How Protein is Measured

Protein is the one type of nutrient that has nitrogen added to the chemical composition. This study demondstrates how the protein content is calculated, which tells one nothing about the quality of protein sources, or what the amino acid makeup is, meaning whether it is, or isn't a complete protein. Along with this very antique Kjeldahl method developed in the late 1800's, there is the Dumas test that can extract ~2% more protein content from a product. There is a comparison of these two on this site.

There are new methods being explored, but they are not readily utilized as consumers are not demanding more proficient methods of measurement in pet foods. The latest accepted test is the NIR test, which tests for peptide bonds in protein that has been extracted from a source. Some of the more recent, cumbersome tests are described here.

Dry Matter Calculations:
Find the moisture percentage on the label (usually 70-80 for canned)
Subtract that from 100, (should be 20-30 for canned)
Now, move the decimal 2 places left (should be .20 to .30)

Use that number to divide into any other percentage on the label to get what is termed "Dry Matter Percentage" for that particular item. For instance, if your answer was .25, and the protein percentage was listed on the label as 10%, you would divide 10 by .25 and come up with 40, indicating that 40% of the dry matter in the food is actually protein content.

Many people have trouble understanding why I will pick a good dry food over a good canned food for weight reduction, so, to take this further, using top quality canned foods and top quality dry foods as an example with high muscle meat protein in both.

Canned Food Example = Fancy Feast varieties at 11% protein.

Dry Food Example = Royal Canin Indoor 40. (40 % protein listed on guaranteed analysis)

First you calculate the Dry matter percentages of the nutrients as shown above. Then you have the final percentage figures listed below, and what follows is the interpretation into caloric count of the food.

Canned food for 100 grams:
80% moisture = 80 grams of moisture leaving 20 grams of nutrition in 100 grams of canned food
50%, (dry matter calculation), of that 20 grams would be 10 grams of protein (40 calories)

22.7 %, (dry matter calculation), of the 20 grams would be 4.54 grams of fat. (40.86 calories)

That leaves about 5.46 grams left for carbohydrates and "ash" or 27.3% of the can's dry matter content. (21.84 calories)

Total amount of caloric content here is 102.7 calories.

Dry food for 100 grams:
10% moisture = 10 grams of moisture leaving 90 grams of nutrition in 100 grams of dry food.
44%, (dry matter calculation), of that 90 grams would be 39.6 grams of protein, (158.4 calories)
9.4%, (dry matter calculation), of that 90 grams would be 8.46 grams of fat, (76.14 calories)
That leaves about 41.94 grams of carbohydrates and "ash" content or 46.6 % of the dry matter content, (167.76 calories)

Total amount of caloric content here is 402.30 calories although Royal Canin is claiming 257 for this measure of their Indoor dry on the package.

According to the NRC, cats need an absolute minimum of 3.97 grams of protein per Kilogram of weight. If you start with a 16 pound cat you have about 7.25 Kilograms of cat to nurture before cutting back on calories. That requires approximately 30 grams of protein provided by the food you feed. This would require 2.8 cans (287.56 calories) of the cat food, or 3/4 of a cup of the dry food  (about 300 calories).

 

Other dry and canned foods are not equal to these calculations.  Most canned foods require more food to provide adequate protein in the diet, and opposite to that, most dry foods have higher caloric count due to fat replacing "carbs" or inappropriate ingredients, which happens with both canned and dry.

 

There would be about a 10 to15 calorie advantage to feeding the canned over the dry, however, we found that we didn't need more than half a cup of the dry food for our boy needing high protein. He started at 16 pounds before weight loss. The advantage to dry is that it can be left in small timed feeding portions. Everyone knows that "portion control" is what drops the weight as the stomach shrinks with time. While I have taken actual figures from the foods I recommend, there are few canned foods you can find that are as high as 11% protein on the guaranteed analysis, so that will easily take up the "15 calorie" difference to equate the provision of adequate protein. However, if you doubt what I say, you can follow the calculations above to come up with your own figures on this.

