Methionine, cat food and chickens - a scientific look

Discussion in 'Feeding & Watering Your Flock' started by gclark94560, Nov 28, 2014.

  1. My intention in starting this thread is to delve into this topic in a neutral and scientific manor. It is NOT intended to stir up discord or discontent. I am aware that there are strong feelings both pro and con on this issue.

    Here's a quote from another area of this forum - -

    "* Regarding feeding CAT FOOD to chickens,

    the following is from DLHunicorn in response to the listing of cat food in this Treats Chart: (A word to the wise, and thank you, DLHunicorn)

    "You all know how I feel on cat food and I have posted the links and reasoning behind my objections several times can potentially be detrimental to your birds health and even deadly in the right circumstances and for this reason I feel it should be left off the chart (as when you put it on it is as if you are condoning its use) I will repost here one of the sources for my objection:

    ..."While it is nutritionally essential, methionine excesses are far more toxic to poultry than similar excesses of tryptophan, lysine, and threonine (National Research Council, 1994). Force feeding methionine to excess can result in death to chicks (National Research Council, 1994). A dosage of 2 g / mature cat / day (20 to 30 g / kg dry diet) for 20 days induces anorexia, ataxia, cyanosis, methemoglobinemia and Heinz body formation resulting in hemolytic anemia (Maede, 1985). ..."


    At first glance this makes methionine look like a serious health problem for chickens. However, this is not the case. First off, I want to see if I can understand the above quote and if so, put it in perspective.

    " Force feeding methionine to excess can result in death to chicks (National Research Council, 1994)."

    Well, of course! Force feeding of water, corn or almost any other substance to excess will cause death in chickens of any age! I fail to see the relevance of data taken from any program of force feeding to excess and the backyard raising of chickens.

    Next, "A dosage of 2 g / mature cat / day (20 to 30 g / kg dry diet)" ....

    This statement fails to identify what substance is being fed to a mature cat but I assume it's 2 grams of methionine per 20 to 30 grams (one ounce approximately). This is a massive overdose of methionine!
    Last edited: Nov 28, 2014
  2. The following is from -"Synthetic Methionine and Organic Poultry Diets" by Dr. Jacquie Jacob Ph.D., University of Kentucky. The article may be found at -

    Some interesting points brought out by Dr. Jacob are:

    1. "Methionine is an essential sulfur-containing amino acid. Synthetic methionine is commonly added to conventional poultry diets, but is restricted in organic poultry diets."

    2. "While all amino acids are important, some cannot be produced by animals and must therefore be supplied in the diet. The amino acids that cannot be produced by animals are referred to as essential amino acids. Methionine is one of the essential amino acids for poultry."

    3. "

    A methionine deficiency typically leads to poor feed conversion, retarded growth in meat birds, and reduced egg production in layers and breeders. Methionine is required to provide the building blocks for immune cells and tissues. This includes the nonspecific mechanisms such as the skin and mucosa, and the specific mechanisms that include T and B lymphocytes. This is particularly important for newly hatched chicks that are highly susceptible to infection during the first two weeks of life.
    Methionine is a major component of feathers. Methionine and cysteine (another sulfur-containing amino acid that is not essential in the diet) are critical to feather formation. A deficiency of methionine results in poor feather growth and increased feather pecking. A methionine-deficient bird will tend to eat feathers in an attempt to obtain enough methionine. Feather pecking can quickly turn into cannibalistic behavior in a flock."

    4. "Conventional poultry diets are typically corn and soybean meal based. Grains are typically low in lysine, and legumes (e.g., soybeans) are low in methionine. With this combination of feed ingredients, methionine is typically the first limiting amino acid. One way of meeting the methionine requirement is to feed excessive protein so that the daily intake of methionine is met. This results in an excess of nitrogen excretion and is not environmentally friendly. The use of synthetic methionine in poultry diets makes it possible to feed lower levels of dietary protein that still meet the daily methionine requirement."
  3. The remainder of the article focuses on how to ensure that your chickens have an adequate supply of methionine, not how to limit it. Here's a graph of good sources of methionine for chickens -


    I will try to look into additional info on methionine and chickens.

