Author: Christal Pollock, DVM, Dipl. ABVP-Avian
Date: September 4, 2007
Keywords: Label, dry matter, moisture, protein, fat, fiber, ingredients.
Key Points
- The guaranteed analysis lists the minimum levels of crude protein and fat and the maximum levels of crude fiber and moisture. These values are comprehensive and are not limited to digestible dietary sources. Therefore guaranteed analysis should always be evaluated in conjunction with the ingredient list.
- To accurately compare the nutrient composition of feeds, it is important to convert all guaranteed analyses to a dry-matter basis.
Components of the food label
The food label must provide information on feed ingredients and the guaranteed analysis. Feeding guidelines are required on products labeled as complete and balanced for any life stage. In the United States, the name and address of the feed manufacturer, distributor, or dealer must be found on the label. Although this is not required, the label may also state caloric content as kilocalories of metabolizable energy.
↑ top
Guaranteed analysis
The guaranteed analysis lists the minimum levels of crude protein and fat and the maximum levels of crude fiber and water or moisture. The term “crude” signifies that all sources of protein, fat, and fiber are included—not just digestible sources. For instance, it is conceivable that a dishonest manufacturer could create a canned food with a guaranteed analysis of 10% protein, 6.5% fat, 2.4% fiber, and 68% moisture, using leather, motor oil, coal, and water. Guaranteed analysis should always be evaluated in conjunction with the ingredient list.
Crude protein levels estimate the total protein content of the diet, but they do not indicate amino acid content, protein quality, or protein digestibility. Crude protein levels are determined by multiplying analyzed levels of nitrogen by a constant.
Crude fat is an estimate of the lipid content of food. Crude fat levels are determined through extraction with ether.
The organic residue that remains after plant material is treated with dilute acidic and alkaline solvents and after mineral components have been extracted is crude fiber. Crude fiber underestimates the true level of fiber in a food.
↑ top
“As-fed” versus dry matter basis
Most pet foods display nutrient content on an “as-fed” basis. This means that nutrient content is determined without accounting for the amount of water present within the product.
All pet foods have different amounts of moisture. To accurately compare the nutrient composition of feeds, it is important to convert all guaranteed analyses to a dry-matter basis. Conversion to dry matter is particularly important when comparing different types of foods such as dry food versus canned foods.
Lafeber Nutri-Meals® contain 12% moisture; therefore each bar contains 88% dry matter. The label states that Breakfast Nutri-Bars® contain 11% crude protein. Divide 11% crude protein by 88% dry matter to get 12.50% as the amount of protein present on a dry matter basis.
Now that we have this information, we can compare Nutri-Meals® with other products. Harrison’s Bird Food Adult Lifetime Coarse® contains 10% moisture and 15% crude protein. On a dry-matter basis, this product contains 16.67% protein. When comparing these products on a dry matter basis, Harrison’s product has more protein.
The same calculations may be used to fat, fiber, and other nutrients on a dry matter basis.
↑ top
Ingredient List
Ingredients may include grains, milling byproducts, added vitamins and minerals, fats or oils, and other nutritional sources. Federal regulations require ingredients be listed on the label in descending order by weight.
Unfortunately there is no way to determine diet quality from evaluation of the ingredient list. An unfortunate and recent example of this problem is the recall of various pet foods containing wheat gluten and rice protein concentrate contaminated with melamine and melamine.
Common ingredients in formulated companion parrot diets include:
- Corn—“ground corn” on the label indicates that the entire corn kernel is ground or chopped
- Corn gluten meal (CGM)—a by-product of corn processing
- Egg—an excellent source of vitamins, minerals, and most essential amino acids
- Soybean meal, soy flour—a by-product of soybean oil production
- Wheat flour
- Oat groats—hulled oat grain which serves as a good source of plant-based protein
- Gelatin—protein derived from boiling specially prepared skin, bones, and connective tissue
Food additives are substances added to food that may provide nutrition, fiber, fragrance, flavor, and/or color. Food additives may also serve as stabilizers, emulsifiers, preservatives, and/or antioxidants.
Common additives include:
- Glycerine—humectant used to keep foods soft and moist
- Mixed tocopherols, citric acid—naturally-derived preservatives which may be less effective than artificial preservatives
- Mixed tocopherols and citric acid are compounds used as natural preservatives or antioxidants
- Natural and artificial coloring
- Vitamins and minerals
Some pet food additives are considered controversial. Propylene glycol is a humectant used in semi-moist diets that has been prohibited in cat foods. Propylene glycol causes Heinz body formation in cat erythrocytes and it also reduces erythrocyte survival time and makes red cells more susceptible to oxidative damage. Ethoxyquin has been approved as a preservative and antioxidant in animal feed for over thirty years, however in recent years, there have been numerous anecdotal reports of a variety of health problems attributed to ethoxyquin in dog food. More research is needed. Health problems have not been identified in birds related to either additive.
The Official Publication of the Association of American Feed Control Officials contains a list of feed ingredients with their definitions.
↑ top
Association of American Feed Control Officials
The Association of American Feed Control Officials (AAFCO) is a group of state, federal, and international regulatory officials responsible for overseeing pet food production. AAFCO standards establish a set of guidelines for the production, labeling, and sale of pet foods.
↑ top
Label claims
Figure 1. Only products containing 95-100% organic ingredients can use the USDA organic symbol.
The term “complete” indicates the product is nutritionally adequate. When fed as the sole ration, it is capable of maintaining life and/or promoting reproduction. “Balanced” means that required nutrients are present in the proper amounts and proportions based upon recommendations from recognized authorities.
Terms that do not have an official definition include "premium", "gourmet", or "natural". "Natural" generally does indicate an absence of artificial flavors, artificial colors, and artificial preservatives in a product.
"Natural" is not the same as "organic" which refers to the conditions under which plants were grown. Since 2002, federal regulations have been in place governing the labeling of foods produced using organic agriculture. Only products with 95 to 100% organic ingredients can use the USDA organic symbol (Fig 1).
↑ top
Feeding instructions
Feeding guidelines are included on most products. Adjustments may need to be made since variations in species, age, activity, metabolism, environmental stressors such as ambient temperature, and other stressors affect daily requirements.
↑ top
References
Palika, L. The Consumer's Guide To Dog Food. Howell Book House of Simon & Schuster/Macmillan Company. New York, NY; 1996.
U.S. Food & Drug Administration Center for Veterinary Medicine. How to understand and use the nutrition facts label. http://www.cfsan.fda.gov/~dms/foodlab.html. Accessed Sep 4, 2007.
U.S. Food & Drug Administration Center for Veterinary Medicine. CVM and Animal Food, Feed Ingredients, and Additives. May 17, 2007. http://www.fda.gov/cvm/animalfeed_info.htm. Accessed Sep 4, 2007.
U.S. Food & Drug Administration Center for Veterinary Medicine. Interpreting pet food labels. http://www.fda.gov/cvm/petlabel.htm. Accessed Sep 4, 2007.
Wortinger A. Pet food labels. In: Nutrition for Veterinary Technicians and Nurses. Blackwell Publishing. Ames, Iowa. 2007. Pp: 95-102.
