The Determination of Metabolic Fecal Nitrogen

Mitchell, H. H.; Bert, Mark H.

doi:10.1093/jn/52.3.483

Cited by 60 publications

(8 citation statements)

References 16 publications

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“…In agreement with results from other studies on nitrogen or AA flow at the terminal ileum this indicates that the absorption rate of nitrogenous fractions is not regulated depending on the level of supply (Mitchell and Bert, 1954;Bielorai et al, 1985;Gruhn and Zander, 1989;Short et al, 1999;Rodehutscord et al, 2004). When quantitative data for intake and digestion are used in a linear regression, the slope can be regarded as a measure of digestibility.…”

Section: Discussionsupporting

confidence: 88%

Variation in precaecal amino acid and energy digestibility between pea (Pisum sativum) cultivars determined using a linear regression approach

Kluth

Mantei²,

Elwert³

et al. 2005

British Poultry Science

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An experiment was conducted to study the variation in the precaecal amino acid (AA) and energy digestibility of 4 cultivars of white-flowering peas (Pisum sativum) for broiler chickens. The 4 cultivars were grown and harvested under the same agronomic and environmental conditions. One basal diet and 8 diets including each pea cultivar at inclusion rates of either 150 or 300 g/kg were used. Peas were included at the expense of starch. Hence, the differences in dietary crude protein and AA concentrations resulted only from the inclusion of peas. Titanium dioxide was included as an indigestible marker. Crude protein concentrations in the complete diets ranged from 164 to 244 g/kg. All diets were fed ad libitum to broiler chickens between 14 and 21 d of age. Seven pens of 12 chickens were allocated to each treatment. Digesta were sampled on a pen basis from the section of the gastrointestinal tract between Meckel's diverticulum and 2 cm anterior to the ileo-caeco-colonic junction. The proportions of crude protein and AAs digested responded linearly to increased intake and the relationships between quantitative intake and digested amounts of AAs were described by multiple linear regressions. The slope determined for each pea cultivar was taken as a measure of AA digestibility without the need for consideration of basal endogenous crude protein and AA secretions. Digestibility of AAs in peas ranged from 0.60 to 0.91. One cultivar had significantly lower AA digestibilities than the other three cultivars. This could be explained neither by the trypsin inhibitor activity nor by tannin levels. The AAs with the highest digestibilities in all cultivars were arginine > glutamic acid > lysine > methionine > phenylalanine > leucine. The AAs with the consistently lowest digestibilities were cystine < threonine. The ranking of the remaining AAs varied slightly between cultivars. The multiple linear regression approach is suitable to study differences in AA digestibilities without the need for consideration of basal endogenous AA losses. Diets containing 300 g/kg of peas had significantly lower energy digestibilities than the pea-free basal diet. The pea cultivar with the lowest AA digestibility caused the lowest energy digestibility at both levels of pea inclusion.

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Section: Discussionsupporting

confidence: 88%

Variation in precaecal amino acid and energy digestibility between pea (Pisum sativum) cultivars determined using a linear regression approach

Kluth

Mantei²,

Elwert³

et al. 2005

British Poultry Science

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“…This has been previously reported in normal subjects (18) and could be due to greater fecal excretion of endogenous protein than fat (7,(31)(32)(33)(34)(35). After RYGB protein absorption coefficients decreased less than fat absorption coefficients, which is consistent with reports of greater reserve capacity for absorption of dietary protein than fat (36,37).…”

Section: Discussionsupporting

confidence: 73%

The contribution of malabsorption to the reduction in net energy absorption after long-limb Roux-en-Y gastric bypass

