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The hypothesis tested was that exposure of broiler chickens to an electromagnetic field (EMF) may reduce the signs of coccidiosis infection, based on recent insights into immunology. The experiment had a 2 x 2 factorial design. An uninfected and an infected group did not receive further treatment, whereas the other uninfected and infected groups were subjected to EMF treatment. In the cages of EMF-treated birds, a field strength of 5 muT root mean square was created for a period of 30 min/d. Infected birds were given a single dose of a mixture of Eimeria species (1.76 x 10(4) sporulated oocysts of Eimeria acervulina, 1.25 x 10(4) sporulated oocysts of Eimeria maxima, and 7.5 x 10(3) sporulated oocysts of Eimeria tenella) through gavage into the crop. Infection with the Eimeria mixture induced intestinal lesions, shedding of oocysts, and a reduction in growth performance. Exposure of broiler chickens to the EMF antagonized the effects of infection. In the EMF-treated birds, the infection caused no effect on weight gain and feed intake, whereas the severity of intestinal lesions mediated by E. acervulina and E. maxima was less than in the infected controls. We suggest that EMF has anticoccidial activities and its application could serve as an alternative to the anticoccidial drugs currently used in poultry production.

A hypothesis is proposed how Low Frequency Electromagnetic Field (LF EMF) exposure can stimulate an immune response, based on recent insights in immunology. We hypothesize that the Immunent EMF treatment induces mild stress to cells, which then produce cytokines that function as alarms or so called danger signals for the immune system. In this way EMF treatment takes the place of multiplying pathogens, and the damage these cause, in the triggering of an immune response. In a first series of experiments in vitro common carp head kidney-derived phagocytes were used to determine ROS production as a measure for immune activation. Exposure to LF EMF signals (200-5,000 Hz) at 5 lT or 1.5 mT led to 42 or 33% increase in immune activity, respectively, compared to negative control values. EMF could also additionally stimulate chemically pre-stimulated samples up to 18% (5 lT) or 22% (1.5 mT). Significance of increase in ROS production in the total series was: p < 0.0001. In a second series of experiments in vitro commercial goldfish were used. Groups of fish were housed under equal conditions in at least four control tanks and 8-16 EMF-exposed tanks. Exposure was done with a predominantly vertical field at field strengths (rms) between 0.15 and 50 lT. Without treatment mortality was about 50% after 18 days, while the treatment at 5 lT reduced it to 20% on average. At field strengths 0.15, 0.5, 1.5, 5, 15 and 50 lT an equally strong effect was found. Reducing the field strength to 0.05, 0.06, 0.01 and 0.003 lT showed a gradually decreasing effect, which only at 0.003 lT is no longer statistically significant. Finally, in vitro experiments were done with 560 commercial broiler chickens exposed to infection pressure from coccidiosis. EMF exposure at 6.5 lT reduced intestinal lesions by 40% and improved feed conversion by 8%.

Problem statement: In a previous study, the exposure of broiler chickens to a weak Electromagnetic Field (EMF) reduced the severity of a coccidiosis infection. The birds were infected by gavage into the crop which was not representative for the field situation. Approach: The possible anticoccidial activity of EMF was investigated in broiler chickens with a simulated, commercial coccidiosis infection. There was an uninfected and infected group not receiving further treatment. Another uninfected and infected group were subjected to EMF treatment. The infection was induced by adding to the litter a mixture of E. acervulina, E. maxima and E. tenella. EMF treatment lasted for 30 min day^-1; the field strength within the cages was set to 5 μTesla rms. Results: Infection with Eimeria resulted in a transient reduction of growth performance in the control chickens. Exposure to EMF counteracted the effect of infection on growth performance. EMF treatment had no effect on oocyst shedding. In the infected birds exposed to EMF, the lesion scores related to the three Eimeria species were generally lower than in the infected controls. Due to cross-contamination, the uninfected birds also showed intestinal lesions, the severity being less than in the infected chickens. In the uninfected birds, EMF treatment also had reduced the severity of the lesions. Conclusion: In this study EMF exposure protected against coccidiosis in broiler chickens. Consequently, EMF was considered as a possible alternative to anticoccidial drugs.

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