Amino Acids Essential Deficiencies ...

Amino Acids Essential Deficiencies in Diet of Laying Hens

Amino Acids Essential 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. Severe deficiencies also result in altered body composition (1, 2)

Some amino acids have additional effects. Methionine deficiency may exacerbate choline or vitamin B12 deficiencies. Lysine deficiency causes 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. (1, 2)

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 reduced. Diets that are devoid of animal by-products are often fortified heavily with feed-grade amino acids. (1, 2)

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. Severe deficiencies also result in altered body composition.  (1, 2)

Observed Clinical Signs Happenings

Egg drop

  • Egg production drops gradually

Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin, abnormalities), skinny body, retarded growth, weight depression

  • Weight depression
  • Loss of body weight in adults


  • Dull feather condition
  • Poor feathering condition or uneven feathers
  • Feather growth and structure affected

Feed Consumption

  • Feed intake reduced

Shell quality

  • Egg size reduced or decreased

Internal Egg quality

  • Watery White or White Haugh unit decreased score should be 70 poor 50

Amino Acids Essential Deficiencies in Diet of Laying Hens DOES NOT show or exhibit or manifest any of the following clinical signs happenings:

  • Egg production declines rapidly
  • Mortality above the standard
  • Visibly sick birds
  • Flock behaviour activity change
  • Droppings abnormalities
  • Respiratory abnormalities
  • Neurological Nervous
  • Lameness or unusual movements, incoordination, reluctance to move
  • Eyes abnormalities
  • Head, Comb, Wattles, Face, Nostrils, Sinuses, Mount, Beak, Earlobes, abnormalities (except eyes)
  • Feed intake increased
  • Diet or Feed Changes (Recent Feed delivery, Recent formulation /diet, Other silo or improper storage, another feed brand)
Causing Agents
Marginal amino acid deficiencies. Commercial diets usually are formulated using a "least cost" approach. for this reason, the limiting amino acids in the diet are typically supplied with very little margin of safety.
Affected Systems/Organs
Egg production System
Mainly Affects
Egg production, Egg Quality, Body Weight, Performance
Adequate levels of limiting amino acids in the diet. Fortifying the limiting amino acids in the diet with feed grade amino acid as required
Suggested Actions
  • Can be managed with feed additives, off-the-shelf medications
  • Veterinary intervention is recommended

Impact on Egg quality


Impact on Liveability


Impact on Production


Overall Economic Impact


  1. Y.M. Saif.2008.Disease of Poultry. 12th Edition. page 1121
  2. David E. Swayne. 2013. Diseases of Poultry 13th Edition. page 1207
  3. Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition. page 30

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