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Five experimental trials were carried out in the present work. In the experiment 1, 216 barrows were used to determine the TID Lys requirements under experimental conditions in a 21 days growth trial. The rest of the experiments were conducted under commercial conditions in different swine facilities. In the experiment 2, 880 pigs were allocated into 40 pens during 16-days-growth trial. In the experiment 3, 840 pigs were used for a 28-days-growth trial; 28 pigs were allotted at each pen. In experiment 4, nine hundred pigs were used at 25 pigs per pen during 28-days-growth trial. Finally, the experiment 5 was conducted by using 792 pigs allotted into 36 pens in a 28 days growth trial. In experiment 1 six experimental treatments were prepared by increasing the dietary Lys inclusion (1.05, 1.12, 1.19, 1.26, 1.33 and 1.40% TID Lys). In experiment 2 and 3 diets consisted in a 5-point titration with TID Lys levels of 1.05, 1.14, 1.23, 1.32 and 1.41% respectively. For experiment 4 and 5 diets were arranged as a 6-point titration with TID Lys levels of 1.05, 1.14, 1.23, 1.32, 1.41 and 1.50% respectively. In all the experiments pigs were weighed and feed disappearance recorded every week in order to calculate ADG, ADFI and G:F.
Results showed an improvement in ADG and G:F with increasing dietary Lys in all the experiments. Combined results from the 5 showed a broken line response, with requirements estimated for TID lys of 1.33 and 1.35% for 11 to 19 kg pigs. Moreover, from these 5 experiments it can be estimated a requirement of 1.30%TID Lys for 11 to 27 kg pigs, equivalent to 19 g of TID Lys/kg of gain.
After combining data from all the experiments under commercial conditions it was estimated that the Lys requirement were at least 1.30% TID Lys to optimize ADG and G:F (greater level than NRC (1998) estimations for the same BW range).
D. C. Kendall, A. M. Gaines, G. L. Allee, and J. L. Usry. 2008, Journal of Animal Science. Vol. 86; 324-332.
