Utilisation of Iron Methionate in Broiler Chickens Compared to Iron Sulphate

35-day tests with broiler chickens treated with Bulgarian iron methionate administered through the food compared to the iron sulphate - heptahydrate in doses of 60 ppm and 300 ppm were conducted. The test involved 55 broiler chickens aged 10 days, divided into 5 groups of 11 chickens. The tests started on May 21st, 2012 and continued 35 days. The basic mixed feed was prepared by using a recipe for growing broiler chickens and an average content of 85.6 ± 2.4 mg Fe/kg. The appetite, health status - clinical one and individual weight of the chickens were controlled. On the 15th day samples of the liver from three euthanized chickens of each group were taken for histological and chemical studies. On the 35th day four more chickens of each group were subjected to the same studies. The liver samples intended for chemical analysis were frozen at -18°C and after 22 days were thawed out and tested for iron content by optical emission spectrophotometer ICP-OES 715-S. Samples of the cloacal content were taken from the chickens euthanized on the 15th and 35th day. They were also frozen and then thawed out, dried and analysed for iron content by using atomic absorption spectrophotometer equipped with graphic cuvette, model Spectra AA 800. The statistical results were processed by three different methods - parametric Anova one-way, non-parametric Mann-Whitney U-test method and by using the tables of Student-Fisher. During the test period no clinical symptoms and signs of disease or mortality were found in all treated chickens; there were no pathomorphological changes in the liver of the chickens. In general, the utilisation was more favourable for the iron methionate compared to the iron sulphate. It was better expressed in the low concentration - 60 ppm - a steady growth, trend for better deposition in the liver and significantly smaller amount - up to two times of iron in the cloacal content beneficial for the environment. The iron deposited in the liver of the treated chickens was from 40 to 60% more than that in the control ones.