Biomedical Engineering Reference
In-Depth Information
likely to require long-term ingestion of a deficient diet as
bone contains significant magnesium. Signs of magnesium
deficiency include: anorexia, vomiting, seizures, and
hyperirritability. Manganese is typically found in diets at
levels well above requirements.
Cobalt is a component of vitamin B
12
, which is required
by nonhuman primates. Symbiotic microbes in the gut are
capable of producing vitamin B
12
if provided with a source
of cobalt, however, the importance of microbial production
of vitamin B
12
is unknown. There is no evidence that cobalt
is required by nonhuman primates, assuming they have an
adequate source of dietary vitamin B
12
. A chromium
requirement also has not been definitively demonstrated.
intestinal enterocyte, which binds copper with high affinity
and prevents its systemic absorption (
National Research
Council, 2005
). Animals kept in galvanized cages can have
high zinc intakes if they lick the caging or drink water that
has been in substantial contact with the galvanized
material, which may increase their copper requirement
(
National Research Council, 2003
).
CONSIDERATIONS FOR FEEDING
PROTOCOLS
Ensuring the animal care staff is properly trained and
understands both the nutritional needs and food limitations
of the animals is essential to ensure nutritional health of the
animals. Animal diets need to always be based on science
and experience with the species. The bias and opinions of
individuals, no matter how well intentioned, can be very
harmful to the animals. Researchers and administrators
need to account for the emotional attachment caretakers
form with the animals they care for and clearly transmit the
rationale for dietary changes and restrictions.
Choice may have enrichment value to animals, but it
also has potential nutritional drawbacks. Cafeteria-style
feeding, in which animals are offered significantly more
food than their caloric needs would require, often results in
improper nutrition (
Oftedal and Allen, 1996
). Animals
rarely choose a balanced diet when offered multiple food
items in excess of their caloric needs; it is more advisable to
offer the base diet in the appropriate amount, and then
provide supplementation and enrichment once the base diet
is consumed.
Iron
Iron status is difficult to ascertain. Iron deficiency will
exhibit as anemia and is also linked to poor neurological
development. Iron toxicity will cause hemosiderosis, or
iron storage disease. There has been some concern
regarding dietary iron levels leading to iron storage disease
in captive lemurs (
Spelman et al., 1989
) and common
marmosets (
Miller et al., 1997
). Dietary iron at 500 mg/kg
dry weight caused 50% mortality in common marmosets
(
Miller et al., 1997
), but that is several times the usual
levels of iron in diets, and five times the NRC suggested
level (
Table 10.1
). Vitamin C enhances iron absorption
from the digestive tract; diets high in vitamin C have been
implicated in iron storage disease in lemurs (
Spelman et al.,
1989
) and in fruit bats (
Farina et al., 2005
).
Zinc
Rhesus and bonnet macaques are used as models of zinc
deficiency for humans. Zinc deficiency affects pregnancy
outcome, growth, bone formation, immune function, skin
(alopecia), appetite, cognitive function, and behavior. Signs
of deficiency include: anorexia, apathy, weight loss,
dermatitis, and reproductive failure. Zinc requirements are
higher during pregnancy. Zinc deficiency has significant
effects on embryogenesis and will adversely affect fetal
development and pregnancy outcome. In squirrel monkeys,
zinc deficiency resulted in poor growth and alopecia
(
Barney et al., 1967
). Phytates in grains can bind to zinc,
reducing bioavailablity. Thus zinc in natural ingredient
diets may not be as available as zinc in purified diets.
Group Feeding
Group housing complicates dietary management. Ensuring
that each animal within a group receives their allotment of
the base diet is the easiest way to ensure good overall
nutritional health. Primate groups behave differently
depending on the species, the housing circumstances, and
the individuals within the group. Because the base diet is
very nutrient dense and enrichment foods often much less
nutrient dense, it is important to ensure that individuals do
not over consume either. For this reason, it is critical that
caretakers understand the feeding dynamics of their groups
and manage food allocation accordingly. Mechanisms to
feed individuals at least part of their diet separately, either
by physical separation or target feeding, can help assure
that all group members get appropriate nutrition.
It is best to formulate a diet for each life stage category
and sex of animal within the group and then to combine the
diets for each category to determine the overall group
allocation of food. This allows the caretaker to easily
understand the needs of each animal within the group. It is
also very helpful when an animal needs to be separated
Copper
In rhesus macaque infants copper deficiency led to hair
depigmentation, alopecia, weakness, and microcytic
anemia. Microcytic anemia occurs because copper is
involved in iron metabolism (
Cater and Mercer, 2005
).
High dietary zinc can reduce copper absorption and lead to
deficiency due to induction of metallothionein in the
