Page 106 - Small Animal Clinical Nutrition 5th Edition

Chapter
6

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Micronutrients:

Minerals and Vitamins

Karen J. Wedekind Lauren Kats
Shiguang Yu Inke Paetau-Robinson
Christopher S. Cowell

“Maybe my variety is due to bad absorption of vitamins.”
Stephen Hawking

manganese, cobalt, molybdenum, fluorine, boron and chromi-
MINERALS um.The last six are assumed to be essential for dogs and cats by
analogy with other species. Calcium, phosphorus, magnesium,
Introduction potassium, sodium and chloride are discussed below. Neither
Definition the Association of American Feed Control Officials (AAFCO)
The term “mineral” is generally used to denote all inorganic ele- nor the National Research Council (NRC) lists a sulfur
ments in a food. These inorganic elements constitute the requirement for dogs or cats (AAFCO, 2007; NRC, 2006).
majority of ash that remains after combustion of all organic Generally, there isn’t a dietary need for sulfur per se, if a food is
matter. Ash analysis is of little value either for expressing min- formulated to meet the sulfur-containing amino acid require-
eral requirements or for indicating the useful mineral content of ments of animals with simple stomachs.
foods for two basic reasons: 1) body requirements are specific Of the microminerals, only iron, zinc, copper, manganese,
for certain inorganic elements (e.g., calcium, zinc, etc.) and 2) iodine and selenium will be discussed here. These trace miner-
ash may not be a measure of total inorganic matter present, als have been deemed essential for dogs and cats (although clin-
because some organic carbon may be bound as carbonate, and ical cases of manganese deficiency have never been reported to
some inorganic elements (e.g., sulfur, selenium, iodine, fluorine occur in dogs or cats) (AAFCO, 2007). Cobalt and molybde-
and even sodium) may be lost during combustion. num are clearly important minerals in ruminant nutrition, but
The most important reason to determine total ash is to calcu- are not considered essential in monogastric species.
late the nitrogen-free extract by difference, as is required in the Information about chromium and boron, two ultra-trace min-
proximate analysis of foodstuffs.Specific minerals of interest can erals, is included because of the potential importance these
then be assayed (if not volatilized) from the ash component. nutrients may have in companion animal nutrition. Other new
More than 18 mineral elements are believed to be essential trace elements discovered since 1970 include arsenic, lead, lithi-
for mammals (McDowell, 1992). By definition, macrominerals um, nickel, silicon, tin and vanadium. The essentiality of these
are required by the animal in the diet in percentage amounts, minerals has not been elucidated in all species and under prac-
whereas microminerals or “trace” minerals are required at the tical conditions may not be essential in the diet.
mg/kg or parts per million (ppm). There are seven macromin-
erals: calcium, phosphorus, sodium, magnesium, potassium, Function
chloride and sulfur. There are at least 11 trace elements or Minerals are fundamental as: 1) structural components of body
micronutrient minerals: iron, zinc, copper, iodine, selenium, organs and tissues, such as calcium, phosphorus and magne-