新生仔猪赖氨酸的需要量研究

本试验旨在研究不同日粮赖氨酸水平对新生仔猪生长性能、氮利用及体沉积的影响,探讨新生仔猪赖氨酸的需要量.选取4日龄、平均体重为(1-90±0.05)kg的杜×长×大三元杂新生仔猪46头,其中40头按窝别和体重分成5组,每组4个重复,每个重复2头猪,另外6头在试验开始时屠宰,测定体成分;各组日粮赖氨酸水平分别为1.27%(对照组)、1.37%、1.47%、1.57%及1.67%,饲养至21日龄.结果表明:1)1.47%～1.67%组仔猪21日龄体重、15～21日龄及4～21日龄平均日增重显著高于对照组(P<0.05),以1.57%组平均日增重最大.1.57%组和1.67%组在15～21日龄及4～21日龄的平均日采食量显著高于对照组(P<0.05).1.37%～1.67%组的仔猪料重比均显著低于对照组(P<0.05).2)1.47%～1.67%组仔猪氮的生物学价值显著高于1.27%～1.37%组(P<0.05).3)日粮赖氨酸水平未显著影响能量和脂肪沉积(P>0.05);随日粮赖氨酸水平的提高,蛋白质的每日沉积量增加,147%~1.67%组显著高于1.27%～1.37%组(P<0.05),以1.67%组最大.综合各项测定指标得出,4～21日龄仔猪日粮赖氨酸适宜水平为1.57%,即赖氨酸含量为73.1 g/kg CP或0.85 g/MJ DE;仔猪每日赖氨酸需要量为2.43 g/d.     

日粮中添加血浆蛋白粉对仔猪生长性能的影响

血浆蛋白粉是一种稳定、高效、安全的动物蛋白原料。通过在仔猪日粮中添加血浆蛋白粉探究血浆蛋白粉对仔猪生产性能的影响,结果发现试验组仔猪的生产性能优于对照组,说明日粮中添加血浆蛋白粉对仔猪的生产性能有改善作用。     

Disodium-fosfomycin pharmacokinetics and bioavailability in post weaning piglets

Disodium-fosfomycin pharmacokinetics has been studied in different species after oral, intravenous, intramuscular and subcutaneous administration. At present there are neither documented clinical experiences of the use of fosfomycin in pigs nor any published studies in weaning piglets, although it is a period of high incidence of infectious diseases. The pharmacokinetics and the bioavailability of sodium fosfomycin were studied in post weaning piglets after intravenous and intramuscular administration of 15 mg/kg of body weight. Plasma concentrations were measured by a high-performance liquid ms/ms. After IV administration the area under the fosfomycin concentration:time curve in plasma was AUC_(0–12) of 120.00 ± 23.12 μg h/ml and the volume of distribution (Vd) of 273.00 ± 40.70 ml/kg. The elimination was rapid with a plasma clearance of 131.50 ± 30.07 ml/kg/h and a T_1/2 of 1.54 ± 0.40 h. Peak serum concentration (C_max), T_max, AUC_(0–12) and bioavailability for the IM administration were 43.00 ± 4.10 μg/ml, 0.75 ± 0.00 h, 99.00 ± 0.70 μg h/ml and 85.5 ± 9.90% respectively. Different authors have determined a minimum inhibitory concentration (MIC₉₀) ranging from 0.25 μg/ml for Streptococcus sp. and 0.5 μg/ml for Escherichia coli. Considering the above, and according to the values of plasma concentration vs time profiles observed in this study, effective plasma concentrations of fosfomycin for sensitive bacteria can be obtained following IV and IM administration of 15 mg/kg in piglets.     

Recombinant pseudorabies virus expressing P12A and 3C of FMDV can partially protect piglets against FMDV challenge

One of the crucial factors for evaluation of an effective genetically engineered vaccine is whether susceptible animals are protected from virus challenge after vaccination. In this study, a recombinant pseudorabies virus (PRV-P12A3C) that expressed capsid precursor polypeptide P12A and nonstructural protein 3C of foot-and-mouth disease virus (FMDV) was used as a vaccine. The expression of P12A3C and its immunogenicity and protective efficacy against FMDV challenge were measured. Humoral and cellular immune responses were evaluated after each immunization. Subsequently, each piglet was challenged with 1000 ID₅₀ (50% infection dose) FMDV serotype O, named OR/80, which is used to produce vaccine in China. PRV-P12A3C induced a high level of neutralizing antibody and FMDV-specific lymphocytes. Inactivated vaccine provided 100% protection, and the vector strain (TK⁻/gE⁻/gI⁻) showed no protection. PRV-P12A3C induced 60% protection, compared with piglets that were vaccinated with TK⁻/gE⁻/gI⁻. The severity of clinical signs for the remaining two piglets was lighter and the appearance of vesicles was delayed.     

