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1.
【目的】探究不同妊娠时期猪胎盘的氨基酸、葡萄糖、脂肪酸转运体的表达模式。【方法】选择15头遗传背景、产仔数接近的杜洛克2~4胎经产健康母猪平均分为3组,所有母猪发情后使用相同公猪精液进行人工授精,在妊娠第40天(D40)、65天(D65)和95天(D95)通过麻醉分别取出每组母猪子宫,快速打开子宫分离出每个胎儿的胎盘组织,提取胎盘组织总RNA并反转录合成cDNA,利用合成的引物进行普通PCR扩增,用2.0%琼脂糖凝胶检测扩增产物。采用实时荧光定量PCR检测并比较3个时期胎盘中氨基酸、葡萄糖、脂肪酸转运体相关基因mRNA相对表达水平。【结果】PCR检测结果显示,氨基酸转运体相关基因(SLC7A1、SLC7A2、SLC7A3、SLC7A4、SLC7A10、SLC1A3、SLC1A5、SLC38A10、SLC36A1)、葡萄糖转运体相关基因(SLC2A1、SLC2A2、SLC2A3、SLC2A10、SLC2A12、SLC2A13)及脂肪酸转运体相关基因(FATP1、FATP2、FATP3、FATP4、FABP3、FABP5、FABP7、CD36)的片段长度均与预期相符。实时荧光定量PCR结果显示,在氨基酸转运体中,D65胎盘中SLC7A4、SLC7A10、SLC38A10基因表达水平显著高于D40胎盘(P<0.05),而SLC7A2基因表达水平显著低于D40胎盘(P<0.05),且D65胎盘的SLC1A3和SLC7A4基因表达水平均显著低于D95胎盘(P<0.05);在葡萄糖转运体中,D65和D95胎盘的SLC2A3和SLC2A13基因表达水平显著高于D40胎盘(P<0.05),D95胎盘的SLC2A1、SLC2A2和SLC2A12基因表达水平显著低于D65胎盘(P<0.05);在脂肪酸转运体中,D65胎盘的FATP2、FATP4、FABP3、FABP5、FABP7和CD36基因表达水平显著高于D40胎盘(P<0.05),而FATP1、FATP4和CD36基因表达水平显著低于D95胎盘(P<0.05)。【结论】在猪妊娠过程中,胎盘中SLC7A10、SLC38A10、SLC7A4、SLC2A3、FATP1、FATP4、FABP5、CD36等基因可能是影响胎儿生长发育的重要营养转运基因。  相似文献   

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3.
本试验旨在根据肉鸡氨基酸需要模型,研究细分饲粮氨基酸供给对肉鸡生长性能、屠宰性能、营养物质采食量及肠道发育的影响。选取1日龄爱拔益加(AA)肉公鸡192只,随机分为4个组,分别为A组(2阶段)、B组(3阶段)、C组(6阶段)和D组(12阶段),每组6个重复,每个重复8只鸡,试验期42 d。结果表明:1)A组肉鸡平均日增重(ADG)显著高于B、C和D组(P0.05)。A、B、C组之间肉鸡平均日采食量(ADFI)差异不显著(P0.05),均显著高于D组(P0.05)。A组肉鸡料重比(F/G)显著低于B、C和D组(P0.05)。2)B组肉鸡屠宰率显著高于A、C和D组(P0.05)。B组肉鸡全净膛率显著高于C和D组(P0.05),与A组差异不显著(P0.05)。A组肉鸡胸肌率显著高于B、C和D组(P0.05)。A组肉鸡腹脂率显著低于B、C和D组(P0.05)。3)D组肉鸡代谢能采食量显著低于A、B和C组(P0.05)。A组肉鸡粗蛋白质及赖氨酸采食量显著高于B、C和D组(P0.05),B、C组肉鸡粗蛋白质及赖氨酸采食量显著高于D组(P0.05)。A组肉鸡蛋氨酸采食量显著高于B和D组(P0.05)。A组肉鸡含硫氨基酸采食量显著高于B和D组(P0.05)。D组肉鸡苏氨酸采食量显著低于A和C组(P0.05)。4)A组肉鸡十二指肠绒毛高度、绒毛高度/隐窝深度(V/C)值显著高于B、C和D组(P0.05)。各组肉鸡空肠、回肠绒毛高度、隐窝深度及V/C值差异不显著(P0.05)。5)42日龄,A组肉鸡体重显著高于B、C和D组(P0.05),B和C组肉鸡体重显著高于D组(P0.05)。B、C和D组肉鸡单位增重成本与A组相比差异不显著(P0.05)。综上,2阶段饲喂能够促进肉鸡十二指肠发育,提高肉鸡营养物质采食量。综合生长性能、屠宰性能及单位增重成本考虑,建议采用2阶段肉鸡饲喂方式。  相似文献   

