Agricultural Institute, BG-9700 Shumen, Bulgaria
PETROV, P., 2006. Testing of compound feeds containing different level of lysine in feeding fattening pigs. Bulg. J. Agric. Sci., 12: 823-829
Two scientific and economic experiments were carried out at the Agricultural Institute - Shumen. The experiments comprised 60 fattening pigs of the Danube White breed. The animals were equally divided into three groups of 10 (6 castrated males and 4 females). The experiments began after weaning the pigs at 8 kg live weight and finished after reaching 110 kg live weight. The animals from the control and experimental groups, during the three sub-periods, were given compound feeds with equal level of metabolizable energy, protein, methionine+cystine, tryptophane and threonine, but with different lysine level. The lysine content in the compound feeds for group II and III during the first sub-period was increased by 0.2 % and 0.4 % compared to group I. This increase during the second and the third sub-periods was 0.1 % and 0.2 % respectively. The higher lysine content in the compound feeds at equal level of metabolizable energy (13.1 -12.9 - 13.0 MJ) and protein (18.0-14.5-12.5%) showed a trend for gain increase by 2.15 and 2.94%. In the animals from the experimental groups, there was a slight trend for decreasing in the conversion of compound feed, protein, methionine+cystine, tryptophane and threonine for 1 kg gain. Lysine conversion was higher by 11.93% (P<0.01) and by 17.23% (P<0.001).