Bioavailability of organic and inorganic sources of chromium in broiler chicken feeds

Chromium bioavailability in animals depends on their species, age and physiological state as well as fodder composition and Cr source. However, inorganic forms of chromium are poorly absorbed compared to organic compounds. One hundred and eighty Isa Vedetta chickens were assigned to 2 groups, with 3 replications of 30 birds each, to determine the effects of different Cr source on its bioavailability, growth performance and carcass characteristics of broiler chickens. All chickens were fed with commercial standard concentrate mixtures (starter, grower and finisher) depending on the birds’ age. The dietary treatments consisted of a basal diet supplemented with chromium chloride (control group) or chromium-enriched yeast (experimental group). The treatments were supplemented with chromium so as to provide the same amount of pure chromium in both groups. Mortality, body weight and feed conversion rate were measured. On the 42nd day, 6 cockerels and 6 hens from each group were randomly selected, decapitated, blood samples were taken and carcass composition was determined. The bioavailability of Cr was evaluated by the level of that trace element in mentioned above soft and hard tissues. Furthermore, dry matter, crude protein and crude fat in muscles were determined and sensory analyses of quality muscles were carried out. Growth performance, feed conversion ratio and mortality were unaffected by treatments. There was no Cr source effect on outcomes of post-slaughter analyses. Cr enriched yeast effected the decrease (P ≤ 0.05) in crude fat and dry matter content in breast and leg muscles compared to chromium chloride. Inclusion of chromium-enriched yeast to concentrate mixtures increased (P ≤ 0.01) the level of Cr in analysed tissues, which might be evidence of its better bioavailability in chickens. It can be assumed that such animal origin products may be a good source of effectively absorbed Cr in human nutrition.