Location of Repository

Digestible lysine levels in low-protein diets supplemented with synthetic amino acids for nursery, growing, and finishing barrows

By J. L. Figueroa, J. Estrada, V. Zamora, J. L. Cordero, M. T. Sánchez-Torres, R. Nieto and J. M. F. Copado


peer-reviewed articleTo investigate the effect of lysine level in low-protein diets (LPD) an experiment was conducted with 36 barrows fed 174, 140 and 118 g/kg of crude protein (CP), and three digestible lysine levels. Low-protein diets were supplemented with crystalline amino acids (AA) to the same concentration as in the standard CP diet. Growth performance, carcass characteristics and plasma urea nitrogen concentration were evaluated. In nursery pigs, the addition of lysine to LPD quadratically increased backfat thickness (BF; P < 0.01), longissimus muscle area (LMA; P < 0.001), and lean meat percentage (LMP; P < 0.05). In the growing phase, reducing dietary protein decreased average daily gain (ADG; P < 0.09), final body weight (BW; P < 0.09), fat free lean gain (FFLG; P < 0.09), and LMA (P < 0.038); and increased BF (P < 0.05). Addition of lysine to LPD quadratically increased ADG (P < 0.01), average daily feed intake (ADFI; P < 0.05), final BW (P < 0.006), and FFLG (P < 0.002). In the finishing period, pigs fed LPD had lower ADFI (P < 0.03) and feed:gain ratio (FGR; P < 0.003). Addition of lysine to LPD linearly increased BF (P < 0.04), and quadratically increased ADFI (P < 0.02), FGR (P < 0.009), BF (P < 0.08), and LMA (P < 0.08). The plasma urea nitrogen concentration was reduced (P < 0.05) in all phases in pigs fed LPD. Lysine requirement for fattening barrows fed LPD may be higher than the recommended concentration for standard CP diets

Topics: Low-protein diets, Lysine levels, Pigs, Plasma urea nitrogen concentration
Publisher: Teagasc
Year: 2012
OAI identifier: oai:t-stor.teagasc.ie:11019/321
Provided by: T-Stór

Suggested articles



  1. (1991). Amino acid supplementation of a lowprotein, grain sorghum-soybean meal diet for growing pigs.
  2. (1990). AOAC (Association of Official Analytical Chemists). doi
  3. (1986). for International Organizations of Medical Sciences). doi
  4. (2009). Levels of true digestible lysine and metabolizable energy for growing pigs: effect on nitrogen and energy balance. doi
  5. Mexicana-NOM-062-ZOO-1999: Especificaciones técnicas para la producción, cuidado y uso de los animales de laboratorio”.
  6. (1962). Modified reagents for determination of urea and ammonia.
  7. (2001). Oficial de la Federación). doi
  8. (1995). Use of plasma urea nitrogen as a rapid response criterion to determine the lysine requirement of pigs.

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.