4.
日粮系酸力水平对羔羊生产性能和养分表观消化率的影响   总被引:1,自引:0,他引:1  
为了研究日粮不同系酸力水平对羔羊生产性能和饲料养分消化率的影响,将24只7日龄萨能奶山羊公羔随机分成4组,A组饲喂基础H粮,B、C和D 3个试验组分别饲喂在基础日粮中添加3.0、9.0和15.0 kg/t酸化剂的试验日粮(补饲料系酸力水平分别为30.0、20.0和10.0 mmol HCI/100 g;日粮系酸力水平分别为39.3、35.2和31.1 mmol HCl/100 g),研究日粮系酸力水平对早期断奶羔羊生产性能和养分表观消化率的影响.结果表明:(1)B、C和D组羔羊日增重极显著高于A组(P<0.01),C、D组显著高于B组(P<0.05);(2)饲料酸化可有效改善羔羊健康状况,B、C和D组羔羊腹泻率分别较A组降低了36.36%、28.65%和81.82%;(3)B,C和D组CP、GE表观消化率极显著高于A组(P<0.01),C、D组极显著高于B组(P<0.01);(4)B、C和D组DM表观消化率极显著高于A组(P<0.01),C、D组极显著高于B组(P<0.01),D组显著高于C组(P<0.05).结果提示,降低羔羊日粮系酸力水平,可以显著改善羔羊日增重、料重比和羔羊对日粮主要养分表观消化率,有效改善羔羊健康状况,在本研究条件下以补饲料系酸力水平10.0 mmol HCl/100 g即日粮系酸力水平31.1 mmol HCl/100 g组效果最好.  相似文献   

5.
A trial was performed with cellulase administration (3 cx per g of ingested feed dry matter) to early weaned calves fed minimum amounts of milk replacer (21 kg per milk nutrition period) and sweet (C, D) and sour (A, B) diets. The groups B and D were supplemented with an enzyme till the age of 90 days. The calves were given free choice of COT concentrate mixture, hay and water. Liveweight gains, feed and nutrient intake and health condition of calves were the characteristics investigated in this trial. Hematocrit value, hemoglobin, glucose and urea contents were determined in blood, in blood plasma buffer capacity was investigated. Although the differences in calf performance are not statistically significant, the best growth of calves in the vegetable nutrition period was observed in calves in group D. Nutrient conversion was also higher in calves of group D in the vegetable nutrition period. In conversion of nutrient consumption per 1 kg liveweight gain the difference in the intake of digestible crude protein and starch units between the group of calves fed sweet milk without enzyme addition in the milk nutrient period (A--digestible crude protein 0.40 +/- 0.005; starch units 1.74 +/- 0.008) and group D (sour diet + 3 cx cellulase--digestible crude protein 0.34 +/- 0.007; starch units 1.52 +/- 0.044) was statistically significant (P less than 0.025 and P less than 0.05) in favour of group D. An analysis of the results of hematological and biochemical investigations during the trial demonstrates that the sour diet is better in view of changes in glucose concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

