[Methodological approaches to the study of protein metabolism during early postnatal period of ontogenesis].
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Animal Population Groups↗
Biomedical subjects
L I Smirnova
Publications and source records attributed to L I Smirnova.
[Biological value of different proteins used in the early period of postnatal development].
A comparison was made of the efficacy of utilizing proteins that differ both in the amino acid composition and susceptibility to alimentary proteinases. Starting from 15 days of age the rats received formula feeding over a week. The formula feeding included mixtures imitating the composition of the rat's milk and containing the test proteins in an amount of 10%. It was shown that the mixture of casein with milk serum proteins was utilized most effectively. The decrease in the casein content in the diet and replacement of casein by egg albumin, bovine serum albumin or milk serum proteins were found to lead to the lowered efficacy of protein utilization. Energy distribution studies have shown that the decreased efficacy of proteins utilization is accompanied by the increased amount of nitrogen excreted with the urine.
Animals↗
[Digestive characteristics of qualitatively different proteins in rats in the early postnatal development period].
Starting from 15 days of age the rats were transferred to formula feeding with liquid diet adapted to the rat milk composition in terms of the main parameters. It was shown that caseine exclusion from the rat diet during the early postnatal period of the development and its replacement by proteins of milk serum or by bovine serum albumin that are not capable of curdling leads to a 2- and 3-fold increase, respectively in the protein evacuation rate from the stomach. As a result, the nitrogen content in the chyme of the small intestine rises. One may think that observed accumulation of protein proteolysis products indicates both considerable intensity of cavitary digestion of proteins qualitatively different from caseine in the small intestine of rats in the early postnatal period of the development and its functional overloading as a result of which the protein proteolysis products formed fail to be absorbed.
Animals↗
[Digestion of incoagulable proteins during the early postnatal period of development].
Substitution of casein by proteins of milk serum or by bovine blood serum albumin in the diet of 15 days old rats, maintained on artificial food, led to a 2-3-fold increase in the rate of transport of alimentary protein from stomach and to a corresponding elevation in content of nitrogen containing material in chymus of the small intestine. Distinct activation of trypsin and chymotrypsin as well as an increase in concentration of low molecular products of the protein proteolysis were found in the chymus of small intestine.
Adaptation, Physiological↗