Protein and CRF

Some of the information around the issue of feeding cats with renal failure is either written in books that have copywrite, or the URL's keep changing. I will try to keep information on this site current.

First there is information written by Daniel P. Carey DVM and Leighann Daristotle DVM, PhD on the importance of protein for felines suffering CRF and demonstrating a concern about restriction of protein in the diet of a CRF patient. Unfortunately, Iams has removed their page from public access.

Then, Kenneth C. Bovée, DVM, MMedSc discusses the fact that there is no scientific basis for restricting good quality muscle meat protein in a cat facing renal failure, at least to the point of meeting the cat's nutritional needs.

Gregory Reinhart PhD's comments quoted from the Iam's Symposium papers in regard to dogs, who need less protein than cats. The same principles apply to cats. I should clarify, here, that Dr Reinhart has been financed by a variety of pet food companies, as are other researchers, and Iams only sponsored these specific symposiums, just as Purina did elsewhere, the same year, as you will see noted at the bottom of one or two of the above referenced papers.

There is also Finco et al who stated, "Results raise questions about the practice of restricting quantity of protein in the diet of cats with chronic renal failure, with the intention of ameliorating development of further renal damage," as part of their conclusion.

Another Note on Protein:

According to this information, written by David J. Polzin, DVM, PhD, Diplomate ACVIM, there are various reasons why your cat can have altered control, or lack of control, of glucose levels. You may note that reference is made to reduction of protein in the diet possibly causing the raised glucose levels.

And on Plant Based Oils:

Also, Scott A. Brown, VMD, PhD, Diplomate ACVIM, suggests trying to improve the Omega 3 fatty acid ratio with a cod liver oil capsule as the study suggests this may help. In a convoluted way the article points out, "However, cats have limited hepatic delta-6 desaturase activity and thus cannot effectively convert linoleic to arachidonic acid and both are considered essential dietary fatty acids in cats.18). In other words cats have "limited" ability to extract fatty acids from plant material, (not a feline appropriate source), so I would head for fish oils where you can, and find cat foods that are supplemented with Omega 3's. At the 28th Congress of WSAVA, Dr. Brown, echoes his theory in his speech. Information on this is echoed on our Petfood Pitfalls page under Flax Seed (Oils). Another study reflecting the absence of D6D activity in cats is here.

The good grains and vegetable content

Corn Gluten Meal as second or lower ingredient:
As I am continually providing information on this subject, I have decided it is best to record it here so that it is readily accessible at any time for those who care to have their facts straight.

• Anyone with training in food chemistry will be able to tell you that the term "gluten" refers to the protein content of corn. The information is backed up on many sites online. The difficulty with corn gluten meal is that it doesn't contain all the amino acids needed by felines, so you definitely need to have muscle meat protein "meal" as a higher protein source than the corn. Remember that "meal" is dry weight and not mostly water.
• At Ingredients 101, there is a breakdown of corn as a commercial ingredient sold for livestock feed. While the protein content there is estimated to be 60%, I have found higher percentages provided online by government inspected enterprises.
• One often finds comments about corn gluten meal being "useless" to felines, however, the prestigious PubMed site shows a study regarding feline assimilation of corn gluten meal where it was found to be 2.5% less bioavailable than chicken meal. In that paragraph, on the third line, click on Table III to confirm the following figures:
  meat meal - 83.3%
  chicken meal - 80.2%
  corn gluten meal 77.7%
• In the above study, in Table IV, the absorption and retention of nitrogen from those figures were slightly more realistic in representation, in that actual nitrogen retention with the remainder being excreted in either urine, or feces was:
  meat meal - 18.3 ± 4.4
  chicken meal - 13.1 ± 4.6
  corn gluten meal - 11.8 ± 7.3
• In the above study, under "Diet", Table II also breaks down amino acid content of corn gluten meal as compared to meat meal and chicken meal. Corn gluten meal contained as much of the sulphur amino acids, (methionine and cystine), as the other two, whereas other grain and vegetables are lacking in these amino acids. The importance of this is in the development of struvite crystals. Sulphur amino acids are needed to provide an acid pH that will prevent crystal development.
• Corn gluten is used as a germination retardent , which is used for sensationalism by those who have an agenda, that has nothing to do with corn gluten meal's capability of safely supplying nutrition to our companion animals. The safety of the ingredient is reflected in the fact that it cannot harm living organisms, and in fact, as it breaks down, becomes a high nitrogen fertilizer because of the protein content.