Odstrcil

Martı́nez

Ana

et al. 2010

The American Journal of Clinical Nutrition

181

105

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Background: Roux-en-Y gastric bypass (RYGB) restricts food intake, and when the Roux limb is elongated to 150 cm, the procedure is believed to induce malabsorption. Objective: Our objective was to measure total reduction in intestinal absorption of combustible energy after RYGB and the extent to which this was due to restriction of food intake or malabsorption of ingested macronutrients. Design: Long-limb RYGB was performed in 9 severely obese patients. Dietary intake and intestinal absorption of fat, protein, carbohydrate, and combustible energy were measured before and at 2 intervals after bypass. By using coefficients of absorption to measure absorptive function, equations were developed to calculate the daily gram and kilocalorie quantities of ingested macronutrients that were not absorbed because of malabsorption or restricted food intake. Results: Coefficients of fat absorption were 92 6 1.3% before bypass, 72 6 5.5% 5 mo after bypass, and 68 6 8.7% 14 mo after bypass. There were no statistically significant effects of RYGB on protein or carbohydrate absorption coefficients, although protein coefficients decreased substantially in some patients. Five months after bypass, malabsorption reduced absorption of combustible energy by 124 6 57 kcal/d, whereas restriction of food intake reduced energy absorption by 2062 6 271 kcal/d. Fourteen months after bypass, malabsorption reduced energy absorption by 172 6 60 kcal/d compared with 1418 6 171 kcal/d caused by restricted food intake. Conclusion: On average, malabsorption accounted for '6% and 11% of the total reduction in combustible energy absorption at 5 and 14 mo, respectively, after this gastric bypass procedure. Am J Clin Nutr 2010;92:704-13.

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“…Apparent digestibilities were measured in all experimental diets. Because the relationship between intake and excretion of protein and amino acids is linear (Mitchell and Bert, 1954;Sibbald, 1979;Rodehutscord et al, 2004), a linear regression approach was then used for calculating digestibilities for the 2 protein sources. Prececal digestibility was determined in experiment 1 and total excreta (TE) digestibility with cecectomized hens in experiment 2.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Amino Acid Digestibility Determined Prececally or Based on Total Excretion of Cecectomized Laying Hens

2008

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This study investigated the possibility of using cecectomized laying hens for the determination of amino acid (AA) digestibility of protein sources as an alternative to measurements made at the terminal ileum. Toasted soybeans and corn gluten meal were used as test protein sources. A low-protein basal diet was based mainly on corn, wheat gluten, and cornstarch. In 4 other diets toasted soybeans or corn gluten meal were included each at 15% or 30% at the expense of cornstarch, so that the changes in the AA concentrations of the diets resulted from the protein sources only. Titanium dioxide was used as the indigestible marker. In experiment 1, two hundred ten 18-wk-old pullets were used. Digesta from the posterior 2-thirds of the intestine between Meckel's diverticulum and 2 cm anterior to the ileo-ceca-colonic junction was obtained from killed hens. In experiment 2, fourteen cecectomized hens were used. They were kept individually, and excreta were quantitatively collected. The apparent digestibility of AA was calculated for each diet. Linear regression analysis was used to calculate AA digestibility for the 2 protein sources. Across all diets, apparent AA digestibility was significantly higher in experiment 2 than in experiment 1. However, AA digestibilities of the 2 protein sources were not different between both experiments. Differences in AA digestibility between the protein sources were not significant in experiment 1, but in experiment 2 significant differences between the protein sources were detected for some AA due to a lower standard error of estimate. It was concluded that AA digestibility of protein sources for laying hens can be evaluated based on quantitative excreta collection with cecectomized hens using the regression approach. This needs fewer animals than the determination of digestibility at the terminal ileum. Differences between protein sources are easier to detect because of the lower standard error of estimate.

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The Determination of Metabolic Fecal Nitrogen

Cited by 60 publications

References 16 publications

Variation in precaecal amino acid and energy digestibility between pea (Pisum sativum) cultivars determined using a linear regression approach

Variation in precaecal amino acid and energy digestibility between pea (Pisum sativum) cultivars determined using a linear regression approach

The contribution of malabsorption to the reduction in net energy absorption after long-limb Roux-en-Y gastric bypass

Comparison of Amino Acid Digestibility Determined Prececally or Based on Total Excretion of Cecectomized Laying Hens

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