[The influence of technogenic pollutants on the immunity to Newcastle disease]
2009
Krukov, D.A. | Zheltov, V.A. | Kushnir, A.T., All-Russia Research and Development Inst. of Veterinary Virology and Microbiology, Pokrov (Russian Federation)
The impact of technogenic environmental pollution affects negatively on the functions of many systems of farm animals and poultry. The authors studied the influence of predominating and dangerous pollutants - compounds of lead and polychlorinated biphenyls (PCB) on postvaccinal immunity in chickens against Newcastle disease virus (NDV). The experiment involved 100 White Leghorn chickens at the age of 3 days which were divided into 5 groups. Imitation of intoxication was performed in 4 groups which were given a feed contaminated with lead acetate (LA) in concentrations of 0.03, 3.0, 3.0, 30 mg/kg of feed which was fed for 45 days. The chicken of the control group received pure feed. At the age of 15 and 45 days all the chickens were immunized with an aerosol of a dry virus vaccine based on the NDV strain La-Sota. Lead acetate had no negative impact on accumulating specific antibodies. When adding 30 mg of LA/kg of feed the antibody titer was 6.3+-0.3 against 5.3+-0.1 log2 in the control group. The challenge of the chickens with strain T-53 in 14 days after the second vaccination caused no their death. Another series of experiments was conducted in 3 groups of chickens, whose feed was added with LA and Sovtol PCB (30 and 20 mg/kg of feed, respectively). The rated dose per head in group 1 was 90 mg of LA and 60 mg of PCB, in group 2 – 9 and 6 mg, respectively. After the first and second vaccinations the level of antibodies in the chickens of 2 experimental groups was almost the same as that in the control group. after the challenge with T-53 strain in group 1 9 of 15 chickens with typical disease signs died, in group 2 and control group no mortality was observed. The combined intoxication with LA and PCB can cause the death of poultry in the presence of antibodies in a blood serum at the level enough to protect. It is recommended to conduct control of feed additives so that the said toxicants are not in the concentrations above allowable levels
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