堆型艾美耳球虫早熟株免疫剂量研究

为确定堆型艾美耳球虫(Eimeria acervulina)早熟株合适的免疫剂量,设立7个早熟株免疫攻虫组、7个母株免疫攻虫组、1个不免疫攻虫组和1个不免疫不攻虫组,7个早熟株/母株免疫组的免疫剂量为孢子化卵囊100、200、400、600、800、1 000、2 000个/羽,经嗉囊感染,7日龄首次免疫,14日龄以同等剂量进行第二次免疫,21日龄以1.5×105个/羽的同源母株进行攻虫,28日龄结束试验,以增重、肠道病变记分和卵囊减少率为试验指标。并对早熟株中免疫保护效果较好的2个免疫剂量进行重复试验,免疫方法、试验周期、试验指标同第一批试验,攻虫剂量为2×105个/羽的同源母株。结果显示,免疫期间,各免疫组的增重与不免疫组差异不显著(P>0.05);攻虫期间,早熟株400、600、800、1 000个/羽和母株600、800、1 000个/羽免疫组的相对增重与不免疫不攻虫组差异不显著(P>0.05);肠道病变记分,除2 000免疫组明显低于不免疫攻虫组(P<0.05)外,其余各免疫组虽低于不免疫攻虫组,但与其差异不显著(P>0.05);卵囊减少率,早熟株和母株400～2 000个/羽免疫组均达90%以上,其中600、800个/羽免疫组达97%以上。用早熟株600、800个/羽进行免疫重复试验,两个免疫组攻虫期间的相对增重和肠道病变记分均与不免疫不攻虫组差异不显著(P>0.05),而与不免疫攻虫组差异显著(P<0.05),其卵囊减少率均在88%以上。研究结果表明,该堆型艾美耳球虫早熟株保持了良好的免疫原性,不同免疫剂量均能诱发鸡产生免疫保护力,其中以600、800个/羽的免疫效果更好,可考虑以600个/羽作为该早熟株在疫苗制备中的推荐免疫剂量。     

鸡巨型艾美耳球虫早熟株免疫效果试验

为确定使雏鸡获得良好免疫效果的最小巨型艾美耳球虫(E.maxima)早熟株接种量,分别于4日龄对免疫攻毒组以不同剂量进行首免,11日龄以首免2倍剂量对二次免疫攻毒组鸡进行二免。一次或二次免疫后7 d或10 d用同源亲本株进行攻毒,检测免疫攻毒鸡相对增重率、卵囊减少率、病变记分减少率(RLS)和抗球虫指数(ACI)。结果显示,一次免疫剂量≥400个孢子化卵囊/只或两次免疫的一免剂量和二免剂量≥100个孢子化卵囊/只和200个孢子化卵囊/只时,各免疫攻毒鸡的相对增重率≥85%,RLS≥70%,卵囊减少率≥75%,相对保护率≥90%,ACI≥170,均达到良好免疫效果。故将E.maxima早熟株的一次免疫最小免疫剂量定为400个孢子化卵囊/只,两次免疫最小免疫剂量定为一免100个孢子化卵囊/只和二免200个孢子化卵囊/只。     

巨型艾美耳球虫早熟株免疫剂量研究

为了确定巨型艾美耳球虫(Eimeria maxima)早熟株合适的免疫剂量,本文设立7个早熟株免疫攻虫组、7个母株免疫攻虫组、1个不免疫攻虫组和1个不免疫不攻虫组,7个早熟株/母株免疫组的免疫剂量为孢子化卵囊100、200、400、600、800、1000和2000个/羽,经嗉囊感染,7日龄首次免疫,14日龄以同等剂量进行第二次免疫,21日龄以8×104个/羽的同源母株进行攻虫,28日龄结束试验,以增重、肠道病变记分和卵囊减少率为试验指标。对早熟株中免疫保护效果较好的2个免疫剂量进行重复试验,免疫方法、试验周期、试验指标和攻虫剂量同第一批试验。结果显示:早熟株和母株200、400、600、800、1000、2000个/羽免疫组攻虫后的增重与健康对照组差异不显著(P>0.05),100个/羽免疫组明显低于健康对照组(P<0.05);各免疫组的卵囊减少率均达90%以上,肠道病变记分均与不免疫攻虫组差异不显著(P>0.05)。用早熟株200、400个/羽进行免疫重复试验,两个免疫组攻虫期间的增重和肠道病变记分均与健康对照组差异不显著(P>0.05),而与不免疫攻虫组差异显著(P<0.05),其卵囊减少率均在86%以上。研究结果表明,该巨型艾美耳球虫早熟株保持了良好的免疫原性,每只鸡免疫200或400个孢子化卵囊均可诱发鸡产生良好的免疫保护力,可考虑以200个孢子化卵囊作为该早熟株在疫苗制备中的推荐免疫剂量。     

