Tryptophan Requirement of Growing Pigs at Three Levels of Dietary Protein

Boomgaardt, John; Baker, David H.

doi:10.2527/jas1973.362303x

Cited by 22 publications

(16 citation statements)

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“…During the past 50 years, many studies have examined the effect of dietary CP on EAA requirements of various species. The results have shown that EAA requirements of chicks (Grau, 1948; Almquist, 1949; Almquist and Merritt, 1950; Grau and Kamei, 1950; Twining et al., 1955; Griminger et al., 1956; Rosenberg and Baldini, 1957; Nelson et al., 1960; Boomgaardt and Baker, 1971, 1973b), pigs (Brinegar et al., 1950; Becker et al., 1957; McWard et al., 1959; Klay, 1964; Sowers and Meade, 1972; Boomgaardt and Baker, 1973a; Baker et al., 1975), rats (Salmon, 1954; Forbes et al., 1955; Bressani and Mertz, 1958) and turkeys (Kratzer et al., 1950) are positively correlated with the concentration of dietary CP. As dietary CP increases, EAA requirements often increase somewhat beyond the percentage increase of dietary CP added.…”

Section: Discussionmentioning

confidence: 98%

“…As dietary CP increases, EAA requirements often increase somewhat beyond the percentage increase of dietary CP added. In these same species when a given EAA is limiting, increasing total dietary amino acids without the limiting amino acid leads to a depression of food intake and body weight gain, especially if total CP is limiting (Boomgaardt and Baker, 1971, 1973a,b; Grau, 1948; Almquist, 1949; Brinegar et al., 1950; Grau and Kamei, 1950; Sauberlich and Salmon, 1955; Griminger et al., 1956; Sauberlich, 1956, 1961; Becker et al., 1957; McWard et al., 1959; Hill and Olsen, 1963; Harper and Rogers, 1965; Baker et al., 1975; Peng, 1979). This effect has been referred to as an amino acid imbalance (Harper et al., 1970).…”

Section: Discussionmentioning

confidence: 99%

“…Essential amino acid (EAA) requirements of chicks (Boomgaardt and Baker, 1971), lambs (Rogers and Egan, 1975), pigs (Boomgaardt and Baker, 1973a) and rats (Bressani and Mertz, 1958) increase as the concentration of dietary crude protein (CP, N × 6.25) increases. When an EAA is limiting in a diet offered to these species, increasing dietary CP without increasing the limiting amino acid progressively decreases body weight gain (Griminger et al., 1956; Sauberlich, 1961; Baker et al., 1975), largely as a result of decreased food intake.…”

Section: Introductionmentioning

confidence: 99%

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Increasing dietary crude protein does not increase the essential amino acid requirements of kittens*

Strieker

Morris

Rogers

2006

Animal Physiology Nutrition

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Essential amino acid (EAA) requirements of omnivores and herbivores (e.g. chicks, lambs, pigs and rats) are directly related to the concentration of dietary crude protein (CP). When an EAA is limiting in the diet, addition of a mixture of EAA lacking the limiting one (which increases dietary CP) results in a decrease in food intake and weight gain. This interaction has been referred to as an AA imbalance and has not been studied in depth in strict carnivores. The objectives of these experiments were to examine the effects on growing kittens (2-week periods) of the addition to diets of a mixture of AA lacking the limiting one. The control diets were at the requirement of the respective limiting EAA (or about 85% of the 1986 National Research Council requirement). In experiment 1, with the dietary EAAs at the minimally determined requirements, the concentration of the essential or dispensable amino acids was increased to determine if CP or an EAA was limiting. Results of growth rates (n = 12) and plasma AA concentrations indicated that tryptophan was limiting, but increased body weight gain also occurred when the concentration of CP was increased as dispensable amino acids without additional tryptophan. Experiment 1 was repeated in experiment 2 using a crossover design. Again, when tryptophan was limiting additional concentrations of dispensable AAs increased body weight gain. This response is the opposite of that in herbivores and omnivores. Experiment 3 consisted of 10 separate crossover trials, one for each of the 10 EAA and examined the effect of two concentrations of dietary CP (200 and 300 g CP/kg diet) on body weight gain of kittens (n = 8) offered diets limiting in each respective EAA. Body weight gain was numerically greater when diets contained 300 g CP/kg than 200 g CP/kg for eight of 10 EAAs (p < 0.05 for only isoleucine and threonine) when each amino acid was limiting. This response is the reverse of that which occurs in chicks, lambs, pigs and rats when an EAA is limiting and dietary CP lacking the limiting EAA is increased. These results indicate that the EAA requirements of kittens are not positively correlated with dietary CP concentrations.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Increasing dietary crude protein does not increase the essential amino acid requirements of kittens*

