Identity

Methionine is a sulfur-containing amino acid and is typically the first limiting essential amino acid in typical commercial corn-soybean diets.

Overview

Methionine is a critical essential amino acid in poultry formulations. Because it is the primary limiting amino acid in standard corn-soy diets, it must be meticulously balanced, often using synthetic DL-Methionine additives, to ensure complete protein utilization and prevent stunted growth. Under analytical verification (IS/ISO 13903), methionine is prone to oxidative degradation during standard acid hydrolysis and requires pre-oxidation with performic acid.

Structured Facts

Classification

Amino Acid > Essential; First-Limiting Amino Acids.

Biological Functions

Initiates peptide translation (as formylmethionine). Acts as a methyl donor via S-adenosylmethionine (SAM) for the synthesis of choline, creatine, carnitine, and DNA methylation. Converted to cysteine via transsulfuration for glutathione (antioxidant) and feather keratin synthesis.

Nutritional Requirements

Expressed as standalone Methionine and combined Methionine + Cystine due to transsulfuration interconversion.

Deficiency

• Clinical Signs: Stunted growth, poor and incomplete feathering.
• Economic Impact: Reduced protein utilization and poor feed conversion.

Toxicity

Interactions

Transsulfuration pathway converts methionine to cysteine.

Feed Phase Requirements

• Pre-Starter: Minimum 0.40%
• Starter: Minimum 0.40% (Broiler Starter) / 0.30% (Layer Chick)
• Grower: Minimum 0.35% (Broiler Grower) / 0.30% (Layer Grower)
• Finisher: Minimum 0.35% (Broiler Finisher)
• Layer: Minimum 0.30% (Layer Phase I and II)

Quantitative Data

• Requirement: Yes, mandatory across all feeding phases.
• Minimum Level: Varies by phase (e.g., 0.40% in early broiler phases, 0.30% in layer phases).
• Unit: Percentage (%) by mass (dry matter basis).

Relationships

• Related Nutrients: Cystine (Cysteine), Choline, Lysine.
• Feed Ingredients: Corn, Soybean Meal.
• Feed Additives: DL-Methionine.
• Breeds: Broilers, Layers, Parent Stock.
• Production Stages: All stages.