6.
A panel of four monoclonal antibodies (MAbs) was evaluated, using a hemagglutination-inhibition test, for its ability to subtype 76 isolates of Haemophilus paragallinarum. The results of the MAb reactions were compared with the results of both the Page and Kume serotyping schemes (the serovars of the Page scheme correspond to the serogroups of the Kume scheme). One MAb (E5C12D10) was raised against a Page serovar A strain and the remaining MAbs (F2E6, D6D8D5, and B3E6F9) against a Page serovar C strain. Six different reaction patterns were found among the 76 isolates of H. paragallinarum. There was total correlation between the MAb reaction pattern and the Page scheme, and thus the Kume scheme, to the serogroup level. All 19 Page serovar A (= Kume serogroup A) strains reacted only with MAb E5C12D10, whereas all five Page serovar B (= Kume serogroup B) strains failed to react with any of the MAbs. All 52 remaining strains were Page serovar C (= Kume serogroup C), and all failed to react with MAb E5C12D10 but showed varying reaction patterns with the three other MAbs. Although the MAbs recognized four subdivisions within Kume serogroup C, these subdivisions differed from the four Kume C serovars. This panel of MAbs can be used to assign isolates of H. paragallinarum to either Page serovars or Kume serogroups. Although the subdivisions recognized by the MAbs within the Page serovar C strains do not correspond to the Kume serovars, they may be useful in epidemiological applications.  相似文献   

7.
试验旨在研究日粮中添加不同诱食剂对安格斯犊牛生长性能、养分表观消化率及部分血清激素的影响。采用单因子随机区组设计,选用平均体重165.1 kg±35.5 kg、约6月龄的健康安格斯肉犊牛24头,随机分为A、B、C、D 4组,每组6个重复。A组为对照组,饲喂全混合日粮(TMR);B、C、D组分别饲喂TMR+0.24%绿色素、TMR+1.2 g/d XTRACT® 7065(香味剂)、TMR+0.4%甜蜜素。预饲期10 d,正饲期30 d。结果显示,与对照组相比,B、C、D组平均干物质采食量(ADMI)均显著提高(P < 0.05)。各诱食剂均能提高犊牛营养物质表观消化率,但各诱食剂的影响程度不同,其中B组酸性洗涤纤维(ADF)表观消化率显著高于其他诱食剂组(P < 0.05),B组中性洗涤纤维(NDF)表观消化率显著高于对照组(P < 0.05)。在试验第31天采食后1 h,各组间神经肽Y(NPY)和5-羟色胺(5-HT)含量差异均不显著(P > 0.05),B、D组NPY含量高于对照组,C组则低于对照组,B、D组5-HT含量均低于对照组,而C组则高于对照组。综合考虑,日粮中添加绿色剂、香味剂及甜味剂均可在一定程度上提高犊牛生长性能及营养物质消化率;绿色剂和甜味剂可以提高犊牛血清中NPY含量,而香味剂则使犊牛血清中5-HT含量升高。  相似文献   

8.
本试验旨在研究代乳品和开口料的饲喂对哺乳中后期羔羊生长性能、血清生化指标和营养物质表观消化率的影响。选择体重相近的30日龄羔羊75只,随机分成5组,每组3个重复,每个重复5只。各组分别饲喂代乳品1+开口料(A组)、代乳品1(B组)、代乳品2(C组)、母乳+开口料(D组)和母乳(E组)。分别在30、40、50、60、70日龄称重并对体尺进行测量,68~70日龄连续收集3 d粪样测定营养物质表观消化率,在70日龄颈静脉采血测定血清生化指标。结果表明:1)30、40、50、60、70日龄D组体重、体长、体高、胸围高于A、E组,E组高于B组,B组与C组间差异不显著(P0.05);但60~70日龄期间,A组平均日增重显著高于D组(P0.05),B组显著高于E组(P0.05)。2)血清尿素氮含量及谷丙转氨酶、谷氨酰转移酶、乳酸脱氢酶活性组间差异不显著(P0.05);血清总蛋白和甘油三酯含量D组显著高于A组(P0.05),E组血清甘油三酯含量显著高于B、C组(P0.05);血清白蛋白和球蛋白含量A、D、E组之间差异不显著(P0.05),但D组有增高趋势,E组显著高于B、C组(P0.05);血清葡萄糖含量A、D、E组显著高于B、C组(P0.05);A组血清碱性磷酸酶活性显著高于其他各组(P0.05);B、C组之间上述血清生化指标差异均不显著(P0.05)。3)各营养物质采食量A组显著高于B、C组(P0.05),B、C组之间差异不显著(P0.05);干物质、钙、磷表观消化率差异不显著(P0.05);粗蛋白质、总能、中性洗涤纤维和酸性洗涤纤维表观消化率A组显著高于B、C组(P0.05),且B、C组差异不显著(P0.05)。由此可见,代乳品和开口料的饲喂对羔羊生长性能、血清生化指标及营养物质表观消化率有不同程度的影响,羔羊代乳品加开口料的饲喂模式可实现羔羊的早期断奶,具有一定的推广价值。  相似文献   

