In addressing the problem of increasing meat production in Ukraine the pig industry plays a big role as one of the most precocious and dynamic livestock industries. The 30–35 % of pig meat and fat is transformed into gross energy feed, whereas in cattle – only 14 %.

Pork contains all the essential amino acids, minerals and vitamins. When compared to other livestock meat – pork contains fewer defective proteins like collagen and elastin. Fat is an important source of essential fatty acids income into the body. The pig industry spends 1.5–2 times less feed per body weight gain as compared to sheep and cattle, pigs have by 25–30 % higher carcass yield. The share of bones in the carcasses of pigs is 2 times less than in cattle.

Zinc plays an important role for animals and humans. Its biological role associated with the activity of the endocrine glands, where it is mostly concentrated. Zinc is necessary for function of the endocrine glands, its participation is necessary in the mechanism of cell division. Thus, the effect of zinc on animals and rations optimization is vivid as this trace element influences the normalization of metabolic processes.

We studied the optimal dose for mixed-ligand complex of zinc in fodder for large white breed young pigs to provide maximum meat productivity.

Research and economic experiment was conducted on fattening young pigs of Large White breed. Feeding growing pigs for meat was performed by own production fodder.

Pork is easily digestible and has a high content of full protein and essential amino acids, and pork fat is a source of essential fatty acids, including arachidonic. Therefore rational nutrition makes a base to improve animals productivity and increase their slaughter weight to produce products of high biological value.

To study the effect of different levels of mixed-ligand complex of zinc on animal slaughter qualities and chemical composition of meat and fat we used the control slaughter of animals.

Analysis of the control slaughter of animals showed that the effect of different doses of zinc chelate to slaughter pigs as positive. Were selected for slaughter pigs with the most consistent average live weight in the group. Thus, the 2nd experimental group pigs weight exceeded control by 1.7 %, the 3rd – 1.8 %; the 4th – by 2.7 % and the 5th – by 3.2 %.

For mass slaughter animals in group 2 analogue control dominated by 2.2 %; 3rd – 2.6; 4th – 4.1 (p≤0,05) and 5th – 5.1 % (p≤0,01).

Animals in the control group were inferior to the analogs from experimental groups at slaughter yield. The value of this indicator in the 2nd experimental group pigs was higher as compared to the control by 0.3 %; 3rd – 0.5; 4th – 0.9 and 5 th – 1.2 %. The results of internal fat weight showed that most of his weight was noted in pigs of the 4th and the 5th experimental groups as compared to control animals by 4.8 % and 6.7 %. Significant difference between the performance of the control animals and experimental groups are not set. As a result of weighing the head, feet and pig skins in the 2nd experimental group did not differ from that of controls. Animals in the 3rd, the 4th and the 5th groups dominated their control counterparts by weight of head, respectively by 1.4 %; 1.6 % and 2.2 %; of feet weight – by 1.2 %; 3.6 % and 4.8 % and skin weight by 0.3 %; 0.5 % and
1.2 %, but the difference was statistically improbable.

The thickness of the bacon over 6–7 thoracic vertebra was the largest in the 3rd and the 4th experimental groups –
35.2 mm. The figure for the 2nd and the 5th experimental group pigs, was same as in control.

The "muscle cell" area under analysis in experimental groups animals as compared with control counterparts was higher and amounted to – 30,2–30,5 sq. cm, which is by 1,3–2,3 % higher than the control figure. Data analysis of carcasses morphological composition showed that the meat yield of experimental groups animals was high.

It is worth noting that by live weight experimental groups pigs dominated counterparts in the control group. The experimental groups meat yield was, respectively by 1.5 %; 3.1; 4.6 (p≤0,05) and 6.6 % (p≤0,01) higher compared with the control. The share of animal fat in meat of the 2nd experimental group exceeded the control by 2.0 %; the 3rd and 4th – by 5.1 % (p≤0,05) and the 5th group – by 7.1 % (p≤0,05).

The smallest bones in pig meat were in the 4th and the 5th experimental groups, the figure was lower than the control by 10.4% (p≤0,05); in pigs of the 2nd and the 3rd groups – by 2.1 % and 6.2 %, respectively. Thus, the feed enrichment for young experimental groups pigs of white breed with zinc chelate improves slaughter performance and morphological composition of carcasses. Thus the highest rates were found in the 5th experimental group animals. Analysis of the chemical composition of meat showed that the moisture content in it ranged from 72.4 to 73.4 %. The difference was statistically improbable. A similar pattern was seen in dry matter content.

The content of protein, which increases the biological value of meat was highest in animals of the 4th and the 5th experimental groups, which is by 0.9 % higher than in control counterparts. The value of this indicator in the 2nd and the 3rd experimental groups pigs was higher, respectively by 0.2 % and by 0.3 %, as compared with the control. The highest fat content in the longest back muscle was found in animals of the 1st control group – 4.84 %. This figure in pigs of the 2nd, the 3rd, the 4th and the 5th experimental groups was somewhat lower, respectively by 0.54 %; 1.06 %; 1.89 % (p≤0,05) and 2.01% (p≤0,05).

The ash content indicators in meat between control and experimental animal groups revealed significant differences that can be attributed to better absorption of zinc chelate. The highest ash content was determined in animals of the 5th – 2.07 % (p≤0,05) group. In animals of the 2nd, the 3rd and the 4th groups this figure exceeded control respectively by 0.04 %; 0.06 %; 0.09 %. The fat in experimental groups by chemical composition did not differ significantly from control. The protein content was highest in fat animals of the 5th experimental group and was 1.93 %, which is by 0.39 % (p≤0,05) higher as compared with counterparts of the 1st control group.

The significant difference between the weight of pigs internal organs was not observed. Feeding pigs by compound feed of different zinc levels in the form of organic mixed-ligand complexes of zinc increases slaughter performance, meat yield and chemical composition. It should be noted that large white breed pigs with the mixed-ligand complexes of zinc 83.2 g/t fodder dose much dominated over the control parameters.

Key words: pigs, mixed-ligand complex of zinc, feed, slaughter weight, carcass yield, morphological composition of carcasses.