Page 7 - Small Animal Clinical Nutrition 5th Edition

8 Small Animal Clinical Nutrition

creatine kinase concentrations may become a useful marker for Instead of separate dog and cat editions, the recently updat-
VetBooks.ir assessing and monitoring nutritional status in animals ed NRC includes information about both species. It provides
nutrient requirements in three formats: minimum requirement,
(Fascetti et al, 1997).
adequate intake and recommended allowance (2006).
Results of a single measurement or test must be interpreted
cautiously, because over- or under-hydration can alter concen- Minimum requirement is defined as the minimal concentration
trations of these proteins. Diagnostics such as radiography and or amount of a maximally available nutrient that will support a
ultrasonography, including echocardiography, may be indicated defined physiologic state. Adequate intake is defined as the
to further characterize the health status of patients. Results of concentration or amount of a nutrient demonstrated to support
laboratory and diagnostic tests should always be viewed in the a defined physiologic state when no minimum requirement has
context of findings from the history, physical examination and been demonstrated. Recommended allowance is defined as the
the patient’s medical record. concentration or amount of a nutrient in a diet formulated to
support a given physiologic state.The recommended allowance
Determine the Key Nutritional Factors and is based on the minimum requirement with consideration for
Their Target Levels the normal variation in bioavailability of the nutrient in typical-
The concept of key nutritional factors is fundamental to the quality feed ingredients. If no minimum requirement is avail-
practical application of clinical nutrition used in this text. able, the recommended allowance is based on adequate intake.
However, to better understand the basis for this concept, a brief Like the old editions, the more recent NRC edition also
review of nutrient requirements vs. nutrient allowances pre- includes safe upper limit levels for a nutrient when data are
cedes the description of key nutritional factors. available (NRC, 2006).
Researchers traditionally have used normal dogs and cats to Neither NRC nor AAFCO has established nutrient profiles
determine nutrient requirements. In the United States, the pri- for geriatric dogs and cats and those with specific disease
mary sources for minimum nutrient requirements of healthy processes.
dogs and cats are the National Research Council (NRC)
Nutrient Requirement bulletins published in 1985 and 1986, Key Nutritional Factors
respectively and recently updated as a combined edition (NRC, Key nutritional factors encompass nutrients of concern and
1985; NRC,1986; NRC,2006).The requirements published in other food characteristics. The concept of nutrients of concern
1985 and 1986 were determined by feeding dogs and cats puri- greatly simplifies the approach to clinical nutrition because
fied diets rather than commercially available foods.These NRC most commercial pet foods sold in the United States provide at
values, therefore, were minimum nutrient requirements that least AAFCO allowances of all nutrients. Thus, if a commer-
had to be extrapolated to the types of foods normally fed to cial food is fed, veterinarians and their health care teams need
dogs and cats. In 1993 and 1994, the Association of American only to understand and focus on delivering the target levels for
Feed Control Officials (AAFCO) published recommended a few nutrients (nutrients of concern) rather than the 40 plus
nutrient profiles for dog and cat foods, respectively (Nutrient nutrients currently recognized for cats and dogs (NRC, 2006 ).
Profiles for Dog Foods, 1993; Nutrient Profiles for Cat Foods, Nutrients of concern encompass nutritional risk factors for
1994).These nutrient profiles have been republished yearly and disease treatment and prevention as well as nutrients that are
are the official source for nutrient profiles for commercial dog key to optimizing normal physiologic processes such as
and cat foods in the United States. growth, gestation, lactation and physical work. The following
The AAFCO nutrient profiles include safety factors similar elements must be considered in determining key nutritional
to those in the recommended dietary allowances (RDAs) that factors and their target levels: 1) the patient’s lifestage and
have been established for people (NRC, 1989). These safety physiologic state, 2) environmental conditions such as temper-
factors compensate for changes in a food’s nutrient availability ature, housing and pet-to-pet competition, 3) the nature of any
due to ingredient and processing variables and for individual disease or injury, 4) the known nutrient losses through skin,
differences in nutrient requirements within dog and cat popu- urine and gastrointestinal tract, 5) the interactions of medica-
lations. Because of these safety factors, the term “allowance” is tions and nutrients, if applicable, 6) the known capacity of the
better suited to describe AAFCO values than “requirements.” body to store certain nutrients and 7) the interrelationships of
AAFCO values are adequate to meet the known nutrient various nutrients.
needs of almost all healthy dogs and cats and are a better Besides requiring specific levels of certain nutrients, some
source of feeding recommendations for most dogs and cats patients have other food-related needs. These needs might
than are minimum requirements. The earlier NRC bulletins include management of acute or chronic systemic acid-base
published for dogs and cats in 1974 and 1978, respectively, also balance, maintenance of a specific urinary pH range, certain
included safety factors and therefore were actually kibble texture, a specific range of digestibility or osmolality,
“allowances.” Besides recommendations for lower limits, avoidance of certain protein sources and presence of specific
AAFCO prescribes upper limits for certain nutrients with the ingredients. Some nutrients and ingredients that are added to
obvious implication that some nutrient excesses can be harm- foods provide other non-nutritive functions that can be
ful. As with RDAs for people, AAFCO allowances for pet important to health and performance. Thus, specific food
food nutrient profiles are not necessarily optimal. characteristics or factors other than the nutrient content may