Strieker

Morris

Rogers

2006

Animal Physiology Nutrition

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“…According to recent research, the concentration of large neutral amino acid (LNAA), in the diet also plays an important role in determining the tryptophan requirement. Some studies indicate that the tryptophan requirement for optimal performance increases in rations with higher protein concentrations and therefore, higher levels of LNAA (Boomgaardt and Baker, 1973;Henry et al, 1992). LNAA compete with tryptophan for transfer across the blood-brain barrier in the brain and therefore interact with the formation of serotonin (Henry et al, 1992).…”

Section: Discussionmentioning

confidence: 98%

Studies on the tryptophan requirement of piglets

Eder¹,

Peganova

Kluge

2001

Archiv für Tierernaehrung

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Three experiments were conducted to determine the requirement of tryptophan for piglets. In the first two experiments dose-response relationships between the dietary tryptophan concentration and performance criteria of piglets were examined in order to determine the dietary tryptophan concentration required for maximum performance. In the first experiment dietary tryptophan levels ranged from 1.09 to 2.32 g per kg, in the second experiment they ranged from 1.70 to 2.60 g per kg. In both experiments a close correlation was observed between the dietary tryptophan concentration and piglet performance criteria (feed intake, daily gains, feed efficiency). In the first experiment, regression analysis using a non-linear model revealed that the optima, defined as 95% of the asymptotic response in the model used, for feed intake and daily gains were achieved at tryptophan levels in excess of the highest concentration of 2.32 g per kg feed. The performance level of the piglets in this experiment was generally very low, however. In the second experiment feed intake, the optimum tryptophan concentration, defined as 95% of the asymptotic response, for daily gains and feed efficiency were achieved within a small range between 2.07 and 2.14 g tryptophan per kg feed, corresponding to 1.84 to 1.91 g precaecal digestible tryptophan per kg feed or 0.153 to 0.159 g tryptophan per MJ ME. These results suggest that the tryptophan concentration for maximum performance of piglets is probably higher than has been implied in numerous studies to date. The third experiment was set up to investigate the effect of the reduced feed intake and the effect of an inadequate tryptophan supply per se on the animals' growth. Here a two-factorial experimental design was used also by varying the energy density of the diet (13 vs. 14 MJ ME per kg feed). In addition to tryptophan deficient groups (1.5 g tryptophan per kg feed), this experiment contained conventional control groups (2.6 g tryptophan per kg feed, ad libitum feeding) and pair-fed control groups (2.6 g tryptophan per kg feed, feed intake identical to that of the tryptophan deficient group). The energy density had no significant effect on the animals' performance and increasing the energy density of the diet did not significantly affect feed and energy intake or daily gains of the tryptophan deficient animals. Feed intake, daily gains and feed efficiency of the tryptophan deficient groups were markedly poorer (by 30, 35 and 10%) than in the ad libitum control groups. When compared with the pair-fed control groups, on the other hand, the performance of the tryptophan deficient groups in terms of daily gains, feed conversion and energy efficiency was only slightly and not significant lower by 1, 4 and 3%, respectively. These results demonstrate conclusively that the growth depression in tryptophan deficiency is almost entirely due to the marked reduction in feed intake rather than to a direct limitation of protein accretion caused by an inadequate tryptophan supply.

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“…The response criteria used to estimate AA requirements have included, among others, rate of body weight gain (Hutchinson et al 195'7 Klain et al 1960), feed efficiency Balloun and Phillips 1957), nitrogen retention (Ishibashi 1973a;Braude and Esnaola 1973) protein gain (Nitsan et al 1983), carcass composition (Kubena et al 1972; Batterham l9l4), feed intake (Batterham et al 1985), metabolizable energy consumption (Petersen 1979), energetic efficiency (Sughara et al 1984), egg production (Fisher and Johnson 1956), and plasma AA concentration (Ishibashi 1973b). Requirement data are expressed in a variety of units including proportion of the diet (Braude and Esnaola 1973), percentage of the diet (Krautmann et al 1958), percentage ofdietary protein Boomgaardt and Baker 1973), per kilogram of body weight (Ishibashi 1973a1' Nitsan et al 1983 per unit of dietary energy (Combs 1962;Mitchell et al 1965). Units for expressing requirements have been discussed by Lewis and Cole (1976).…”

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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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Tryptophan Requirement of Growing Pigs at Three Levels of Dietary Protein

Cited by 22 publications

References 0 publications

Increasing dietary crude protein does not increase the essential amino acid requirements of kittens*

Increasing dietary crude protein does not increase the essential amino acid requirements of kittens*

Studies on the tryptophan requirement of piglets

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

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