The high toxicity, bioaccumulative and increased distribution of cadmium (Cd) in the environment, makes it the most dangerous to any biological system, including immune system in human and animals. The effect of dietary intake of Cd (8.25 mg per kg) on accumulation and distribution of this heavy metal in various tissues, and functional changes in organs of immunity (thymus, bursa of Fabricius, spleen) in 35-day-old broiler cockerels were investigated, using biochemical and immunological methods. Significant increases in the Cd concentration both in central immunocompetent organs (thymus, bursa of Fabricius) and peripheral (spleen) were established. Excessive tissue level of Cd induced the prooxidative effect of this heavy metal in the organs. It was manifested in an increase of cell membrane lipid peroxidation (the enhanced malondialdehyde (MDA) concentration) in immune system organs. The oxidative stress resulted in immunocompetent cell damage. The fall of vital dye absorptive ability of immunocyte indicated the increase in the injured cell number. This harmful effect is in accordance with T- and B (C3) – population prominent depletion, organ relative mass reduction, and growth retardation in chicks, and was established as a result of dietary Cd loading for 5 weeks of the experiment.

In Latvia have not been carried out comparable studies regarding chemical pollution in organic and conventional milk, therefore the aim of the present study was to investigate the level of contamination in organic and conventional milk samples by heavy metals and aflatoxin M1. A total of 9 organic bulk milk and 9 conventional bulk milk samples were collected from different regions of Latvia. The content of lead, cadmium, copper, iron, and zinc were detected by flame technique, using atomic absorption spectrophotometer (AAS). The level of aflatoxin M, in organic and conventional milk samples was determined by high-performance liquid chromatography. The means of lead concentration in organic and conventional samples were 0.024 and 0.31 mg kgE-1 wet weight that exceed the permissible level for such a product. The cadmium content in organic and conventional milk samples is very low and fairly constant in all types of milk. The legally accepted upper limits of iron, copper and zinc are not exceeded by any analyzed milk sample, not even from conventional bulk milk. The study including heavy metals and aflatoxin M1 in a range of organic and conventional milk samples found no significant differences between organic and conventional milk (p=0.05) in the level of aflatoxin M1 and the heavy metals.