Eimeria brunetti and Eimeria necatrix in chickens of Argentina and confirmation of seven species of Eimeria

Ten poultry farms (broiler breeder pullets, layer pullets, and broilers) in the provinces of Entre Rios and Buenos Aires in Argentina were examined for presence of Eimeria spp. Litter samples obtained from flocks 7-11 wk old were taken to the laboratory for oocyst counting and sporulation, then concentrated for inoculation into coccidia-free chickens. Species were identified by prepatent period, oocyst size, location and appearance of lesions in the intestine, microscopic examination of mucosal smears, and histology (to confirm Eimeria brunetti). On this basis, Eimeria praecox was found in two samples, Eimeria mitis in two, Eimeria acervulina in nine, Eimeria maxima in seven, Eimeria necatrix in three, Eimeria tenella in seven, and E. brunetti in four. These results confirm the presence of all seven recognized species of Eimeria in chickens in the Republic of Argentina.     

Isolation and pathogenicity of Australian strains of Eimeria praecox and Eimeria mitis

Objective To determine the presence of E praecox and E mitis in Australia, to isolate representative strains of these species from chickens and determine their pathogenicity.
Design Morphological, physiological and cross protection studies were undertaken to confirm the identity of Australian isolates of E praecox and E mitis.
Procedure Oocysts were isolated from a backyard flock at Jimboomba, southeastern Queensland and numbers of E praecox and E mitis enriched by passage in chickens immune to five other species of poultry Eimeria . Oocysts of mean conformation and size of the two species were purified by single oocyst passage. Two isolates that closely matched recorded parameters for E praecox and E mitis were selected and designated JP and JM respectively. The cross protection between the isolates and E acervulina was determined by infection and challenge experiments. The virulence of the two isolates was determined by comparing weight gains of groups of birds inoculated with JP isolate or JM isolate with untreated groups.
Results Isolates JP and JM most closely matched recorded parameters of E praecox and E mitis respectively. Groups of chickens, previously infected with JP and JM isolates, showed no significant protection against infection with E acervulina . In a separate trial, groups of susceptible chickens inoculated with 10⁵ oocysts of JP and JM isolates showed significantly reduced weight gains compared with untreated controls.
Conclusion Isolates JP and JM are E praecox and E mitis respectively, confirming the presence of these species in Australia. These isolates were found capable of causing significant reductions in weight gains in susceptible chickens.     

Immunohistochemical study of S100-like protein in Eimeria brunetti and Eimeria acervulina

We have investigated the expression of a calcium-binding protein, the S100 protein, in Eimeria brunetti and Eimeria acervulina stages. For this purpose, paraffin sections of distal ileum and bursa of Fabricius or duodenum from experimentally infected chickens were treated with anti-alpha-S100 (anti-alpha subunit of S100 protein) and anti-beta-S100 (anti-beta subunit of S100 protein) monoclonal antibodies and anti-S100 whole molecule polyclonal antibody. The avidin-biotin peroxidase method was used to demonstrate immunoreactivity. In the ileum, our results reveal a positive immunoreaction for the beta subunit and S100 whole molecule within the macrogametes of E. brunetti, whereas they were devoid of immunostaining after treatment of the paraffin sections with the anti-alpha-S100 antiserum. Schizonts and oocysts of E. brunetti and all the E. acervulina stages gave a negative reaction after treatment with any of the three antiserum used in the study. This result indicated that the S100 protein molecules within these stages were not recognized by the antibodies, suggesting that these molecules are different from those identified in macrogametes of E. brunetti. By contrast, in the epithelial cells, lining the lumen of the bursa of Fabricius, macrogametes of E. brunetti were stained by the three antibodies used. These results may indicate the existence of metabolic adaptations that enable the parasite to invade tissue sites different from those where the parasite usually develops.     