9.
刘哲  闫峻  刘仲昊  穆淑琴 《中国畜牧兽医》2020,47(11):3460-3466
试验旨在探究短期饥饿处理对成脂分化C2C12细胞中脂滴生长发育的影响,为阐释及利用补偿生长机制奠定基础。通过胰岛素等激素混合物诱导C2C12细胞成脂分化,将成脂分化12 d的C2C12细胞分为两组:对照组(Control),高糖培养24 h;饥饿处理组(FAST),无血清低糖培养24 h。通过BODIPY染色和甘油三酯测定观察脂滴形态变化,并使用Western blotting方法测定脂滴表面结构蛋白perilipin1-5表达量的变化。结果显示,C2C12细胞成脂诱导12 d,可以使细胞达到较好的充脂状态。通过无血清低糖饥饿处理后,成脂分化C2C12细胞中甘油三酯含量极显著下降(P<0.01);脂滴平均尺寸极显著减小(P<0.01),脂滴平均数量极显著增多(P<0.01);脂滴表面结构蛋白出现变化,perilipin2、perilipin5表达极显著上调(P<0.01)、perilipin3表达显著上调(P<0.05)。综上,无血清低糖处理可以诱发脂滴形态重塑,改变脂滴表面结构蛋白的表达。  相似文献   

10.
This study was aimed to explore the effect of short-term starvation treatment on the growth and development of lipid droplets in adipogenic differentiation C2C12 cells,provide the foundation for the interpretation and utilization of compensatory growth mechanisms.Adipogenic differentiation C2C12 cells were divided into two groups:Control group,high glucose treatment for 24 h,and starvation treatment group (FAST),serum-free and low-glucose medium starvation treatment for 24 h.The morphological changes of lipid droplets was observed by BODIPY staining and triglyceride determination,and Western blotting was used to determine the change of the expression level of perilipin family protein (perilipin 1-5) on the lipid droplet.The results showed that C2C12 cells induced adipogenesis for 12 days,which could make the cells reach a better fat-filling state.After treatment with serum-free and low-glucose starvation,the levels of triglycerides in adipogenic differentiation C2C12 cells decreased extremely significantly (P<0.01),the size of lipid droplets decreased extremely significantly (P<0.01),and the number of lipid droplets increased extremely significantly (P<0.01).The perilipin protein on the lipid droplets was changed,the expression level of perilipin2 and perilipin5 were extremely significantly up-regulated (P<0.01),and the expression level of perilipin3 was significantly up-regulated (P<0.05).In summary,serum-free and low-glucose starvation could induce the remodeling of lipid droplets and change the expression level of perilipin proteins on the lipid droplets.  相似文献   

11.
蝇蛆生物活性肽的生产工艺研究   总被引:1,自引:0,他引:1  
以蝇蛆为试验材料,设酶解温度、复合酶量、酶配比、酶解时问和pH值5个因素,每个因素4个水平进行L15(4^5)正交试验设计,以水解度作为评价指标,筛选脱脂蝇蛆粉的最佳酶解条件。结果表明:脱脂蝇蛆粉的最优酶解条件为A1B3C3D4E3,即温度(A)45℃,酶量(B)8000U/g,风味酶:木瓜酶:胃蛋白酶:胰蛋白酶的配比(C)是35%:50%:5%:10%,酶水解时间(D)为7h,pH(E)为7.5。脱脂蝇蛆粉溶液水解度的最大影响因素为酶解温度。  相似文献   