仔猪胰腺细胞体外培养体系的建立

为了研究体外培养仔猪胰腺细胞的适宜条件,试验选取1日龄的仔猪胰腺组织置于冰上清洗、修剪,对消化酶、离心方式、培养皿铺被方式、培养液及添加不同促生长因子等多种因素进行筛选和优化。结果表明:0.25%胰酶消化所获得的细胞强于0.1%胶原酶消化获得的细胞,细胞清亮,易于生长;采用500 r/min离心5 min、多次离心所获得的细胞较Percoll不连续密度梯度离心和5%BSA等密度梯度离心所获得的细胞贴壁率高,生长能力强,易于培养传代;采用0.1%明胶或20μg/mL的层黏连蛋白铺被培养皿均比无铺被的培养皿获得更多的贴壁细胞;以RPMI 1640、M199、F12、L-DMEM多种培养液培养仔猪胰腺细胞,表现出多种细胞形态和生长趋势;在基础培养液中添加上皮生长因子、角质化生长因子、β-巯基乙醇和白血病细胞抑制因子、转铁蛋白与亚硒酸盐混合试剂等促干细胞增殖因子可促进不同形态细胞的增殖。说明按此方式培养可获得大量、多种细胞形态的仔猪胰腺祖/干细胞。     

Virus Location and Lymphocyte Apoptosis in Lymph Nodes of Piglets Infected with PCV-2

The present study has been performed to understand the location of the virus, type of apoptotic cells, and their relation to lymph nodes of piglets infected with porcine circovirus type Ⅱ （PCV-2）. Nine 32-day-old conventional piglets free of infection with PCV-2 were used, and distributed into three groups： control group （n = 3）, piglets inoculated with PCV-2 alone （PCV-2, n = 3）, and PCV-2 inoculated and KLH immunostimulated group （PCV-2 ＋ KLH, n = 3）. Superficial inguinal lymph nodes from all piglets were collected for histological examination after 32 days postinoculation, and immunohistochemistry for PCV-2 detection. Location of apoptotic cells was detected with TdT-mediated dUTP nick end labeling （TUNEL） and cell cycle, and the apoptotic rates were measured by flow cytometry. The characteristic histopathological lesions of the piglets in PCV-2 and PCV-2 ＋ KLH were lymphocyte depletions in the cortex and paracortex of the lymph nodes, epithelioid-like macrophage infiltration, and intracytoplasmic inclusion bodies presented in epithelioid-like macrophages. PCV-2 was mainly found in epithelioid-like macrophages by immunohistochemistry. In the lymph nodes, lymphocytes presented higher apoptotic rates in the cortex by TUNEL, special B-cell areas, and similar apoptotic cells were found in this compartment in the control. The apoptotic rates of the lymph nodes were 0.41, 3.34, and 4.88% in the control, PCV-2, and PCV-2 ＋ KLH groups by flow cytometry, respectively. The apoptotic rates of lymph nodes for PCV-2 and PCV-2 ＋ KLH piglets were significantly higher than those for the control group （P〈0.05 and P〈0.01）. The proliferation index （PI） was 0.17_＋0.01, 0.12_＋0.01 and 0.12_＋0.04 in the control, PCV-2, and PCV-2 ＋ KLH group, the PI of the control group was higher than that of the other groups, but without the statistical difference. PCV-2 can induce lymphocyte depletion in lymph nodes of piglets by blocking cell proliferation and promoting apoptosis. This is one o     

