；单宁酸1，20 mg；单宁酸2，10 mg；单宁酸2，20 mg。测定各处理的胃蛋白酶、淀粉酶、胰蛋白酶和糜蛋白酶的活性。试验二考察玉米-豆粕型饲粮添加单宁酸对猪仿生消化中胃、小肠阶段消化酶活性及养分消化率的影响。采用单因素完全随机设计，设5个处理，单宁酸在饲粮中的含量分别为0 mg·（2 g）^-1；单宁酸1，10 mg·（2 g）^-1；单宁酸1，20 mg·（2 g）^-1；单宁酸2，10 mg·（2 g）^-1；单宁酸2，20 mg·（2 g）^-1。测定仿生消化中胃阶段0.5和4 h时胃蛋白酶活性，小肠阶段0.5、4和8 h时淀粉酶、胰蛋白酶和糜蛋白酶活性及生长猪胃-小肠仿生消化测定饲粮的干物质和粗蛋白消化率。结果表明：1）无饲粮的情况下，和空白对照组相比，2种单宁酸对模拟胃液中胃蛋白酶活性无显著影响（P>0.05），单宁酸1比单宁酸2更高地降低了模拟小肠液中淀粉酶、胰蛋白酶和糜蛋白酶的活性（P<0.05）。2）在饲粮进行仿生消化的胃消化0.5～4 h内，除4 h时10 mg·（2 g）^-1添加量外，添加单宁酸1时胃蛋白酶的活性均显著高于添加单宁酸2时的相应值（P<0.05），除单宁酸2在消化0.5 h外，2种单宁酸在添加10 mg·（2 g）^-1时胃蛋白酶活性均显著高于20 mg·（2 g）^-1添加量的相应值（P<0.05）。在小肠仿生消化0.5 h时，饲粮中添加单宁酸1、2的2个水平对消化液中淀粉酶活性无显著影响（P>0.05），但均显著降低了糜蛋白酶的活性（P<0.05）；单宁酸1的消化液中胰蛋白酶活性高于单宁酸2的相应值（P<0.05）。在小肠仿生消化4 h时，除添加水平为20 mg·（2 g）^-1时的糜蛋白酶活性外，饲粮中添加单宁酸1消化液中淀粉酶、糜蛋白酶活性高于添加单宁酸2的相应值，而胰蛋白酶活性低于添加单宁酸2的相应值（P<0.05）。单宁酸1、2的两个添加量均降低了胰蛋白酶和糜蛋白酶的活性（P<0.05）。在小肠仿生消化8 h时，饲粮中单宁酸的添加量影响了淀粉酶的活性，但单宁酸1和单宁酸2各两个添加量在淀粉酶的平均活性上无显著差异（P>0.05）。单宁酸1、2的两个添加量均降低了胰蛋白酶、糜蛋白酶的活性（P<0.05）。3）与对照组相比，两种单宁酸在两种添加水平下均显著降低了饲料粗蛋白消化率（P<0.05），且单宁酸2比单宁酸1更多地降低了饲粮粗蛋白的消化率（P<0.05）。综上所述，在有、无饲粮条件下，单宁酸对消化酶活性呈现不一致影响。单宁酸影响饲粮粗蛋白的消化率可能主要与消化液中糜蛋白酶活性降低以及单宁酸与饲粮中的化学成分形成螯合物降低了小肠消化酶的水解效率有关。     

猪臭鼻克雷伯氏菌的分离与鉴定

从呼吸系统症状明显、高热、耳朵等薄皮处发绀的病猪血与病死猪的心血、肝、脾中分离到1株细菌，经形态学观察、生化试验鉴定为臭鼻克雷伯氏菌；经人工感染小白鼠试验，表明具有较强的毒性。选用药敏试验筛选的敏感药物——头孢曲松钠治愈了病猪，控制了疫情。     

