Paul J Moughan's research while affiliated with Massey University and other places

Publications (370)

Article
Background It is not feasible to determine the true ileal amino acid (AA) digestibility of protein sources in humans on a routine basis and the growing pig has been recommended as an animal model for this purpose but requires further validation. Objectives To determine and compare true ileal AA digestibility between adult human ileostomates and gr...
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Background and aims: GlucoTRIG, based on postprandial plasma insulin and triglyceride concentrations, has been recently developed as a novel index to determine the postprandial metabolic response to the meals. This study aimed to test GlucoTRIG as a measure for ranking composite meals for their metabolic effects. Methods: In a randomized cross-ove...
Article
This study investigated the structural and physicochemical changes that occur in milk, a naturally designed complex structured emulsion, during gastric digestion using the bottle-fed piglet as an animal model. The gastric digestions of cow, goat, and sheep milk were compared in male piglets euthanized at different postfeeding times to collect the s...
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Background The respective roles of plant- and animal-sourced foods in sustainable healthy diets for humans remain unclear. Nutritional quality and the monetary cost of diets are key criteria among others for sustainable food production. Objective Linear programming (LP) was used to determine the composition of nutritionally adequate dietary patter...
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The aim was to study the complementary effect between cereals and pulses on protein quality. The values for the digestible indispensable amino acid score (DIAAS) in cooked cereals and pulses, given alone, and blends of cooked cereals and pulses, were determined. True ileal digestibility (TID) values of amino acids for adult humans were obtained. It...
Article
Background The degree of ileal organic matter (OM) fermentation appears to be comparable to hindgut fermentation in growing pigs. Objectives This study aimed to determine if dietary fiber sources with known different total gastrointestinal tract (GIT) fermentability in humans affect ileal and hindgut microbial communities and ileal fermentation in...
Article
Kiwifruit (KF) fiber, a mixture of soluble and insoluble fibers, elicits mucosal changes in the gastrointestinal tract (GIT). This study aimed to define the nature of these changes in mucosal features throughout the GIT of the growing pig in response to semi-synthetic iso-fiber diets containing cellulose (CEL, low GIT luminal functionality) as the...
Article
The oxygen (O2) concentration of gastrointestinal tract (GIT) contents decreases distally, but little is known about how O2 concentrations are influenced by ingestion of a meal. The O2 concentration in luminal contents at different GIT locations (stomach [cardia and pylorus], proximal, mid‐ and distal small intestine and caecum) and how these conce...
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Objectives The protein quality digestible indispensable amino acid scores (DIAAS) require determination of amino acid (AA) bioavailability, which is often quantified as the net disappearance of dietary AAs at the end of the small intestine, so-called true ileal digestibility. It is often assumed that bioavailability is mainly influenced by protein...
Article
It is common practice in food sustainability studies to calculate population-based average protein intakes and express environmental footprints on a gross protein basis. Such analyses, however, assume that the requirement for protein is also expressed as gross protein which is not the case. This ignores the critical role of dietary protein as a sup...
Article
Background Calcium (Ca) can complex with free fatty acids in the gastrointestinal tract (GIT), leading to the formation of insoluble unabsorbable Ca-fatty acid soaps, contributing to the proposed effect of Ca on weight loss in humans. Objectives We determined the effect of dietary Ca concentration and the individual long-chain fatty acids on Ca-fa...
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Purpose: The purpose of the study was to determine if an actinidin protease aids gastric digestion and the protein anabolic response to dietary protein. Methods: Hayward green kiwifruit (containing an actinidin protease) and Hort 16A gold kiwifruit (devoid of actinidin protease) were given in conjunction with a beef meal to healthy older subject...
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The original version of this article unfortunately contained a mistake. Unfortunately, the Figs. 3 and 4 overlapped. Figures 3 and 4 should be.
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Determination of whole body rates of protein synthesis, breakdown and net balance in human subjects still has an important role in nutrition research. Quantifying the anabolic response to dietary protein intake is a particularly important application. There are different models with which to accomplish this goal, each with advantages and limitation...