12.
This study was conducted to evaluate the effects of single or carbohydrases cocktail in low-nutrient-density diets on growth performance, nutrient digestibility, blood characteristics, and carcass traits of growing–finishing pigs. A total of 96 pigs with an average initial BW of 47.50 ± 1.25 kg were used in this 8-week growth trial. Pigs were randomly allocated to 1 of the 4 treatments according to its BW and sex (4 pigs/pen, 6 replicate pens/treatment). The diets included: 1) control (CON) corn–soybean meal diet (DE, 3400 kcal/kg; CP, 17%), 2) low-nutrient-density (LC) diet with 6% DDGS and 5% tapioca (DE, 3280 kcal/kg; CP, 15%), 3) LC + 0.05% β-mannanase (LCS), and 4) LC + 0.05% enzyme mixture (LCM). The LC treatment had a lower ADG, and G/F compared to the other treatments in 0–4 weeks and the overall period of the feeding trial (P < 0.05). The ADFI were decreased in LC, LCS, and LCM groups related to CON (P < 0.05). The LCS treatment had higher DM digestibility than pigs in both the LC and LCM groups (P < 0.05) on 4 weeks while LCM improved N and energy digestibility compared to LC treatment. Blood urea nitrogen and creatinine values were not affected by the experimental treatments. After the feeding period, pigs (2 per pen) which reached marketing BW were collected meat samples from slaughter house. Backfat thickness was decreased in LC, LCS and LCM groups (P < 0.05). No numerical differences were observed in meat color, pH value and water holding capacity among four treatments. In conclusion, the results of this study indicate that single or carbohydrases cocktail in low-density diets can partially improve ADG, G/F, nutrient digestibility, and meat quality in finishing pigs, which can counteract the negative effects caused by the decreased nutrient concentration.  相似文献   

13.
Despite its medical use, little is known about the mechanisms underlying amikacin-induced embryotoxicity, including fin reduction, in zebrafish. In this study, we examined the expression of well-known autophagy markers mTOR (target of rapamycin), atg10 (autophagy-related gene), atg12 and LC3 (mammalian homolog of Atg8) in amikacin-treated zebrafish embryos. Our results indicated that the mRNA expression level of atg12 in the amikacin-treated group was significantly increased by 1.5-fold (p<0.05) compared with the corresponding mock control group, while the expression levels of atg10 and mTOR were significantly decreased by 0.74-fold (p<0.05) and 0.58-fold (p<0.05), respectively. Western blot analysis revealed that LC3 protein expression was induced by amikacin. Taken together, these data suggest that amikacin-induced fin reduction is mediated by fin cell autophagy.  相似文献   

14.
本试验旨在研究粗饲料组合对奶牛饲粮养分消化率、能量和氮的利用的影响。试验采用单因素随机区组设计,将 16头体重、年龄、胎次相近的,处于干奶期的健康荷斯坦奶牛分为 4组,每组 4头。以常用的粗饲料设计 A(玉米青贮 +玉米秸秆)、B(玉米青贮 +羊草)、C(玉米青贮 +玉米秸秆 +羊草)、D(玉米青贮 +苜蓿草 +羊草)4种粗饲料组合的饲粮。结果表明:饲粮D干物质、有机物和中性洗涤纤维的消化率最高,显著高于其他各饲粮(P<0.05),其次为饲粮B和饲粮 C,饲粮 A最低,显著低于其他各饲粮(P<0.05),各饲粮的酸性洗涤纤维消化率差异不显著(P>0.05)。粗饲料组合显著影响饲粮摄入总能、能量消化率和能量代谢率(P<0.05),饲粮 D甲烷能占摄入总能比显著低于其他 3种饲粮(P<0.05)。各饲粮的粪氮、尿氮占摄入总氮比差异不显著(P>0.05),饲粮 D的氮消化率显著高于饲粮 B与饲粮 C(P<0.05),且饲粮 B显著高于饲粮 A(P<0.05);饲粮 B、饲粮 D的氮利用率显著高于饲粮 A(P<0.05)。由此可见,玉米青贮 +苜蓿草 +羊草型饲粮的养分消化率、能量和氮的利用均优于其他各饲粮,羊草与玉米秸秆之间存在正组合效应,两者搭配使用可提高玉米秸秆的消化率,优化能量和氮的利用。  相似文献   

