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Five hundred and forty five primiparous and multiparous sows were evaluated to understand the impact of feeding crystalline amino acids on lactation performance. 29 sows ranging from first parity to third parity were blocked by parity and randomly allotted to one of 5 experimental diets containing different levels of L-lysine-HCl (0.1, 0.2, 0.3, 0.4, and 0.4% + valine, respectively) within parity block, replacing intact lysine, mainly from soybean meal. L-Threonine and methionine were included in the diets as necessary to maintain the SID Thr:Lys and SID M+C:Lys ratios above 65% and 49%, respectively. In addition, the last treatment with 0.4% crystalline lysine was supplemented with 0.025% valine to increase the SID Val:lys ratio from 64 to 69, respectively. All diets were formulated to have the same SID lysine (1.12%) and 3.45 Mcal ME/kg and contained vitamins and minerals that exceeded recommendations (NRC, 1998). Primiparous sows were allowed a maximum feed intake per day of 5.2 kg, parity 2 females were allowed a maximum feed intake per day of 5.5 kg, and parity 3 females were allowed a maximum feed intake per day of 5.7 kg.
Increasing L–lysine-HCl resulted in similar litter and reproductive performance. The average litter gain was 2.70, 2.72, 2.67, 2.71, and 2.64 kg/d (P < 0.30) when sows were fed 0.10, 0.20, 0.30, 0.40, and 0.40% L–lysine-HCl plus valine, respectively. Interestingly, the addition of valine did not improve litter growth rate or improve subsequent total born (13.85, 13.98, 13.73, 13.84, and 13.81 pigs respectively, P < 0.96).
This study demonstrates that corn/soybean meal lactation diets for all parities can contain up to 0.40% L–lysine-HCl with only supplemental threonine and a methionine source and have no detrimental effect on litter growth rate and subsequent total born. The SID Val:Lys ratio does not appear to be greater than 64%.
L Greiner, J Usry, C Neill, N Williams, J Soto, J Connor, G Allee. 2011. The use of crystalline amino acids in lactating sow diets. Journal of Animal Science, 89, E-Suppl. 2: page 102-103.