Today it is known that the final weight of broiler chickens of modern crosses is determined in a large extent by feeding character in the first week of life of the starting period, when intestinal microflora is forming and there is an intensive growth of the internal organs, especially the gastrointestinal tract, the size and number of intestinal villi are increasing, which deter

mine the absorption capacity of the intestine, and hence feed intake, digestion and assimilation of nutrients and poultry growth [1, p. 25; 2, p. 33; 3, p. 27]. Our investigations are aimed at determining the optimal dose of NuPro and its impact on feed digestibility, metabolism, performance and meat quality of broiler chickens.

In accordance with the plan of research, a scientific and economic experiment was held - on the establishment of the optimal dose of feeding broilers chickens at the start of NuPro feed additive taking into account certificate of its quality and composition. The experiments were performed in a production environment of Staroselskyi plot LLC "Cherkassy Poultry Plant" on broiler chickens cross Ros- 308. The material for the study were broiler chickens cross Ros-308. 500 one-day broiler chickens were selected for the experiment – analogues of body weight, mobility, agility, size of prenatal yolk, pubescence, the state of limbs, beak, eyes, umbilical cord, cloaca and cover of wings with feathers, from which five groups of 100 heads each were formed, 1 – control, 2, 3, 4 and 5th – research. With the age the chickens at the beginning and end of the experiment and their total length were the same – 1 and 42 day. In the experiment the chickens of the 2, 3, 4 and 5^th experimental groups during the first 7 days received NuPro feed additive with forage instead of soybean meal correspondingly at a dose of 10, 20, 30 and 40 g / kg, thus its optimal dose was ascertained at 20 g / kg.

Despite of the fact that the broiler chickens of experimental groups received NuPro feed additive with a forage only during the first 7 days of the staring period, their digestibility of nutrients at the age of one month in all groups clearly dominated. The nature of the effects of different doses of NuPro preparation in forage on the chemical composition of broiler chicken meat was judged by the results of laboratory analysis of the chest major muscle. Analysis of the results showed that the studied dose of NuPro effected differently on the individual indicators of meat composition.

Among the organic constituents of meat the most important is protein. In our studies, the introduction of NuPro in the forage on the first week of the staring period of broilers growing of research groups contributed to the increase in their meat mass of protein by 0.24–0.82 %. Regarding to fat, we marked the tendency to reducing its content in the meat of broilers of research groups under the influence of NuPro feeding.

Thus, the overall analysis and evaluation of the obtained results leads to the following conclusions:

– introduction of 1, 2, 3, and 4 % of NuPro (for the weight of forage) into forage improves, compared to the control, consumption of feed by broiler chickens during all the periods of their growth by 1.75–7.34 %;

– with the content of 1, 2, and 3 % of NuPro in the forage improves the safety of broiler chickens by 1 %;

– adding during the 7-day of starting period of 1–4 % of NuPro (for the weight of forage) to the forage has a positive impact on the growth rate of broiler chickens;

– usage of NuPro in the forage during the first 7 days at doses of 10–40 g / kg instead of soybean meal improves meat quality of broiler chickens.

Therefore, the data showed that feeding broiler chickens with NuPro feed additive in the first week of life contributes to the formation in their organism potential possibilities to improvement of digestibility of nutrients, which is evident throughout the all growing period. With stimulating effect of NuPro additive on digestibility of the nutrients of the diet realizes almost completely at the dose of 20 g / kg.

Key words: broiler chickens, productivity, dose, time of feeding, NuPro.