Utilization of dietary protein in the vitamin B12-deficient rats.
Utilization of dietary protein in vitamin B12 (B12)-deficient rats was evaluated by determinating the content of plasma protein, urinary excretion of nitrogen compounds, and nitrogen-balance after the rats were fed on a B12-deficient soy bean protein diet by pair-feeding for 100 days. The severe B12-deficiency was confirmed in rats by a remarkable increase in urinary methylmalonic acid excretion and a remarkable decrease in the hepatic B12 level. Growth of B12-deficient rats was significantly retarded as compared both with ad libitum-feeding control rats and pair-feeding control rats. The growth retardation due to B12-deficiency was alleviated by the administration of 1 microgram/day of CN-B12 for 30 days. Plasma total protein and albumin levels in rats fed on a B12-deficient diet decreased, compared with those in pair-feeding control, and increase in urea-nitrogen was observed. The excretion of urinary nitrogen compounds, such as urea-nitrogen, allantoin, and creatinine, was significantly depressed by B12-deficiency compared with those in pair-feeding control. The administration of CN-B12 to B12-deficient rats for 30 days resulted in the recovery of the changes in plasma proteins and urinary excretion of nitrogen compounds. The above results suggested that the extreme B12-deficiency depressed the utilization of dietary protein in rats. Moreover, the decrease in urinary urea-nitrogen excretion was supposed to be due to the adaptation by the depression of the dietary protein utilization.
Kawata
T
T
Faculty of Education, Okayama University, Japan.
Tashiro
A
A
Tamiki
A
A
Suga
K
K
Kamioka
S
S
Yamada
K
K
Wada
M
M
Tadokoro
T
T
Maekawa
A
A
D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D004044:Dietary Proteins / Q000008:administration & dosage*; D008297:Male; D008764:Methylmalonic Acid / Q000652:urine; D009584:Nitrogen / Q000008:administration & dosage / Q000652:urine; D051381:Rats; D017208:Rats, Wistar; D014806:Vitamin B 12 Deficiency / Q000503:physiopathology*; D014886:Weaning; D015430:Weight Gain
D001798:Blood Proteins; D004044:Dietary Proteins; D008764:Methylmalonic Acid; D009584:Nitrogen