堆型艾美耳球虫早熟株免疫雏鸡后血清抗体水平动态变化的研究

用堆型艾美耳球虫早熟株对雏鸡进行一次免疫和二次免疫试验 ,研究雏鸡血清抗体的动态变化。试验结果显示 ,在一次免疫试验中 ,各剂量组雏鸡均在免疫后 2天血清抗体出现较高的 OD值 ,之后呈下降趋势 ,11天后逐渐上升 ,到 12～ 13天时出现第 2个峰值 ,各组间的血清抗体 OD值比较 ,3 0 0 0个卵囊 /只剂量组极显著 (P<0 .0 1)高于 10 0 0个 /只、2 0 0 0个 /只和 5 0 0 0个 /只剂量组。在二次免疫试验中 ,8日龄首免、14日龄二免组雏鸡的抗体水平动态变化整体呈上升趋势 ,峰值 (0 .3 75 )出现在二免后第 10天 ,其后稳定地维持在较高水平 (平均 OD值为 0 .3 5 ) ,并且其抗体水平显著地高于 6日龄首免、12日龄二免组 (P<0 .0 5 )。抗体水平动态变化表明 ,堆型艾美耳球虫早熟株有较强的免疫保护力 ,其免疫方式可选用一次免疫 ,剂量为 3 0 0 0个卵囊 /只 ,也可采用二次免疫 ,即 8日龄首免 (15 0 0个 /只 ) ,14日龄二免 (15 0 0个 /只 ) ,从抗体动态变化的稳定性看 ,二次免疫更佳     

柔嫩艾美耳球虫早熟株免疫剂量研究

为了确定柔嫩艾美耳球虫（Eimenatenella）早熟株合适的免疫剂量,本文设立7个早熟株免疫攻虫组、1个不免疫攻虫组和1个不免疫不攻虫组,免疫组的免疫剂量为孢子化卵囊100、200、400、600、800、1000和2000个／羽,经嗉囊感染,7日龄首次免疫,14日龄以同等剂量进行第二次免疫,21日龄以8×10^4个／羽的同源母株进行攻虫,28日龄结束试验,以存活率、增重、肠道病变记分、血便数量、卵囊减少率为观测指标。对免疫保护效果较好的3个免疫剂量进行重复试验,同时设置商品化球虫疫苗对照组,免疫方法、试验周期、试验指标同第一批试验。结果显示：攻虫后,不免疫攻虫组出现5％死亡,而各免疫组来出现死亡;各免疫组卵囊减少率在61．57％～69．52％;200～2000免疫组的增重与不免疫不攻虫组差异不具备显著统计学意义（P〉0．05）;600～2000免疫组的肠道病变记分和血便数量均明显少于不免疫攻虫组（P〈0．05）。用600、800和1000进行重复试验,三个免疫组攻虫期间均来出现死亡,而不免疫组和疫苗对照组均出现5％死亡;三个免疫组的增重均明显高于不免疫攻虫组和疫苗对照组（P〈0．05）;早熟株免疫组的肠道病变记分和血便数量明显低于不免疫攻虫组（P〈0．05）,而疫苗对照组与不免疫攻虫组的相当（P〉0．05）;卵囊减少率在66.30％-78．75％,高于疫苗对照组的51．82％。结果表明,该柔嫩艾美耳球虫早熟株保持了良好的免疫原性,不同免疫剂量均能诱发鸡产生免疫保护力,其中600、800和1000个／羽的免疫效果均优于疫苗对照组,可考虑以600个／羽作为该早熟株在疫苗制备中的推荐免疫剂量。     

堆型艾美耳球虫早熟减毒株的选育

用早熟选育方法对堆型艾美耳球虫保定株进行了12代早熟选育,获得了潜隐期为74h的P_9株和62h的P_(12)株两个早熟株.两个早熟株不经选择传递2代,仍保持了早熟的特性.早熟株较其亲代株繁殖能力下降,致病力降低,但仍然保持了良好的免疫原性.早熟选育改变了虫体的内生性发育过程,引起了潜隐期的缩短.P_9株的裂体生殖为3代,P_(12)株的裂体生殖为2代.     

