Essential Amino Acids Marginal Defi ...

Essential Amino Acids Marginal Deficiencies in Diet of Laying Hens

In contrast to the specific signs that may occur as a result of vitamin or mineral deficiencies, the effects of essential amino acid deficiencies are nonspecific: reduced growth, reduced feed consumption, decreased egg production and egg size, and loss of body weight in adult hens. The decreased of feed intake occurs within hours of consumption of a deficient diet and is due to a distortion in plasma and tissue amino acid levels.

Practical ingredients usually are limiting in one or more amino acids. It is often cost effective to supply the limiting amino acids in the form of synthetic amino acids, especially lysine and methionine. Other amino acids such as threonine, tryptophan, arginine, and isoleucine can become limiting when unusual protein sources are used or when the dietary protein level is reduce. Diets that are devoid of animal by-products are often fortified heavily with feed-grade amino acids.

Unlike severe deficiencies, marginal amino acid deficiencies often result in increased food intake, or the maintenance of food intake, with concomitant reduction of body weight gain and lean tissue growth resulting in increased body fat.

Some amino acids have additional effects. Methionine deficiency may exacerbate choline or vitamin B12 deficiencies. Lysine deficiency cause impaired pigmentation. Arginine deficiency tends to cause the wing feathers to curl upward, giving a distinct ruffled feathers appearance. Several others amino acids have been reported to affect feather growth and structure.

Causing Agents
Limiting amino acids in the diet with very little margin of safety as a result of formulated diet using a "least cost" approach
Affected Systems/Organs
Reproductive System
Mainly Affects
Egg Production, Egg Quality, Body Weight, Performance
Adequate essential amino acid requirements in the diet. Fortifying the limiting amino acids in the diet with feed grade amino acid as required.
Suggested Actions
  • Technical assistance recommended
  • Can be managed with feed additives, off-the-shelf medications
  • Diagnosis should be confirmed with rapid assays and/or a certified laboratory
  • Veterinary intervention is recommended

Impact on Egg quality


Impact on Liveability


Impact on Production


Overall Economic Impact


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Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition.

Paul McMullin. 2004. A pocket Guide to Poultry Health and Disease. First Edition.

Steven Leeson, John D. Summers. 2008. Commercial Poultry Nutrition. Third Edition.

Donald D. Bell, Williams D. Weaver. 2009.  Commercial Chicken Meat and Egg Production. Fifth Edition.

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