HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) 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 Cox, J. L. Articles by Jensen, A. H. Search for Related Content PubMed PubMed Citation Articles by Cox, J. L. Articles by Jensen, A. H.

Response of Pregnant Rats to Sources of Dietary Nitrogen and Cold Exposure

Illinois Agriculture Experiment Station, Urbana

Abstract

Two experiments were conducted to evaluate the influence of dietary nitrogen source and level on gestation performance of rats exposed to cold. Diets with 5% protein, or 5% protein plus 10 essential amino acids (simulated casein pattern) or glutamic acid or both were fed. Pregnant rats were placed in a 7° or 23° C. environment on the day of mating and fed 18 and 12 gm., respectively. Nitrogen retention for each of five consecutive 4-day periods was determined.

At 23° C. supplementation of the basal diet with the essential amino acids increased weight gain. However, at 7° C. weight gain was not significantly affected. At both temperatures the amino acid mixture stimulated nitrogen retention during early gestation (first through fourth day).During the subsequent three 4-day periods, the amino acid mixture stimulated nitrogen retention at 23° C. However, at 7° C. during the same three periods, a positive response was not attained and the levels of nitrogen retained were only slightly above those from the unsupplemented diet at 23° C. The energy intake of the rats at 7° C. may have been inadequate to permit retention of the additional nitrogen consumed. In the final 4-day period (17th through 20th day) nitrogen retention from the amino acid supplemented diets at 7° was equal to that at 23° C. on the diet containing both essential amino acids and glutamic acid. Glutamic acid addition to the diet with essential amino acids increased nitrogen retention at 23° but not at 7° C.

¹ Present address: Merck Institute for Therapeutic Research, Rahway, New Jersey.

² This paper represents part of a thesis submitted by the senior author to the Graduate College of the University of Illinois in partial fulfillment of the requirements for the Ph.D.