Name essential amino acids for pigs and poultry and why supplementation matters.

• A. Pigs: lysine, threonine, methionine, tryptophan; Poultry: methionine, lysine, threonine, tryptophan, isoleucine.
• B. Pigs: methionine, lysine, threonine, tryptophan; Poultry: lysine, methionine, threonine, tryptophan, isoleucine.
• C. Pigs: lysine, methionine, threonine, valine; Poultry: methionine, lysine, threonine, tryptophan, isoleucine.
• D. Pigs: histidine, arginine, leucine, isoleucine; Poultry: threonine, lysine, methionine, tryptophan, valine.

Answer: (B)

Essential amino acids are those the animal cannot make in sufficient amounts and must come from the diet. For pigs, the four most critical essential amino acids to meet for good growth and production are methionine, lysine, threonine, and tryptophan. Lysine is typically the first limiting amino acid in corn–soybean-based pig diets, with methionine often next in importance; threonine supports gut health and immune function, while tryptophan influences appetite, niacin synthesis, and overall amino acid balance. In poultry, the balance is similar but isoleucine becomes the additional essential amino acid to consider because birds have strong needs for branched-chain amino acids and the isoleucine requirement is significant relative to lysine. Supplementing with crystalline forms of these amino acids lets diet formulators meet exact amino acid needs without overdoing crude protein, improving growth, feed efficiency, and health while reducing nitrogen excretion. So the best answer reflects these specific essential amino acids for each species and recognizes why targeted supplementation matters for optimal performance.