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1.
Vaccines composed of either virulent or attenuated Eimeria spp. oocysts have been developed as an alternative to medication of feed with ionophore drugs or synthetic chemicals. The purpose of this study was to evaluate the use of gel-beads containing a mixture of Eimeria acervulina, Eimeria maxima, and Eimeria tenella oocysts as a vaccine against coccidiosis. Newly hatched chicks (Gallus gallus domesticus) were either sprayed with an aqueous suspension of Eimeria oocysts or were allowed to ingest feed containing Eimeria oocysts-incorporated gel-beads. Control day-old chicks were given an equivalent number of Eimeria oocysts (10(4) total) by oral gavage. After 3 days, chicks were randomly assigned to individual cages, and feces were collected between days 5 and 8 postinfection. All samples were processed for total Eimeria oocysts. At 4 wk of age, all chickens and a control nonimmunized group received a high-dose E acervulina, E maxima, and E. tenella challenge infection. Oocyst excretion by chicks fed gel-beads or inoculated by oral gavage was 10- to 100-fold greater than that of chicks spray-vaccinated with the Eimeria oocysts mixture (log 6.3-6.6 vs. log 4.8). Subsequent protection against challenge as measured by weight gain and feed conversion efficiency was significantly greater (P < 0.05) in gel-bead and oral gavage groups compared with spray-vaccinated or nonimmunized groups. Also, gel-bead and oral gavage groups showed no significant difference (P > 0.05) in weight gain and feed conversion efficiency compared with nonchallenged controls. These findings indicate that incorporation of Eimeria spp. oocysts in gel-beads may represent an effective way to deliver live oocyst vaccines to day-old chicks for preventing subsequent outbreaks of coccidiosis in the field.  相似文献   

2.
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.  相似文献   

3.
Experiments were conducted to determine whether chukar partridge (Alectoris chukar) chicks would develop protective immunity after inoculation with coccidia. Young chukar chicks in battery cages inoculated with 100 or more oocysts of Eimeria kofoidi or Eimeria legionensis had significant protection at challenge 4 wk later, as measured by greatly reduced oocyst shedding and improved weight gain as compared with unvaccinated, challenged controls. However, when birds were housed in litter pens and vaccinated by various regimens (including two species of chukar coccidia at 100/dose), coccidiosis rapidly spread through all treatments and caused significant mortality. Vaccination with Coccivac-T or with 100 oocysts of Eimeria dispersa did not prevent mortality resulting from accidental contamination, and feed treatment with a Lactobacillus competitive-exclusion product had no benefit. Most if not all of the mortality was from E. kofoidi. This study illustrated the natural fecundity of chukar coccidia in a floor-pen environment where multiplication rate and reinfection combine to produce clinical disease from a small original exposure. Further, these results cast doubt on the potential use of low doses of live oocysts as a vaccine in the chukar partridge.  相似文献   

4.
Donor chickens given feed medicated with one or two levels of decoquinate or given non-medicated feed were infected with oocysts of Eimeria tenella or E. maxima per os. Twelve hours after inoculation with oocysts liver, mid-intestine or ceca homogenates were fed to previously uninfected recipient chickens. The results showed that continuous medication with decoquinate was effective in preventing the transfer of sporozoites from the intestine to the liver. Oocysts were detected in the feces of all recipients of tissue from non-medicated donors, showing that some sporozoites of E. maxima and E. tenella are normally transferred to liver. Young broiler chickens were immunized by oral inoculation of E. maxima oocysts. The immune status of similar chickens inoculated with sporozoites of the same species directly into the liver or spleen were assessed. During the experimental period half of the chicks were provided with non-medicated food and the remainder were given feed supplemented with decoquinate; decoquinate was effective in arresting the development of the sporozoites. Two weeks after initial infection the birds were challenged with oocysts of E. maxima per os. Injection of sporozoites into the spleen did not protect against challenge. Birds inoculated with sporozoites into the liver were unable to develop a significant level of immunity. When the drug pressure was removed from these birds, parasitism of the intestine occurred and immunity developed.  相似文献   

