Immunosuppressive effects of aflatoxin B1 in Indian major carp (Labeo rohita).

Aflatoxin B1 (AFB1) is a potent immunomodulator in endotherms. The experiment was carried out to study the immunosuppressive nature of AFB1 in one ectothermic species of Indian major carp. Graded levels (0, 1.25, 5.00 mg/kg of body weight) of purified AFB1 were intraperitoneally (i.p.) injected into rohu (Labeo rohita) fingerlings weighing 30-50 g, and the fish were observed for a period of 90 days. At the end of the trial, blood samples were collected from the control group as well as the AFB1 injected fish and were screened for nitroblue tetrazolium (NBT) assay, serum total protein, albumin, globulin, albumin-globulin ratio (A:G), serum bactericidal activity and bacterial agglutination titre against Edwardsiella tarda. The aflatoxin-treated fish revealed a reduction of total protein, globulin levels, bacterial agglutination titre, NBT and serum bactericidal activities, as well as an enhanced A:G ratio without change in albumin concentration, irrespective of dose levels of toxin treatment, when compared to the control group. Thus, AFB1 proved to be immunosuppressive in rohu even at the lowest dose (1.25 mg/kg body weight) of toxin treatment. This could be of economic significance in intensive culture systems of rohu.     

嗜水气单胞菌与迟缓爱德华氏菌亚单位二联疫苗对小鼠的免疫效果

将嗜水气单胞菌（Ａｈ）Ｊ－１株的ＨＥＣ毒素和胞外蛋白酶（ＥＣＰ）分别与迟缓爱德华氏菌（Ｅｔ）３８株的脂多糖（ＬＰＳ）及脱毒多糖（ＰＳ）偶联,制成３种亚单位二联疫苗;ＨＥＣ－ＰＳ、ＨＥＣ－ＬＰＳ。将它们与ＡｈＪ－１和Ｅｔ３８全菌灭活疫苗一同分别免疫小鼠,并设注射ＰＢＳ对照组,检测各组小鼠体液免疫及细胞免疫水平。结果显示,用间接ＥＬＩＳＡ、溶血抑制和全菌凝集试验检出这３种亚单位疫苗的抗体水平无明显差异     

鲟源荧光假单胞菌的分离鉴定及药敏特性分析

从患病鲟体内分离到1株细菌,通过形态学观察、生理生化特性鉴定、16SrRNA基因序列分析及系统进化树构建等方法对分离菌种属进行确定,采用纸片扩散法对分离菌进行药物敏感性分析。结果显示:分离菌为革兰阴性杆菌;可分解葡萄糖和木糖,氧化酶和鸟氨酸脱羧酶试验阳性;16SrRNA基因测序分析与荧光假单胞菌(Pseudomonas fluorescens)同源性大于99%,在系统发育树上与荧光假单胞菌聚为一枝;药敏结果显示,分离菌对氧氟沙星、多西环素、复方新诺明等敏感,对氟苯尼考、卡那霉素、阿莫西林等耐药;人工感染试验结果显示,该菌对小鼠有致病力。本研究为贵州地区鲟细菌性疾病预防及合理用药提供依据。     

半滑舌鳎致病性荧光假单胞菌的分离鉴定及其感染的病理损伤

2015年6月,河北省秦皇岛市某养殖场半滑舌鳎发生以腹水、烂尾、内脏器官肿大、出血与坏死为特征的疾病。从自然发病的半滑舌鳎肝脏与肾脏中分离到1株细菌,通过细菌形态观察、培养特性、生化特性分析、动物试验和16SrRNA基因序列分析等方法,对该病原菌进行了分析鉴定。结果显示:致病菌株为革兰阴性杆菌,培养特性、生化特性分析与荧光假单胞菌较接近,以16SrRNA基因为遗传标记构建系统发育树,致病菌菌株与荧光假单胞菌菌株相似性为99%。结果表明:本次引起半滑舌鳎腹水烂尾病的病原菌为荧光假单胞菌。对分离到的菌株进行了常用抗药物的药敏试验,该菌对氧氟沙星、氨曲南、红霉素等药物高度敏感,对利福平、妥布霉素等药物中度敏感,对卡那霉素、新霉素不敏感。组织病理学观察发现,荧光假单胞菌感染半滑舌鳎对多个组织器官都造成明显的病理损伤,尤其是肝脏、肾脏、脾脏、肠及脑的损伤较为严重,表现为明显的淤血、出血,变性、坏死及炎症细胞浸润。     