Eimeria praecox infection ameliorates effects of Eimeria maxima infection in chickens

The effect of Eimeria praecox on concurrent Eimeria maxima infection was studied in susceptible chickens. Clinical signs of coccidiosis were assessed in single E. praecox or E. maxima infections and compared to dual infection with both Eimeria species. Groups infected solely with 10(4)E. maxima oocysts displayed weight gains that were 48% of weight gain in uninfected controls. Weight gain in chickens infected only with 10(4)E. praecox oocysts was 90% of uninfected controls. Average weight gain in chickens infected with both E. maxima and E. praecox was 79% of controls, and showed no significant difference (P>0.05) from weight gain in E. praecox-infected chickens. Feed utilization (feed conversion ratio, FCR) in chickens infected with both species showed no significant difference (P>0.05) from FCR in non-infected controls or chickens infected with E. praecox alone; all showing a significant difference (P<0.05) from FCR in chickens infected solely with E. maxima. Although E. praecox did not appear to have a negative effect on weight gain and FCR, it did cause a significant decrease in serum carotenoids. Analysis of oocysts excreted by chickens during dual infection showed little effect of E. praecox on E. maxima oocyst production.     

斯氏艾美耳球虫的致病性及病理学研究

用纯种斯氏艾美耳球虫孢子化卵囊人工感染25只断奶幼兔,进行致病性和病理学研究。试验兔分为1个不感染对照组和4个感染组,各感染组每只幼兔分别口服感染2.0×103、1.0×104、5.0×104、2.5×105个孢子化卵囊。与对照组相比,接种2.0×103个和1.0×104个孢子化卵囊的两个感染组的平均病变记分、肝重指数、血清转氨酶活性有显著差异(P<0.05);接种5.0×104个和2.5×105个孢子化卵囊的两个感染组上述指标有极显著差异(P<0.01)。表明斯氏艾美耳球虫对幼兔具有很强的致病性,能导致严重的肝球虫病。     

毒害艾美耳球虫纯种卵囊收集鉴定及致病性测定

鸡球虫是养鸡业的一大疾病 ,严重阻碍着我国养鸡业的发展。在各种鸡病中 ,球虫病的发生率最高 ,占 1 /6～ 1 /5。Rose和 Long( 1 980 )报道英国养禽业因球虫病每年损失 5 5 0万英镑 ,其中一半是药物费用 ;在美国损失可能达到 5 0 0 0万英镑。 Rose和Long( 1 985 )保守地估计全世界养禽业每年球虫造成的损失为 5亿美元左右 ,其中 2 .5亿美元用于药费支出 [1]。中国是养鸡大国 ,养鸡数量居世界之首 ,但由于集约化程度低 ,饲养环境差 ,保健系统不完善因素的影响 ,球虫病所造成的损失 ,可能高于世界平均水平。球虫病所造成的经济损失至少 5 0 …     

Energy and nitrogen metabolism of chickens infected with either Eimeria acervulina or Eimeria tenella.

1. The effects of sublethal infections of E. acervulina and E. tenella on the energy and nitrogen metabolism of groups of five broilers aged 16 d were studied for 16 d in respiration chambers. 2. The metabolisable energy content of the diet for chickens infected with E. acervulina was 0.689 of its gross energy content and N retention was 42.5 g/100 g N intake compared with 0.738 and 47.1 g respectively, in uninfected pair-fed controls. Chickens infected with E. tenella were similarly affected. 3. Efficiency of utilisation of ME by chickens infected with E. acervulina was 0.43 during the first 8 d after infection, and 0.52 during the second 8 d compared with an overall efficiency by non-infected chickens fed ad libitum of 0.73. Maintenance energy requirement of infected chickens was higher during the first 8 d after infection than during the second 8-d period. 4. Body composition measurements showed that of the total gain in weight of chickens infected with E. acervulina, only 7.5 g/kg gain was fat and 213 g/kg was protein compared with 45 g and 210 g respectively for non infected chickens fed ad libitum. 5. E. acervulina and E. tenella infections reduced the apparent digestibility of total mineral, calcium and phosphorus.     

Effects of Natustat supplementation on performance, feed efficiency and intestinal lesion scores in broiler chickens challenged with Eimeria acervulina, Eimeria maxima and Eimeria tenella

The effects of dietary supplementation of Natustat™, a propriety plant derived product (Alltech Inc., KY, USA) and Salinomycin, on performance, feed efficiency and intestinal lesion scores were observed during two Eimeria challenge trials in broiler chickens. In the first trial chickens were challenged with Eimeria sp. via infecting the litter with a known amount of Eimeria oocysts. In the second trial the source of the Eimeria challenge was the litter from the first trial and the same treatment groups were assigned to the same pens as in the initial trial.