5.
Anticoccidial effects of green tea (GT)-based diets were evaluated in chickens following oral infection with Eimeria maxima an ubiquitous intestinal parasite of poultry that impairs the growth and feed efficiency of infected birds. Five-week-old chickens were assigned to four groups (GT 0.5%, GT 2.0%, untreated/infected and non-infected control) and each group consisted of 15 chickens. Chickens were fed a standard diet supplemented with ground green tea for 2 weeks prior to infection with E. maxima (10,000 sporulated oocysts per bird). The effects of green tea on E. maxima infection were assessed by two parameters, fecal oocyst shedding and body weight gain. The green tea-fed chickens produced significantly reduced fecal oocysts (P<0.05) when compared to the E. maxima-infected group fed standard diet. The green tea-based diet, however, did not improve body weight loss caused by E. maxima infection. This study is the first to demonstrate anticoccidial effect of green tea on Eimeria parasites.  相似文献   

6.
The anticoccidial efficacy of amprolium, clazuril, and monensin were studied in sandhill cranes (Grus canadensis) infected with a mixture of Eimeria spp. oocysts. Five groups of four 1-day-old sandhill crane chicks were maintained on a crumbled ration containing no coccidiostat, amprolium at 2.2 ppm, clazuril at 1.1 ppm, clazuril at 5.5 ppm, or monensin at 99 ppm. After 2 wk on their respective feeding regimens, birds in each of the five groups were administered 25 x 10(3) pooled sporulated Eimeria spp. oocysts per os and observed for another 3 wk. A sixth group of four chicks served as nonmedicated, nonchallenged control during the study. Clinical signs and lesions consistent with disseminated visceral coccidiosis were observed in all challenged controls and birds fed amprolium and clazuril. Birds in these groups died 9-10 days after challenge. In contrast, only one monensin-medicated bird had clinical signs of disseminated visceral coccidiosis, and it died 13 days after challenge (DAC). This and an asymptomatic bird that were necropsied at study termination had less-severe gross and microscopic lesions of disseminated visceral coccidiosis. Two of three monensin-treated birds that survived challenge passed from 50 to 500 coccidial oocysts 11 to 18 DAC but were negative at study termination. Of the coccidiostats tested, monensin, at the dietary level of 99 ppm, was the only anticoccidial drug that provided protection against experimentally induced disseminated visceral coccidiosis in sandhill cranes.  相似文献   

7.
The effects of diclazuril and monensin, when included in the feed of turkeys from 0 to 10 wk, upon performance and development of immunity to Eimeria species was investigated. Birds were initially inoculated with a low dose of oocysts of three species of Eimeria at 3, 5, 7, and 9 days of age in order to simulate a natural infection. Weight gain and feed intake from 0 to 6 wk of age was significantly greater in medicated birds compared with those that received no anticoccidial medication. Weight gain and feed intake from 6 to 10 wk was greater in birds that received diclazuril than in unmedicated birds. No differences in performance were evident after drug withdrawal from 10 to 16 wk. Immunity to Eimeria species developed by 10 wk in birds that received no anticoccidial medication but did not develop in those given diclazuril or monensin.  相似文献   

8.
Nine thousand commercial breeder chicks (Chankee) reared in a floor pen were exposed to restricted numbers of Eimeria tenella and E. necatrix oocysts to confer immunity. Antibody induction in these chicks was examined by the enzyme-linked immunosorbent assay (ELISA) with antigen prepared from E. tenella oocysts. The oocyst excretion pattern demonstrated recycled infections which continued in these chicks for greater than or equal to 22 days after exposure. Antibody levels in their sera, as determined by the mean absorbence values in ELISA, increased gradually up to 38 days post-inoculation. Mean absorbence values of sera from control chicks remained at a low level. When infected and control chicks were challenged with the two species of coccidia, the test chicks were protected against both species. The antibody level did not change for 8 days in the challenge groups, while in the control chicks, absorbence in ELISA rose significantly and the mean absorbence value was higher than that in immunized chicks. Some factors which influence the results of ELISA are considered and the applicability of this method to measuring immunity against coccidiosis in chickens is discussed.  相似文献   

9.
Coccidiosis is the major parasitic disease of poultry. In this study, the role of the commercial probiotic MitoMax which contains Pediococcus acidilactici and Saccharomyces boulardii was evaluated by measuring body weight gain, fecal oocyst shedding, and serum antibody responses as an alternative control method of prophylactic drug against coccidiosis. Day-old broiler chicks were fed regular or probiotic diets supplemented with MitoMax at 0.01%, 0.1%, or 1.0% of diet, and challenged 2 weeks later with 5000 oocysts of either Eimeria acervulina (EA) or Eimeria tenella (ET). Birds fed 1.0% or 0.1% MitoMax-supplemented diets in EA- or ET-infected groups shed less (P<0.05) oocysts than control-infected chickens. Also, chickens fed 0.1% MitoMax-supplemented diet and infected with EA exhibited higher (P<0.001) serum Eimeria-specific antibodies than other groups. These results demonstrate that MitoMax may enhance the resistance of birds against coccidiosis by enhancing humoral immunity when included at > or = 0.1% of the broiler diet.  相似文献   

