J. Schwager et J. Schulze, DEPENDENCE OF GROWTH, BONE METABOLISM AND FUNCTIONS OF POLYMORPHONUCLEAR LEUKOCYTES ON ASCORBIC-ACID IN PIGS, International journal for vitamin and nutrition research, 68(1), 1998, pp. 48-58
Pigs with hereditary ascorbate deficiency (OD pigs) were depleted of;
or supplemented with, ascorbic acid by respective diets. Depletion of
young (i.e. 5-7 weeks old) animals for at least three weeks had a nega
tive effect on growth, body temperature and levels of bone alkaline ph
osphatase and induced symptoms of scurvy. Doses of 5 mg ascorbic acid
kg(-1) body weight day(-1) were sufficient to reverse these effects. T
he level of ascorbic acid sharply decreased in plasma within one week
of depletion, whereas in leukocytes it declined more slowly and to a l
ower extent, Bone alkaline phosphatase levels substantially declined i
n ascorbic acid depleted animals. Supplementation with > 100 mg ascorb
ic acid kg(-1) body weight day(-1) did not improve growth, Dietary asc
orbic acid was absorbed from the intestinal lumen into the blood withi
n less than I hour and reached a peak 5-6 hours after the meal. The ex
tent of this absorption depended on the systemic ascorbic acid level.
Ascorbic acid influenced leukocyte function, since the production of r
eactive oxygen intermediates by polymorphonuclear leukocytes decreased
in supplemented animals. Thus, this animal model permits to establish
the level of dietary ascorbic acid that is critical for growth of pig
s as well as to study its absorption into the blood and the associated
alterations in polymorphonuclear leukocytes and bone metabolism.