Article
The behavior of fat globules during the gastric digestion of raw and pasteurized cow, goat, and sheep whole milks was studied using a human gastric simulator. Microstructural and physicochemical analysis revealed that, initially, the coagulation of the milks in the human gastric simulator resulted in the majority of the milk fat globules being entr...
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Values for the digestible indispensable amino acid score (DIAAS) of a protein are based on true ileal amino acid (AA) digestibility values obtained in adult humans or in the growing pig as an animal model. An experiment was conducted using growing pigs to determine the true ileal digestibility (TID) values of AA in six cooked Chinese pulses (kidney...
Article
Background Recent in silico and in vitro studies have shown that gastrointestinal endogenous proteins (GEP) are a source of bioactive peptides. To date, however, the presence of such peptides in the lumen of the digestive tract has not been demonstrated. Objective We investigated the generation of GEP-derived bioactive peptides in the growing pig...
Article
The effects of orally administered ovine serum immunoglobulin on dental plaque and associated oral immunity in cats were investigated. The two treatment groups consisted of 1) cats that were fed unsupplemented kibble (control diet) and 2) cats that were fed the same kibble but coated with a freeze-dried ovine serum immunoglobulin preparation (ovine...
Article
Coagulation of milk in the stomach is the first crucial step in its digestion. Using a human gastric simulator, the dynamic gastric digestion of goat and sheep skim milk were compared with that of cow skim milk, focusing particularly on their physical characteristics. The gastric contents were analyzed for changes in dry matter and microstructure,...
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Background: The traditional dairy-cattle-based industry is becoming increasingly diversified with milk and milk products from non-cattle dairy species. The interest in non-cattle milks has increased because there have been several anecdotal reports about the nutritional benefits of these milks and reports both of individuals tolerating and digestin...
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This study characterised the in vitro ileal fermentability of different substrates in the growing pig, adopted as an animal model for the adult human, and compared in vitro ileal and caecal fermentation in the pig. Substrates (arabinogalactan 'AG', cellulose, fructooligosaccharide 'FOS', inulin, mucin, citrus pectin, and resistant starch) were ferm...
Article
Background The quantification of faecal Ca-fatty acid soaps is important to understand how fatty acids behave in the gastrointestinal tract. Objective As current methods to extract Ca-fatty acid soaps from faeces give low recoveries an accurate assay to determine the amount of fatty acid soaps in faeces was developed. Method Ca-fatty acid soaps a...
Article
Spray‐dried animal plasma sourced from bovine, porcine or other animal origin is often used as a main feed ingredient in the diets of weanling piglets to improve growth performance. The objective of this study was to determine the effect of animal plasma in diets on the performance of piglets in the post‐weaning period, with and/or without pathogen...
Article
Digestible indispensable amino acid score (DIAAS) has been recommended by the FAO for the evaluation of protein quality in human foods, but the application of DIAAS is currently limited because of a lack of published data on the true ileal amino acid (AA) digestibility of AAs in foods. The importance of DIAAS is highlighted. To calculate DIAAS, it...
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The amounts of animal-sourced foods required to achieve a least-cost nutritious diet depend on the food prices prevalent in each country. Using linear programming, we determine least-cost dietary patterns in the United States and the constituent amounts of animal-sourced foods. We considered local foods and prices from 2009–2010, and the average en...
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Background: This study aimed to develop a novel criterion, GlucoTRIG, to rank meals for healthiness, that considers both glycaemic (serum insulin) and lipaemic (serum triglycerides) responses. Methods: Healthy volunteers (n = 10) were recruited with the aim of deriving a standard GlucoTRIG value for a reference meal. Volunteers consumed the refe...
Article
Dietary fibre fermentation in humans and monogastric animals is considered to occur in the hindgut, but it may also occur in the lower small intestine. This study aimed to compare ileal and hindgut fermentation in the growing pig fed a human-type diet using a combined in vivo/in vitro methodology. Five pigs (23±1.6 kg (mean±SD) bodyweight) were fed...
Article
Dynamic low-amplitude oscillatory rheology was used to study the gelation properties of skim milk gels made at 37°C, using glucono-δ-lactone alone (acid gels) or a combination of glucono-δ-lactone and porcine pepsin (“combination gels”). The protein contents of the skim milks increased in the order goat milk < cattle milk < buffalo milk < sheep mil...
