184
Effects of standardized ileal digestible isoleucine and valine:lysine ratio on growth performance of 12 to 25 kg nursery pigs
Two 21 d studies were conducted to determine the Ile:Lys and Val:Lys (Exp. 1) and Val:Lys ratios (Exp. 2) that optimized pig growth performance. Twenty-one days post-weaning, a total of 2001 (1001, 12.9 ± 0.54 kg BW and 1000 pigs, 13.9 ± 0.43 kg in Exp. 1 and 2, respectively) mixed-sex pigs were allotted to one of six dietary treatments in a randomized complete block design using previous treatment and weight as blocking criterion. There were 27-28 pigs per pen with 6 replications per treatment. Experimental diets were corn-soybean meal based with 10% DDGS. In Exp. 1, treatments 1-3 contained 70% Val:Lys and 1) 60% Ile:Lys, 2) 55% Ile:Lys 3) 50% Ile:Lys and treatments 4-6 contained 60% Ile:Lys and 4) 60% Val:Lys; 5) 65% Val:Lys; or 6) 70% Val:Lys. Diets 1-5 were formulated to 1.1% SID Lys and treatment 6 to 1.3% SID Lys. In Exp. 2, treatments consisted of increasing levels of Val:Lys: 1) 70%; 2) 60%; 3) 63%; 4) 66%; 5) 69%; or 6) 72%. Treatment 1 was formulated to 1.1% SID Lys and treatments 2-6 were 1.30% SID Lys. In Exp 1, pigs fed increasing Val:Lys had improved ADG, G:F (quadratic, P < 0.04) and ADFI (Linear, P < 0.05). Pigs fed increasing levels of Ile:Lys showed an improvement in G:F (linear, P< 0.05). In Exp. 2, as Val:Lys increased from 60 to 72%, ADG, ADFI (quadratic; P < 0.03) and G:F (Linear, P < 0.01) were optimized. Mean separation indicates that Val:Lys ratios below 0.65 will result in reduced ADG and G:F, moreover Ile:Lys ratios below 0.55 will result in poorer G:F.
Exp. 1, d 0-21 |
|||||||||
Dig Lys, % |
1.10 |
|
1.30 |
|
|||||
Ile: Lys, % |
60 |
|
55 |
50 |
60 |
60 |
|
60 |
|
Val:Lys, % |
70 |
|
70 |
70 |
60 |
65 |
|
70 |
SEM |
ADG, g2 |
638b |
|
629b |
627b |
521a |
614 b |
|
677c |
12.02 |
ADFI, g1 |
931b |
|
931b |
954b |
828a |
907b |
|
941b |
16.78 |
G:F2,3 |
0.684c |
|
0.676c |
0.657b |
0.629a |
0.677c |
|
0.719d |
0.005 |
Exp. 2, d 0-21 |
|||||||||
Dig Lys, % |
1.11 |
|
|
1.30 |
|
||||
Val:Lys, % |
70 |
|
60 |
63 |
66 |
69 |
|
72 |
|
ADG, g2 |
669c |
|
672c |
695b |
712ab |
720a |
|
710ab |
7.78 |
ADFI, g2 |
995bc |
|
975c |
995bc |
1017ab |
1027a |
|
1009ab |
9.65 |
G:F1 |
0.673c |
|
0.689b |
0.698a |
0.700a |
0.700a |
|
0.703a |
0.004 |
abcd Within a row, means without common superscript differ (P < 0.05). |
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Keywords: Isoleucine, Valine, Pigs