BIOPOTENCY OF VITAMIN-E IN LUCERNE MEAL FOR CHICKENS

In order to estimate the biopotency of vitamin E in lucerne/alfalfa me al in comparison to that of dl-alpha-tocopheryl acetate (dl-alpha-Ta; all-rac-alpha-Ta) a study was conducted with newly hatched White Legho rn male chicks. An increase in the vitamin E level in the liver and pl asma, and the prevention of nutritional encephalomalacia (NE) were use d as criteria for biopotency. After a vitamin E depletion period of on e week posthatching, the chicks continued on a semipurified, vitamin E free basal diet without vitamin E supplementation, or were repleted w ith graded levels of that vitamin for six weeks, provided as extracted lucerne oil or as dl-alpha-Ta. High performance liquid chromatography (HPLC) with fluorescence detection was used for the analysis of the v itamin E homologues. The diagnosis of NE was based on clinical and his topathological observations. A significant increase (P < 0.05) in vita min E content in the liver and plasma was observed in response to diet ary supplementation with both vitamin E sources. The linear increase b oth in the liver and plasma storage assays was associated with a reduc ed incidence of NE. The disease was totally prevented by a dietary sup plement of 7.50 and 5.40 mg vitamin E/Kg feed provided as dl-alpha-Ta or lucerne oil, respectively. The natural biopotency of the vitamin E in lucerne meal compared with that of dl-alpha-Ta in the liver and pla sma storage assays and in the prevention of NE was 123, 105 and 99 %, respectively, as calculated by the slope ratio technique.