Article
The objective of this study was to evaluate the relationship among the number of bacteria, number of goblet cells, gut mucin gene expression, mucin protein and immunity protein levels of rats fed a diet containing freeze‐dried ovine Ig (FD). Sprague Dawley male rats were used in a 21‐days study and were fed a basal control diet (BD; no Ig) and a te...
Article
Background: Endogenous amino acids (AAs) contribute to terminal ileal digesta and must be corrected for in determining coefficients of true ileal digestibility. Such estimates are also needed for the factorial calculation of AA requirements. Objective: The effect of the form of delivery of dietary AAs on endogenous nitrogen and AA flows at the e...
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Background: A highly soluble iron-casein complex has been developed for food fortification purposes with the aim to provide high iron bioavailability. Objective: We aimed to determine the iron bioavailability of the iron-casein complex relative to that of ferrous sulfate (control) when given with whole milk in healthy young women. Methods: A r...
Article
Dietary amino acid digestibility is a fundamental measure of importance in protein quality evaluation. Determining amino acid digestibility in humans, as the disappearance of an amino acid across the total digestive tract, has been discredited. Extensive cecal and colonic microbial metabolism renders fecal estimates of amino acids misleading. True...
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Whole-body protein turnover (protein synthesis, breakdown, and net balance) model enables quantification of the response to a variety of circumstances, including the response to meal feeding. In the fed state, the whole-body protein turnover model requires taking account of the contribution of absorbed tracee to the observed total appearance of tra...
Article
The natural food-derived compound curcumin (from turmeric root) is known for its anti-inflammatory and anti-oxidant effects. However, due to its poor solubilty when consumed in isolation, it is poorly bioavailable. In this crossover study we compared the bioavailability of curcumin from a meal containing either curcumin powder, turmeric powder or g...
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Immunoglobulin (Ig) is the one of the main anti‐infective components of blood, colostrum and breast milk. It is the unique glycoprotein that defends the body from harmful bacteria, viruses and other environmental pathogens by either binding to them or by forming an encapsulating barrier. The expansion of antimicrobial and immunomodulatory products...
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Objectives This study aimed to compare ileal and hindgut fermentations in the pig model using a combined in vivo/in vitro methodology. Methods Pigs (23 kg bodyweight, n = 5) were fed a human-type diet for 15 days. On day 15, pigs were euthanased and the small intestine was immediately dissected out and ligated in three equal lengths. Digesta from...
Article
Intrinsically-labeled dietary proteins have been used to trace various aspects of digestion and absorption, including quantifying the contribution of dietary protein to observed post-prandial amino acid and protein kinetics in human subjects. Quantification of the rate of appearance in peripheral blood of an unlabeled (tracee) amino acid originatin...
Chapter
Many in vivo, in vitro and combined in vivo–in vitro methodologies have been developed to study the mechanisms involved and sites of nutrient digestion and absorption in the gastrointestinal tract. Moreover, different approaches within each of these methodologies have also been developed. Some of the methodologies/approaches can be applied to multi...
Article
The effect of kiwi fruit at two dietary levels on the adaptation of intestinal fermentation over time in the growing pig was studied. A semi-synthetic fibre-free diet and two semi-synthetic diets containing kiwi fruit as a model fibre source (133 or 266 g/kg (DM basis); 28 or 48 g fibre/kg) were formulated and the diets contained titanium dioxide a...
Article
Background: Actinidin, a cysteine protease in kiwifruit (KF), increases both the gastric digestion and gastric-emptying rate of beef muscle protein. Objective: This study aimed to determine the relation between the rate of digested nitrogen entering the small intestine (SI; a function of the extent of gastric digestion and gastric-emptying rate)...
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Background The form of dietary nitrogen (free peptides or intact proteins) may influence the amount of endogenous amino acids found at the terminal ileum of the pig, and it has been speculated that hydrolyzed dietary protein may lead to increased endogenous amino acids. Objective To compare the effect of dietary free peptides on ileal endogenous n...
