Age-dependent accumulation of essential and toxic chemical elements in feather of Arbor acres broilers (Gallus gallus L.) reared in the South Ural biogeochemical province of Russia

Microelement imbalances are a serious threat to the health and productive traits of farm animals and poultry, so it is important to control and optimize input of chemical elements with regard to the conditions of a biogeochemical province and anthropogenic pollution. Currently, blood is used as a biosubstrate to determine the elemental status in birds. However, preference is given to feather when it comes to assessing the elemental status over a relatively long period, also because obtaining this biosubstrate is minimally invasive. The amount of available information on macro- and microelements content in the feather of poultry breeds and crosses is limited (especially in terms of age), which makes it difficult to objectively interpret laboratory data. In the presented work, we confirmed the possibility of using feathers as a biomaterial for determining the essential and toxic chemical elements status in Arbor Acres cross broiler chickens in commercial breeding in the conditions of South Ural biogeochemical province with areas of technogenic pollution. In addition, the age-related changes in elements content in chickens’ feathers under the specified conditions were characterized for the first time, and the percentile ranking of the obtained indicators was performed according to the method recommended for determining the physiological norm in the sample. The aim of the study was to determine the essential and toxic elements content in Arbor Acres broiler chickens of different ages under the conditions of South Ural biogeochemical province and to rank the obtained indicators by percentiles to estimate the limits of the age norm for the sample. The research was carried out on the territory of South Ural biogeochemical province of Russia on clinically healthy Arbor Acres broiler chickens at the age of 7 days ( n = 120), 21 days ( n = 120) and 35 days ( n = 120). The content of nutrients, macro- and microelements in the diet of the examined birds was within the limits of the requirements for broiler chickens during the corresponding growing periods. Blood and feathers (the flight feathers were plucked out) were used as compared biosubstrates. The proximal part of the feather weighing at least 0.4 g was selected for research. The elemental composition of feathers and blood serum was determined by inductively coupled plasma atomic emission and mass spectrometry (ICP-DRC-MS). The results of the quantitative determination of each element in feather were ranked in ascending gradation in the form of an ordered series according to the recommendations of the American Society for Veterinary Clinical Pathology (2.5 and 97.5 percentile). It was found that the content of P, Cr, I, Se, Li, Si, As, Hg, Sn, Sr in feather of broiler chickens varied significantly depending on age. In this regard, the age factor must be taken into account when developing reference intervals for specific regions. In this study, percentile ranking (2.5 and 97.7 percentiles with a confidence interval СI = 90 %) of data on 25 chemical elements (Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, I, K , Li, Mg, Mn, Na, Ni, P, Pb, Se, Si, Sn,