Page 165 - Small Animal Clinical Nutrition 5th Edition

Commercial Pet Foods 167

VetBooks.ir Box 8-3. FDA Perspective: Veterinary Medical Foods.

A “medical food” is defined by law as “a food that is formulated to be
labels are exempt from the requirement to include feeding directions.
consumed or administered enterally under the supervision of a physi- Despite label restrictions, companies often establish the intended
cian and is intended for the specific dietary management of a disease use of their veterinary medical food products as “drugs” through
or condition for which distinctive nutritional requirements, based on brochures, advertisements or other promotional materials. However,
sound scientific principles, are established by medical evaluation.” FDA recognizes that there are scientifically sound reasons for use of
Although the definition is only in reference to foods for human con- these products in some cases of disease in dogs and cats; thus these
sumption, it could also be adapted to apply to “veterinary medical products serve a purpose for veterinarians, their clients and their
foods,” which are generally intended to be offered as the sole source patients. Also, veterinarians obviously must be informed of the indica-
of nutrition to animals with specific medical conditions, and usually tions, contraindications and directions for use of the products. Thus,
contain restricted amounts of certain nutrients to aid in the mitigation FDA generally exercises regulatory discretion with respect to distribu-
of some disease processes. tion of truthful information on diet and disease to veterinarians.
These products are often identified on the market by the label The same information distributed to pet owners; however, is of
bearing the phrase “use under the direction of a veterinarian” or more concern. Proper use of these types of products requires ade-
some similar wording. As foods, veterinary medical foods are subject quate veterinary supervision. An owner who feeds a product for its
to the same labeling requirements as are any other nonmedicated pet desired therapeutic effect solely on the basis of labeling or advertis-
food.As such, labels generally may not bear drug claims.This restric- ing claims may cause harm resulting from improper diagnosis or
tion also applies to product names. Thus, these products are often treatment. However, FDA appears to grant some laxity in allowing
given names that would not be easily recognized by the average con- claims on labels and consumer-directed information for products for
sumer, such as initials or numbers. Also, veterinary medical food which distribution is maintained under a valid veterinarian/client/
labels must meet the same criteria for substantiation of nutritional patient relationship.
adequacy by meeting the AAFCO nutrient profile or passing an
AAFCO feeding trial protocol or include the phrase “for intermittent or David A. Dzanis, DVM, PhD, Dipl. ACVN
supplemental feeding only.” Because directions for use are presumed Dzanis Consulting & Collaborations
to be given to the owner by the veterinarian, veterinary medical food Santa Clarita, CA, USA

Palatability foods, thus the preferred food would be termed more “palat-
Pet Food Preference and Acceptability able.” However, the “losing” food could still be quite palat-
Measuring the sensory aspects of eating evaluates the sum of able and could be consumed in sufficient quantity to support
the pleasant and unpleasant sensations that arise from the pres- body weight.
entation and ingestion of food. Although “taste” is obviously
important, the gustatory attributes of a food are only one of the Preference Tests
variables involved. Olfaction, texture and eating experience also Two-pan palatability tests are broadly used in the pet food
influence food intake. industry to assess comparative food preferences. During the
test, animals have simultaneous access to an excess quantity of
PREFERENCE AND the test foods. This allows the animal to eat all of one of the
ACCEPTANCE TESTING foods and none of the second, or some of each food and not
“Preference” and “acceptance” are specific measurement tech- become hungry. The total food consumed from each pan is
niques to assist in the investigation of alleged pleasant or measured after a timed interval. At each successive meal, the
unpleasant sensations of food intake. Obviously, investigators position of the food pans is alternated within the animal’s
must infer these sensations indirectly in nonverbal animals.The enclosure to cancel any bias for a favored or habitual eating
measurement methods used in such tests must be of sufficient location.
statistical power to reduce bias errors.Testing should also incor- The duration and number of animals required for a prefer-
porate controls for potentially confounding variables such as ence test depend on the animal days necessary to yield the sta-
high or low caloric density, hunger, preference for a single-feed- tistical power requisite for test objectives. Sixty animal test days
ing pan position and environmental distractions. (30 animals for two days) provide a stable and repeatable assess-
The two primary assessment tools are the one-pan accept- ment platform for screening purposes. However, 120 to 240
ance test (monadic test) and the two-pan preference test.The animal test days are commonly used for more statistically rigor-
one-pan test measures acceptability; that is, it simply deter- ous preference examinations.
mines if a given food is palatable enough to be eaten in suf- Although there are several methods of quantifying and
ficient quantity to maintain the subject’s body weight in a expressing preference results, the only bias-free method is based
neutral state. The two-pan preference test measures “choice” on the intake ratio (IR) (Griffin, 1995): IR = A ÷ (A + B),
between a pair of test foods that are fed simultaneously side where A and B are an individual animal’s daily food consump-
by side. In application, the results of a two-pan preference tion of each of two different foods. As an example, an animal
test may indicate that animals distinctly prefer one of the ingests 200 g of Food A and 110 g of Food B. Using the equa-