10.
An isolate of Eimeria meleagridis Tyzzer, 1927 was obtained by harvesting oocysts from the ceca of a turkey from northwest Arkansas and a pure line was established by infecting birds with a single oocyst. Oocysts were first produced in the ceca of infected birds from 102 to 108 hr after inoculation and were of similar size (mean length X width, 24.9 X 17.0 microm) to those of Eimeria adenoeides Moore and Brown, 1951 and Eimeria gallopavonis Hawkins, 1952. The line was identified as E. meleagridis based upon the development of large schizonts in the midintestine, and small schizonts in the ceca. Two generations of large schizonts were found 48 and 72 hr after infection, and at least two generations of small schizonts were found from 60 to 108 hr after infection. An inoculum of 2 X 10(5) oocysts was found to cause a significant reduction in weight gain from days 0-3 and 0-6 after infection, suggesting that the significance of this species of Eimeria as a pathogen of turkeys should be reassessed.  相似文献   

11.
Sublines of chickens selected for high antibody (HA) or low antibody (LA) response that differed at the major histocompatibility complex (MHC) were tested for response to Eimeria tenella. In Expt. 1, the first exposure to E. tenella was natural (in floor pens), and chicks were challenged orally 21 days later with 0, 928, or 1855 oocysts. In Expt. 2, chicks were reared in wire-floored batteries, vaccinated orally with 928 oocysts, and challenged orally 12 days later with 15,844 oocysts. Corticosterone (20 mg/kg) was mixed with feed from 24 hr before vaccination to 120 hr after vaccination in Expt. 2. In Expt. 1, LA chicks had more-severe cecal lesions but gained relatively more body weight after challenge than did HA chicks. In Expt. 2, cecal lesions were least severe in HA chicks that had been fed corticosterone, most severe in LA chicks fed corticosterone, and intermediate in chicks that were not fed corticosterone. No differences in response to E. tenella occurred as a result of haplotypes at the MHC.  相似文献   

12.
An experiment was carried out to assess the influence of tannic acid (TA) on integrity of the intestine in broiler chicks vaccinated against coccidiosis and challenged with the disease. In a 2 × 2 factorial design, the trial had five groups of 10 chickens each, including positive (group 2) and negative (group 1) controls. The chickens were kept on wood shavings and fed a commercial maize and soybean-based starter-grower diet. From day 1, groups 3 and 5 received TA (10 g kg(-1)) in their diet. On day 4, birds of groups 4 and 5 were vaccinated orally against coccidiosis with anti-coccidial vaccine, Livacox T?. Each dose of the vaccine contained 300-500 sporulated oocysts of each of Eimeria acervulina, Eimeria maxima and Eimeria tenella. On day 18, all experimental groups except for the negative (group 1) were challenged with 10-fold dose of Livacox T? to produce a mild coccidiosis infection. Faecal samples of individual birds were collected on day 23, and the number of faecal oocysts was determined. d-Xylose absorption test was also carried out on all birds on day 23. Immediately after d-xylose absorption test, all birds were killed humanely and the intestinal tract was removed, weighed and examined for gross lesions. Results showed that negative (group 1) and positive controls (group 2) had the highest and lowest levels of plasma d-xylose post-ingestion of the substrate, respectively. Vaccination and/or feeding TA raised the level of plasma d-xylose in infected birds, although this was not significant for TA-fed birds. Vaccination reduced but TA increased the total number of oocysts per gram of faeces. Birds of groups 2-5 had distinct intestinal lesions when compared with group 1. However, vaccination prevented intestinal lesions. Relative weights of intestinal parts were the lowest in group 1 and the highest in group 2. Vaccination but not TA reduced the relative weights of intestinal parts in infected birds. It was concluded that dietary tannins may reduce the efficacy of anticoccidial vaccines and alter the proper development of immunity against the disease.  相似文献   

