Tryptophan Requirement of Growing Chicks as Affected by Dietary Protein Level

Boomgaardt, John; Baker, David H.

doi:10.2527/jas1971.333595x

Cited by 56 publications

(19 citation statements)

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“…Our results tend to confirm this. However, that this finding should not be assumed as typical of essential amino acids in general is indicated by similar or even lower gain/feed than gain requirements for tryptophan (Boomgaardt and Baker, 1971), sulfur amino acids at University of Wisconsin-Oshkosh on June 10, 2015 http://ps.oxfordjournals.org/ Downloaded from (Boomgaardt, 1972) and aromatic amino acids (Sasse and Baker, 1972). emy of Science, Phi Kappa Phi, Phi Sigma, Poultry Science Association, Sigma Xi, and the Society for Experimental Biology and Medicine."…”

Section: Discussionmentioning

confidence: 86%

“…During the 13-day pretest period chicks were fed a 24% protein cornsoybean meal pretest diet and were debeaked on day 8. On day 13 the birds went through the normal fasting routine; that is, feed was removed at 9 a.m. and replaced at 1 p.m. after which both feed and water were removed at 3 p.m. On day 14, chicks were selected and allotted to ex-AND D. H. BAKER perimental treatment as described previously (Boomgaardt and Baker, 1971). Feed and water were available ad libitum throughout the assay period.…”

Section: Methodsmentioning

confidence: 99%

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The Lysine Requirement of Growing Chicks Fed Sesame Meal-Gelatin Diets at Three Protein Levels

Boomgaardt

Baker

1973

Poultry Science

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Diets providing three levels of protein (14, 18.5 and 23%) and six levels of lysine (3.43, 3.93, 4.43,4.93, 5.43 and 5.93% of C.P.) were fed to triplicate groups of eight male crossbred chicks for the period 14 to 28 days posthatching. The basal 23% protein ration contained protein from sesame meal and gelatin and was supplemented with quantities of essential amino acids equal to the difference between the level supplied by the dietary protein and that recommended by N.R.C. (1971). Amino acid pattern of the 14 and 18.5% protein diets was similar to that of the 23% protein diet since proteinaceous ingredients and crystalline amino acids were reduced in direct proportion to the reduction in protein level. The lysine requirement for maximal weight gain was estimated to be 4.73,4.72 and 4.60% of the protein at 14, 18.5 and 23% dietary protein, respectively. Expressed as a percent of the diet the requirement values were estimated at 0.66, 0.88 and 1.05% at 14, 18.5 and 23% dietary protein, respectively. The results confirm earlier observations that the requirement for an essential amino acid remains essentially constant as dietary protein level is varied between deficiency and adequacy.

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Section: Discussionmentioning

confidence: 86%

Section: Methodsmentioning

confidence: 99%

The Lysine Requirement of Growing Chicks Fed Sesame Meal-Gelatin Diets at Three Protein Levels

Boomgaardt

Baker

1973

Poultry Science

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“…Birds consuming lower protein levels synthesize smaller amounts of protein and so need less of each amino acid, and vice versa. Amino acids are needed in direct proportion to the dietary protein level [3][4][5][6][7][8]. One of the factors determining feed consumption in published studies [3][4][5][6][7][8] is the dietary protein level.…”

Section: Description Of Problemmentioning

confidence: 99%

“…Amino acids are needed in direct proportion to the dietary protein level [3][4][5][6][7][8]. One of the factors determining feed consumption in published studies [3][4][5][6][7][8] is the dietary protein level. With higher protein levels, some genetic strains maintain consumption levels but grow more, resulting in improved feed utilization efficiency, whereas other genetic strains consume less feed but maintain growth levels, resulting in improved feed utilization efficiency [9][10][11][12][13].…”

Section: Description Of Problemmentioning

confidence: 99%

Impact of dietary amino acid and crude protein levels in broiler feeds on biological performance

Pesti

2009

Journal of Applied Poultry Research

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The concept of a requirement for dietary protein has been controversial since it was discovered that proteins are composed of amino acids and that some amino acids are dietary essentials for maximum growth and performance. In addition to the 10 essential amino acids and 3 that can be accreted only from limited substrates, poultry need a quantity of amino acids to synthesize the other 8 that are needed to synthesize body proteins. Adding purified amino acids or amino acid precursors has been known for more than 50 yr to allow for reduced levels of intact proteins to provide adequate levels of essential and nonessential amino acids (CP). It has been recognized that individual essential amino acid requirements are functions of the total CP level. Increasing the total CP level while maintaining ideal ratios of essential amino acids increases growth, feed utilization efficiency, and carcass yields (i.e., decreases carcass fat). A published data set is used here to demonstrate 1) that potential problems arise from analyzing combined data sets inappropriately; 2) that in the overwhelming majority of studies, there is a positive response in growth (P < 0.0002) and feed utilization efficiency (P < 0.0002) to increasing dietary protein levels; 3) that the relationships are much stronger in faster growing broiler strain birds; and 4) that there is no clear break point or "requirement" for CP in the range of dietary protein levels typically studied. Regardless of whether it is called "CP level" or "essential + nonessential amino acid level," there is no clear requirement, only a smooth response curve that approaches maxima at lower levels for growth, and then feed utilization efficiency, and then lean meat yield, and finally the minimum for carcass fat. As a result, decisions on feeding levels for essential and nonessential amino acids should depend on the input-output relationships and costs.

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“…Duplicate lots of chicks originating from the cross of Columbian females to New Hampshire males were used in all assays. The pre-experimental care, selection, allotment to treatment and environmental conditions have been described previously (Boomgaardt and Baker, 1971). The basal diet shown in Table 1 is similar to the Illinois reference standard (R.S.)…”

Section: Methodsmentioning

confidence: 99%

Sequence of Limiting Amino Acids in Gelatin for the Growing Chick

Boomgaardt

Baker

1972

Poultry Science

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Several 6-day growth assays were conducted to delineate the amino acid limitations of gelatin for chick growth. At a dietary level of 14.5% crude protein, gelatin was observed to be severely deficient in nine essential amino acids. Tryptophan, sulfur amino acids and isoleucine were first, second and third limiting, respectively. Aromatic amino acids, threonine and valine were found to be equally fourth limiting, while leucine, histidine and lysine were seventh, eighth and ninth limiting, respectively. Arginine, glycine-serine and proline were observed to be adequate to super-adequate. Rate and efficiency of gain by chicks fed the completely-supplemented diet were such as to suggest rather high availabilities of amino acids in the protein of gelatin.

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Tryptophan Requirement of Growing Chicks as Affected by Dietary Protein Level

Cited by 56 publications

References 0 publications

The Lysine Requirement of Growing Chicks Fed Sesame Meal-Gelatin Diets at Three Protein Levels

The Lysine Requirement of Growing Chicks Fed Sesame Meal-Gelatin Diets at Three Protein Levels

Impact of dietary amino acid and crude protein levels in broiler feeds on biological performance

Sequence of Limiting Amino Acids in Gelatin for the Growing Chick

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