Determination of SID Tryptophan to Lysine Ratio in Nursery Pigs

  • Trey A. Kellner (Iowa State University)
  • Stacie A. Gold (Iowa State University)
  • Dean Koehler (Vita Plus)
  • Lynnea Courtney (Vita Plus)
  • Leah Gesing (Vita Plus)
  • John F. Patience (Iowa State University)


Four hundred and fiftynewly weaned nursery pigs were observed over a 35-day period at the Iowa State University Swine Nutrition Farm. Pigs were weighed and allotted to 1 of 5 treatments upon arriving, averaging 6.49 ± 0.40 kg for an initial bodyweight. All pigs were had ad libitumaccessto feed and water. The 5 treatments consisted of differing ratios of SID tryptophan to lysine, as follows: 0.150 Trp:Lys, 0.175 Trp:Lys, 0.200 Trp:Lys, 0.225 Trp:Lys, and 0.250 Trp:Lys. The overall data indicate that there is no further advantage in termsof growth performance and feed efficiency by having a diet containing a Trp:Lys ratio greater than 0.175 for nursery pigs. The Trp:Lys ratio largely explained variation in feed efficiency, but not ADG or ADFI. These data are supportive of the Trp:Lys ratio (Trp:Lys = 0.170) specified by the NRC (2012).

How to Cite:

Kellner, T. A., Gold, S. A., Koehler, D., Courtney, L., Gesing, L. & Patience, J. F., (2017) “Determination of SID Tryptophan to Lysine Ratio in Nursery Pigs”, Iowa State University Animal Industry Report 14(1). doi: https://doi.org/10.31274/ans_air-180814-331

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Published on
01 Jan 2017
Peer Reviewed