Productivity and Nitrogen Metabolism in Pigs Fed Low-Protein Diets with Various Levels of Essential Amino Acids

摘要

In the trial carried out on 30 growing pigs, it is indicated that the use of low-protein diets with different levels of protein up to 124, 115,and 105 g/kg and high concentrations of essential amino acids—lysine to 9.6, 8.1, and 6.6; threonine to 6.0, 5.2 and 4.7; and methionine + cysteine to 6.3, 5.5, and 4.4 f/feed kg; with the ratio of lysine to metabolizable energy (g/MJ), threonine to lysine, and methionine + cysteine to lysine of 0.77, 0.62, and 0.65 during growing and 0.69, 0.64, 0.54 and 0.68, 0.71, and 0.67 during fattening, respectively—did not have a significant impact on the live weight gains. At the same time, the indices of consumption of feed protein per unit of weight gain, plasma blood concentration of urea and free amino acids, and excretion of nitrogen with urine were lower, and use of amino acids contributed to biosynthetic processes more efficiently.