堆型艾美耳球虫早熟株对常用抗球虫药的敏感性测定

The study was aimed to explore the sensitivity of Eimeria acervulina （E.acervulina） precocious strain to some common anticoccidials (diclazuril, toltrazuril, sulfamonomethoxine, dinitolmide, decoquinate, nicarbazin, maduramicin, salinomycin and oxytetracycline). The sensitivity of E.acervulina precocious strain to 9 kinds anticoccidials was assessed by using 4 indices: anticoccidial activity percentage (POAA), reduction of lesion scores (RLS), relative oocyst production (ROP) and anticoccidial index (ACI). The results of these sensitivity trials indicated that the four indices POAA, RLS, ROP and ACI of groups toltrazuril, sulfamonomethoxine, dinitolmide, decoquinate, nicarbazin, salinomycin and oxytetracycline were all negative; the ROP index of diclazuril group was positive, the other three indices were negative. The ROP and ACI indices of maduramicin group were positive, the other two indices were negative. The results showed that the Eimeria acervulina precocious strain was sensitive to diclazuril, toltrazuril, sulfamonomethoxine, dinitolmide, decoquinate, nicarbazin, salinomycin and oxytetracycline, it was partly sensitive to maduramicin.     

堆型艾美耳球虫早熟株与强毒株致病性和繁殖力的比较

为了比较堆型艾美耳球虫（E．acervulina）早熟株与强毒株的致病性和繁殖力情况,通过测定接种 E．acervulina 早熟株与强毒株后鸡只的精神状态、临床症状、增重、病变记分和卵囊产量,表明早熟株的排卵囊高峰出现在第5天,比强毒株提前1 d,早熟株的繁殖力是强毒株的85．8％;早熟株感染后对鸡只增重的影响较小,接种剂量在2．40×104个卵囊／羽之内时,相对增重率均大于90．0％,早熟株组鸡的肠道病变记分显著低于同剂量的强毒株组的肠道病变记分（P ＜0．05）。由此认为,该早熟株符合球虫早熟株的低致病性特性,可用于鸡球虫病早熟苗的制备。     

鸡堆型艾美耳球虫南昌株分离纯化与初步鉴定

对南昌市场购买的成年鸡肠道,采用饱和盐水漂浮法检查,同时从肠内容物中获取混合球虫卵囊.在制备好的琼脂薄层的载玻片上滴加稀释适度的混合卵囊液.在显微镜下用手术刀片小心切割琼脂薄层,达到琼脂薄层上仅剩单一卵囊的严格要求.把单一卵囊包襄后经口感染雏鸡,又从感染雏鸡粪便中收集大量球虫卵囊待孢子化后再次重度感染雏鸡,掌握该球虫虫...     

Characterisation and histopathological observations of a selected Brazilian precocious line of Eimeria acervulina

Precocious lines of Eimeria acervulina "Cu" and "I" strains were obtained after 25 passages of oocysts in chickens that showed a shortening of the prepatent period for first oocyst output from 96 h to 81 and 82 h, respectively. Both precocious lines were evaluated for pathogenicity using as criteria weight gain, lesion score and total oocyst production. Infection of the "Cu" precocious line in chickens showed a high weight gain, low lesion score and low oocyst production, when compared to parent strain infected chickens. However, the results did not show a significant difference in relation to the criteria used above for the E. acervulina "I" precocious line when compared to its parent strain. This suggests a low degree of attenuation for the "I" strain but good attenuation for the precocious "Cu" line. The histopathological observations of chickens infected with the E. acervulina "Cu" parent strain and precocious line, comparing life cycle and intestinal lesions, showed: (1) parasite stages only in the border cells of infected chicken intestinal villi, for the precocious line; (2) parasite stages in the border cells of the intestinal villi and submucosa cells near the Lieberkühn glands of the intestine; and (3) high degree of inflammatory cells around the parasites in chickens infected with the parent strain. The "Cu" strain was also characterized for sensitivity against eight anticoccidial drugs. Sensitivity was observed for four anticoccidial drugs and partial resistance for four other drugs, although the strain had never had previous contact with anticoccidial drugs, suggesting the presence of a natural resistance factor. This Brazilian E. acervulina "Cu" precocious line showed attenuation for pathogenicity in chickens, suggesting that it could be a suitable strain for use as a live vaccine in Brazil.     

柔嫩艾美耳球虫山西株早熟系的免疫特性

对鸡柔嫩艾美耳球虫山西株早熟系的免疫特性进行了研究。结果表明：该株的早熟系与亲本株具有相同的免疫原性,但致病性大大降低;其最佳免疫剂量和次数：首次免疫为1500个/只,14 d后以2000个/只二免,二免后免疫保护期可达90 d以上,免疫后鸡群的抗球虫能力与血清中特异性IgG的变化规律一致;提示该早熟系具备早熟疫苗株的免疫特性。     

Absorption and deposition of xanthophylls in broilers challenged with three dosages of Eimeria acervulina oocysts

1. An experiment was designed to evaluate the effect of different doses of oocysts of Eimeria acervulina on intestinal absorption and skin deposition of xanthophylls (XAs) in broilers.

2. A total of 192 broiler chickens were randomly assigned to 4 groups: an uninfected control group and three groups inoculated with either 1 × 10², 1 × 10⁴ or 1 × 10⁵ sporulated oocysts of E. acervulina by gavaging at 21 d. There were 4 replicate pens (2 male and 2 female) per group.