黄金鲫致病性维氏气单胞菌的分离鉴定及耐药性分析

为确定吉林省黄金鲫鱼发病死亡的原因,从患病黄金鲫体内分离到致病菌JLJ-1,对该菌进行形态学观察及生理生化特性的鉴定,并对16S rDNA和管家基因gyrB、rpoD、dnaJ序列、毒力基因携带情况及耐药性进行了分析。结果表明,该菌为革兰阴性菌,结合细菌形态学特征及其生理化生化特性与维氏气单胞菌(Aerornonas veronii,A.veronii)基本相同;16S rDNA与gyrB、rpoD、dnaJ序列进化比对分析显示,该病原菌与A.veronii同属一个分支,且同源性较高。将分离菌人工感染黄金鲫,7d后黄金鲫全部死亡,且临床症状与自然病例相似。通过毒力基因检测发现,JLJ-1株可扩增出6种毒力因子:气溶素(aer)、细胞毒性肠毒素(act)、黏附素(Aha)、丝氨酸蛋白酶(ser)、核酸酶(exu)及脂肪酶(lip)。药敏试验显示,该菌对氟苯尼考、头咆哌酮及头炮曲松等药物比较敏感。本研究为黄金鲫感染A.veronii的鉴定及治疗药物的选取提供科学依据。     

团头鲂对3种致病菌外膜蛋白(OMP)的免疫应答

利用从柱状黄杆菌(Flavobacterium columnare)、嗜水气单胞菌(Aeromonas hydrophila)和温和气单胞菌(Aeromonas sobria)中提取的外膜蛋白(outer membrane protein,OMP)作为免疫原,注射接种团头鲂(Megalobrama amblycephala)后,通过测定受免鱼的交叉凝集抗体效价、肾脏和血液中吞噬细胞的吞噬活性和采用A.hydrophila活菌攻毒方法,比较了3种致病菌OMP对团头鲂的免疫原性。试验结果表明,从3种致病菌中提取的OMP对团头鲂均具有较强的免疫原性,受免鱼的血清中存在对3种致病菌的交叉凝集抗体,与对照鱼相比,肾脏和血液中吞噬细胞对吞噬原的吞噬活性和对A.hy-drophila活菌攻毒的相对免疫保护率(relative percent survival,RPS)明显上升。说明在3种致病菌的OMP上不同程度地存在共同保护性抗原。     

Effect of Edwardsiella tarda immunization on systemic immune response,mucosal immune response and protection in catla (Catla catla)

The effect of immunization on systemic and cutaneous mucosal immune responses of fish and their possible relation with protection has not been fully assessed. In this study, healthy catla (Catla catla) were immunized against Edwardsiella tarda using two antigenic preparations namely, whole cell bacterin (B) and bacterin mixed with Freund’s complete adjuvant in a 1:1 (v/v) ratio (B+A) followed by a booster dose after 3 weeks of first injection. Different systemic and cutaneous mucosal immune responses were measured at weekly interval upto 8th week post vaccination (pv). Fish were challenged 8 weeks pv with live E. tarda to study vaccine induced protection. The result showed that although there were strong systemic as well as mucosal immune responses, particularly after booster dose, the challenge produced low to moderate protection in terms of relative percent survival (RPS). The maximum RPS (50 %) was recorded in the adjuvanted bacterin group after 8 weeks pv. Low to moderate protection after challenge, which may be attributed to the intracellular nature of E. tarda and/or use of crude antigenic preparation, accounts for new strategy to be developed for immunization programme against such intracellular pathogen. The results collectively suggest possible involvement of systemic as well as mucosal immune responses in inducing protective immunity in catla.     

Gelatinized to non-gelatinized starch ratio in the diet of Labeo rohita: effect on digestive and metabolic response and on growth

A 60-days experiment was conducted to study the optimum gelatinized (G) to non-gelatinized (NG) starch ratio in the diet of Labeo rohita juveniles with respect to digestive and metabolic response and on growth. Two-hundred and thirty-four juveniles (avg. wt 2.53 ± 0.04 g) were randomly distributed in six treatment groups with each of three replicates. Six semipurified diets either containing NG and/or G corn starch viz., T₁ (100% NG, 0% G starch), T₂ (80% NG, 20% G starch), T₃ (60% NG, 40% G starch), T₄ (40% NG, 60% G starch), T₅ (20% NG, 80% G starch) and T₆ (0% NG, 100% G starch) were prepared. The dry matter digestibility and carbohydrate digestibility were highest (p < 0.05) in T₆ group and lowest in T₃ and T₄ groups. The amylase activity in intestine increased as G:NG level increased in the diet. Protease activity in intestine was highest in T₆ group and lowest in T₁ group. Similar trend was recorded for specific growth rate, protein efficiency ratio and apparent net protein utilization. Liver glycogen, hepatosomatic index and blood glucose level increased linearly with the increasing level of G starch in the experimental diet. The results indicate that higher nutrient digestibility and growth was recorded either at low (20% G starch, T₂) or high (100% G starch, T₆) G starch fed group. But high G starch fed group (T₆) exhibits higher liver glycogen and blood glucose level, which may lead to stress due to long-term feeding. Hence, it is suggested that 20% G and 80% NG starch is optimum for better nutrient digestibility and growth in L. rohita juveniles.     

