Digestible methionine+cysteine in the diet of commercial layers and its influence on the performance, quality, and amino acid profile of eggs and economic evaluation

Poult Sci. 2018 Jun 1;97(6):2044-2052. doi: 10.3382/ps/pey036.

Abstract

This work aimed at evaluating the effects of 4 digestible Met+Cys levels on the diet of commercial layers and their influence on the productive performance, quality, and amino acid profile of eggs and economic viability of the activity. A total of 576 white Lohmann LSL-Lite layers was distributed into 6 replicates of 24 birds for each diet. The experimental design was completely randomized, with 4 treatments defined by levels evaluated in the feed (0.465, 0.540, 0.581, and 0.647%). The productive performance was measured for 30 weeks. The quality (34 and 50 wk old) and the amino acid profile of eggs (43 wk old) also were evaluated. A linear positive response was observed at higher Met+Cys levels for feed intake, number of eggs per housed bird, and digestible Met+Cys intake. Egg production, egg weight, egg mass, feed efficiency, and weight gain had their optimal values determined by the quadratic regression model at 0.638, 0.654, 0.647, 0.644, and 0.613% digestible Met+Cys, respectively. In the 34th wk, eggshell thickness decreased linearly at higher Met+Cys levels. In the 50th week, the optimal levels detected for eggshell thickness and percentage were 0.571 and 0.570% digestible Met+Cys, respectively. The percentages of proteins, branched-chain amino acids (leucine, isoleucine, and valine), histidine, and proline in eggs (albumen+yolk) showed a linear negative response in function of higher Met+Cys levels. Higher digestible Met+Cys levels (>0.630%) led to a good performance of layers, while lower Met+Cys levels improved the eggshell quality of layers in peak production. Optimal Met+Cys levels may change according to the price of the synthetic amino acid.

MeSH terms

  • Amino Acids / metabolism*
  • Animal Feed / analysis
  • Animals
  • Chickens / physiology*
  • Cost-Benefit Analysis
  • Cysteine / administration & dosage
  • Cysteine / metabolism*
  • Diet / economics
  • Diet / veterinary*
  • Dietary Supplements / analysis
  • Dose-Response Relationship, Drug
  • Female
  • Methionine / administration & dosage
  • Methionine / metabolism*
  • Ovum / drug effects*
  • Ovum / physiology
  • Random Allocation

Substances

  • Amino Acids
  • Methionine
  • Cysteine