15.
Polyclonal immunoglobulin (Ig) G autoantibodies against insulin have been identified in sera of healthy cats. We purified and fractionated insulin-binding IgGs from cat sera by affinity chromatography and analyzed affinity of insulin-binding IgGs for insulin and their epitopes. Following the passing of fraction A, which did not bind to insulin, insulin-binding IgGs were eluted into two fractions, B and C, by affinity chromatography using a column fixed with bovine insulin. Dissociation constant (KD) values between insulin-binding IgGs and insulin, determined by surface plasmon resonance analysis (Biacore™system), were 1.64e−4 M for fraction B (low affinity IgGs) and 2e−5 M for fraction C (high affinity IgGs). Epitope analysis was conducted using 16 peptide fragments synthesized in concord with the amino acid sequence of feline insulin by an enzyme-linked immunosorbent assay. Fractions B and C showed higher absorbance (affinity) of the peptide fragment of 10 amino acid residues at the carboxyl-terminal of the B chain (peptide No. 19), followed by peptide fragments of 6 to 15 amino acid residues of the B chain (peptide No. 8). Fraction C showed a higher absorbance to 7 to 16 amino acid residues of the B chain (peptide No. 5) compared with the absorbance of fraction B. Polyclonal insulin-binding IgGs may form a macromolecule complex with insulin through the multiple affinity sites of IgG molecules. Feline insulin-binding IgGs are multifocal and may be composed of multiple IgG components and insulin.  相似文献   

16.
The objectives of this work were to evaluate whether the sperm penetration speed is correlated to the in vitro fertility and whether adapting the gamete co-incubation length to the kinetics of the bull improves in vitro fertility and affects the sex ratio. In vitro matured oocytes were co-incubated with spermatozoa from four different bulls (A-D). At various post-insemination (p.i.) times (4, 8, 12, 16 and 20 h), samples of oocytes were fixed and stained with DAPI for nuclei examination, while the remaining ones were transferred into culture to evaluate embryo development. The blastocysts produced were sexed by PCR. Two bulls (A and B) had faster kinetics than the others (C and D), as shown by the higher penetration rates recorded at 4 h p.i. (43%, 30%, 11% and 6%, respectively for bulls A, B, C and D; p<0.01). The differences in the kinetics among bulls did not reflect their in vitro fertility. The incidence of polyspermy was higher for faster penetrating bulls (36%, 24%, 16% and 4%, respectively for bulls A, B, C and D; p<0.01) and at longer co-incubation times (0%, 16%, 19%, 30% and 34%, respectively at 4, 8, 12, 16 and 20 h p.i.; p<0.01). The fertilizing ability of individual bulls may be improved by adapting the co-incubation length to their penetration speed. A sperm-oocyte co-incubation length of 8 h ensured the greatest blastocyst yields for the two faster penetrating bulls. On the contrary, 16 h co-incubation was required to increase (p<0.01) cleavage rate of the two slower bulls. Bulls with a faster kinetics did not alter the embryo sex ratio towards males. The female/male (F/M) ratios recorded were 2.1, 1.4, 1.2, 1.3 and 1.6, respectively at 4, 8, 12, 16 and 20 h p.i.  相似文献   

17.
The Rabbit Hemorrhagic Disease Virus (RHDV) induces a severe disease that fulfils many requirements of an animal model of fulminant hepatic failure. However, a better knowledge of molecular mechanisms contributing to liver damage is required, and it is unknown whether the RHDV induces liver autophagy and how it relates to apoptosis. In this study, we attempted to explore which signalling pathways were involved in the autophagic response induced by the RHDV and to characterize their role in the context of RHDV pathogenesis. Rabbits were infected with 2 × 104 hemmaglutination units of a RHDV isolate. The autophagic response was measured as presence of autophagic vesicles, LC3 staining, conversion of LC3-I to autophagosome-associated LC3-II and changes in expression of beclin-1, UVRAG, Atg5, Atg12, Atg16L1 and p62/SQSTM1. RHDV-triggered autophagy reached a maximum at 24 hours post-infection (hpi) and declined at 30 and 36 hpi. Phosphorylation of mTOR also augmented in early periods of infection and there was an increase in the expression of the endoplasmic reticulum chaperones BiP/GRP78, CHOP and GRP94. Apoptosis, measured as caspase-3 activity and expression of PARP-1, increased significantly at 30 and 36 hpi in parallel to the maximal expression of the RHDV capsid protein VP60. These data indicate that RHDV infection initiates a rapid autophagic response, perhaps in an attempt to protect liver, which associates to ER stress development and is independent from downregulation of the major autophagy suppressor mTOR. As the infection continues and the autophagic response declines, cells begin to exhibit apoptosis.  相似文献   

