Agrarian Science and Food Technologies

Kulik M.F., Doctor of Agricultural Sciences, Professor, Corresponding

Member of the National Academy of Agriculture Sciences of Ukraine

Didorenko T.O., Junior Researchers

Gonchar L.O., Junior Researchers

Institute of Feed Research and Agriculture of Podillya

Tkachenko T.Yu., Postgraduate Student

Vinnytsia National Agrarian University

Urea is the main nitrogenous end product arising from the catabolism of amino acids that are not used in biosynthetic reactions in mammals. Urea production should reflect not only alterations in the dietary intake of protein and patterns of utilization of amino acid but also an animals ability to retain dietary nitrogen in the body. Improving feed efficiency of pigs with dietary application of amino acids (AAs) is becoming increasingly important because this practice can not only secure the plasma AA supply for muscle growth but also protect the environment from nitrogen discharge with feces and urine. Lysine, the first limiting AA in typical swine diets, is a substrate for generating body proteins, peptides, and non-peptide molecules, while excess lysine is catabolized as an energy source. From a regulatory standpoint, lysine is at the top level in controlling AA metabolism, and lysine can also affect the metabolism of other nutrients. Dietary deficiency of lysine will impair animal immunity and elevate animal susceptibility to infectious diseases. Because lysine deficiency has negative impact on animal health and growth performance and it appears that dietary lysine is non-toxic even at a high dose of supplementation, nutritional emphasis should be put on lysine supplementation to avoid its deficiency rather than toxicity. Nevertheless, the underlying metabolic and molecular mechanisms regarding lysine effect on muscle protein accretion merits further clarification. Urinary urea excretion of pigs fed diets differing in amino acid adequacy was measured. It has been established that the urea content in blood, muscle tissue (meat) and liver in the experimental group of pigs is lower compared to control at a higher level of lysine in raw diet proteins. The urea content in the blood, muscle and liver of pigs in the control group is 12 g, 2 g, respectively, and much less in the liver. At the same time, the data in the pigs of the experimental group will be lower by 22-24%, while the content of lysine in the raw protein of the ration is higher by an average of 29%. Results of studies of urea content in pig blood indicate that in the experimental group it was 24% lower than control. Thus, the content of lysine in the raw pig protein of the experimental group was 6,67% in the first period versus 4,88% in the control and consequently in the final 4,8% and 4,15%, which indicates a lower level of deamination of amino acids and as a consequence a higher level of protein synthesis in muscle tissues and a higher increase in live weight of animals. The analysis of urea content in blood, muscle tissue and liver in the experimental group of pigs is lower compared to the control at higher levels of lysine in the raw protein. One can make a conclusion about the feedback between the level of lysine in the raw protein protein and the content of urea in the blood, muscle tissue and the liver of pigs. The higher level of lysine in the raw protein of the ration is provided by lower levels of urea in the body of animals. If after the slaughter to balance the urea content in the blood, muscle and liver of the pigs in the control group, its content in the total amount of muscle tissue (meat) is about 12 g, blood is  about 2 g and the liver is much smaller. In pigs in the experimental group, these indicators will be lower by 22-24%, while the content of lysine in the raw protein of the ration is higher by an average of 29%. These data suggest that total urinary excretion levels can be used as an indicator of protein quality and possibly to assess the amino acid requirements of swine and other non ruminant animals.

1. Pond U.Dzh. & Khaupt K.A. (1983). Byolohyia svyny [Pig biology]. Moskva: Kolos [in Russian].

2. Kulyk M.F. & Krasnoselska M.P. (2017). Zabiini pokaznyky svynei pry vykorystanni v hodivli ekstrudovanoi soi v poiednanni z biolohichno mineralnoiu dobavkoiu na osnovi lizynu i saponitu [Slaughter rates of pigs when used for feeding extruded soya in conjunction with a biologically mineral additive based on lysine and saponite]. Ahrarna nauka ta kharchovi tekhnolohii. 51-59 [in Ukrainian].

3. Kalashnykov, A.P., Fisinin (2003). Normy i ratsyony kormlenyia selskokhoziaistvennykh zhyvotnykh. Spravochnoe posobye. 3-e yzd. pererab. y dop. [Norms and diets feeding farm animals. Reference manual. 3rd ed. reclaiming and add.] Moskva: Nauka [in Russian].

4. Petrychenko, V.F. (2016). Soya: monografiya / Vinny`cya: Dilo. [in Ukrainian].

5. Ovsiannykov, A.Y. (1989). Metodyka opytnoho dela [Experimental technique]. Moskva: Ahropromyzdat. [in Russian].

6. Vlizlo, V.V. (2012). Laboratorni metody doslidzhen u biolohii, tvarynnytstvi ta veterynarnii medytsyni: dovidnyk [Laboratory methods of research in biology, livestock and veterinary medicine: a guide]. Lviv: Spolom [in Ukrainian].