Comparative Evaluation of Some Techniques Used in Determinations of Nitrogen and Energy Content of Feces From Pigs

Saben, H. S.; Bowland, J. P.

doi:10.4141/cjas71-107

Cited by 2 publications

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References 5 publications

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“…The (Wu 1954 (Saben and Bowland 1971). Jdrgensen et al (1984) found that the protein digestibilities of four feedingstuffs did not differ when the feces were freeze-or oven-dried.…”

Section: Sibbald -Bioavailable Amino Acid Estimation 251mentioning

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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“…The (Wu 1954 (Saben and Bowland 1971). Jdrgensen et al (1984) found that the protein digestibilities of four feedingstuffs did not differ when the feces were freeze-or oven-dried.…”

Section: Sibbald -Bioavailable Amino Acid Estimation 251mentioning

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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“…Faeces were dried at 60 C for 72 h (Saben and Bowland 1971 amino acid analyzer equipped with a vari-pump using the method described by Piez and Morris (1960). The hydrolyzates were prepared by acid hydrolysis (Kohler and Palter 1967) …”

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confidence: 99%

Lysine, Threonine, Methionine and Isoleucine Supplementation of Peace River Barley for Growing Pigs

Chung¹,

Beames²

1974

Can. J. Anim. Sci.

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The supplementation of Peace River barley was investigated in both a growth trial and a metabolism trial. The control diet consisted essentially of barley and soybean meal and provided 15.8% crude protein containing 0.75% total lysine. In the other diets, barley, as the sole source of protein, was supplemented with L-lysine HCl to provide 0.75 and 0.90% total lysine, with the former level also tested with 0.05% added L-threonine, alone or with 0.10% DL-methionine or with 0.10% DL-methionine plus 0.10% L-isoleucine. The growth trial incorporated three replicates, each with three gilts and three barrows group-fed on each diet, whereas in the metabolism trial, six observations per diet were made. The control diet produced greater daily gain, better feed utilization and leaner carcasses than any of the amino acid-supplemented diets. Gilts, but not barrows, grew more rapidly with the increase in lysine content from 0.75 to 0.90%. Addition of 0.05% L-threonine to the 0.75% lysine diet to provide 0.29% total threonine significantly improved daily gain and feed efficiency. Addition of methionine either with or without isoleucine to this latter diet had no effect on growth or feed utilization, but slightly improved nitrogen retention. Although nitrogen retained (expressed as a percentage of nitrogen absorbed) for all diets containing threonine was greater than the value for the control diet, values for nitrogen digestion and total nitrogen retention were less than for the latter diet.

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Comparative Evaluation of Some Techniques Used in Determinations of Nitrogen and Energy Content of Feces From Pigs

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Cited by 2 publications

References 5 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

Lysine, Threonine, Methionine and Isoleucine Supplementation of Peace River Barley for Growing Pigs

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