Page 259 - Small Animal Clinical Nutrition 5th Edition

264 Small Animal Clinical Nutrition

VetBooks.ir tein levels greater than 12%. A daily protein intake for adult with certain diseases that may have a hypertensive component
such as obesity, renal disease and some endocrinopathies
0.75
maintenance of 4.3 to 5.0 g digestible protein/BW
(biolog-
kg
ic value = 70) or 4.0 to 6.5 g digestible protein/100 kcal ME is (Anderson and Fisher, 1968; Cowgill and Kallet, 1986;
recommended (Gesellschaft, 1989b). The minimum recom- Rocchini et al, 1987; Littman, 1990; Ross, 1992). Uncontrolled
mended allowance for DM crude protein is 10% for a commer- high blood pressure may lead to kidney, brain, eye, heart and
cial food with an energy density of 4 kcal/g DM (NRC, 2006). cardiovascular damage (Cowgill and Kallet, 1986; Littman,
Foods formulated to meet the lower limits in crude protein must 1990). Dietary sodium chloride restriction is the first step in,
also have the recommended allowances for essential amino and an important part of, antihypertensive therapy (Cowgill
acids. Thus, the recommended range of DM crude protein for and Kallet, 1986; Littman, 1990; Ross, 1992).
foods for young adult dogs is between 15 to 30%. It is prudent to meet but not greatly exceed sodium and chlo-
ride requirements when selecting foods for adult dogs.The best
Phosphorus estimate for a minimum requirement of sodium is about 4
Minimum requirements for phosphorus for adult dogs are not mg/kg body weight/day (Morris et al, 1976). Generally, 25 to
very different from those established for other mammals. 50 mg/kg body weight/day (Gesellschaft, 1989a) is recom-
Commercial foods contain adequate and sometimes excessive mended for adult maintenance; these levels are six to 12 times
amounts of phosphorus and, therefore, should not be supple- more than the minimum. The minimum recommended
mented. allowance for sodium content of commercial foods is 0.08%
Based on endogenous losses, a daily intake of 75 mg phos- (DM); this allowance is for foods with an energy density of 4
phorus/kg body weight is adequate (Gesellschaft, 1989a). At an kcal/g (DM) (NRC, 2006). For risk factor management, the
energy density of 3.5 kcal (14.6 kJ)/g DM this corresponds to recommended range for dietary sodium is 0.2 to 0.4% (DM),
an average content of about 0.4 to 0.6% DM phosphorus. which is more than adequate. Sodium levels in commercial
These levels are adequate, but not excessive; daily intakes 20 to foods for adult dogs range from 0.11 to 2.2% DM and are
30% less are still sufficient (Gesellschaft, 1989a). Therefore, it higher in moist foods than in dry foods. In the absence of stud-
is unnecessary to feed foods with higher levels of phosphorus, ies establishing chloride requirements in dogs, a value 1.5 times
or to add calcium-phosphorus supplements to commercial the sodium requirement is recommended.
foods. Moreover, higher phosphorus levels are contraindicated
for a substantial part of the dog population; up to 25% of the Antioxidants
young adult dog population may already be affected by subclin- The consequences of prolonged oxidative stress (i.e., free radi-
ical kidney disease (Oehlert and Oehlert, 1976; Rouse and cal damage) to cell membranes, proteins and DNA may con-
Lewis, 1975; Shirota et al, 1979). One clinical study revealed tribute to and/or exacerbate a wide variety of degenerative dis-
that 22.4% of all dogs over five years of age examined at a eases. A partial list includes cancer, diabetes mellitus,
European veterinary teaching hospital for a variety of reasons kidney/urinary tract disease, heart disease, liver disease, inflam-
had abnormally elevated kidney function tests (Leibetseder and matory bowel disease and cognitive dysfunction (Ames et al,
Neufeld, 1991). Excess dietary phosphorus can accelerate pro- 1993; Kesavulu et al, 2000; Ha and Le, 2000; Thamilselvan et
gression of chronic renal disease (Brown et al, 1991), whereas al, 2000; Freeman et al, 1999; Cheng et al, 1999; Center, 1999;
phosphorus restriction may slow the progression of chronic Knight, 1999).The consequences of free radical damage to cells
renal disease and improve long-term survival (Brown et al, and tissues have also been associated with the effects of aging
1991; Finco et al, 1992). It is therefore prudent to feed foods (Harman, 1956).
that contain adequate but not excessive amounts of phosphorus The body synthesizes many antioxidant enzyme systems
(Chapter 37 contains more information about how excess and compounds but relies on food for others. Commonly sup-
dietary phosphorus affects progression of kidney disease). plemented food-source antioxidants include vitamins E and
The minimum recommended allowance for phosphorus in C, β-carotene and other carotenoids, selenium and thiols.
foods for adult dogs is 0.3% (DM); this recommendation is Fruits and vegetables are good sources of flavonoids, polyphe-
appropriate for foods with an energy density of 4 kcal/g (DM) nols and anthocyanidins. The following discussion focuses on
(NRC, 2006). The recommended range of phosphorus for vitamins E and C and selenium as antioxidant key nutritional
foods intended for young adult dogs is 0.4 to 0.8% (DM) when factors because: 1) they are biologically important, 2) they act
the energy density ranges from 3.5 to 4.5 kcal/g DM. synergistically (e.g., vitamin C regenerates vitamin E after it
has reacted with a free radical), 3) they are safe and 4) infor-
Sodium and Chloride mation about inclusion levels in pet foods is usually available.
Essential hypertension is not considered a common problem in For improved antioxidant performance, foods for mature dogs
dogs; therefore, higher intakes of dietary sodium and chloride should contain at least 400 IU vitamin E/kg (DM) (Jewell et
have not been considered harmful in young, healthy dogs al, 2000), at least 100 mg vitamin C/kg (DM) and 0.5 to 1.3
(Bodey and Mitchell, 1996; Bovée, 1990). However, one study mg selenium/kg (DM).
suggested that up to 10% of apparently healthy dogs may have
high blood pressure (Remillard et al, 1991). VITAMIN E
High sodium and chloride intake is contraindicated in dogs Vitamin E is the main lipid-soluble antioxidant present in