V. КUDASHEVA1, N.I. RYABOV1 1All-Russian Research Institute of Beef Cattle Breeding, Federal Agency of Scientific Organizations, 29, ul. 9 Yanvarya, Orenburg, 460000 Russia, e-mail sizova-l78@ya.ru, vniims.or@mail.ru; 2Orenburg State University, 13, prosp. <...> Pobedy, Orenburg, 460018 Russia, e-mail elenka_rs@mail.ru, osipaylova@mail.ru Acknowledgements: Hematological studies were performed using standard techniques in the Laboratory of Agroecology of Nanomaterials and Test Center of All-Russian Research Institute of Beef Cattle Breeding (accreditation certificate RA. <...> Analysis of chemical elements was performed in the laboratory of ANO Center for Biotic Medicine, Moscow (accreditation certificate GSEN.RU.TSAO.311, registration number in the State Register ROSS RU. 0001.513118). <...> Supported by Russian Scientific Foundation (project ¹ 14-36-00023) Received May 25, 2016 A b s t r a c t The problem of joint use of antagonist elements in the nutrition of farm animals is solved through a separate feeding with such trace elements and through an increase in the dosage of substances. <...> The unique properties of nanomaterials allow us to suggest the promising alternative solutions by combining antagonists in a single drug, i.e. ultra-fine powders of metal alloys. <...> In this paper, we for the first time compared the growth, haematological and biochemical parameters of broiler chickens (Russian cross Smena 7) after feeding them with individual salts of two microelements or their alloy in the form of nanoparticles. <...> The pair of antagonists (iron and cobalt) was chosen due to the same mechanism of their absorption in intestine. <...> Salts FeSO4Ÿ7H2O and CoCl2 (group I) or the derived nanoparticles (d = 62.5 ± 0.6 nm) of the metal alloy (group II) were used as sources of iron and cobalt and mineral supplement. <...> After calculation of the proportion of common microelement pool to the value of its entry with fodder expressed in percentage, the excess of iron up to 50.0 % was registered in the group when alloy nanoparticles applied (comparing to the pure iron), and the excess of cobalt was 34.7 %. <...> In this case, growth rate increased and metabolism changes in chicken were registered. <...> Feed costs for growing chickens in the control group was 2.48 kg that is by 9.3 and 13.7 % more than in groups I and II, respectively. <...> Using Co-Fe alloy <...>