Friday, Jul 24, 2026 The claims desk. Receipts included. POWERED BY LENZ ↗
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SCIENCE

The Claim

In piglets weaned at 27 days of age, the dietary standardized ileal digestible (SID) methionine-to-lysine ratio has no significant effect on average daily weight gain.

Verified by Lenz ·

The Short Version

The evidence does not support a no-effect conclusion. Peer-reviewed studies and recent meta-analytic reviews indicate that methionine or sulfur amino acid to lysine ratios influence nursery pig growth and that average daily gain is optimized at specific ratios. The claim overstates the evidence by turning a question about where the optimum lies into a claim that the ratio has no significant effect at all, including for piglets weaned at 27 days.

Caveats

  • The phrase "no significant effect" is absolute and conflicts with studies showing dose-response or optimization effects on average daily gain.
  • Evidence on nursery pigs does not specifically validate a null effect in piglets weaned at exactly 27 days; that subgroup detail is unsupported.
  • Some cited non-journal or repository sources are weaker than the peer-reviewed primary studies and meta-analyses and should not outweigh them.

The Receipts

  1. Determination of the optimum standardised ileal digestible sulphur amino acid to lysine ratio in nursery pigs

    ScienceDirect

  2. Optimal sulfur amino acid to lysine ratio for post weaning piglets based on performance, plasma urea nitrogen and plasma free amino acids

    PubMed Central

  3. Recent updates on amino acid requirements of pigs based on meta-analyses

    Animal Bioscience

  4. Determination of the Optimal SID ARG:LYS in Nursery Pigs

    CJ BIO

  5. Recent updates on amino acid requirements of pigs based on meta-analysis

    PubMed Central

  6. Appropriate Methionine:Lysine Ratio For The Segregated Early Weaned Pig

    Pork Gateway

  7. The Optimal Valine to Lysine Ratio for Performance Parameters in Weaned Piglets

    PMC

  8. Effect of standardized ileal digestible arginine:lysine on growth ...

    Oxford Academic

  9. Review: Optimising health, welfare and performance in weaned pigs

    ScienceDirect

  10. An Estimation of the Requirements of the Standardized Ileal Digestible Essential Amino Acid to Lysine Ratio in Pigs by Meta-Regression Analysis

    MDPI

+ 8 more sources — see the full list on Lenz

Filed Under

Average Daily Weight GainPigletsStandardized Ileal Digestible Methionine-To-Lysine Ratio