Escherichia coli challenge and one type of smectite alter intestinal barrier of pigs

An experiment was conducted to determine how an E. coil challenge and dietary clays affect the intestinal barrier of pigs. Two groups of 32 pigs （initial BW： 6.9 ± 1.0 kg） were distributed in a 2 x 4 factorial arrangement of a randomized complete block design （2 challenge treatments： sham or E. coil, and 4 dietary treatments： control, 0.3% smectite A, 0.3% smectite B and 0.3% zeolite）, with 8 replicates total. Diarrhea score, growth performance, goblet cell size and number, bacterial translocation from intestinal lumen to lymph nodes, intestinal morphology, and relative amounts of sulfo and sialo mucins were measured. The E. coli challenge reduced performance, increased goblet cell size and number in the ileum, increased bacterial translocation from the intestinal lumen to the lymph nodes, and increased ileal crypt depth. One of the clays （smectite A） tended to increase goblet cell size in ileum, which may indicate enhanced protection. In conclusion, E. coli infection degrades intestinal barrier integrity but smectite A may enhance it.     

Spike glycoprotein cleavage recognition site analysis of infectious bronchitis virus.

The spike glycoprotein of infectious bronchitis virus (IBV), a coronavirus, is translated as a precursor protein (So), then cleaved into two subunits (S1 and S2) by host cell serine proteases. In this study, we compared the cleavage recognition site of 55 IBV isolates to determine if the cleavage recognition site sequence, which consists of five basic amino acid residues, correlates with host cell range, serotype, geographic origin, and pathogenicity as it does in orthomyxoviruses and paramyxoviruses. The most common cleavage recognition site observed (33 of 55 viruses) was Arg-Arg-Ser-Arg-Arg, representing at least 11 different serotypes. Thus, cleavage recognition site does not appear to correlate with serotype. We also determined that cleavage recognition site sequence does not correlate with pathogenicity because attenuated and pathogenic isolates (different passages of the same virus) contain identical cleavage recognition site sequences. In addition, nephropathogenic strains had the same cleavage recognition site sequence as many nonnephropathogenic isolates. Cleavage recognition site sequence does correlate with viruses in different geographic regions, which may be an important characteristic to examine in epidemiologic studies. An IBV monoclonal antibody neutralization-resistant mutant (NR 18) had an unusual substitution of Ile for Arg at the fourth position, giving the sequence Arg-Arg-Ser-Ile-Arg, which likely prevents cleavage and, thus, destroys the conformationally dependent monoclonal antibody binding epitope. Six residues on the amino-terminal side of the cleavage recognition site are conserved in 31% of the isolates and consist of only one or two basic amino acids. Thus, the number of basic residues around the cleavage recognition site does not appear to correlate with increased cleavability, host cell range, and increased virulence as it does with envelope glycoproteins in orthomyxoviruses and paramyxoviruses.     

Therapeutic effect of hyaluronic acid on experimental osteoarthrosis of ovine temporomandibular joint.

A symptomatic relief by hyaluronic acid (HA, MW: 3.5 x 10(6)), which is synthesized by Streptococcus spp, was investigated in experimental ovine osteoarthrosis. Bilateral osteoarthrosis (OA) of the temporo-mandibular joints (TMJs) was induced by perforating discs and by scrapping subchondral condylar surface. HA was intra-articularly injected into the left joints of 6 sheep on 7, 10, 14, 17 and 21 days after the operation and physiological saline as the control was injected into the contralateral (right) joints on the same day. Three sheep were killed at I month post-operation (MPO) and the remaining three sheep were killed at 3 MPO. Various responses such as proliferation of fibrous tissue, denudation, erosion, osteophyte formation, subcortical cyst formation and ankylosis were observed radiographically and histopathologically. The treatment of HA ameliorated the degenerative changes and lowered the osteoarthrotic score in the left joints at I MPO (9.96 vs 5.81) and 3 MPO (10.86 vs 5.29) compared to the right joints. These results indicate that a repeated intra-articular injection of HA inhibits the progression of OA in ovine TMJs by inducing the development of articular cartilage and by reducing the proliferation of fibrotic tissue.     

