THE EFFECT OF VEGETABLE DIET ON SOME VALU ES OF PROTEIN AND FAT-METABOLISM IN LEN RATS OF DIFFERENT AGE

Male len rats at the age of 30 - 140 days were administered a diet wit h an optimum content of nutrients in dependence on their age in which the source of proteins was this: milk casein (essential acid to noness ential acid ratio E/N = 0.79), soya (defatted and without inhibitors o f digestive enzymes, E/N = 0.73), wheat gluten (E/N = 0.30), and their mixture (with one-third portions of each protein, E/N = 0.54). The di etary protein values were adjusted to optimum values according to the quality with respect to casein (without amino acid fortification). Pro tein utilization (net protein ratio NPR) was determined in weekly inte rvals, triacylglycerol and cholesterol concentrations in the blood ser um were determined on the 70th and 140th day of age. A proteosynthesis rate was determined isotopically as L-/U-C-14-tyrosine incorporation in the protein fraction of liver and muscle in 12 hours after intrapen toneal aplication of the isotope in the rats in the period of rapid gr owth and in the adult rats on a casein - gluten diet. The isotopically determined values of tyrosine in the liver and muscles are significan tly lower for the age of 70 days and gluten diet in comparison with th e casein values. The proteosynthesis rate at the age of 140 days is id entical. A direct relation was also found between protein utilization and the values of the amino acid score of limiting amino acids AS and the potential biological value of the diet BH(p) in growing rats at th e age of 30 - 98 days (AS - K/Met + Cys/2/67, S/Met + Cys/2/63, G/Lys/ 28, mixture/Met+Cys/2/ 67; BH(p) - K 70.0; S 65.1; G 54.1; mixture 77. 0, NPR /70 days/ - K 2.00; S 1.48; G 1.22; mixture 2.07). In adult rat s (from the age of 105 days) the utilization of the diet from vegetabl e sources is equalized with the utilization of the diet from animal so urces, hence it does not depend on the aminogram quality. The results demonstrate the unsufficiency of vegetable sources of food with respec t to proteosynthesis and the content of limiting amino acids (decisive for the synthesis of peptide chains) in the period of the organism de velopment. In adult rats the values of the aminograms of food vegetabl e sources are sufficiently high with respect to the lower rate of prot eosynthesis (not for the growth but for the organism maintenance, tiss ue regeneration). The values of cholesterol and triacylglycerol concen trations in the blood serum of len rats are lower for vegetable and mi xed diets in comparison with dietary casein, and they are in direct pr oportion to the dietary Lys/Arg and Met ratio and in indirect proporti on to the Arg+Glu+Gly sum.