Effect of dual infections of Escherichia coli and pure caecal Eimeria sp. in broiler chickens.

The interactive effect of Escherichia coli and pure caecal Eimeria spp. in broiler chickens was studied. Single and dual orally inoculations were assessed in six groups of 20 chicks each. Neither mortalities nor clinical signs were recorded on inoculated groups or control. There was a significant decrease in body weights in groups infected, either with E. coli or caecal Eimeria spp. or with both pathogens. The total oocyst output and caecal lesion score were high and severe in chicks infected with caecal Eimeria sp. alone or with E. coli prior to caecal Eimeria infection. Low oocyst output and moderate caecal lesion score were noticed in chicks inoculated with E. coli prior to or together with caecal Eimeria infection. The results suggested a synergistic action between E. coli and caecal Eimeria sp. in producing gross lesions. The electrophoretic distribution of serum proteins decreased in all chicks compared with control. The changes in serum protein fractions differed in inoculated groups and all protein components decreased quantitatively compared with controls. It was also shown that E. coli did not always invade the blood stream.

Effect of trickle infections with Cryptosporidium baileyi for a short duration on development of specific immunity in chickens.

This work was conducted to determine the effects of inoculations of low level of Cryptosporidium sporulated oocysts for the first and second weeks of life (trickle infection method) on the development of specific immunity in chickens. The results revealed that the specific immunity in chicken inoculated daily at one to 16 days of age with 200 sporulated oocysts was better than that of chicken inoculated form 8 to 15 days, and that inoculated with 1600 sporulated oocysts once at 8th day of age or twice at first and 8th day of age.

Influence of dietary aflatoxin on the severity of coccidial infection in quails.

One hundred-sixty one day old Japanese quail-chicks were divided into four groups and kept for 6 weeks. The first group was kept as control. Group 2 received 1 ppm of dietary aflatoxin from day zero of chick life till the end of experiment. Group 3 was inoculated with 5 x 10(4) sporulated oocysts of Eimeria alone. Quail-chicks of group 4 were inoculated with coccidial oocysts orally and received aflatoxin in their rations. The combination of aflatoxin and coccidia produced higher mortality rate, higher faecal scores with increased oocysts output and reproductive potential than those quails received aflatoxin or coccidia alone. Body weight and efficiency of feed utilization decreased in all treated groups. The maximal losses of body gain and efficiency of feed utilization were recorded in quail-chicks infected with Eimeria and received aflatoxin in their ration. The lowest erythrocytic count, hemoglobin values, PCV and leukocytic count were recorded in quails that infected with coccidia and received aflatoxin. The levels of total serum proteins, gamma globulins, calcium and phosphorus were decreased in case of quails infected with coccidia and received dietary aflatoxin. Total bilirubin and GOT activity appeared to be higher in quails infected with Eimeria and received aflatoxin.

Effect of some stressors on pathogenicity of Eimeria tenella in broiler chicken.

The present investigation was carried out to study the effect of stress on severity of Eimeria tenella infection in chickens. Stressors applied were vaccination and crowdness. One hundred and twenty five one-day old chicks were divided into five groups. The groups were as follow: group (1) control negative, group (2) control positive, group (3) crowded non-vaccinated, group (4) vaccinated, and group (5) vaccinated crowded. The chicks of 2-5 groups were inoculated with 10 x 10(3) sporulated oocysts of E. tenella per chick at 3rd day old, then challenged with 15 x 10(3) sporulated oocysts of E. tenella on day 28. The results revealed that, the highest mortality percent, oocysts production and caecal scores were recorded in the crowded vaccinated group. This group also exhibited the lowest weight of body, spleen, bursa and thymus. At the last four weeks, it was found that overstocking of chickens lead to elevation of corticosterone levels. Total proteins, glucose, calcium and phosphorus levels decreased in crowded vaccinated group.