Immune responses of orange-spotted grouper,Epinephelus coioides,against virus-like particles of betanodavirus produced in Escherichia coli

Betanodaviruses are the causative agents of viral nervous necrosis (VNN), a serious disease of cultured marine fish worldwide. Virus-like particles (VLPs) are one of the good novel vaccine candidates to control this disease. Until now, betanodavirus vaccine studies mainly focused on the humoral immune response and mortality after virus challenge. However, little is known about the activation of genes responsible for cellular and innate immunity by vaccines. In the present study, VLPs of orange-spotted grouper nervous necrosis virus (OGNNV) were produced in prokaryotes and their ability to enter Asian sea bass cells was the same as native virus, suggesting that they possess a similar structure to OGNNV. VLPs immunogenicity was then determined by intramuscularly vaccinating Epinephelus coioides at different concentrations (1.5 or 15 μg g^?1 fish body weight, FBW) and immunizing frequencies (administration once, twice and thrice). A single vaccination with the dosage of 1.5 μg g^?1 FBW is enough to provoke high titer antibodies (average 3 fold higher than that of negative control) with strong neutralizing antibody titer as early as 1 week post immunization. Furthermore, quantitative PCR analysis revealed that eleven genes associated with humoral, cellular and innate immunities were up-regulated in the liver, spleen and head kidney at 12 h post immunization, correlating with the early antibody response. In conclusion, we demonstrated that VLP vaccination induced humoral immune responses and activated genes associated with cellular and innate immunity against betanodavirus infection in orange-spotted grouper.     

湖南省某生猪批发市场疫病传播风险评估

为评估湖南省某生猪批发市场猪群疫病的发生风险,找出可能的风险因素,便于提出针对性预防措施,采用自行设计的调查问卷,结合访谈和现场调查,对27户经营户进行了调查,并将调查结果和调运数据相结合进行了疫病传播风险定性评估。结果显示:该市场疫病传入的可能性"高",内部传播的可能性"中等",疫病传出的可能性"高"。生猪调运频次多、数量大,经纪人行为复杂,运输车辆清洗消毒不彻底是可能的风险因素。评估结果提示,应尽量减少经纪人行为影响,重点加强对运输车辆的清洗消毒。     

蛋白质营养水平对工蜂初生重和咽下腺发育的影响

利用不同配比的茶花粉和黄豆粉饲料饲喂蜂群,测定后代工蜂的初生重和咽下腺宽度。结果发现,饲喂100％茶花粉与饲喂“75％茶花粉＋25％黄豆粉”的蜂群,所育工蜂的初生重差异不显著,与饲喂100％黄豆粉的蜂群相比,差异极显著;饲喂100％茶花粉与饲喂“75％茶花粉＋25％黄豆粉”的蜂群相比,6日龄、9日龄、12日龄工蜂咽下腺宽度差异均不显著,与饲喂100％黄豆粉的蜂群相比,6日龄、9日龄差异不显著,而12日龄差异显著。本试验结果表明,蛋白质营养水平对工蜂初生重和咽下腺发育均具有显著的影响。     

Ultrasonographic evaluation of renal dimension and resistive index in clinically healthy Korean domestic short-hair cats