Birds were placed 55 per pen with seven pens per treatment. Performance parameters were recorded on days 21 and 42 during both trials. Intestinal lesion scores were assessed on days 14 and 21 during Trial 1 and on day 21 during Trial 2. Average weight gain and feed conversion ratios were significantly improved in the Natustat™ and Salinomycin treatment groups when compared to the non-supplemented infected group. Furthermore, lesion scores were lower on all sampling days in the Natustat™ and Salinomycin groups when compared to the non-supplemented group. However, only lesions associated with Eimeria tenella were significantly lowered by Natustat™ and Salinomycin supplementation.

Natustat™ and Salinomycin were equivalent in alleviating the negative performance effects associated with coccidiosis challenge. In summary, Natustat™ has the potential to be used as a natural alternative to chemotherapeutic drugs for Eimeria control.     

Vaccination of rabbits against coccidiosis using precocious lines of Eimeria magna and Eimeria media in Benin

Three groups of twelve 35-day-old rabbits were used for the experiment. Two groups were vaccinated with a mixture of precocious lines of Eimeria magna and Eimeria media originating from corresponding wild strains isolated in Benin. One group benefited of a booster whereas the second one was kept without booster. A third non-vaccinated group was used as control. All groups were challenged per os with an equal mixture of the wild strains of E. magna and E. media at a dose of 104 oocysts per animal. Three weeks after the challenge inoculation, no case of diarrhoea was recorded in the two groups of vaccinated rabbits, as compared to the non-vaccinated rabbits that developed diarrhoea. No mortality was recorded in the three groups. During the patent period, oocyst output of vaccinated rabbits was significantly lower than that of control animals (P < 0.01), confirming a good immunogenic characteristic of the precocious lines. No booster effect was noticed for the boost vaccinated group. The daily weigh gain of the two groups of vaccinated rabbits was significantly higher than that of the non-vaccinated rabbits (P < 0.05). Consequently the precocious lines of Benin origin turned out to be immunogenic and therefore constitute good potential candidates for vaccine production for this country.     

Attenuation of Eimeria species: further characterisation of two lines of Eimeria mitis

The immunogenicity of a 'precocious' and attenuated line (HP10) of Eimeria mitis was studied and the stability of attenuation of two precocious lines was compared with that of an embryo-adapted line. Chicks housed in wire-floored cages and given 1 X 10(5) oocysts of the HP10 line were protected against challenge with the parent Houghton strain and two field strains, but remained partially susceptible to the Durham and one other field strain. However, when chicks were kept in litter pens so that reinfection could occur freely, inoculation with as few as 1 X 10(3) oocysts of the precocious line resulted in complete immunity to both the Houghton and Durham strains for at least five weeks afterwards. The stability of attenuation of the precocious and embyro-adapted lines was examined by relaxing the selection pressures used to produce attenuation and then testing the virulence of the resulting lines. The precocious lines remained attenuated after several consecutive relaxed passages, in contrast to the embyro-adapted line which showed a marked reversion to virulence after six passages in chickens.     

鸡艾美耳球虫哈尔滨株的分离与鉴定

为研究鸡艾美耳球虫哈尔滨株单一虫种的生物学特性,本研究利用单卵囊分离技术分离了6种鸡艾美耳球虫哈尔滨株,用分离的单卵囊接种雏鸡,同时应用PCR方法对收集的单卵囊分离株进行球虫种类鉴定并进行同源性和系统进化分析.结果显示,分离得到的6株鸡艾美耳球虫分别为柔嫩艾美耳球虫、毒害艾美耳球虫、堆型艾美耳球虫、早熟艾美耳球虫、和缓艾美耳球虫和布氏艾美耳球虫,PCR结果表明单卵囊分离株确为该6种纯株.本研究表明毛细吸管单卵囊分离法简便易行,使接种难度降低,提高了接种成功率,为球虫的分子生物学研究奠定了基础.