The 11 essential amino acids in cats

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All cats are capable of obtaining nutrients from the prey they hunt. However, in the case of domestic cats, if they are not fed correctly, they can suffer nutritional deficiencies, such as essential amino acids. Especially, a deficiency of taurine and arginine it can have serious consequences on the health of our companion animals. Normally essential amino acid deficiencies occur when cats do not follow a diet with high animal protein, for example because they are fed dog food or because they are on a vegetarian diet at the wish of their caregivers. This is a serious mistake, since cats are strict carnivores, which means that they cannot feed on anything other than meat and animal protein, since it is in it where they will find all the amino acids they require, especially the essential ones, which they can't get any other way than with a high protein diet.

¿Do you want to know more about the essential amino acids in cats? Keep reading this AnimalWised article where we will talk about them, why they are so important and what could happen to your cat if it has deficiencies.

You may also be interested in: Foods rich in taurine for cats Index
  1. What are the essential amino acids in a cat?
  2. Taurine
  3. Arginine
  4. Methionine and cysteine
  5. Lysine
  6. Phenylalanine and tyrosine
  7. Leucine, Isoleucine, and Valine
  8. Histidine
  9. Threonine
  10. Tryptophan

What are the essential amino acids in a cat?

Because cats are strict carnivores, it is very important to choose feed formulated with a high amount of animal protein that guarantees the obtaining of all essential amino acids, since it is in meat where they are usually obtained. Also, if they don't get the amount of protein they need from their diet, by not be able to modifying your metabolism on a low-protein diet, they begin to consume exclusively what is stored in their body, affecting their health.

The amino acids are the basis of protein formation, that is, proteins are made up of chains of amino acids. In cats we find 20 different amino acids, of which only 11 are essential, or what is the same: they must be obtained with the diet, since they cannot be produced by your body. If your cat does not get these essential amino acids, its physiological function will begin to be damaged, the synthesis of essential protein will be impeded and the health of your feline will be compromised in many aspects. In the case of kittens, their growth will be affected.

The essential amino acids in cats they are:

  • Taurine.
  • Arginine.
  • Methionine (and cysteine).
  • Lysine.
  • Phenylalanine (and tyrosine).
  • Leucine.
  • Isoleucine.
  • Valine.
  • Histidine.
  • Tryptophan.
  • Threonine.

Next, we will talk about each one separately, its functions, what can cause its deficiencies and in what type of food they can be found..


Taurine meets the following functions in the body of cats:

  • Bile production.
  • Conjugation of bile acids.
  • Acts as an antioxidant.
  • Regulation of calcium outside and inside cells.
  • Prevents liver diseases.
  • Supports healthy heart and eye function.
  • Works as a neurotransmitter.
  • They play an important role in the correct muscular and nervous function.
  • It intervenes in the adequate reproductive function.
  • It acts as a maintainer of the proper functioning of cell membranes.

Symptoms of taurine deficiency in cats

Taurine deficiency will not cause immediate death, but your feline's body it will gradually weaken, Alterations in the functions mentioned above will appear and, after five months of deficiency, it may be responsible for serious long-term health problems, such as:

  • Heart trouble: specifically a dilated cardiomyopathy (enlargement of the ventricles of the heart), which is usually accompanied by pleural effusion (leakage of fluid in the membrane that covers the lungs),
  • Retina problems: a disease known as central retinal degeneration (the retina converts the images detected by the eyeball into electrical signals, sending them to the brain through the optic nerve and thus vision occurs), so its degeneration can cause blindness in our cat.

While the progression from cardiomyopathy to congestive heart failure and its complications can be practically reversed with taurine supplementation, damage to the retina of our cat they won't heal, we will simply prevent its progression.

¿Where is taurine obtained?

Our little felines can get taurine especially in organs such as the heart, lung, liver and kidney, as well as the musculature or nervous system. In addition, it is more abundant in poultry and fish than in lamb or veal. It is estimated that a cat should eat between 200 and 300 mg of taurine per day and if there are deficiencies, it should be supplemented with 250 mg twice a day. For more information, we encourage you to consult this other article on Foods rich in taurine for cats..


Arginine is important for the synthesis of urea from ammonia and participates in its elimination. If arginine is absent, a ammonia poisoning in our cat, which can be fatal in a time interval of hours.