Renal length, height, width, resistive index (RI), size of cortex, and medulla were determined by renal ultrasonography in 50 healthy Korean domestic short-hair cats. In the sagittal plane, the renal length was 3.83 ± 0.51 cm (mean ± SD) in the left kidney and 3.96 ± 0.48 cm in the right kidney, whereas the renal height was 2.42 ± 0.27 cm in the left kidney and 2.36 ± 0.28 cm in the right kidney. In the transverse plane, the renal height was 2.42 ± 0.28 cm in the left kidney and 2.38 ± 0.27 cm in the right kidney, whereas the renal width was: 2.65 ± 0.35 cm in the left kidney and 2.63 ± 0.31 cm in the right kidney. In the dorsal plane, the renal length was 3.84 ± 0.53 cm in the left kidney and 3.97 ± 0.54 cm in the right kidney, whereas the renal width was 2.65 ± 0.34 cm in the left kidney and 2.66 ± 0.33 cm in the right kidney. There were no significant differences (p > 0.05) among the same structure sizes measured in different planes. In the sagittal plane, the size of the renal cortex was 0.47 ± 0.08 cm in the left kidney and 0.47 ± 0.08 cm in the right kidney, whereas of the size of the renal medulla was 0.55 ± 0.30 cm in the left kidney and 0.50 ± 0.07 cm in the right kidney. RI evaluated by pulsed wave Doppler sonography was 0.52 ± 0.05 in the left kidney and 0.55 ± 0.05 in the right kidney. The actual renal dimensions determined by gross examination were not statistically different from those determined by ultrasonography. Furthermore the renal dimensions and RI were statistically correlated to the body weight of cats.     

Reproduction of postweaning multisystemic wasting syndrome in pigs by prenatal porcine circovirus 2 infection and postnatal porcine parvovirus infection or immunostimulation

Postweaning multisystemic wasting syndrome (PMWS) was reproduced in prenatally porcine circovirus 2 (PCV2)-infected pigs by either postnatal infection with porcine parvovirus (PPV) or by immunostimulation. Twenty-four randomly selected piglets from 3 sows, which had been experimentally infected during gestation with PCV2, were randomly divided into 3 groups; group 1 (prenatal PCV2 infection, with postnatal PPV infection), group 2 (prenatal PCV2 infection, with postnatal keyhole limpet hemocyanin, emulsified in incomplete Freund's adjuvant [KLH/ICFA] injection), and group 3 (prenatal PCV2 infection only). Twenty-four randomly selected piglets from 3 uninfected sows were randomly divided into 3 groups; group 4 (no prenatal infection, with postnatal PCV2 and PPV infection), group 5 (no prenatal infection, with postnatal PCV2 infection), and group 6 (negative control pigs). Body weight in negative control pigs (group 6) was increased significantly compared with pigs in groups 1, 2, and 4 at 49, 52, 56, 59, and 63 days of age. The granulomatous inflammatory reaction and lymphoid depletion that are typical lesions in pigs with PMWS were observed in the lymph node of piglets in groups 1, 2, and 4 at 63 days of age. Pigs in group 3 had significantly fewer PCV2-positive cells than those from groups 1, 2, 4, or 5. When the prenatally PCV2-infected pigs were infected with PPV or injected with immunostimulant in the postnatal period, they developed PMWS. Thus, factors that potentiate the progression of prenatal PCV2 infection to PMWS are postnatal infection with PPV or immune stimulation.     

人工践踏对无土草坪基质的影响

本试验采用人工践踏的方式,研究了不同组合配比的基质对无土草坪耐践踏性的影响。结果表明,良好的无土草坪基质配比及适合的厚度是保证无土草坪优良的耐践踏性及观赏性的关键。本试验中,草坪草生长基质层和弹性材料层均为25 mm,结构合理、厚度适中,克服了现有草坪基质薄、持水力差的缺点。在相同践踏强度下,能维持较高水平的草层高度、草坪盖度和草坪草分蘖数,分别达到了5.14 cm、97.60%和123.97 个·dm-2,且停止践踏后草坪质量能快速恢复。均匀混合的草坪草生长基质层和弹性材料层,在厚度一致的前提下并不耐践踏,实际效果不好。土壤坪床的处理效果最差。因此,具有独立的草坪草生长基质层和弹性材料层且厚度适中的基质,适用于生产耐践踏性好的无土草坪。