My first Publication CC May Edition for Web | Page 42

Pet Nutrition
Dietary fl uoride
Th e analysed concentrations of total fl uoride
(F) in dry and wet dog foods (3-8) were
generally lower than 170 mg/kg dietary dry
matter (ddm). One brand of dry dog food
contained 460 mg/kg ddm, which was due
to rock phosphate added as mineral source
(6). Two foods (presumably canned) had
326 and 550 mg F/kg ddm (7). Th e three
excessive levels were reported in 1984 (6)
and 1985 (7).
Mammalian bone meal may contain 200
to 600 mg total F/kg (4, 7). When its ash
content is put at 40%, then animal meal
with 20% ash has up to 300 mg F. Fish meal
may hold 100 to 400 mg F/kg (7) and feed
phosphates can bring along 70 to 3860 mg/
kg (9). Th ere is only about 1 mg F/kg in
grains (10). Besides the ingredients, the
water added during production also is a
source of F in petfood.
Dental and skeletal fl uorosis
Dogs living in areas endemic for fl uorosis
may display conditions featuring dental
and/or skeletal fl uorosis. Such dogs, from
locations in China (11), India (12) and
Turkey (13), were subjected to clinical
studies. Th e occurrence of mottled teeth
and bony exostoses in dogs at three kennels
has been attributed to the feeding of a
commercial dry food containing 460 mg
total F/kg ddm (6, 14).
Puppies and their mothers were fed one
of four diets with similar calcium and
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phosphate levels (4). Th e control diet
contained pure calcium phosphate. Test
diets had either calcium phosphate plus
NaF, bone meal or feed phosphate. Control
and test diets provided 15 and 193 mg F/kg
ddm. Only the permanent teeth of puppies
fed NaF (n = 4) developed dental fl uorosis.
Dogs aged 7-14 weeks were fed a basal
ration without (n = 2) or with (n = 6) 0.1-0.2
g NaF per day (15), equivalent to about 500
mg F/kg ddm. Eruption of permanent teeth
was considerably delayed in all dogs fed F.
Discolored hypoplasias of the premolars
and molars were seen. Ten to 14 weeks aft er
F administration, bones were markedly
thickened, due to periosteal bone formation,
while the original cortex was thin.
Absorption and metabolism
Th e concentration of soluble F in the
intestinal content determines quantitative
F absorption. Th e hydroxyl group in
hydroxyapatite can be replaced by F, so
forming fl uorapatite. Th e two premises
explain that young dogs fed iso-fl uorous
diets accumulated drastically more F in
their femurs when NaF was the F source
instead of bone meal or feed phosphate (4).
Dog chow with F-rich rock phosphate
markedly raised plasma F (14). Femur F
increased over time in growing dogs (3)
and was directly related with NaF intake
in weanling (16) and adult dogs (5). NaF
feeding enhanced bone remodeling in adult
dogs (17).
Creature Companion | May 2019 • Vol. XII • Issue 5 • Noida
In young dogs dosed orally with NaF (18),
equivalent to 45 mg F/kg ddm, the increase
in urinary F excretion corresponded with
48% of the dose. Net intestinal F absorption
was higher than 48%, as there was F body
retention (18) and biliary excretion (19).
Osteosarcoma
Fluoridated drinking water and high-
fl uoride food are considered potential
causes of canine osteosarcoma (8, 20, 21). A
case-control study (22) found that dogs with
osteosarcoma (n = 161) were not exposed
to community fl uoridation more frequently
than dogs with other types of cancer.
Rodenticides
Fluoroacetate
was,
and
sodium
fl uoroacetamide is used as rodenticide.
In 1979 it was reported that one or both
organofl uorides were present in marketed
frozen, minced poultry meat, causing mass
poisoning in dogs (23).
List of references is available on request from
the author ([e-mail])
* Dr Anton C Beynen writes this exclusive
column on dog and cat nutrition every month.
He is affi liated with Vobra Special Petfoods.