The laboratory rat as a model animal for determining ileal amino acid digestibility in meat and bone meal for the growing pig

Donkoh, A.; Moughan, Paul J.; Smith, W. C.

doi:10.1016/0377-8401(94)90081-7

Cited by 22 publications

(32 citation statements)

References 14 publications

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“…In a related study13 the food intakes for rats fed a variety of protein diets (lactalbumin, wheat gluten, fish fillets, soy protein isolate, zein) were in the range of 8.7–13.3 g, which indicates that, within the practical range of food intakes observed in the present feeding trial, there is no practical significance to the statistically significant slopes for the isoleucine and cystine data. Food intakes found in other studies using similar‐sized rats fed meat and bone meal diets were also found to be at the top end of and beyond the range used in the present study 25. 26 From a practical perspective the use of endogenous flow data expressed as a proportion of food dry matter intake is justified in calculating true ileal amino acid digestibility.…”

Section: Discussionsupporting

confidence: 50%

The effect of food dry matter intake on the flow of amino acids at the terminal ileum for rats fed an enzyme‐hydrolysed casein‐based diet

et al. 2002

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The aim of the study was to determine whether food dry matter intake had an effect on endogenous ileal amino acid flows in the rat when the flows were expressed in units of mg g À1 dry matter. Eighty 200 g body weight rats were trained for 7 days to consume a casein-based diet over a daily 3 h feeding period, and then an enzyme-hydrolysed casein (MW < 5000 Da)-based diet, with chromic oxide as an indigestible marker, was fed for a further 8 days. The mean ratio of food intake to metabolic body weight over all 80 rats was determined on days 11 and 12. On day 15, food was offered to groups of 10 rats at each of eight intake levels. The intake levels were calculated from the mean food intake value and individual metabolic body weights and scaled in increments of 0.1 by factors ranging from 0.3 to 1.0. Digesta were collected from the terminal ileum 3 h after the start of the meal, and endogenous ileal amino acid flows were determined after amino acid and Cr analyses of the diet and endogenous ileal digesta fractions prepared by centrifugation and ultrafiltration (10 000 Da molecular weight cut-off). The linear regression relationships between ileal amino acid flows, expressed as mg g À1 dry matter, and dry matter intakes demonstrated that all slopes were negative but that the slopes for nine of these amino acids were not significantly different from zero (P > 0.05). There were significant slopes (P < 0.05) for the other eight amino acids, although the magnitudes of the effect were small. When the data were re-examined after removing the lowest feeding level, the slopes for most of these amino acids were no longer statistically significant. The results showed that the measures of amino acid flow (mg g À1 dry matter), except for isoleucine and cystine, over a wide range of food intakes were not materially affected by food intake. From the perspective of bioassay logistics the results indicate that expressing ileal amino acid flows proportional to dry matter intake is justified over the range of intakes found in practice for determining true ileal amino acid digestibility by the enzyme-hydrolysed casein method.

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Section: Discussionsupporting

confidence: 50%

The effect of food dry matter intake on the flow of amino acids at the terminal ileum for rats fed an enzyme‐hydrolysed casein‐based diet

et al. 2002

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“…Higher protein digestibilities of dried and toasted pea diets in nebacitintreated rats compared with ileal digestibility in pigs have also been found by Canibe et al (1997). In contrast, with the slaughter method a close agreement was found between conventional rats and pigs for the apparent ileal digestibilities of N from meat and bone meal and blood meal (Donkoh et al 1994;Pearson et al 1999). It is difficult to decide whether the good agreement between rats and pigs in these latter studies are due to the fact that in both species digestibilities were measured in ileal samples, or whether the proteins investigated, i.e.…”

Section: Nebacitin-treated Rats As a Modelmentioning

confidence: 81%

The rat as a model for pigs: comparative values for the digestibility of NSP and other macronutrients