13.
Repeated inoculation (immunization) of 2-week-old white leghorn chickens with 10(6) oocysts of the turkey coccidia Eimeria adenoeides or E. meleagrimitis partially protected chickens against moderate challenge with E. tenella or E. acervulina oocysts, but not with E. necatrix oocysts. After challenge, mean weight gains of the immunized chickens and the unchallenged controls did not differ significantly, but weight gains of unimmunized chickens were significantly lower. The mean feed-conversion ratio of the immunized challenged chickens was 3.14, as compared with 4.42 for unimmunized challenged control chickens. In general, immunization did not markedly reduce intestinal lesions. Repeated inoculation of chickens with the turkey coccidium E. gallopavonis failed to produce statistically significant protection against challenge with E. tenella, E. acervulina, or E. necatrix, as determined by weight gain, feed-conversion efficiency, and lesion scores. Antibody profiles of individual chickens did not correlate with protection.  相似文献   

14.
To determine whether northern bobwhite quail (Colinus virginianus) could be immunized against Eimeria lettyae by a low-dose inoculation of oocysts, we inoculated 30 birds each with either 100 or 1000 oocysts at 2 days of age (given orally by pipette). Four weeks after immunization, the immunized birds and unimmunized controls were challenged with 1 x 10(6) E. lettyae oocysts. Eight days after challenge, birds were killed and weighed, and their intestines examined for gross lesions. Effectiveness of the immunization was measured by analyzing weight gain, intestinal lesions, severity of diarrhea, feed conversion ratio, and oocyst production. After challenge, birds immunized with 100 or 1000 oocysts gained an average of 33.3 g and 28.9 g, respectively, whereas unimmunized challenged birds gained an average of 11.5 g. Immunized quail produced approximately 99.7% fewer oocysts, had minimal gross intestinal and cecal lesions, had minimal diarrhea, and had a 50% lower feed conversion ratio compared to unimmunized challenged controls. These findings indicate that vaccination is a viable option for controlling coccidiosis in quail and that further research into vaccination is warranted.  相似文献   

15.
给18日龄鸡胚接种一定剂量的柔嫩艾美耳球虫(Eim eria tenella)和/或堆形艾美耳球虫(E.acervulina)孢子化卵囊,出雏后在无球虫环境中笼养,1~10日龄每天收集各组粪便样本,计数克粪便卵囊数(OPG),并于14日龄时以大剂量同源孢子化卵囊攻虫,以相对增重率(RWG)、饲料转化率(FCR)、相对卵囊产量(ROP)评价免疫保护效果。结果显示,以E.tenella或E.acervulina卵囊免疫18日龄鸡胚,其卵囊排出的潜隐期及达到峰值的时间与1日龄雏鸡接种组相一致,有相似的排卵囊曲线,提示其诱导免疫的建立是在出雏后开始建立的。攻虫后各免疫组的RWG由攻虫对照组的31.9%~51.7%提高到了76.5%~83.6%,RCR由攻虫对照组的4.11~4.89改善为2.72~2.96,ROP降至4.7%~23.5%。结果表明以一定剂量E.tenella和E.acervulina卵囊单独或混合经羊膜腔免疫18日龄鸡胚都可以建立起针对出雏后14日龄同源攻虫的良好免疫保护力。比较混合免疫E.tenella和E.acervulina卵囊组与单一接种E.tenella或E.acervulina卵囊组的免疫效果发现,混合免疫组的各项指标均稍优于后者。  相似文献   

16.
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.  相似文献   

17.
The efficacy of leucocyte extract (LE) and sulphadimidine in preventing coccidiosis in naturally infected lambs on pasture was evaluated in 3 separate experiments, whereas the prophylactic effect of levamisole was studied in 1 of the experiments. LE prepared from ewes immune to coccidia (Eimeria spp.) was administered either intravenously or intraperitoneally to young lambs 7, 5, or 2 days before they were turned out on pastures contaminated with coccidia. In all experiments, LE failed to transfer protective immunity to the lambs against the first coccidial infection on pasture. The LE preparations used apparently had an immunosuppressive effect, which resulted in more severe clinical signs of coccidiosis in the recipients. The lambs given LE showed a higher incidence of diarrhoea, a poorer weight gain, a higher mortality, and a higher oocyst output than the untreated control lambs. In lambs treated with sulphadimidine at 200 mg/kg on days 12, 13, and 14 after turnout there was a reduced severity of the coccidial infections in all experiments. The sulphadimidine-treated lambs had better weight gains and passed fewer oocysts than the controls during the third and fourth week after turnout, but some of them developed diarrhoea. Lambs treated with levamisole at 2 mg/kg 2 days before turnout, at turnout, and 2 days after turnout were more severely affected by the first coccidial infection on pasture than the controls.To study the lambs’ immunity against a heavy challenge infection with coccidia as compared with their immunity against the natural reinfection on pasture, some of the lambs from the original groups (untreated, sulphadimidine-treated, LE-treated) were each inoculated with 2 mill. Eimeria spp. oocysts about 6 weeks after turnout. The oocyst counts of the challenged lambs, except the LE-treated lambs, increased to a new peak 19–20 days after challenge. The challenge infection caused a softening of the faeces and a marked depression in weight gain in all challenged groups of lambs, mainly between days 10 and 17 after challenge. The lambs were thus only partially immune to coccidia after the first coccidial infection on pasture. The lambs treated with either LE or sulphadimidine in connection with the first coccidial infection on pasture were not appreciably more susceptible to the challenge infection than the untreated lambs.  相似文献   

