The chick was used as a rapid metabolic model to determine the fate of ingested
fructose vs.
glucose in noninfected chicks and in those subjected to the stress of
avian tuberculosis. The chicks were crop-loaded with either a 72%
fructose or
glucose solution 21 and 28 days post TB inoculation and killed 2 and 4 hr after loading. In noninfected chicks, both
sugars were rapidly converted to
glycogen, and there was an interaction with time and the amount of
glycogen formed from each
sugar.
Infection depressed
glycogen formation from both
fructose and
glucose. While the total amount of
glycogen formed from
glucose could be directly correlated to increased liver size in the TB chicks loaded with
glucose, in the chicks loaded with
fructose less
glycogen was formed even though liver size was increased as a result of the TB
infection. The depression in
glycogen formation was not related to the severity of the
infection since the TB involvement was not the same in the two experiments conducted; but in both cases chicks loaded with
fructose showed a greater reduction in the capacity of the liver to synthesize
glycogen.