Article

Effect of anticoccidials and antibiotics on the control of blackhead disease in broiler breeder pullets

J. Appl. Poult. Res 01/2002; 11:351-357.

ABSTRACT Broiler chicks inoculated with both Histomonas and cecal coccidia developed moderately severe blackhead disease. Antibiotics tested at normal feed or water additive levels had little effect on Histomonas lesions or weight gains. Bacitracin at 100, 200, or 300 g/ton reduced liver lesion scores (P < 0.05) but had no other positive effects. Apramycin at 300 ppm in water reduced liver lesion scores (P < 0.05), but did not improve cecal lesions or weight gains. Penicillin (100 ppm), chlortetracycline (100 ppm), tylosin (110 ppm), and sarafloxacin (40 ppm) in water did not improve liver or cecal blackhead lesions. Weight gains were improved relative to infected controls by treating with penicillin, tylosin, or sarafloxacin (P < 0.05). Five anticoccidials (salinomycin, diclazuril, nicarbazin, roxarsone, and lasalocid) were tested at common use levels in two trials. Results were similar in both trials; liver lesion scores in the nicarbazin treatment were reduced (P < 0.05) compared with controls and other medicated groups, and the number of birds positive for liver lesions was lower (P < 0.05). Otherwise, anticoccidials had no effect on liver or cecal lesion scores or weight gains. Control of coccidiosis by the anticoccidials (as shown by oocyst counts) varied among products but was not correlated with severity of blackhead lesions. These results suggest that the effect of cecal coccidia on susceptibility of chickens to Histomonas meleagridis is not a simple function of mechanical damage to the cecal mucosa.

1 Bookmark
 · 
139 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Paromomycin is an aminoglycoside antibiotic with activity against protozoa. Currently, paromomycin is registered for food producing animal species. In a pilot study we evaluated the efficacy of different doses of paromomycin in the feed against Histomonas meleagridis in experimentally challenged turkey poults. Groups consisting of 30 birds each were given feed with 100, 200 and 400 ppm paromomycin, respectively, starting on day 1 through to day 42. One group of 30 birds was left untreated. On day 21 all birds were infected intracloacally with H. meleagridis. Additionally, 10 birds were kept as a non-infected and non-treated control group. Before the challenge there was no significant difference between untreated and treated groups with regards to feed consumption and feed conversion rate. After the challenge, mortality was 80% in the infected nontreated birds. In the treated groups the mortality rate was 73.3%, 43.3% and 20%, respectively. No histomonal DNA was found in caeca and livers of the surviving birds. In addition, higher doses of paromomycin (200 and 400 ppm) led to reduced counts of Clostridium perfringens in the droppings. In conclusion, a prophylactic application of paromomycin as a feed additive was effective against the challenge with H. meleagridis under experimental conditions.
    Archives of animal nutrition 02/2010; 64(1):77-84. · 1.10 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Five different Artemisia annua-derived materials (i.e. dry leaves, pure artemisinin, and hexane, dichloromethane or methanol extracts of leaves) were screened for their in vitro activities against six clonal cultures of Histomonas meleagridis. Except for the methanol extract, all tested materials displayed in vitro activity against all tested protozoal clones. Neither the dry plant material, extracts nor artemisinin showed any antibacterial activity against the xenic bacteria accompanying the six H. meleagridis clones at concentration levels identical to the antihistomonal setting. The dichloromethane extract of dry leaves (Ext-DCM) (minimal lethal concentration=1.0 mg/ml) and artemisinin (half-maximal inhibitory concentration=1.295 mg/ml) had the most promising antihistomonal properties and were therefore subsequently tested in a standardized experimental infection model in both turkeys and chickens infected with clonal H. meleagridis. There were no differences between treatment groups, where all infected turkeys showed severe clinical histomonosis and demonstrated severe typhlohepatitis typical for histomonosis. Consistent with the infection model used, the infected chickens did not show any adverse clinical signs but contracted severe lesions in their caeca 7 and 10 days post infection (d.p.i.), liver lesions were absent to mild after 7 d.p.i. and progressed to severe lesions at 10 d.p.i.; thus no differences between treatment groups were observed. In conclusion, neither artemisinin nor Ext-DCM was able to prevent experimental histomonosis in turkeys and chickens at the given concentrations, which is contrary to the antihistomonal effect noticed in vitro even though the same clonal culture was used. The results of this study therefore clearly demonstrate the importance of defined in vivo experimentation in order to assess and verify in vitro results.
    Avian Pathology 08/2012; 41(5):487-96. · 1.73 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In recent years, a number of studies about Histomonas meleagridis, and more specifically about experiments in vivo involving H. meleagridis to investigate the pathogenicity and efficacy of drugs or vaccines, have been published. Together with older publications, a considerable amount of information about experimental infections with H. meleagridis exist, which is helpful for planning future animal studies and can reduce the number of birds used in such studies toward better animal welfare. One hundred sixty-seven publications describing experimental infections with H. meleagridis were published in scientific journals between 1920 and 2012. One hundred forty-two of these publications describe infections of turkeys (Meleagris gallopavo) and 52 infections of chickens (Gallus gallus). In 18 studies, experiments involving other species were done. The most popular routes of infection were the intracloacal application of histomonal trophozoites from culture material, from lesions or from feces of infected birds, or using larvae of the cecal worm Heterakis gallinarum (83 studies) and the oral application of eggs or other stages of the cecal worm containing histomonal stages (83 studies). During the last 10 years, intracloacal application of trophozoites has become the most popular way to experimentally infect birds with H. meleagridis due to its high reproducibility and reliability. In most studies, infection doses of several 10,000 or 100,000 histomonal trophozoites were used for infection, and the resulting mortality in turkeys was more than 70 %. First mortality can occur as early as 6 days p.i.; peak mortality usually is 13-15 days p.i. Lower infection doses may delay mortality about 2 days. In chickens infected by the intracloacal route, mortality and clinical signs are rare, but infection rates are similar. Cecal lesions can be observed from 3 to 4 days p.i., lesions up to 3 weeks p.i.; liver lesions may be lacking completely or be present only in a small number of birds. In most studies infecting birds with Heterakis eggs containing histomonal stages, several 100 to 1,000 Heterakis eggs were used. However, lower doses might be sufficient, as infection with as few as 58 eggs per bird caused a mortality up to 90 % in turkeys. Clinical symptoms start 9 days p.i., and first mortality occurs after 12 days, while most of the infected birds die between 19 and 21 days p.i. The infectivity of Heterakis eggs containing histomonal stages for chickens is similar as for turkeys, but mortality and clinical signs are rare. Further infection was done by oral application of histomonal trophozoites either grown in culture or using lesions or feces of infected birds (26 studies). These yielded very mixed results, with infection rates between 0 and more than 80 % in turkeys and chickens. After successful oral infection of turkeys, mortality occurs at roughly the same time as after intracloacal infection. Further 18 studies employed seeder birds to infect in-contact birds. Other means of infection were exposure to contaminated soil or litter (22 studies), feeding contaminated earthworms (7 studies), intracecal inoculation (4 studies), or parenteral injection (4 studies). Main methods to assess the course of the infection were mortality, observation of clinical signs and pathological lesions, monitoring of the weight of the infected birds, and detection of the parasite by various methods.
    Parasitology Research 11/2012; · 2.85 Impact Factor

Full-text

View
1 Download
Available from