18.
Anticoccidial effects of xanthohumol   总被引：1，自引：0，他引：1  
Allen PC 《Avian diseases》2007,51(1):21-26
Xanthohumol (XN), a prenylated chalcone from the hops flower, was examined for its ability to reduce invasion of Madin-Darby bovine kidney (MDBK) cells by Eimeria tenella sporozoites (SZ), as well as to reduce invasion by E. tenella and E. acervulina SZ in the chick host. Additionally, XN was tested as an anticoccidial feed additive at 20 ppm against challenge infections with E. acervulina, E. maxima, and E. tenella. Cell invasion by E. tenella SZ was inhibited 66% by treatment of SZ with 22 ppm XN. This inhibition was associated with an apparent physical disruption of the apical ends of the SZ. Rectal challenges with E. tenella SZ treated with 5, 10, and 20 ppm XN resulted in significantly reduced gross-lesion scores and normal chick-host weight gains compared with challenge with untreated SZ. Oral challenges with similarly treated E. acervulina SZ, accomplished with prior antacid treatment, resulted in significantly reduced gross lesions and reduced oocyst shedding compared with challenge with untreated SZ and were associated with physical disruption of sporozoite morphology. In a pilot test, provision of feed supplemented with 20 ppm XN for 3 days before challenge to 6 days after challenge did not control challenge infections with E. acervulina, E. maxima, or E. tenella as judged by measurements of weight gain, feed conversion, and gross lesions. Although XN-fed chicks infected with E. acervulina and E. maxima shed fewer oocysts than those on control feed, the differences in numbers were not statistically significant (P > 0.05).  相似文献   

19.
To assess muscle breakdown during avian coccidiosis, the level of the non-metabolizable amino acid 3-methylhistidine (3MH) was determined in muscle and plasma from turkey poults that received an infection with a field isolate containing a mixture of Eimeria species. The effect of increased levels of parasitism was evaluated at 6 days postinoculation (DPI) in birds receiving 2.5 x 10(4), 1 x 10(5), or 2 x 10(5) oocysts each. The changes in 3MH levels during recovery from acute infection were assessed at 6-29 DPI in animals given 1.9 x 10(5) oocysts per bird. In some experiments, uninoculated birds given the same amount of feed as infected birds (pair fed) were used to determine the impact of feed deprivation on weight loss and 3MH levels. Infected birds had significantly elevated plasma and muscle 3MH at 6 DPI after a single dose of Eimeria oocysts. The plasma and muscle 3MH returned to control levels after 14 DPI. The 3MH levels increased with increased dose of oocysts. Plasma and muscle 3MH levels were well correlated, and an inverse curvilinear relationship between weight gain and plasma 3MH concentrations levels was observed. Plasma and muscle 3MH levels were significantly elevated in pair-fed birds, but 3MH levels in infected birds were increased by 30% over pair-fed birds. The results suggested that muscle breakdown, as assessed by plasma and muscle levels of 3MH, increased during the acute stage of Eimeria infection in turkey poults.  相似文献   

20.
Diclazuril, a new anticoccidial drug, was tested in young pheasants artificially infected with the three most common pathogenic species of Eimeria, E colchici, E duodenalis and E phasiani. In two replicate experiments each with 40 birds the mortalities in the infected controls were 50 and 25 per cent. Diclazuril was administered in the feed at dose levels of 1, 2 and 4 ppm from the day before the inoculation of coccidia until the end of the test on day 6 after infection. The 1 ppm dose failed to inhibit the development of the parasite completely, as was shown by a reduction of the weight gain of the birds and the output of a small number of oocysts. Diclazuril at 2 or 4 ppm adequately controlled the infection, with weight gains similar to those of the uninfected controls. At all dose levels, mortality, intestinal lesions and diarrhoea were prevented.  相似文献   

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