三种致病菌粗脂多糖(LPS)对团头鲂的免疫原性

<正>国内外大量研究表明,从革兰氏阴性菌中提取的脂多糖(lipopolysaccharide,LPS)对养殖鱼类具有比较强的免疫原性和良好的免疫保护作用。Kawai等(1987)采用温酚法从鳗弧菌(Vibrio anguillarum)中提     

Modulary effects of temperature on antibody response and specific resistance to challenge of channel catfish, Ictalurus punctatus, immunized against Edwardsiella ictaluri

The effects of various temperature treatments on the level of the humoral antibody response in channel catfish immunized with formalin killed Edwardsiella ictaluri was determined in laboratory controlled experiments. Immunized fish that were held at 25 degrees C for 30 days and 12 degrees C for an additional 30 days had higher antibody titers, and were more protected upon challenge, than immunized fish held at 25 degrees C for 60 days. Also immunized catfish held at 25 degrees C for 5 or 10 days followed by 12 degrees C water had higher antibody titers than immunized fish held at 12 degrees C or 25 degrees C for 60 days. In a field experiment carried out during winter and spring (February-May) fingerling channel catfish were vaccinated with E. ictaluri using intraperitoneal injection or immersion with either sonicated or whole cell preparations. Following challenge, the fish vaccinated by immersion in the sonicated preparation had 11.8% mortality whereas the groups immersed in whole cell bacterin, injected with the whole cell bacterin in adjuvant, or injected with sonicate showed 24.6, 57.9 and 41.7% mortality, respectively. Although the fish vaccinated by immersion with the sonicated bacteria had lower antibody titers than those vaccinated by the other methods the immersion vaccinates were more protected against challenge with the pathogen.     

Serum and abomasal antibody response of sheep to infections with Haemonchus contortus

Serum and abomasal IgA, IgG and IgM antibody response against adult worm, L3 and egg antigens of Haemonchus contortus was monitored by the ELISA technique after one or two infections with this nematode. Following the first infection, antibody levels in serum did not change materially. After administration of a challenge dose of infective larvae, antibodies of the three immunoglobulin classes in infected animals rose slightly, but this rise appeared later than the fall in the faecal egg counts. In contrast, in abomasal mucosa, IgA anti-larval antibody levels, which did not increase materially after the primary infection, rose rapidly after a transient inhibition when sheep were challenged. A close temporal relationship was observed between the rise in local anti-worm IgA antibodies and the self-cure reaction, but antibody levels fell rapidly after worm diminution. The local antibody response was thus considered to be related to immunity of sheep to H. contortus.     

Serum IgG and IgM antibody response in cattle to antigens of Pasteurella haemolytica

The serum IgG and IgM antibody responses of 48 cattle vaccinated with live Pasteurella haemolytica (LIVE), formalin-killed P. haemolytica in Freund's incomplete adjuvant (FIA), or formalin-killed P. haemolytica in aluminum hydroxide adjuvant (ALH) to a variety of P. haemolytica antigens were evaluated. Enzyme-linked immunosorbent assays (ELISAs) were used to determine the sequential and day 21 IgG and IgM antibody responses to whole P. haemolytica (WB), a capsular carbohydrate-protein subunit (CPS) extracted from the organism, P. haemolytica capsular carbohydrate (CC), and P. haemolytica leukotoxin (LT). LIVE and FIA vaccinates developed generally higher IgG and IgM responses to all antigens compared to ALH vaccinates. LIVE vaccinates developed IgG responses to LT which were significantly higher (P less than 0.05) than all other vaccinates. In contrast, FIA vaccinates developed significantly higher IgG responses to CPS than all other vaccinates. On the basis of the ELISA results, similar or cross reacting antigenic sites were present in preparations containing surface antigens (WB, CPS and CC), but not LT. Disease resistance, as determined by experimental lesions induced in the 48 calves by transthoracic challenge with P. haemolytica, was significantly greater in the LIVE and FIA vaccinates compared with ALH vaccinates. No significant difference in resistance was detected between LIVE and FIA vaccinates. Lesions in ALH vaccinates were not significantly different than those in phosphate-buffered saline (PBS) controls. Increased IgG responses to all antigens were significantly associated with resistance to experimental disease; however, IgG responses to CPS were most highly correlated with resistance. The only IgM response which was significantly correlated with resistance was the response to CPS. These studies indicate that serum IgG antibody responses to various surface antigens of P. haemolytica, as well as LT, can enhance resistance to experimental pneumonic pasteurellosis. Serum IgM responses, however, do not appear to play a major role in resistance to experimental disease.     