18.
Media-based bacteriological testing will fail to detect non-culturable organisms and the risk of consuming viable but non-culturable (VBNC) Listeria monocytogenes is unknown. We have here studied whether L. monocytogenes obtained from seafoods, processing environment and clinical cases enter the VBNC state and assessed the virulence of the non-culturable forms of the bacteria. A number of 16 L. monocytogenes strains were starved in microcosm water at 4 °C until loss of culturability. Metabolic activity in the VBNC form was measured as ATP generation using a luciferase assay and membrane integrity was examined using the LIVE/DEAD BacLight assay. All tested L. monocytogenes strains entered the VBNC state after starvation in microcosm water. Ongoing mRNA synthesis of hly in VBNC L. monocytogenes cells re-incubated in culture medium indicated a potential virulence of these forms. Sodium pyruvate and replenishment of nutrient were used in attempts to resuscitate VBNC cells. However, VBNC L. monocytogenes were not resuscitated under these conditions. VBNC L. monocytogenes were tested for virulence in a cell plaque assay and by intraperitoneally inoculation in immunodeficient RAG1−/− mice. Inoculation of VBNC L. monocytogenes in immunodeficient mice did not cause morbidity, and plaque assay on HT-29 cells in culture indicated that the VBNC cells were avirulent. The results indicate that the risk of non-culturable L. monocytogenes in foods, when the VBNC state is induced by starvation, is negligible.  相似文献   

19.

Background

The aim of the study was to test the effect of two treatments in cases of acute puerperal metritis (APM) and clinical metritis (CM).

Methods

Cows with APM and CM (n = 40)) were matched according to plasma fibrinogen levels (Fb) into three groups. Two negative control groups D (n = 11) and E (n = 17) were composed of healthy cows. The proportion of animals with APM and CM was similar within the groups. Treatment was started on the 3rd day postpartum (PP). In group A (n = 15), intramuscular (i.m.) administration of ceftiofur was used for five days in combination with flunixin for three days. Group B (n = 15) received i.m. administration of ceftiofur for five days followed by two injections of prostaglandin F2α, with an interval of 8 h, on the 8th day PP. Group C (n = 10) served as a control group with no treatment. The general health status, body temperature (BT) and vaginal discharge were evaluated daily. Endometrial biopsies for bacteriology were taken once a week for seven weeks PP. Blood samples for the analysis of acute phase proteins were collected once a week for six weeks PP. Samples for progesterone analysis were taken twice a week for seven weeks PP. Fertility performance data were recorded.

Results

The area under the curve of BT was higher in group B than in group D cows (P < 0.05). No differences were found for vaginal discharge. There were no differences in bacterial growth, start of ovarian activity or serum amyloid-A or fibrinogen levels among the groups. The haptoglobin concentration was higher in the first and second weeks PP in group B compared with the other groups (P < 0.05). The number of days open was higher in group A than in both groups B and D (P < 0.05). The pregnancy rate after the first two services was higher (P < 0.05) in groups B and D than in groups A and C. The number of services per pregnancy was lower in group B than in group C (P < 0.05).

Conclusions

Regardless of more severe uterine inflammation found in animals from group B, these cows showed the same fertility parameters as healthy animals.  相似文献   

20.
选择年龄相近 ,健康无病 ,体重约 1kg的珍珠系长毛兔 1 0 0只 ,根据体重、性别 ,按组间相似的原则分为 4组 ,每组 2 5只 ,A、B、C 3组为试验组 ,分别添加 1 ,2 ,3号复合添加剂 ,D组为对照组 ,添加市售微量元素、多维素添加剂 ,蛋氨酸。试验各组基础日粮完全相同。60d的饲养试验结果表明 ,对照组的发病率显著高于试验组 ,而成活率则低于各试验组。B、C两组的平均增重显著高于对照组 (P <0 0 5 ) ;3个试验组相比 ,B、C组比A组增重分别提高1 0 34%和 1 4 94% ,差异显著 (P <0 0 5 ) ,而B、C两组间增重差异不显著 (P >0 0 5 )。  相似文献   

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