Wisker

Knudsen

2003

Br J Nutr

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The present investigation was undertaken to study whether conventional male Wistar rats could be used as a model for pigs with regard to total tract digestibilities of NSP and macronutrients and whether nebacitin-treated rats could be used as a model for small intestinal digestibility in pigs. Nineteen experimental diets prepared from different fractions of wheat and oats, and which all had been evaluated in experiments with ileal cannulated pigs, were used for the present study. There was a close relationship between the total tract digestibilities of organic matter in the two species. The same was the case with regard to the digestibility of total NSP and arabinoxylans, but the values were on average 6 % lower in rats than in pigs. On average, there were no significant differences between rats and pigs with regard to faecal protein digestibility. However, protein in oat-based diets was significantly better digested in the rat than the pig. The digestibility of fat was consistently higher in rats than in pigs, with the biggest difference being found in oat-based diets, in which most of the fat was locked in cell structures. For the wheat-based diets, in which a large proportion of the fat was present as added fat, there was a greater similarity between the two species. In nebacitin-treated rats the digestibility of organic matter, starch, protein and fat was negatively related to the dietary level of NSP, but this model could not be used to predict the small intestinal digestibility of NSP and macronutrients in ileal-cannulated pigs.Digestibility: Non-starch polysaccharides: Protein: Fat: Pigs: RatsThe laboratory rat has been widely used to investigate basic principles of nutrition in single-stomached animals. In contrast to human nutrition, however, the use of rats as models in pig nutrition is less well accepted, because it is relatively easy to obtain results from the pig itself. The great value of the rat as a model lies in the economic factors associated with facilities and time, which allows the use of large numbers of animals and a rapid production of results.The digestibility of energy and protein in the pig and rat is highly correlated for several diets (Eggum, 1973;Eggum et al. 1982), indicating that the rat may be a good model for pigs for these variables. However, it is less clear whether rats are also suitable models for pigs with regard to the digestibility of other nutrients and the fermentation of non-digestible carbohydrates, primarily as NSP, by the gut microflora. Like the pig, rats harbour a permanent bacterial flora in the stomach and small intestine, and similar groups of bacteria were found in the large intestine of both species (Jensen, 1992). However, there are obvious differences between rats and pigs that may be of importance for the microbial fermentation. The relative size of the caecum in rats is bigger than in pigs and the rat may practise coprophagy. Further, the rat is a small animal with a faster transit through the gut, and this can reduce bacterial polysaccharide breakdown co...

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“…The reliability of the digestibility data depends on the collection of a sufficient quantity of ileal digesta to ensure that the chemical analyses can be carried out with accuracy and repeatability. The ideal length of ileum to achieve adequate and representative digesta samples for rats fed semi‐synthetic diets has been investigated13, 20 and found to be the terminal 20 cm of ileum which was used in this study.…”

Section: Discussionmentioning

confidence: 99%

“…Also, the laboratory rat has been shown to be a suitable model for the pig for the determination of protein and amino acid digestibility at the terminal ileum 12. 13…”

Section: Introductionmentioning

confidence: 99%

The effect of digesta sampling time and dietary protein source on ileal nitrogen digestibility for the growing rat

Butts¹,

James²,

Koolaard³

et al. 2002

J Sci Food Agric

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The effect of time that digesta were collected on the quantity and representativeness of ileal digesta and on the determination of apparent and true ileal nitrogen (N) digestibility for growing rats was investigated. Semi‐synthetic diets containing chromic oxide as an indigestible marker were given to 200 g live weight rats for 8 days as a single daily meal. The experimental treatments comprised six diets (lactalbumin, soy protein isolate, wheat gluten, fish, protein‐free (PF), enzymically hydrolysed casein (EHC)) and four ileal digesta sampling times (3, 4, 5 and 6 h after the start of feeding). On the eighth day the rats were fed and slaughtered according to treatment, and digesta were sampled from the terminal ileum. Endogenous ileal nitrogen excretion was determined using both the protein‐free and peptide alimentation methods. There was a significant (P = 0.027) effect of experimental diet averaged across sampling times for chromium recovery (CrRec). The CrRec was higher for the rats fed the PF diet than for the other diets. Responses to sampling time varied significantly (P < 0.05) among diets for ileal digesta weight (IDW), nitrogen/chromium (N/Cr) ratio, ileal digesta weight relative to dry matter intake (IDW/DMI), CrRec, N flow, apparent N digestibility and true N digestibility (determined using the protein‐free method). The optimal digesta sampling times for each of the diets were 3 h for PF, EHC, lactalbumin and fish and 4 h for soy protein isolate and wheat gluten. Consequently, 3 or 4 h after the start of feeding is recommended as the optimum ileal digesta sampling time for most purified protein sources when fed to the growing rat as a single daily meal. © 2002 Society of Chemical Industry

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The laboratory rat as a model animal for determining ileal amino acid digestibility in meat and bone meal for the growing pig

Cited by 22 publications

References 14 publications

The effect of food dry matter intake on the flow of amino acids at the terminal ileum for rats fed an enzyme‐hydrolysed casein‐based diet

The effect of food dry matter intake on the flow of amino acids at the terminal ileum for rats fed an enzyme‐hydrolysed casein‐based diet

The rat as a model for pigs: comparative values for the digestibility of NSP and other macronutrients

The effect of digesta sampling time and dietary protein source on ileal nitrogen digestibility for the growing rat

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