QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Salmon, W. D. Search for Related Content PubMed PubMed Citation Articles by Salmon, W. D.

Relative Potency of Diets Containing Amino Acids and Proteins for Promoting Growth of Rats^1,2,

Auburn University Agricultural Experiment Station, Department of Animal Science, Auburn, Alabama

The necessity for inclusion of certain nonessential amino acids and of the high levels of essential amino acids sometimes used in diets for rats was investigated. The rate of weight gain of rats produced by the best amino acid diets was compared with that produced by diets containing intact protein or combinations of intact protein and amino acids. Data are presented on weight gains of young rats subjected to 23 different dietary treatments for 8 weeks. Accumulated weight gains for the first 4-weeks appeared to be somewhat more dependable than for the first 2-week period; there was no advantage in extending the test over an 8-week period. A mean weight gain of 44+ g/rat/week for a 4-week period was supported by a protein-free diet containing 14 amino acids and 2.16% total nitrogen; of this 0.66% was supplied by L-glutamic acid. A diet containing 19 amino acids and 3.03% total nitrogen was less effective. Similar diets containing 20% of casein, lactalbumen or protein equivalent of dried lean beef supported mean weight gains of 50+ g/rat/week over the same period. This was a significantly higher (P < 0.005) rate of gain than was produced by the best amino acid diet. When adequately supplemented with amino acids, 25% of peanut meal, 20% of wheat gluten or 10% of casein in the diet likewise produced mean weight gains of 50+ g/rat/week over a 4-week period. Thus, it was shown that there was a growth-stimulating effect of the intact proteins not observed in any of the amino acid combinations tested.

² Some of the data in this paper were presented at the Federation of American Societies for Experimental Biology Meetings in Atlantic City, New Jersey, 1962.

Manuscript received 27 August 1963.