Article
Background: The loss of endogenous (nondietary) amino acids (AAs) from the gastrointestinal tract (GIT) is an important component underlying the adult human dietary requirement for protein and essential AAs (EAAs). Although data with regard to endogenous AA losses to the end of the small intestine have been published, to our knowledge there are no...
Article
Background: Cooking processes affect the physical, chemical, and structural properties of meat proteins. Cooking may also affect the protein quality of meat, as indicated by the true ileal digestibility of individual amino acids, the content of each truly digestible amino acid, and the digestible indispensable amino acid score (DIAAS). Objective:...
Article
Traditionally, the study of nutrition has been based on a reductionist approach, reducing a food down to constituent nutrients and then investigating the effects of these nutrients, either singly or together, on metabolism and metabolic outcomes. However, nutrients per se are not consumed by a person, but rather are consumed in the form of foods. B...
Article
Background Substantial microbial fermentation may occur mainly in the lower small intestine (SI) of human adults, but there is no established methodology to determine this. Objective The study aimed to develop a combined in vivo and in vitro methodology for ileal fermentation based on the pig as an animal model for digestion in human adults. Meth...
Article
Protein is the only dietary macronutrient required for life. As such, it is reasonable to consider dietary protein as the centerpiece of a healthy eating pattern. To do so requires consideration of what type of protein should be eaten. Account should be taken of the quality of the protein, the density of the protein in the protein food source, and...
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One of the limitations for ranking foods and meals for healthiness on the basis of the glycaemic index (GI) is that the GI is subject to manipulation by addition of fat. Postprandial lipemia, defined as a rise in circulating triglyceride containing lipoproteins following consumption of a meal, has been recognised as a risk factor for the developmen...
Article
Dietary protein quality has been recognized as a critical issue by international authorities because it can affect important functions of the body. To predict protein quality, the FAO introduced the Digestible Indispensable Amino Acid Score. This score depends on ileal amino acid (AA) digestibility; therefore, the assumption is made that AAs are no...
Article
Protein is the most satiating macronutrient and is source dependent, with whey protein thought to be particularly satiating. The purported satiating effect of whey protein may be due to the unique mixture of proteins in whey or to the major constituent individual proteins (β-lactoglobulin and α-lactalbumin). The objective of the study was to compar...
Article
Body protein and therefore dietary protein have a central role metabolically. Dietary protein is digested in the gastrointestinal tract by the action of both mammalian and bacterial enzymes, and small peptides and free amino acids are absorbed mainly in the small intestine by a tightly controlled integrated system. Absorbed amino acids may have spe...
Article
Background: It has been assumed that short-chain fatty acids (SCFAs) in the colon originate mainly from dietary fiber fermentation. However, SCFAs in the colon are also produced from the fermentation of nondietary material. Objectives: We aimed to predict the relative contributions of dietary and nondietary substrates in the production of SCFAs...
Article
Dietary protein is considered more satiating than carbohydrate, and whey protein is more satiating than other protein sources. The purported satiating effect of whey protein may be due to direct effects of the unique mixture of proteins in whey, due to the effects of peptides released upon digestion and/or its amino acid composition. The objective...
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Human gastrointestinal endogenous proteins (GEP) include the proteins mucins, serum albumin, digestive enzymes, and proteins from sloughed epithelial and microbial-cells. GEP play a vital role in the digestion of food, but are also simultaneously digested by proteases and peptidases of the gastrointestinal tract (GIT). Recent studies suggest that d...
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The aim of this review is to identify the origin and implications of a nondietary material present in digesta and feces that interferes with the determination of dietary fiber in gastrointestinal contents. Negative values for ileal and fecal digestibility of dietary fiber are commonly reported in the literature for monogastric animal species, inclu...
Article
Gastric protein hydrolysis may influence gastric emptying rate and subsequent protein digestibility in the small intestine. This study examined the gastric hydrolysis of dietary protein from raw and roasted almonds in the growing pig as a model for the adult human. The gastric hydrolysis of almond proteins was quantified by performing tricine-sodiu...
