Utilization of Amino Acids from Protein by Weanling Pigs

Babcock, M. J.; Markley, R. A.

doi:10.1093/jn/93.3.368

Cited by 7 publications

(5 citation statements)

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“…This study showed that both dietary nitrogen level and length of feeding period must be considered when evaluating the utilization of amino acids for protein formation from diets such as those described here. Previous experiments had tentatively ascribed WGAA as inferior to CLAA in this respect (Babcock and Markley, 1967;Morse et al, 1969;Radke et al, 1969). The experiments in this study showed that such was not the case if the dietary nitrogen level was increased from 1.6% N to 2.4% N. Instead, the CLAA diet appeared to show a less efficient use of its amino acids for protein formation; however, this function was time dependent.…”

Section: Discussionmentioning

confidence: 93%

“…Since a difference in response to the three diets was found, the cause must lie in the properties of the intact proteins, since the total nitrogen content, total content of essential amino acids, and pattern of added nonessential amino acids was the same. Digestibilities of the nitrogen portions of the three diets were the same for pigs (Babcock and Markley, 1967); therefore, timing of the release of amino acids from the protein and in their movement through the intestinal wall was likely to have had a greater effect on nitrogen utilization during the initial 6 weeks. After 8 weeks, enzyme activity changes in the intestinal wall or liver could have been responsible for similar utilization of nitrogen from the three diets.…”

Section: Discussionmentioning

confidence: 99%

“…The NE-52 diet pattern of amino acids has been described by Babcock and Markley (1967). The diets in the present work were based on the same amino acid pattern.…”

Section: Methodsmentioning

confidence: 99%

“…Differences in utilization of amino acids for protein formation were found among the three diets. The casein-lactalbumin diet showed a consistent superiority for nitrogen utilization compared to the wheat gluten diet when studied in humans (Morse et 1969), pigs (Babcock and Markley, 1967), and rats (Radke et al, 1969).…”

mentioning

confidence: 99%

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Comparison of the utilization of supplemented wheat gluten and other amino acid sources in the rat

Cook¹,

Radke²,

Haas³

1971

J. Agric. Food Chem.

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

“…The NE-52 diet pattern of amino acids has been described by Babcock and Markley (1967). The diets in the present work were based on the same amino acid pattern.…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Comparison of the utilization of supplemented wheat gluten and other amino acid sources in the rat

Cook¹,

Radke²,

Haas³

1971

J. Agric. Food Chem.

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“…Studies with turkeys showed lysine analogues to differ widely in activity (Parsons et ai. 1980) as do analogues of tryptophan and methionine (Parsons and Potter 1981)" Free AA added to feed, even L-isomers, do not necessarily have the same activity as those present in proteins (Babcock and Markley 1967 ;Batterham 1919) perhaps because they can be absorbed more rapidly (Rolls et al 1912 Pigs and poultry require AA (National Research Council 1979. There are numerous publications concerning this sublect and a thorough review is not appropriate.…”

mentioning

confidence: 99%

Estimation of Bioavailable Amino Acids in Feedingstuffs for Poultry and Pigs: A Review With Emphasis on Balance Experiments

Sibbald¹

1987

Can. J. Anim. Sci.

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A bioavailable nutrient has the potential to be utilized when ingested. Ideally, the nutrient requirements of animals and the nutrient concentrations of feedingstuffs should be expressed in terms of bioavailable units. Bioavailability is an abstract concept which cannot be measured but it can be estimated. The purpose of this review is to describe, evaluate and compare procedures used to estimate the concentrations of bioavailable amino acids (BAA) in feedingstuffs for pigs and poultry. Accurate and precise measurement of total amino acid (AA) concentrations is of fundamental importance to many assays. Problems are encountered both in making the AA available for measurement (hydrolysis) and in the measurement procedures. There is need for standardization of methodology but until this is achieved caution must be exercised when comparing data obtained by different techniques or even from different laboratories. In vitro assays for BAA are relatively fast and can be made without access to animals. Enzymic digestion has the potential to be a good estimator of BAA but is constrained by a lack of information about the bioavailabilities of the peptides which are liberated. Chemical assays and dye binding produce data which sometimes, but not always, correlate with biological estimates of BAA. The future of such assays seems to be in quality control where comparisons are made among samples within ingredients. Among the indirect biological assays, those based on microbial growth have received the most attention. The major weakness of such assays resides in the difference between animal and microbe in the ability to utilize peptides. Plasma free amino acids are not satisfactory estimators of BAA although they can help to identify limiting AA in feedingstuffs. Nitrogen digestion lacks the sensitivity to be a predictor of BAA. Growth assays are thought by many to be the ultimate measure of bioavailability but in fact they measure utility which is not the same. Nevertheless, growth assays can provide valuable estimates of BAA providing that their limitations are understood. The assays are expensive and slow and the results can be affected by many variables including changes in nutrient concentrations when a test material is added to an assay diet. Much of the review is devoted to balance experiments which require great care and attention to detail if reliable, reproducible data are to be obtained. Procedures have been refined during many years of use and with the advent of new equipment and techniques. Concern is currently focussed on corrections for metabolic and endogenous losses and on the effects of the microflora of the alimentary tract. Recent developments have increased assay efficiency, particularly with poultry. The balance experiment provides BAA estimates, that can be used effectively in diet formulation, at a much faster rate than growth assays. The final section of the review makes comparisons among various methods of estimating BAA. Interspecies comparisons are useful because they provide guidance when attempting to apply data derived with one species to formulate diets for another. The search for a single assay which provides data applicable to several species is a worthwhile objective. In the meantime, there are many assays used to estimate BAA which have specific applications and limitations. Key words: Pigs, poultry, amino acids, assay methodology, feedingstuffs, review

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Utilization of Amino Acids in Casein-Lactalbumin and Wheat Gluten when Equalized to Levels of the FAO Pattern

Morse¹,

Tucker²,

Braucher

et al. 1969

The American Journal of Clinical Nutrition

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Utilization of Amino Acids from Protein by Weanling Pigs

Cited by 7 publications

References 0 publications

Comparison of the utilization of supplemented wheat gluten and other amino acid sources in the rat

Comparison of the utilization of supplemented wheat gluten and other amino acid sources in the rat

Estimation of Bioavailable Amino Acids in Feedingstuffs for Poultry and Pigs: A Review With Emphasis on Balance Experiments

Utilization of Amino Acids in Casein-Lactalbumin and Wheat Gluten when Equalized to Levels of the FAO Pattern

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