Abstract
Two experiments were conducted to test the effect of casein and soy protein isolate (SPI) on the nutritional status of vitamin B6 in rats. Adult Long-Evans rats were fed with a casein or SPI diet at a 40% protein level with (control) or without (B6-deficient) 7 mg of pyridoxine/kg diet. Vitamin-B6-deficient rats were depleted of B6 with (experiment 1) or without (experiment 2) deoxypyridoxine. In experiment 1, each rat was loaded with 150 mg ofDL-tryptophan after 5 weeks of pair feeding. The rats on the vitamin-B6-deficient SPI diet (SPI-B6) excreted twice the amount of urine xanthurenic acid in 24 h than did the rats on the vitamin-B6-deficient casein (casein-B6) diet (p<0.05). In experiment 2,L-tryptophan was loaded in a 20-mg dose at the end of each week. The excretion of xanthurenic acid was higher in the SPI-B6 group than in the casein-B6 group over the 5-week period of the experiment (p<0.05). Erythrocyte transaminase (EGOT and EGPT) activities were lower, while EGOT and EGPT indexes were higher in the SPI-B6 group than in the casein-B6 group (p<0.05). The results suggest that the source of dietary protein significantly influenced the status of B6 nutrition in these rats.
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Lu, SC., Huang, PC. Effect of casein and soy protein isolate on vitamin B6 nutritional status in rats. J Biomed Sci 4, 120–124 (1997). https://doi.org/10.1007/BF02255602
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DOI: https://doi.org/10.1007/BF02255602