3. Plasma xanthophyll (PX) and skin yellowness (SY) were measured in live birds weekly. At 42 d of age, SY was measured in the breast and abdomen after chilling and in the breast 24 h post-processing on refrigerated carcasses.

4. In general, in all challenged treatments, and for the duration of the study, the average PX decreased by 0.02 μg/ml (R² = 61.6%) for every 1000 inoculated oocysts, whereas PX increased by 1.26 μg/ml/d in uninfected birds.

5. The average SY in live birds from 21 to 42 d of age decreased by 0.019 b*/every 1000 oocysts administered, while SY of uninfected controls increased by 0.57 b*/d. It was also noted that in all treatments females had a greater SY (6.17 b*) than males for the duration of the study. The SY of the breast and abdomen was correlated (r = 0.76) in chilled carcasses. Breast SY in 24 h refrigerated carcasses was greater in the control group and for female birds.

6. Oocyst excretion was different between inoculated treatments only on 7 d post-inoculation (PI). Coccidia lesion scores in the duodenum averaged 1+ in infected birds and 2+ in birds given the highest oocyst dose.     

Relative virulences of a drug-resistant and a drug-sensitive strain of Eimeria acervulina, a coccidium of chickens

The virulence of a field strain of the chicken coccidian parasite Eimeria acervulina (Boreham I), dually resistant to the chemically unrelated anticoccidial agents decoquinate and clopidol, was compared with that of a drug-sensitive laboratory strain (Ongar) of the same species. Following a single heavy infection (prevented from recycling), both strains exhibited pathogenic effects typical of their species, viz., pathognomonic lesions, adverse effects on body weight gain and feed conversion ratio (FCR), but no mortality. One week after infection, chicks infected with either strain had a statistically significantly worse weight gain than the uninfected control; the Boreham I strain produced more oocysts, and caused slightly more severe duodenal lesions and poorer FCRs than the Ongar strain (all those effects being non-significant). After 3 weeks, there were no significant differences between any cumulative effects of either strain, nor any differences from the uninfected control. However, from 2 to 3 weeks after infection, chicks infected with either strain had a greater feed consumption and growth rate than uninfected chicks. When chicks reared on solid floors were given lighter infections of either strain, which were allowed subsequently to recycle naturally, there were no consistent reductions in weight gains, but feed consumption was higher than that of uninfected chicks. Whatever, the mode of infection, there were no significant differences between the weights of infected and uninfected chicks after 3 weeks, but the FCR of infected chicks was usually poorer than that of uninfected chicks. The difference between the virulences of the Boreham I and Ongar strains was not greater than that between various drug-resistant strains or between various sensitive strains of several Eimeria species recorded in the literature. It is therefore concluded that there was no difference between the virulences of the two strains of E. acervulina that could be attributed to the drug-resistance of one of them.     

帝克珠利对鸡堆型艾美尔球虫的药效实验

球虫病是威胁养鸡业的重要疾病之一,目前对该病的防治仍主要依赖药物［１］。但耐药虫株的出现使现有许多抗球虫药物疗效降低甚至丧失。因此,除了采取轮换用药及穿梭用药等方法以减少或延缓耐药性的产生外,开发评价和应用新型抗型抗球虫药物极为重要和必要。本文报道我...     

Isolation and selection of ionophore-tolerant Eimeria precocious lines: E. tenella, E. maxima and E. acervulina

Eimeria parasites were isolated from Nanhai Guangdong province (southern China) and studied in chickens in wire cages to evaluate their drug resistance against commonly used ionophores: monensin (100 mg/kg of feed), lasolacid (90 mg/kg), salinomycin (60 mg/kg), maduramicin (5 mg/kg) and semduramicin (25 mg/kg). Chinese Yellow Broiler Chickens were infected with 40,000 crude sporulated Eimeria oocysts at 15 days of age and prophylactic medication commenced a day prior to infection. Drug resistance was assessed for each ionophore drug by calculating the anticoccidial index (ACI) and percentage optimum anticoccidial activity (POAA) based on relative weight gain, rate of oocyst production and lesion values. Results revealed that Nanhai Eimeria oocysts comprising of E. tenella, E. maxima and E. acervulina, were resistant to monensin, sensitive to both salinomycin and lasolacid and partially sensitive to maduramicin and semduramicin. By selection for early development of oocysts during passage through chickens, the prepatent time of E. tenella, E. maxima and E. acervulina were reduced by 49, 36 and 22 h, respectively. The precocious lines are less pathogenic than the parent strains from which they were selected and conferred a satisfactory protection for chickens against coccidiosis. These ionophore-tolerant precocious lines could have wider applications in the development of anticoccidial vaccines for sustainable control of coccidiosis.