Symptoms of Arginine Deficiency in Cats

If our cat does not consume enough arginine, the following can occur:

  • Weightloss.
  • Vomiting.
  • Excessive salivation.
  • Muscle tremor.
  • Neurological signs.
  • waterfalls.
  • Death.

¿Where is arginine obtained?

In general, cats can get arginine in muscles, organs and jelly.

Methionine and cysteine

Methionine and cysteine ​​are important sulfur amino acids for keratin synthesis, which is the main protein of the skin, nails and hair. Methionine is more essential than cysteine, since cysteine ​​can be synthesized from methionine. However, if it is obtained in good quantity through the diet, it frees up methionine to be used in its entirety for its function..

Symptoms of methionine and cysteine ​​deficiency in cats

In general, its deficiency can cause:

  • Alopecia or hair loss.
  • Slow hair growth.
  • Brittle, matte and dull appearance of the coat.
  • Poor keratinization of nails and dry skin.

¿Where are methionine and cysteine ​​obtained??

In the proteins of the fish and egg, as well as casein from dairy. Wheat and corn can also be an important source.


Lysine is usually the amino acid that has the highest risk of becoming deficient if the cat food is not formulated correctly, it is also sensitive to high temperatures. It is involved in the formation of proteins and helps natural immunity of your cat.

Symptoms of lysine deficiency in cats

Among the symptoms of lysine deficiency in cats, the following stand out:

  • Weightloss.
  • Alteration in calcium absorption.
  • Compromises muscle building and growth hormone release.

¿Where is lysine obtained?

Lysine is usually obtained from animal sources, especially from the musculature. Also soy proteins are a good source of this essential amino acid.

Phenylalanine and tyrosine

Phenylalanine is essential for the production of hormones thyroid, coat color (yellow to red and black pigments), and iris pigmentation.

Tyrosine is involved in the formation of adrenaline, norepinephrine and dopamine, necessary for proper brain function and reproductive activity.

Symptoms of a lack of phenylalanine and tyrosine in cats

A deficiency of these essential amino acids in cats can cause the following:

  • Neurological system dysfunction.
  • Uncoordinated gait.
  • Hyperactivity.

¿Where do you get phenylalanine and tyrosine??

Phenylalanine can be found in most protein sources from poultry, pork, beef and fish. Rice contains good amounts of tyrosine.

Leucine, Isoleucine, and Valine

They are branched-chain amino acids that are involved in protein synthesis and in delaying its breakdown in muscles. Furthermore, isoleucine is essential in the formation of hemoglobin and is involved in blood clotting.

Symptoms of Leucine, Isoleucine and Valine Deficiency in Cats

If your cat shows a deficiency in these essential amino acids, the following can occur:

  • Alteration in DNA and muscle synthesis.
  • Impaired blood sugar regulation.
  • Weightloss.
  • Lethargy.
  • Rough fur.
  • Scabs around the eyes and mouth.
  • Peeling of the epidermis of the pads.
  • Uncoordinated gait.

¿Where are leucine, isoleucine, and valine sourced??

These three essential amino acids are typically obtained from beef, lamb, poultry, and eggs..


Histidine, in addition to protein formation, is involved in the synthesis of compounds such as histamine, which is a substance that is involved in allergic processes.

Histidine deficiency symptoms in cats

If your cat suffers from a histidine deficiency, these symptoms will appear.

  • Weightloss.
  • Anorexy.
  • waterfalls.

¿Where is histidine obtained?

In the flesh and blood of animals and fish.


Threonine acts as a precursor to pyruvate, which is involved in the energy production in cells of your cat. In addition, together with aspartic acid and methionine, it intervenes in the metabolism of fats.

Symptoms of threonine deficiency in cats

A deficiency in threonine can cause:

  • Weightloss.
  • Anorexy.
  • Nervous system problems.

¿Where is threonine obtained?

It can be found in poultry, lamb, pork, beef, and fish.


Tryptophan is a precursor to niacin and melatonin, and acts in the regulation of anxiety, sleep and stress as it is also a precursor of serotonin.

Symptoms of tryptophan deficiency in cats

If your cat is deficient in tryptophan, the following symptoms will appear:

  • Anorexy.
  • Weightloss.

¿Where to get tryptophan?

The main sources of tryptophan for cats are poultry meat, fish, eggs and cereals.

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