    For reference, I have a Doctor of Chiropractic degree and retired after practicing full time for 20 years. My educational background included several organic chemistry and human nutrition courses.
    Last edited: Nov 28, 2014
  4. Now with all that said, I did find several articles discussing the dangers of excess methionine intake in chickens. While discussion started at .5% overdose of methionine and went up from there.

    I found the following in an article titled - Methionine Toxicity in the Chick: Nutritional and Metabolic Implications

    In this article I found the following resommendation for methionine levels in chick food.

    The minimal requirements for both threonine and glycine for maximal growth (in the presence of an adequate level of methionine, i.e., 0.35%) were established as being close to 0.55 and 0.60%, respectively (figs. 1 and 2).

    I am currently looking at a bag of "Pet Pride" Kitten Formula dry cat food. There is no mention anywhere on the bag regarding methionine content. It isn't even listed in the ingredients. It is sold by Kroger and made by Inter-American Products, Inc., Cincinnati, OH 45202 800-697-2448
  5. And if you aren't already overloaded by all this -


    Methionine (Met) plays many important metabolic functions in humans and animals, and therefore may be classified as a functional amino acid (AA). Functional AAs are defined as those AAs that participate in and regulate key metabolic pathways to improve health, survival, growth, development, and reproduction of organisms. As the first-limiting AA in poultry diets, Met affects poultry production parameters such as body weight gains, feed conversion ratio and carcass quality. The results of many experiments on chickens fed diets with different levels of Met (from 0.3 to 1.2% in the starter period, and from 0.3 to 0.9% in the grower period) indicate that commercial broiler chickens do not require more than 0.50 and 0.38% Met in starter and grower diets, respectively, for optimum growth and feed efficiency, whereas higher inclusion rates of Met are needed to stimulate immune responses. The results of recent experiments on chickens are insufficient to define the optimal dietary levels of Met, which has been shown to exert immunostimulatory activity. A few experiments on layer hens have demonstrated that Met requirements for immune competence are higher than for optimum production, but the inclusion levels of this AA needed to stimulate the immune system of birds have not been defined. In the absence of such research, it remains unknown whether feeding growing turkeys diets supplemented with Met above NCR recommendations, as suggested by B.U.T. (British United Turkeys), stimulates the immune system of birds."

    The upshot of all this is methionine is absolutely needed in a chickens diet. We aren't precisely sure how much is needed and I can find no information regarding just how much is in cat foods.
  6. Additional comments and findings on actual methionine content in cat or chicken feed is most welcome! [​IMG]
  7. Folly's place

    Folly's place Free Ranging

    Sep 13, 2011
    southern Michigan
    I would hope that people feeding cat food to chickens are using it as a treat or supplement, not a total diet. The feed manufacturer should be able to tell you the actual content of the food in question; only a phone call away! Cats are obligate carnivores and have very different nutritional needs than chickens, so there's no reason to think that any cat food is anything but a marginal part of their diet. I realize that there's no known prion issue with chickens eating chicken, but personally just am not a fan of this practice. Mary
  8. A quick study of the label on Purina Start & Grow vegetarian feed shows 0.36% Methionine. Right at the recommended level.

    I absolutely agree that dry cat food should only be a treat, not the main course of their diet.
    Last edited: Nov 29, 2014
  9. LindaB220

    LindaB220 Crowing

    Aug 23, 2013
    Portland/Vancouver area
    [​IMG] A very interesting thread. Kudos. I'm going to keep an eye on this. I haven't bought any Methionine yet, but see the necessity of it.
  10. As has been pointed out elsewhere on BYC, methionine is added to cat food to prevent kidney stones. With the very high protein diet required by cats, calcium oxilate kidney stones are a real issue.

    In cats, higher levels of methionine cause the formation of mild levels of sulphuric acid in the urine. This either disolves the stones or keeps them from forming.

    PLUS - in most animals, it is an essential amino acid. Chickens included. This means they cannot make it from any other amino acid and it is needed to make a complete protein.

    I have blended a 5 pound bag of Pet Pride dry kitten food (Kroger) with 25 pounds of scratch and am using it as a daily treat only.


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