Development of a multiplex PCR assay to detect Edwardsiella tarda,Streptococcus parauberis,and Streptococcus iniae in olive flounder (Paralichthys olivaceus)

A multiplex PCR protocol was established to simultaneously detect major bacterial pathogens in olive flounder (Paralichthys olivaceus) including Edwardsiella (E.) tarda, Streptococcus (S.) parauberis, and S. iniae. The PCR assay was able to detect 0.01 ng of E. tarda, 0.1 ng of S. parauberis, and 1 ng of S. iniae genomic DNA. Furthermore, this technique was found to have high specificity when tested with related bacterial species. This method represents a cheaper, faster, and reliable alternative for identifying major bacterial pathogens in olive flounder, the most important farmed fish in Korea.     

Serum antibody isotype responses of Fasciola-infected sheep and cattle to excretory and secretory products of Fasciola species

This study investigated the immunoglobulin isotype responses of sheep and cattle chronically infected with Fasciola hepatica and Fasciola gigantica to adult F. hepatica excretory/secretory products (Fh-ES) or F. gigantica excretory/secretory products (Fg-ES), respectively. An antibody enzyme-linked immunosorbent assay (Ab-ELISA) was used to determine serum antibody (total Ig, IgG(1), IgM, IgG(2) and IgA) responses. At necropsy, the mean number of flukes recovered was lower in cattle than in sheep. All F. hepatica and F. gigantica infected sheep and cattle showed an increased total Ig levels from 3 to 4 weeks post-infection (wpi). Among isotypes IgG(1) was most dominant while IgM was the earliest (2 wpi) to be detected in both sheep and cattle infected with both F. hepatica and F. gigantica animals. IgG(2) response was early (2 wpi) in sheep infected by F. hepatica but there was no response in sheep infected with F. gigantica. There was a late and strong IgG(2) response in cattle infected with both flukes. The IgA isotype showed an early and a clear biphasic response in sheep with F. hepatica but was less pronounced in F. gigantica infected sheep. While IgA response to Fh-ES was noticed 5 wpi in F. hepatica infected cattle, it appeared much later (21 wpi) in those infected with F. gigantica. The dominance of IgG(1) isotype in infected sheep and cattle suggest an associated Th2 response. This early response to adult Fasciola spp. ES antigen suggests an early exposure to the antigen presumably through the cross-reacting ES products of juvenile flukes. There is clearly difference in IgG(2) isotype response in cattle (resistant) compared to sheep (susceptible). The late IgG(2) response in cattle may suggest late Th1 involvement in bovine cellular responses to adult Fh-ES/Fg-ES.     

Dose dependence specific and non-specific immune responses of Indian major carp (<Emphasis Type="Italic">L. rohita</Emphasis> Ham) to intraperitoneal injection of formalin killed <Emphasis Type="Italic">Aeromonas hydrophila</Emphasis> whole cell vaccine

Specific and non-specific immune response to different doses of formalin killed whole cell vaccine of Aeromonas hydrophila to Indian major carp (Labeo rohita) was evaluated in laboratory condition. Three different doses (10⁵ CFU/ml, 10⁷ CFU/ml, 10¹⁰ CFU/ml) were administered (0.2 ml/fish) intraperitoneally for 1 month. Among the three doses, 10¹⁰ CFU/ml elicited the highest antibody and protective response followed by the doses 10⁷ CFU/ml and 10⁵ CFU/ml. Upon challenge with the virulent strain of A. hydrophila, the relative percentage of survival was recorded up to 80% at highest dose of 10¹⁰ CFU/ml. The non-specific responses, similar to the specific immune responses were also maximum at highest dose of 10¹⁰ CFU/ml. Similar to the specific immune responses, the non-specific responses were maximum at highest dose of 10¹⁰ CFU/ml. Therefore, dose containing 10¹⁰ CFU/ml of formalin killed cells was found to be the most effective dose for vaccination which increased the immunity in Indian major carp (Labeo rohita) to a larger extent.     