The next two products are discussed at a site that reflects some of the recent research done on fermentable fibres for felines done by Sunvold and Reinhart. You may notice in Table 6 that both acceptable fibre sources are moderately fermentable, and have low solubility. This article is a composite of other papers presented at different times to their peers.
Rice Bran:

Rice bran is the outside layer of the rice kernel, which contains the bran, and part of the rice germ. It is the part of the rice kernel that is removed to make brown rice. The first URL, and this one, take you to nutritional breakdowns of the product.

Beet Pulp:

Beet pulp is the other, more commonly used fermentable fibre with low solubility, and moderate fermantability, as recommended in the Reinhart and Sunvold paper presented to the 1996 Iams Symposium. It is the vegetable matter, which remains after sugar is extracted from sliced sugar beets.

Some interesting studies on this subject can be found here, here, and references are made in the National Research Council, (2006) book on Nutrient Requirements of Dogs and Cats Page 38 of these notes from the Iam's symposium states, "Fiber digestibility was greatest for cats consuming a diet containing beet pulp (a moderately fermentable fiber), a diet containing the highly fermentable blend of fibers and a diet containing a combination blend of fibers designed to provide moderate fermentation (beet pulp, rice bran, citrus pectin, and carob bean gum)"

Moducare

For a number of years there have been questions regarding Moducare, suggesting that it is not appropriate for felines because of the alleged quantity of simple carbohydrate used as an anti caking agent, etc., so I am hoping to spend time providing a good list of reference material for those who have a sincere interest in using available resources for their companion animals. Some of the reference material will relate to AIDS studies as our own collection has been focused upon our dear FIV+ boy, Legolas. However, we are finding that Moducare does a very good job of maintaining our diabetic, Hamlet, who also suffered from asthma, previous to using this product. Moducare appears to be keeping this in check so that we don't need to resort to inhaled steroids, which would concern us more, as the residue from the steroids has to go somewhere, and so far there are no good scientific answers we find acceptable. You will notice that the company has a few studies listed at their site attached to the hypertext above.

One of the most comprehensive lists of abstracts and studies that I have run across is put out by Big Five Veterinary Pharmaceutical Company (Pty) Ltd.  **Note, this site seems to be down.  While hunting to reconnect I am finding that South Africa is developing a protectionism because some of their products have been patented by foreigners without benefit to the natives originally providing the use.  There are a number of papers cited on the actual Moducare site that I haven't yet rechecked but previously they were similar to the "Big Five" papers.

A good site with general information on the use of Moducare, including recommended dosage, and the need to use without animal fats is The Analyst site.

The use of these specific phytosterols in animals is discussed in VETERINARY CLINICS OF NORTH AMERICA: SMALL ANIMAL PRACTICE Volume 34, Issue 1: Nutraceuticals and Other Biologic Therapies References to research are found at such sources as PubMed: Modulation of immune response through nutraceutical interventions: implications for canine and feline health.

April 21, 2009

Recently I have had more opportunity to research subjects close to Moducare use and have run across the following information around its use in cats:
CONCLUSIONS: The results confirm the correlation between apoptosis and the other parameters noted during the previous study and allows a comparison with FIV- cats. Spontaneous CD4+ apoptosis possibly protects the FIV+ cat by reducing the number of virus producing cells. This phenomenon was enhanced in the group treated with the immune modulator.