Effects Of Different Diet Levels Of Standardized Ileal Digestible Isoleucine On Growth Performance And Plasma Amino Acids Of Growing-Finishing Pigs

Three different growth stages of experiments were conducted to investigate different levels of standardized ileal digestible isoleucine (SID Ile) on growth performance, plasma amino acid and PUN for growing-finishing pigs. (1) In this experiment,750 crossbred growing pigs were randomly allocated to 5 groups, every group had 6 replicates and 25 pigs per replicate. The average initial BW was 30 kg, the growth period was 30-55 kg. The experiment diet was corn soybean diet which was designed according the Nutrient Requirements of Swine (NRC,2012), the SID Lys level was 0.98% and the SID Ile levels were 0.46%,0.51%,0.56%,0.61% and 0.66% respectively when supplemented with isoleucine, SID He:Lys ranged 47% from 67%. The result showed that there were no significant difference on growth performance and PUN of 5 groups with different SID Ile levels, in addition to Phenylalanine, Valine and Arginine had significant difference and accorded with quadratic regression, the other plasma free amino acids had no significant difference, therefore,0.46% SID Ile could meet the needs of production for growing pigs, and 0.56% SID Ile could achieve better growth peformance. (2) 550 crossbred finishing pigs (initial BW was 55 kg) were randomly allocated to 5 groups, every group had 5 replicates and 22 pigs per replicate, the growth period was 55-80 kg. The experiment diet was corn soybean diet which was designed according the Nutrient Requirements of Swine (NRC, 2012), the SID Lys level was 0.85% and the SID Ile levels were 0.40%,0.45%,0.50%, 0.55% and 0.60% respectively when supplemented with isoleucine, SID Ile:Lys ranged 47% from 71%. The result showed that there were no significant difference on growth performance, plasma free amino acids and PUN of 5 groups with different SID Ile levels, therefore,0.40% SID Ile could meet the needs of production for early-finishing pigs, and 0.55% SID Ile could achieve better growth peformance. (3) 525 crossbred finishing pigs (initial BW was 80 kg) were randomly allocated to 5 groups by a single-factor design, every group had 5 replicates and 21 pigs per replicate, the growth period was 80-105 kg. The experiment diet was corn soybean diet which was designed according the Nutrient Requirements of Swine (NRC,2012), the SID Lys level was 0.74% and the SID Ile levels were 0.34%,0.39%,0.44%,0.49% and 0.54% respectively when supplemented with isoleucine, SID Ile:Lys ranged 46% from 73%. The result showed that there were no significantly difference on growth performance, plasma free amino acids and PUN of 5 groups with different SID Ile levels, therefore,0.34% SID Ile could meet the needs of production for finishing pigs, and 0.44% SID Ile could achieve better growth peformance.