Page 131 - Small Animal Clinical Nutrition 5th Edition

132 Small Animal Clinical Nutrition

Table 6-5. Blood levels, allowances and tests for B-complex vitamins in cats and dogs.
VetBooks.ir Cats AAFCO NRC

Vitamin
5.6 mg/kg
5 mg/kg
Erythrocyte transketolase activity
Thiamin Blood level allowance* allowance* Best test
20-90 ng/ml (WB)
Riboflavin 196-660 ng/ml (WB) 4 mg/kg 4 mg/kg Erythrocyte glutathione reductase**
Urine riboflavin
Niacin 1.8-5.8 µg/ml (WB) 60 mg/kg 40 mg/kg Urine methyl nicotinamide or methyl-pyridones**
Pantothenic acid 104-270 ng/ml (WB) 5.0 mg/kg 5.75 mg/kg Urinary excretion of pantothenate
Pyridoxine 86-350 ng/ml (P) 4.0 mg/kg 2.5 mg/kg Blood levels of pyridoxine
Urinary metabolites of pathway intermediates
Folic acid 3.2-34 ng/ml (P) 0.8 mg/kg 0.75 µg/kg Serum folate
Vitamin B 12 120-1,200 pg/ml (WB) 20 µg/kg 22.5 µg/kg Blood levels of cobalamin
Serum and urine methylmalonic acid
Biotin 1,000-3,000 pg/ml (WB) 70 µg/kg 75 µg/kg Urinary biotin
Urinary organic acids
Choline 180-490 µg/ml (P) 2,400 mg/kg 2,550 mg/kg Plasma choline and phosphatidylcholine
Dogs
AAFCO NRC
Vitamin Blood level allowance* allowance* Best test
Thiamin 46-112 ng/ml (WB) 1.0 mg/kg 2.25 mg/kg Erythrocyte transketolase activity
Riboflavin 185-420 ng/ml (WB) 2.2 mg/kg*** 5.25 mg/kg Erythrocyte glutathione reductase**
Urine riboflavin
Niacin 2.7-12 µg/ml (WB) 11.4 mg/kg 17 mg/kg Urine methyl nicotinamide or methyl-pyridones**
Pantothenic acid 120-380 ng/ml (WB) 10 mg/kg 15 mg/kg Urinary excretion of pantothenate
Pyridoxine 40-270 ng/ml (P) 1 mg/kg 1.5 mg/kg Blood levels of pyridoxine
Urinary metabolites of pathway intermediates
Folic acid 4-26 ng/ml (P) 0.18 mg/kg 0.27 mg/kg Serum folate
Vitamin B 12 135-950 pg/ml (WB) 22 µg/kg 35 µg/kg Holotranscobalamin II**
Biotin 530-5,000 pg/ml (WB) None established 0 † Urinary biotin
Urinary organic acids
Choline 235-800 µg/ml (P) 1,200 mg/kg 1,700 mg/kg Plasma choline and phosphatidylcholine
Key: WB = whole blood, P = plasma, AAFCO = Association of American Feed Control Officials, NRC = National Research Council.
*AAFCO allowances are similar for growth and adult maintenance and are expressed on dry matter basis (AAFCO Official Publication,
2007). NRC allowances are “recommended allowances” for adult maintenance and are also expressed on a dry matter basis (NRC.
Nutrient Requirements of Dogs and Cats. Washington, DC: National Academies Press, 2006.
**Not currently available in veterinary medicine.
***Investigators have shown a riboflavin requirement approximately 20 to 33% higher than the AAFCO allowance listed here. (Cline JL,
Odle J, Easter RA. The riboflavin requirement of adult dogs at maintenance is greater than previous estimates. Journal of Nutrition 1996;
126: 984-988.)
†For normal foods not containing raw egg whites, adequate biotin is probably provided by intestinal microbial synthesis (assuming the
patient is not receiving antimicrobial therapy).

recommended allowance for thiamin is 5.5 mg/kg DM for (Case 6-9).
growth, 5.6 mg/kg DM for maintenance and 6.3 mg/kg DM Thiamin antagonists may be synthetic or natural compounds
for gestation and lactation. Table 6-5 lists AAFCO and NRC that modify the thiamin structure rendering it inactive. The
allowances for dogs and cats. natural antagonists include thiaminases (enzymes that degrade
thiamin), and polyhydroxyphenols (caffeic acid, chlorogenic
DEFICIENCY AND TOXICITY acid, tannins), which inactivate thiamin by an oxyreductive
Clinical thiamin deficiency is rarely observed in dogs and process. Thiaminases are found in high concentrations in raw
cats because most commercial pet foods have adequate sup- fish, shellfish, bacteria, yeast and fungi (Table 6-6). Cooking
plementation. Signs of thiamin deficiency are often related to destroys thiaminases.
the nervous system and heart. They include anorexia, failure Thiamin deficiency may be diagnosed by measuring erythro-
to grow, muscle weakness, paraparesis, convulsions, seizures, cyte transketolase activity or thiamin metabolites in blood
ventriflexion of the head, ataxia and cardiac hypertrophy directly. Table 6-5 lists concentrations of thiamin in blood for
(Read and Harrington, 1981; Jubb et al, 1956; Everett, 1944). cats and dogs (Baker et al, 1986). Activity of erythrocyte trans-
Thiamin deficiency may result from inadequate intake of ketolase is an excellent indicator of thiamin status, if deter-
thiamin, attributable to foods with low-thiamin content or mined in a laboratory familiar with the analysis. Thiamin toxi-
processing losses, or high intake of thiamin antagonists. The cosis via the oral route is very rare.
processing conditions used to prepare commercial pet foods
are destructive to thiamin. However, this anticipated loss is SOURCES
overcome by adding synthetic thiamin before processing Thiamin occurs in animal tissues almost entirely in phospho-