Vitamin Generally Not Required in Poultry Feed

Correct Answer: Niacin

Poultry generally do NOT require Niacin (Vitamin B₃) in the feed because it can be synthesized endogenously from the amino acid tryptophan, which is its precursor.

Tryptophan → Niacin Conversion

• 60 mg of tryptophan is converted to approximately 1 mg of Niacin.
• As long as the diet provides adequate tryptophan, poultry can meet their Niacin needs.
• This is why Niacin is not listed as a dietary requirement in standard poultry feed formulations.

Niacin Deficiency (when it occurs)

• Deficiency causes Perosis (slipped tendon / black tongue in poultry) — though Perosis is more typically linked to Mn, Biotin, Choline, and Folic acid deficiency.
• In practice, corn-based diets (low in tryptophan) may require Niacin supplementation.

Note on Vitamin C

Vitamin C is also NOT required under normal conditions (synthesized by poultry), but Niacin is the textbook answer for this question based on the answer key of the Animal Science Refresher.