Our research was conducted in the conditions of Bila Tserkva National Agrarian University vivarium. For experiments there were formed 5 chicken groups (one control and four experimental) with 100 heads each. Chickens were kept on deep litter. Poultry in the control group was fed without supplementary feed additive cellulase enzyme; the I, II, III, IV experimental groups had cellulase enzyme according to advanced biotechnology.

For study of chemical composition and biological examination of carcasses on experimental broiler chickens there were selected four samples of pectoral and thigh muscles from each group. The poultry meat was determined for: moisture – by drying the sample in oven at temperature of 60–65 °C to constant weight; crude fat – by the method of binary mixtures; protein – by biuret method; crude ash – by ashing sample in oven at 450–500 °C. Biological evaluation of broiler meat, which were fed by cellulolytic enzymes, obtained by different techniques, conducted with infusoria culture Tetrachymena puriformis strain WH14 (micromethod).

It is established that feeding broilers by complete diet with cellulase affected the chemical composition of the breast and femor muscles. With increasing content of dry matter in the breast muscles increases the content of organic matter, and the bulk of the organic matter accounted for meat protein.

Thus, when broiler chickens experimental group II was fed by cellulases, obtained from strain Aspergillus terreus,  grown in culture fluid with copper content in organic – mineral form of 0.5 mg/L, there was an increase in the contents of the chest muscle protein and dry matter, respectively, by 8.2 and 4.6 % (p≤0,05), compared to control group. There was observed a tendency to increase of protein and organic matter content in the pectoral muscles, the difference from control was 5,2 %. However, cellulase reduced carbohydrate content in poultry of control group II by 13,2 % (p≤0,05), the fat content in the breast muscles of young poultry in experimental groups was on the same level as of control one.

Feeding second experimental group chickens with cellulase was also accompanied by the growth of content in the femoral muscle of dry and organic matter, respectively by 4,5 and 4,6 % compared with the control group, but the difference was not credible. The dry matter content increase in the femoral muscle increased its organic matter content, the bulk of which refers to protein. This figure was higher than in control group by 13,6 %. Chicken broilers of III and IV control groups exceeded control counterparts by the level of protein in femoral muscles, respectively by 7,8 and 2,9 %, but the difference was not credible. The femoral muscles of control groups chickens accumulated less fatty tissue – by 6,4–20,9 %, which significantly improves the quality indices and biological value of meat. The difference had a tendency trend.

Determination of the biological value of broiler chickens meat was conducted taking into account the rate of Tetrachymena puriformis ciliates cell proliferation on the nutrient medium with added homogenized poultry muscle tissue samples. The criterion for determining the biological value was the number of cell culture, which created during 72 hours of cultivation on nutrient medium with meat content from poultry of experimental group, compared to the microorganisms number, obtained by growing them in nutrient medium, containing meat of broiler chickens that consumed feed of cellulase obtained by traditional biotechnology (control).

During the experiment it was established, that the tetrahimeny cells biomass increase intensity on nutrient medium with meat content of broiler chickens, which were grown in compound feed, containing cellulase derived from a strain Aspergillus terreus, which were cultivated in nutrient medium with adding 0,5 mg/l of copper chelate compounds, was higher than in the media with muscle tissue of the control poultry.

The biological value of poultry meat under research was slightly higher compared with the control – by 3.1 %. It was experimentally proved that cellulase inclusion in animal feed, obtained by advanced biotechnology, did not deteriorate the quality of broiler chickens meat. The biological value of the poultry muscle tissue as food, increases.

Thus, the use cellulase enzyme derived from a strain Aspergillus terreus, which were cultivated in nutrient medium containing 0.5 mg/l of copper organic complex compounds in feeding of broiler chickens, contributed to greater deposit of protein in meat of broiler chickens, which is important in terms of nutritional and dietary properties of poultry meat, obtained from the use of biologically active substances. Intensity increasing biomass of Tetrashumena puriformis cells showed that the biological value of broiler chickens meat, which were grown in compound feed with cellulase enzyme content, was higher by 3.1 % compared to the control. This indicates that the biocatalyst action in the poultry muscle tissue from fodder transforms more essential nutrient factors.

Key words: cellulases, protein, fat, crude ash, broiler chickens, biological value.