Evaluation of the erythrocyte aspartate aminotransferase activity coefficient as an indicator of the vitamin B-6 status of postpubertal gilts.

In two experiments, postpubertal gilts, individually housed in gestation stalls, were fed daily 1.9 kg of a purified diet providing 0.45, 1.5, 2.1 or 83 mg of vitamin B-6/d. The erythrocyte aspartate aminotransferase (more commonly known as glutamic-oxaloacetic transaminase) activity coefficient (EGOT-Ac) of gilts fed the low vitamin B-6 diet (0.45 mg vitamin B-6/d) for 121 d increased 200%, while the EGOT-Ac of gilts fed the high vitamin B-6 diet (83 mg vitamin B-6/d) remained unchanged. Two gilts were fed the low vitamin B-6 diet for 241 d at which time hair loss was observed. Muscle glutamic-oxaloacetic transaminase activity was reduced 75% in vitamin B-6-deficient gilts. The EGOT-Ac of gilts consuming 2.1 mg vitamin B-6/d was 100% greater than that of control animals (83 mg vitamin B-6/d). These findings indicate that the current NRC estimated vitamin B-6 requirement for mature swine (1.8 mg vitamin B-6/d) is inadequate. Prior intake of excess vitamin B-6 did not prevent the subsequent development of a vitamin B-6 deficiency.