Abstract
Abstract. Title of the Paper: Investigation on N-reduced feeding and use of free amino acids in fattening pigs The aim of the present study was to investigate the N-reduced feeding by fattening pigs feed by cereals rieh feedmixture supplemented with the free amino-acids L-lysine, DL-methionine, L-threonine, L-tryptophane, Lleucine, L-isoleucine, L-histidine and L-valine. It was to test extreme low crude protein content by requirement sufficient supply on amino-aeid. The reaction of the animals in growth, carcass quality and the reduction of Nexeretion was to investigate. The pigs were divided in two groups (control and experimental group) with 24 animals per group (12 females and 12 castrates). The experiment was divided into three periods (25–60, 60–85 and 85–110 kg body weight). The protein content of the feedmixture was by the control group 18.3, 15.6 and 13.6% and by the experimental group 14.0, 11.8 and 10.7%, respectively. The lysine-energy ratio of the feedmixture was by all three feeding periods by 0.72 or 0.74, 0.61 or 0.62 and 0.55 or 0.57 g lysine per MJ ME in control feedmixture or experimental feedmixture, respectively. By a high Performance are the average daily life weight gain (control group 869 and experimental group 863 g) and the lean meat rate (control group 55.2 and experimental group 55:0%) not influenced by the high of crude protein supply. The calculated N-excretion were by the control group 4.16 kg (as 100%) and by experimental group 2.60 kg (62.5%) per 100 kg body weight gain.