Assessment of the biological effect of combined irradiation in sheep for “safe” levels of radiation exposure

After a ground-based nuclear explosion, a large amount of fused melted radioactive particles (MRP) is formed. Entering the body of pasture animals with food, they accumulate in the proventriculus and abomasum, irradiating them against the background of total radiation exposure in sublethal doses. Research on combined irradiation of sheep (MRP+1.6 Gy) was carried out under the guidance of Professor B.N. Annenkov in 1978 on 48 sheep irradiated at a dose of 1.6 Gy in combination with feeding sheep with ORF activity from 9.99 to 51.80 MBq/kg of live weight. One group of animals served as non-irradiated controls. In addition, the work used experimental data obtained on 10 sheep irradiated at a dose of 2 Gy. Experimental data were analyzed using mathematical statistics methods. Combined irradiation is accompanied by moderate leukopenia, increased blood viscosity and damage to the gastrointestinal tract. Changes in the gastrointestinal tract are characterized by atony of the proventriculus, pain in the area of the xiphoid cartilage (mesh) and abomasum, hemorrhages and ulcers on the mucous membranes, as well as a decrease in the consumption of feed and water, which led to loss of live weight and death of animals. A study of the dynamics of death of irradiated sheep (probit analysis) showed that the minimum values of death (1 and 5%) can be caused by the consumption of MRP + 1.6 Gy with activity from 4.07 to 6.57 MBq/kg of live weight. Similar data were obtained when analyzing the values of ruminal motility (rumination) in irradiated sheep (3.6 and 5.4 MBq/kg live weight). Therefore, the “safe” level of ORS activity can reach 6.6 MBq/kg live weight of sheep +1.6 Gy of total irradiation.