Serum antibody response of Castellana sheep to Haemonchus contortus infection and challenge: relationship to abomasal worm burdens

Primary and secondary serum antibody responses to Haemonchus contortus were studied in Castellana sheep. Ten-month-old sheep were infected (200 L3/kg live weight (lw)) and challenged (400 L3/kg lw) or uninfected and equally challenged with H. contortus. Primary infections induced a partially protective response upon challenge, characterized by higher serum protein levels, longer prepatent periods, lower fecal egg counts, and significant reduction in the establishment rate of the parasite and abomasal adult and L4 worm burdens. The resistant status of the infected and challenged sheep was not clearly related either to the serum specific antibody levels (IgG: IgG1, IgG2; IgM; IgA) estimated by ELISA or to immunodetection patterns in the Western blots.     

Serum antibody response to Mycoplasma hyopneumoniae measured by enzyme-linked immunosorbent assay after experimental and natural infection of pigs

Studies were conducted under experimental and field conditions to determine the effect of infection with M. hyopneumoniae on the immune response in serum as measured by ELISA. Following intratracheal challenge or contact exposure, serologically negative pigs derived from mycoplasma-free piggeries developed an immune response within 10 days. This response continued to rise for a further 50 days. In a field study in a commercial piggery, no animals (0/44) were observed to have M. hyopneumoniae antibodies at day 86 of life. However between day 86 and day 144, 97.7% (42/43) animals sero-converted. These results are discussed in terms of infection spread, particularly in the grower/finisher shed.     

The development of morphologic changes and the antibody response in guinea pigs experimentally infected with Brucella suis, biotype 2 bacteria

Sixty-two guinea pigs were infected vaginally, perorally, intranasally, conjunctivally and subcutaneously with the bacteria B. suis, biotype 2. The inoculum contained 13.8.10(9) of brucellas in 1 ml of physiological solution. Subcutaneous infection lasted 151 days, the other types of infection 56 days. All types of infections resulted in brucellotic changes developing in relation to the type and duration of infection. The least marked changes were observed after peroral infection. Brucellosis was chronical and the changes in liver, spleen, lungs, and after subcutaneous infection also in regional lymphoglandulae, were found out incessantly. Microscopically these changes were histiocytic granulomas. The pathogenesis of brucellosis process in guinea pig organism is influenced primarily by haematogenous propagation. The highest serological reactivity was caused by subcutaneous infection, the lowest by peroral infection. In the course of different types of infection the titres of agglutination and complement-fixation antibodies varied and the highest values were recorded between the 21st and 56th day. The diagnostic effectiveness of the surface fixation test was verified and no decrease in its sensitivity, not even in the chronic phase of infection, was observed. An incomplete correlation between morphological changes and serological reactivity in guinea pigs was detected. The highest number of Brucella infections was identified by histopathological examination which helped to reveal the initial stages of granulomas at the time when specific antibodies were not yet determined by serological tests.     

Serum antibody response to canine parvovirus, canine adenovirus-1, and canine distemper virus in dogs with known status of immunization: study of dogs in Sweden

Serum antibody titers to canine parvovirus (CPV), canine adenovirus-1 (CAV-1), and canine distemper virus (CDV) were measured in dogs with known immunization status. The dogs represented 3 groups: nonvaccinated dogs less than 12 months old; vaccinated dogs less than 12 months old; and adult dogs greater than 12 months old. For practical reasons, the population from which the specimens were obtained could be considered as free from natural infection with CAV-1 and CDV. In nonvaccinated dogs less than 12 months old, antibodies against all 3 viruses were measured at the time the dogs were given their first vaccination. Altogether, 50.7% of the dogs had titer greater than or equal to 1:10 to CPV, and 26.1 and 46.2% had titer greater than or equal to 1:8 to CAV-1 and CDV, respectively. The concentration of maternal antibody seemed to be of major importance for failure of immunization with use of inactivated CPV vaccine, but not with CAV-1 and CDV vaccination. In dogs less than 12 months old and vaccinated against CPV infection with inactivated virus, only 11.5% had titer greater than or equal to 1:80. In dogs vaccinated against infectious canine hepatitis and canine distemper, 63.2 and 78.3%, respectively, had titer greater than or equal to 1:16. In adult dogs greater than 2 months old and vaccinated against CPV infection, less than 50% had titer greater than or equal to 1:80, regardless of time after vaccination. There was no significant difference in titer between vaccinated and nonvaccinated dogs.(ABSTRACT TRUNCATED AT 250 WORDS)