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

The Journal of Applied Poultry Research (Impact Factor: 0.59). 12/2002; 11:351-357. DOI: 10.1093/japr/11.4.351

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
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The immune response to Histomonas meleagridis and dynamics of lateral transmission was investigated in turkeys. The inoculation of birds 2-16 weeks old produced no evidence of age differences in susceptibility. Commingling of uninoculated poults with infected poults in battery cages showed that litter type was not important in transmission, but infection rates were higher on bedding compared with wire floors. Repeated infection and treatment with dimetridazole produced birds resistant to reinfection, shown by reduced liver and cecal lesions. Immune protection was investigated by inoculation of poults with live or dead Histomonas from cultures. Vaccination by subcutaneous or intramuscular routes produced a protective response as shown by a reduction in the number of infected birds and the severity of lesions after commingling with infected birds. An ELISA test was devised to analyze the antibody response. Turkeys produced IgG antibodies in response to infection and after vaccination with killed histomonads.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Several studies have shown differences in the course of histomonosis, the infection with the trichomonad parasite Histomonas meleagridis, in different chicken breeds. In the present study, 10 specific-pathogen-free (SPF) layer-type (LT) chickens and twelve SPF meat-type (MT) chickens were infected intracloacally with 200,000 H. meleagridis trophozoites. One and two weeks postinfection (p.i.), three birds of each group were euthanatized. The remaining birds were euthanatized 3 wk p.i. Infected birds showed severe gross lesions typical for histomonosis in ceca at the first and second week p.i., while livers showed necrotic foci at 2 and 3 wk p.i., but only very rarely at 1 wk p.i. Differences between groups in the severity of lesions were statistically insignificant. In histopathology, LT chickens showed a significantly more-severe necrosis and ablation of the cecal epithelium 1 wk p.i. Parasites without inflammation were also found in most investigated spleens and lungs but only in a few kidneys. Investigation of these organs for histomonal DNA by real-time PCR confirmed these results. In addition, the humoral immune response against histomonal actinin 1 and 3 was measured by an ELISA. The humoral immune response against actinin 1 started sooner and was significantly higher in LT chickens than in MT chickens. In conclusion, the results of the present study suggest that the genetic background of the birds influences the reaction to infection with H. meleagridis.
    Avian Diseases 09/2014; 58(3):427-32. DOI:10.1637/10782-012814-Reg.1 · 1.11 Impact Factor


Available from