The nutritional requirements of the protein-depleted chicken

Wessels, J. P. H.; Fisher, Hans

doi:10.1079/bjn19650006

Cited by 5 publications

(12 citation statements)

References 14 publications

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“…Basak showed that the N losses of human subjects kept for a short period on a protein-free diet were primarily non-protein in origin and represented about 6% of the total body N of human adults on a normal diet. This quantity is similar to the estimated magnitude of I967 N stores in the adult cock (6.9 yo of body N) as measured by the depletion technique of Wessels & Fisher (1965).…”

supporting

confidence: 81%

“…Two experiments, involving a total of forty-eight cocks, were carried out. The care and maintenance of the birds, the depletion and repletion procedures, as well as the composition of the basal diets used, were similar to those previously described (Wessels & Fisher, 1965).…”

Section: E X P E R I M E N T a Lmentioning

confidence: 99%

“…Although the results of the studies cited all show considerable N retention from supplementation with sources of non-essential amino acid N, they are, nevertheless, incomplete in that they do not provide clear evidence that the retained N has been, or could be, utilized for the synthesis of previously depleted nitrogenous body components. Wessels & Fisher (1965) were able to show only a limited repletion of nitrogenous liver components in repleted cocks that were in positive N balance.…”

mentioning

confidence: 93%

“…The amount of body nitrogen loss in adult cocks on a protein-free diet beyond which repletion does not occur with a supplement of non-essential amino acids to a maintenance mixture of essential amino acids has been regarded as a measure of the size of the protein reserve pool (Wessels & Fisher, 1965). This estimate of the magnitude of the body'sprotein reserves was based upon the observations of Shapiro & Fisher (1962) that partial repletion of body N stores could be attained by non-essential amino acid N in adult cocks depleted to the endogenous level of N excretion.…”

mentioning

confidence: 99%

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Protein reserves and muscle constituents of protein-depleted and repleted cocks

Ashley

Fisher

1967

Br J Nutr

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I . Body-weight changes and nitrogen balance were studied, together with the concentration of various nitrogenous muscle components, in adult cocks before and after a 6-day period on a N-free diet and again after a 16-day repletion period on diets supplying various amounts and types of dietary N. 2.In the first experiment a comparison was made during the repletion period between a fish-protein supplement and a supplement of glycine + glutamic acid added to an essential amino acid mixture.3. During the depletion period the muscle concentration of RNA, DNA and of two transaminase enzymes decreased significantly ; during the repletion period these components increased again significantly, and usually to levels greater than the pre-depletion concentration.There were no differences in these responses obtained during repletion with the two N supplements, although the cocks given the glycine-glutamic acid supplement differed from those receiving fish protein in being in negative N balance and in losing body-weight during the repletion period.4. In the second experiment one group of depleted cocks was given an essential amino acid mixture alone as the dietary N source and a second group this mixture supplemented by aspartic acid. .A decrease in RNA and in the transaminase enzymes during depletion was followed by a significant increase during repletion, but the increase was greater for the group receiving the aspartic acid than for that receiving only the essential amino acid mixture. 6.It was concluded that adding non-essential amino acids to a maintenance mixture of essential amino acids will permit greater repletion in mature cocks.7. The fluctuations in concentration of RNA and of certain enzymes with dietary protein supply may well be a controlling factor in the regulation of N losses and accretions during protein deficiency and sufficiency.8. The relative constancy of muscle DNA in contrast to the fluctuations in other nitrogenous muscle constituents provides additional support for the concept of protein reserves.The amount of body nitrogen loss in adult cocks on a protein-free diet beyond which repletion does not occur with a supplement of non-essential amino acids to a maintenance mixture of essential amino acids has been regarded as a measure of the size of the protein reserve pool (Wessels & Fisher, 1965). This estimate of the magnitude of the body'sprotein reserves was based upon the observations of Shapiro & Fisher (1962) that partial repletion of body N stores could be attained by non-essential amino acid N in adult cocks depleted to the endogenous level of N excretion. Logical support for these experimental findings may be derived from a study by Bas& (1958). Basak showed that the N losses of human subjects kept for a short period on a protein-free diet were primarily non-protein in origin and represented about 6% of the total body N of human adults on a normal diet. This quantity is similar to the estimated magnitude of

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supporting

confidence: 81%

Section: E X P E R I M E N T a Lmentioning

confidence: 99%

mentioning

confidence: 93%

mentioning

confidence: 99%

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Protein reserves and muscle constituents of protein-depleted and repleted cocks

Ashley

Fisher

1967

Br J Nutr

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“…Adult, White Leghorn cocks between 1-5 and 2.5 years old were housed in individual cages. They were given a protein-free diet (for composition see Table r, Wessels & Fisher, 1965) and their N excretion was measured continuously, Groups of four cocks were killed after 0, 2, 4 and 10 days on the protein-free diet.…”

Section: Studies On Site Of N Lossmentioning

confidence: 99%