A design for studies on cognitive bias in the domestic pig

Studies on consequences of affect on cognitive processing (cognitive bias) seem to provide proxy measures of the valence (positive/negative) of affective states. This article presents a pilot study testing a design for studies of judgment bias we adapted to the specific needs and abilities of domestic pigs. We used a spatial judgment paradigm, in which subjects learned to discriminate a food rewarded from an unrewarded position of a goal box during a training period, and then were tested for their responses to 3 equidistant intermediate probe positions during a testing period. After the training period, half of the subjects were repeatedly isolated from their social group to manipulate their affective state. Subjects learned the required discrimination task (positive vs. negative stimulus) and showed consistent differences in approach latencies toward and exploration of stimuli of different valence. Hence, the subjects' expectations could be inferred from their behavior. However, repeated social isolation had no effect on judgment of ambiguous stimuli and on both basal and test-related cortisol levels. In conclusion, the spatial judgment approach seems to provide a useful tool to detect and discriminate diverse affective states in domestic pigs based on their responses to graded ambiguous stimuli.     

沙拉沙星对实验性感染猪链球菌病及大肠杆菌病的药效学

为兽医临床合理应用沙拉星（Ｓarafloxacin）提供理论依据,就其对实验性感染猪链球菌 病及大肠杆菌病的药效学进行了研究。以试管２倍稀释法测得沙拉沙星对兰氏Ｃ群类马链球菌（Ｃ５５１２０）和猪大肠杆菌（Ｏ５５）的最小抑菌浓度（ＭＩＣ）分别是０．８mg/Ｌ及０．０５mg/Ｌ。肌注给药对猪链球菌病和大肠杆菌病的试验性治疗结果不明,低、中 高剂量沙拉沙星组２．５、５、１０mg/kg）及环丙沙星组（５mg/kg）用药５d（每隔１２     

不同生长期金荞麦营养成分含量及消化率测定研究

为系统地测定分析不同生长期金荞麦的常规营养成分、氨基酸、微量元素含量及其回肠末端消化率, 本研究用3头安装“T”型瘘管, 并做回-直肠吻合切除盲肠的巴克夏-驯养野猪-高坡黑猪(巴-野-高)三元杂交生长猪作为试验动物, 采用3×3拉丁方试验设计开展消化试验。结果表明, 分枝期、孕蕾期和初花期金荞麦OM、CP、EE、Ca、P、CF含量分别为88.59%、22.72%、2.34%、1.05%、0.39%、13.51%, 89.10%、20.57%、1.69%、1.25%、0.42%、15.50%和89.63%、17.54%、1.37%、1.29%、0.46%、19.75%;EAA、NEAA和TAA含量分别为9285、7982、6244 mg/100 g, 14334、10810、9320 mg/100 g和23619、18792、15564 mg/100 g。随着生长期的后延, 营养成分含量显著降低, 在体和离体消化率也随着生长期的后延而显著降低。分枝期与孕蕾期间营养成分含量差异显著(P<0.05), 分枝期与初花期间营养成分含量差异极显著(P<0.01), 孕蕾期与初花期间营养成分含量差异显著(P<0.05)。从分枝期到孕蕾期, 金荞麦CP、EE、EAA及TAA下降较慢, CF含量升高较慢, 营养成分消化率下降也较慢;从孕蕾期到初花期, 金荞麦CP、EE、EAA及TAA下降较快, CF含量升高也较快, 营养成分消化率下降也较快。以分枝期、孕蕾期和初花期体外法测定常规营养成分及微量元素消化率值为自变量, 以对应的动物饲养试验回肠末端表观消化率值为因变量建立的回归方程拟合度好,可用于推算对应的回肠末端表观消化率。本实验证明, 金荞麦营养丰富、消化率高, 必需氨基酸比例高、适合动物消化吸收。孕蕾期为金荞麦适宜收割期, 在适宜收割期内, 收割时间点应选择孕蕾后期。