Attaining the high level of the productivity of animals on condition of maintenance of their health and receipt ecologically clean products is impossible without providing them with biologically-active substances. In this connection in recent years much attention is paid to research of influence of different vitamin-mineral additives of organic origin on animals productivity.

In the system of the procedures led to the increase of production of goods of the pig breeding, next to the improvement of terms of feeding and maintenance and improvement of pedigree qualities of animals a large role is taken to the study of metabolism in early periods of post natal ontogenesis.

In zootechnical experiments the study of balance of substances that enter in the organism of animal is widely applied, and on this index we come to the conclusion about sufficiency of feed in the conditions of the tested feeding.

Balance of Nitrogen gives an opportunity to set the level of the use of protein of feed in the organism and estimate the influence of assimilated nitrogen of feed on formation of muscular tissue of the body.

The aim of the work was a study of economic action of mixed ligade of Copper in the composition pre-starter mixed fodder on balance of Nitrogen in the organism of piglets taking into account their breeds.

Full value of the mixed fodder, fed to the piglets during experience and protein that was contained in it may be estimated on the balance of Nitrogen.

On the amount of assimilated Nitrogen, in the first experience, pigs of large white breed of the 2nd, 3d, 4th and 5th tested groups exceeded control respectively on 2,1; 2,9; 5,2 and 6,3 %. Different levels of Copper in the ration stipulated a difference between the groups of pigs on the amount of Nitrogen released with an excrement. So, on the indicated index animals of the 2nd, 3d, 4th and 5th tested

On the amount of Nitrogen released with urine, animals of the 2^nd and the3d tested groups were the same. Advantage of pigs from the 4^th and the 5^th tested groups over the control group was respectively – 4,7 and 5,1%.

Ratio between the amount of assimilated and used nitrogen the pigs of the 2^nd  tested group prevailed control on 1,0 %; the 3d – on 1,4; the 4th – on 2,7; the 5^th – on 3,1 %. Administration of chelates of Copper to the mixed fodder of pigs of Landrass breed did not influence substantially on balance of Nitrogen in their organism, certain differences took place though. So, animals of the 2d,the 3d, the 4th and the 5th tested groups Nitrogen was assimilated more on 2,1; 4,3; 6,3 and
4,6 % respectively with the analogues of control group.

Pigs from control and tested groups differed between each other by the amount of released nitrogen with an excrement. So, for piglets of the 2d and the 3d tested groups nitrogen with an excrement was even, and the animals of the 4th  and the 5th tested groups released  it with an excrement on 8,2 and 6,6 % less in compare with control group.

On the amount of Nitrogen released with urine, animals of the 2d, 3d, 4th and 5th tested groups were leg behind from the control group on 0,9; 6,1; 4,3 and 3,7 %.

An important economic index is ratio of assimilated Nitrogen to fed with a fodder. On this criterion animals of the of the 4th tested group exceeded the control group on 3,1 %. Pigs of the 2d, the 3d and the 5th tested groups also prevailed the animals of control group on 1,3, 2,6 and 2,5 % respectively.

Thus, at feeding to the pigs of Large White and Landrass breeds the full ration mixed fodder with the different doses of organic mineral compound of Copper the balance of Nitrogen in the organism of the tested animals was positive. However, Nitrogen was best assimilated in an organism of those animals, content of mixed ligade complex of Copper in the mixed fodder presented for the Large White breed – 2,72 g/t and Landrass – 5,45 g/t of mixed fodder. On the indicated index these animals prevailed pigs that consumed a ration with the sulfate of Copper (15,1 g/t) on 6,3 and 6,4 %.

In the second conducted experiment on the three- and four breed hybrids the balance of Nitrogen the animals of experience groups had positive and clearly differed from the analogues of control groups. Using of different doses of mixed ligade complex of Copper in rations stipulated a difference between the groups of pigs on the amount of nitrogen released with an excrement. So, on the indicated index three breeds hybrids of the 2d, the 3d and the 4th tested  groups were leg behind to the pigs of control group on 1,1, 5,1 and 2,0 % respectively, and for the animals of the 5th tested group an amount of Nitrogen in excrement was less on 0,3 % in compare with control. On the amount of Nitrogen released with urine, advantage of pigs of the 2d, 3d, 4th and 5th tested groups presented 1,7; 7,8; 2,4 and 2,6 % respectively.

Using сhelates of Copper in the mixed fodder led to the increase of amount of assimilated Nitrogen in pigs of all tested groups I compare with the control group. This increasing was 2,5; 7,3; 2,8 and 2,5 % for the animals of the 2d, 3d, 4th, 5th tested groups.  

Purebred hybrids of the control and tested groups were fed by equal amount of Nitrogen there was no difference in the excrements and digestion among the groups. Animals of the 2d, 3d, 4th and 5th tested groups released nitrogen with excrement on 2,6; 5,5; 1,7 and 1,2% less than analogues of the 1st group. It testifies that animals from the 3d tested group used Nitrogen better then animals from the 2d, 4th and 5th groups. So, animals from the 2 d group assimilated Nitrogen – 11,46 g; 3d – 11,98g; 4th – 11,51 g; 5th – 11,53 g. Animals from the 3d group assimilated Nitrogen on 7,1% less then animals from the 1st group.            

The use of digested Nitrogen on sustentation and increase of body weight was high for the animals of all groups and presented in the 1st group 59,75 %, 2 – 60,65 %, 3 – 62,88, 4 – 60,62 and 5 – 60,73 %.

Thus, the most subzero index of the use of Nitrogen was shown in the piglets of control group, in feeding of that used the inorganic forms of Copper. Introduction in the composition of the mixed fodder for piglets on fattening of chelates of Copper in an amount of 10,9 g/t of mixed fodder assists the increase of amount of assimilated Nitrogen that testifies more intensive growth of muscular tissue in the organism of piglets of tested groups.

Key words: young pigs, rations, productivity, mixed fodler, live weight, Nitrogen balance.