寡糖的作用机理及其在养猪生产中的应用

寡糖被视为可以替代抗生素的绿色饲料添加剂。本文系统阐述了寡糖的主要作用、作用机理以及在养猪生产中的应用现状 ,并指出在我国养猪生产中的应用和研究方向     

寡聚糖、抗生素、益生素对仔猪生长性能和肠道菌群影响的研究

选择 12窝仔猪 ,随机分为 6组 ,每组 2窝 ,从 7日龄开始进行为期 8周的饲养试验 ,在4周末断奶 ,研究了基础日粮中添加寡聚糖、益生素、金霉素以及寡聚糖取代部分抗生素对仔猪生长性能和肠道菌群的影响。结果表明 ,与对照组相比 ,寡聚糖或其与金霉素配伍 ( 2 5mg及 12 .50mg· kg-1饲粮 )使用 ,使仔猪在 0～ 4周日增重分别提高 16.81% ( P>0 .0 5)、 15.91 ( P>0 .0 5)、 15.32 ( P>0 .0 5) ;腹泻率分别降低 7.83 ( P<0 .0 1)、 8.68 ( P<0 .0 1)、 8.35( P<0 .0 1)。在 5～ 8周 ,使仔猪日增重分别提高 9.55 ( P>0 .0 5)、 4 8.84 ( P<0 .0 5)、 38.74( P<0 .0 5) ;料肉比分别降低 0 .2 1( P<0 .0 5)、 0 .4 1( P<0 .0 1)、 0 .4 6( P<0 .0 1) ;腹泻率分别降低 12 .78 ( P<0 .0 1)、 2 2 .2 3 ( P<0 .0 1)、 2 0 .88 ( P<0 .0 1)。 0 .15益生素使 0～ 4周的仔猪腹泻率降低 4 .82 ( P<0 .0 5) ,在 5～ 8周使料肉比降低 0 .17( P<0 .0 5) ,腹泻率降低 4 .90( P<0 .0 5)。金霉素 ( 50 mg· kg-1饲粮 )组在 5～ 8周腹泻率降低 5.16% ( P<0 .0 5)。抗生素、益生素在 0～ 4及 5～ 8周对日增重的影响不大 ( P>0 .0 5)。 2 1日龄和 4 9日龄取新鲜粪样测定结果表明 :寡聚糖或寡聚糖与     

一例仔猪腹泻的病原学诊断

为了解某猪场仔猪腹泻发生的原因,对病死仔猪进行病原学诊断.结果：检测出PCV20RF2特异性片段,并分离鉴定到埃希氏大肠杆菌,未发现TGEV与PEDV感染,表明导致仔猪腹泻的原因是PCV2继发感染大肠杆菌所致.     

Effects of low-protein diets supplemented with crystalline amino acids on performance and intestinal development in piglets over the first 2 weeks after weaning

This study was conducted to determine the effects of low-protein diets supplemented with crystalline amino acids (AA) on performance and intestinal development in barrows (n = 32) over 2 weeks after weaning at 18 ± 1 day. Four maize-soybean meal based diets providing 0.93 g standardized ileal digestible lysine/MJ ME were prepared. The treatments were a control diet containing 23.1% CP (crude protein) and three low-protein diets (21.2, 18.9, and 17.2% CP, respectively), which were supplemented with crystalline AA to achieve an ideal AA pattern. Piglets were raised individually and had free access to feed and water. Average daily gain (ADG) and average daily feed intake (ADFI) were measured weekly. Severity of diarrhea was monitored twice per day. Blood from all piglets was taken for determining serum urea nitrogen on d 0, 7, and 14 and serum free AA concentration on d 14. At the end of the experiment, all piglets were killed to measure morphology of the small intestine and disaccharidase activities. Reducing CP level did not affect ADFI (P > 0.10) but resulted in poorer (linear, P < 0.05; quadratic, P < 0.05) ADG and feed:gain ratio (F:G) over the 2-week study period. However, most of the effect of dietary CP was due to the significant deterioration of performance with the 17.2% CP diet. Faecal consistency was improved linearly (P < 0.01) with dietary CP decrease. Reducing dietary CP from 23.1 to 17.2% resulted in a linear (P < 0.001) and quadratic (P < 0.001) decrease in serum urea nitrogen levels on d 7 and 14. Serum arginine (P < 0.001), glutamine (P < 0.05), and proline (P < 0.05) concentrations were decreased in pigs fed the 17.2% CP diet compared with those fed the control diet on d 14. Villous height was decreased (P < 0.05) in the duodenum and jejunum by the reduction of dietary CP. As dietary CP declined, lactase and sucrase activities were reduced (P < 0.01) in the proximal jejunum. In conclusion, reducing CP concentration from 23.1 to 17.2% led to decreased growth performance associated with morphological changes of the gut and reduced disaccharidase activities in the small intestine. But reducing dietary CP from 23.1 to 18.9% did not affect intestinal morphology and disaccharidase activities.