A growth assay with chicks for the lysine content of protein concentrates

Carpenter, K. J.; March, B. E.; Milner, C. K.; Campbell, Rebecca E.

doi:10.1079/bjn19630034

Cited by 44 publications

(13 citation statements)

References 14 publications

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“…Estimates of available sulphur amino acid concentrations were remarkably similar whether made in vitro by enzymic digestion or in vivo using the feed conversion efficiency of rats as the response criterion (Pieniazek et al 1975). However, the ability of enzymic digestion to predict availability was affected by the severity of heat damage (Ford and Salter 1966 (Hung and Kermorgant 1982 (Carpenter et al 1963) or turkeys (Noll et (Batterham etal. 1978(Batterham etal.…”

Section: Nylon Bag Assaymentioning

confidence: 97%

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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Section: Nylon Bag Assaymentioning

confidence: 97%

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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“…Temperature exposure during processing is the single most important factor that determines protein digestibility and amino acid bioavailability in fish meal (Carpenter, March, Milner & Campbell 1963; FAO 1986; Pike et al . 1990; Schmidtsdorff 1995; Hardy 1995, 1996; Goddard 1996).…”

Section: Introductionmentioning

confidence: 99%

Recent advances in the development of innovative chemical methods for determining the nutritional value of fish meals and aquafeeds

Luzzana

2001

Aquaculture Research

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Aspartic acid racemization and oxysterol content have been evaluated as indicators of fish meal and aquafeed nutritional value in a series of studies reviewed in the present paper. Kinetic studies and assessment of the d‐aspartic acid content of commercial fish meals and fish feeds supported the use of the extent of racemization of this amino acid as a reliable indicator of the thermal history of fish meal. Preliminary results suggest that d‐aspartic acid could be a useful indicator of the protein nutritional value for fish, expressed by nitrogen retention or in vivo digestibility. However, species‐related differences seem to occur. Therefore, further studies are needed to evaluate the reliability of d‐aspartic acid content as an indicator of protein nutritional value affected by processing conditions. With regard to lipid quality, two major oxysterols, namely 7β‐hydroxycholesterol and 7‐ketocholesterol, have been identified and quantified in commercial fish meals. The measured levels were very low compared with the values reported in the literature for fish products, probably because of antioxidant addition during fish meal processing. An effect of storage time on cholesterol oxidation was also demonstrated in a laboratory‐scale experiment. Research needs for the future include a deeper understanding of the chemical reactions affecting the nutritional quality of aquafeeds, development of innovative and reliable chemical methods for raw material and feed quality assessment, and identification of critical control points in the manufacturing process to try to maintain the original nutritional value of raw materials.

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“…More recently, Carpenter, March, Milner and Campbell (1963), and Guttridge and Lewis (1964) described bioassay procedures for lysine and the sulphur-containing amino acids, using the young chick as test animal. Some, but not all, of the features of a valid bioassay were fulfilled in these procedures.…”

Section: Introductionmentioning

confidence: 98%

Chick bioassay of Lysine

Lewis

1966

British Poultry Science

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A growth assay with chicks for the lysine content of protein concentrates

Cited by 44 publications

References 14 publications

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

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

Recent advances in the development of innovative chemical methods for determining the nutritional value of fish meals and aquafeeds

Chick bioassay of Lysine

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