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|Title:||An Investigation of Factors Affecting the Pyridoxine Requirement of Postpubertal Gilts (Metabolism, Phosphorylase, Muscle)|
|Author(s):||Russell, Louis Edward|
|Department / Program:||Animal Science|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Agriculture, Animal Culture and Nutrition|
|Abstract:||Various nutritional factors were investigated with respect to their effect on the dietary B6 requirement of swine. Factors investigated included the extent and significance of B6 storage in muscle tissue, the effect of a riboflavin deficiency on B6 metabolism and thus on B6 status, and finally the contribution of gut microbial B6 synthesis to the pool of absorbable B6 and its subsequent utilization by the host animal. In addition to these specific factors, biochemical criteria were evaluated for use as measures of B6 nutritional status and the current estimate of the B6 requirement was reevaluated. In addition to swine, mice were used in some experiments as model animals.
Muscle tissue was found to have a great capacity to accumulate B6 when dietary excesses of the vitamin were consumed. It is suggested that the affinity of B6 for proteins within a given tissue may be an important aspect controlling the release of B6 from tissues; however, the mechanism is not fully understood. In these experiments, a B6 deficiency was ineffective in triggering the release of muscle B6.
In swine, the erythrocyte glutamate-oxaloacetate transaminase activity coefficient (EGOT-Ac) appeared to be a reliable index of B6 status in short-term, controlled experiments (16 weeks). During an extended depletion period ((GREATERTHEQ) 32 weeks), the EGOT-Ac appeared to lose some sensitivity to dietary B6 intake.
Biochemical changes indicative of a B6 deficiency were observed in mice fed a riboflavin-deficient diet. Thus, it is suggested that B6 metabolism may be impaired in riboflavin-deficient animals. It was also noted that the B6 requirement is positively correlated to dietary protein concentration.
In growing pigs, recovery of dietary B6 in the urine as 4-pyridoxic acid was 105%. 4-Pyridoxic acid excretion was not affected by high dietary sulfamethazine but only by the amount of B6 ingested. It was concluded that microbially synthesized B6 from the intestine does not account for a substantial percentage of the total B6 absorbed.
The current recommendation of 1.8 mg B6/day for postpubertal gilts appears to be inadequate.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984.
|Date Available in IDEALS:||2014-12-15|