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The intestinal epithelium of adult humans acts as a differentially permeable barrier that separates the potentially harmful contents of the lumen from the underlying tissues. Any dysfunction of this boundary layer that disturbs the homeostatic equilibrium between the internal and external environments may initiate and sustain a biochemical cascade...
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A recently proposed paradigm suggests that, like their dietary counterparts, digestion of gastrointestinal endogenous proteins (GEP) may also produce bioactive peptides. With an aim to test this hypothesis, in vitro digests of four GEP namely; trypsin (TRYP), lysozyme (LYS), mucin (MUC), serum albumin (SA) and a dietary protein chicken albumin (CA)...
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The Food and Agriculture Organization of the United Nations recently recommended the adoption of a new and improved scoring system (Digestible Indispensable Amino Acid Score [DIAAS]) to quantify dietary protein quality. The DIAAS is based on the relative digestible content of the indispensable amino acids (IAAs) and the amino acid requirement patte...
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The biological processes underlying the partitioning of amino acids and energy during animal growth are well understood qualitatively. However, if a deeper mechanistic understanding is to be achieved, such as to allow generalised predictions of growth outcomes, these biological processes need to be described quantitatively, along with critical cont...
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It is well known that endogenous bioactive proteins and peptides play a substantial role in the body's first line of immunological defence, immune-regulation and normal body functioning. Further, the peptides derived from the luminal digestion of proteins are also important for body function. For example, within the peptide database BIOPEP (http://...
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The effect of dietary kiwifruit inclusion level on the digestibility of kiwifruit fibre and dietary nutrients was studied. Ileal cannulated pigs (50 ± 1.9 kg) were fed a fibre-free diet for seven days (n = 14) followed by kiwifruit-containing diets (133 or 266 g kiwifruit/kg dry matter) (n = 7) for 44 days followed by the fibre-free diet (n = 14) f...
Article
Combined in vivo (ileal cannulated pig) and in vitro (faecal inoculum-based fermentation) digestion methodologies were used to predict the production and absorption of SCFA in the hindgut of growing pigs. Ileal and faecal samples were collected from animals ( n 7) fed diets containing either 25 or 50 g/kg DM of kiwifruit fibre from added kiwifruit...
Article
Reported negative ileal and total tract dietary fiber (DF) digestibility values are physiologically untenable and suggest the presence of nondietary material in the gut contents that interferes with the DF determination. The objective of this study was to demonstrate the importance of interfering material (IM) when the Prosky method was used to det...
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Lactobacillus fermentum is commonly found in food products, and some strains are known to have beneficial effects on human health. However, our previous research indicated that L. fermentum AGR1487 decreases in vitro intestinal barrier integrity. The hypothesis was that cell surface structures of AGR1487 are responsible for the observed in vitro ef...
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The amount of endogenous, as opposed to undigested dietary, protein in digesta is a measure of fundamental interest related to gut physiology and function. The objective of this study was to determine whether alimentation with proteins having differing amino acid compositions influenced endogenous ileal amino acids (EIAAs) and true ileal amino acid...
Article
The FAO has recommended replacing the protein digestibility-corrected amino acid score (PDCAAS) with the digestible indispensable amino acid score (DIAAS). The objective of this study was to compare aspects underlying the calculation of the DIAAS and PDCAAS, including 1) fecal digestibility vs. ileal digestibility, 2) using a single nitrogen digest...
Article
Background/objective: A distinct suppressive effect of a whey protein (including glycomacropeptide)-enriched preload drink on subsequent food intake in comparison with a maltodextrin carbohydrate-enriched preload was demonstrated in an earlier companion study with the same female subjects; however, the potential mediators underlying the effect are...
Chapter
Traditional methods for describing the "available" energy contents of foods may be in error for some foods and food ingredients. The size of such errors may be of practical importance in the development of specific weight-loss foods, often containing relatively high amounts of protein, non-starch polysaccharides, and sucrose and fat substitutes. A...
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For over 100 years it was believed that dietary protein must be completely hydrolysed before its constituent amino acids could be absorbed via specific amino acid transport systems. It is now known that the uptake of di- and tripeptides into the enterocyte is considerable, being transported across the intestinal endothelium by the PepT1 H+/peptide...