Aspartic protease supplementation enhancing the performance, carcass characteristics, nutrient digestibility and economic viability, without changing blood parameters and salivary cortisol of pigs.

Aiming to study the performance, carcass characteristics, nutrient digestibility, blood parameters, salivary cortisol levels, and economic viability of pigs administered aspartic protease, a total of 135 pigs were housed in pens in a randomized block design, divided into five treatments with nine replications. The experimental diets were positive control (PC), basic diet with a 5.0% reduction in protein and amino acid requirements; negative control (NC) with a 7.5% reduction in protein and amino acid requirements; NC + 100 g/mT of aspartic protease (NC100); NC + 150 g/mT of aspartic protease (NC150); and NC + 200 g/mT of neutral serine protease (NC200). The inclusion of protease, independently of the source and amount, increased the average daily weight gain (P < 0.05) of animals compared with the control treatments (PC and NC), improved feed conversion (P < 0.05) in early stages, and improved diet digestibility (P < 0.05) compared with the PC. Treatment with NC150 and NC200 resulted in greater carcass weights (P < 0.05) than treatment with the PC. NC100 led to a greater carcass yield than PC (P < 0.05), and NC150 resulted in a greater loin eye area than PC (P < 0.05). No differences (P > 0.05) in the blood parameters or salivary cortisol levels were found. Regarding economic viability, proteases increased the profitability, with NC150 leading to the best results. Thus, the use of aspartic proteases is recommended to improve performance and further facilitate pork production.

Specific dynamic action: the energy cost of digestion or growth?

The physiological processes underlying the post-prandial rise in metabolic rate, most commonly known as the 'specific dynamic action' (SDA), remain debated and controversial. This Commentary examines the SDA response from two opposing hypotheses: (i) the classic interpretation, where the SDA represents the energy cost of digestion, versus (ii) the alternative view that much of the SDA represents the energy cost of growth. The traditional viewpoint implies that individuals with a reduced SDA should grow faster given the same caloric intake, but experimental evidence for this effect remains scarce and inconclusive. Alternatively, we suggest that the SDA reflects an organism's efficacy in allocating the ingested food to growth, emphasising the role of post-absorptive processes, particularly protein synthesis. Although both viewpoints recognise the trade-offs in energy allocation and the dynamic nature of energy distribution among physiological processes, we argue that equating the SDA with 'the energy cost of digestion' oversimplifies the complexities of energy use in relation to the SDA and growth. In many instances, a reduced SDA may reflect diminished nutrient absorption (e.g. due to lower digestive efficiency) rather than increased 'free' energy available for somatic growth. Considering these perspectives, we summarise evidence both for and against the opposing hypotheses with a focus on ectothermic vertebrates. We conclude by presenting a number of future directions for experiments that may clarify what the SDA is, and what it is not.

Nutritional value, productive performance, and economic efficiency response to the degree of steam-flaked yellow corn in growing rabbits.

The performance of a corn steam flaker was evaluated to improve steam-flaked corn (SFC) quality and investigate its feeding effects on nutritional value, productive performance, digestibility coefficients, and economic efficiency of growing rabbits. The flaker performance was studied as a function of change in steaming time, steam chest temperature and roll gap. Performance evaluation of the flaker was carried out in terms of flake thickness (FT), flake density (FD) and processing index (PI) as well as rabbit feeding trials. Experimental results clarified that values of FT, FD and PI are in the optimal limits under conditions of 118°C steam chest temperature, 40 min steaming time and 0.80 mm roll gap. Steam flaking is an acceptable process for rabbit feeds as SFC with optimal FD of between 0.36 and 0.39 kg/L corresponding to a PI of between 50.14% and 54.32% significantly improve the nutritional value of SFC compared with whole corn grain by 1.31%, 1.26% and 160.75% respectively. Also, SFC severely decreased the total count of harmful bacteria, fungi count and mortality rate compared to whole corn grain. Rabbits fed SFC processed to the density of 0.36 kg/L of the diet had better body weight gain, feed conversion ratio, organic matter digestibility, net revenue and economic efficiency of 9.29%, 8.89%, 4.65%, 15.62% and 15.43% compared with rabbit fed whole yellow corn grain respectively. In conclusion, it is convenient to entirely substitute whole corn grain with SFC to be utilised in rabbits' diets where achieved the best feeding effects results.

Assessment of corn wet distillers grains fed to crossbred bulls on feeding behavior, rumen morphology, liver abscesses and blood parameters.

Corn ethanol production has been growing in Brazil in the last ten years, generating by-products to feedlot diets. This study evaluates the effects of the inclusion of low-fat corn wet distillers grains (LF-WDG) on feeding behavior, ruminal health, liver abscesses and blood parameters of F1 Angus-Nellore bulls feedlot finished. Our hypothesis is that evaluation of data from feeding behavior, rumen and liver health would help to explain animal performance. In this trail, one-hundred animals were fed for 129 days with diets containing amounts of 0 (control), 15, 30 and 45% of LF-WDG replacing corn grain and soybean meal. Evaluations of fluctuation of dry matter intake (DMI) were carried out. Additionally, feeding behavior data were assessed by monitoring (24-h period) the feeding, rumination, time spent eating (TSE), and time expended on other activities (resting and number of meals per day). Blood variables such as pH, bicarbonate, total CO2 content, and base excess in extracellular fluid (Beecf) were determined. After slaughter, rumen epithelium was classified according to the incidence of lesions (rumenitis) and abnormalities (papillae clumped), and samples were collected for morphology and histology evaluations. Moreover, livers were scored for severity of abscesses as follow: as unabscessed (0), one or two small abscesses (A-), two to four small active abscesses (A) or one or more large, active abscesses (A+). The DMI (kg/day) differed (P = 0.03) among treatments and there is a tendency of 15 and 30 LF-WDG (% DM) had lower %DMI fluctuation compared to 0 or 45%. The TSE increased linearly (P < 0.01) as the amounts of inclusion of LF-WDG increased. Moreover, neutral detergent fiber (NDF) intake, NDF consumption rate and NDF rumination efficiency increased linearly (P < 0.01) in response to LF-WDG feeding. The incidence of rumenitis tended (P = 0.08) to be greater at 45% LF-WDG, while keratin thickness decreased linearly in bulls fed LF-WDG (P < 0.01). The severity of liver abscesses (score A+) increased linearly (P = 0.02). Regarding blood parameters, only Beecf decreased linearly (P < 0.01) in response to LF-WDG feeding. Therefore, the hypothesis of the current study was confirmed. We previous reported that F1 Angus-Nellore bulls fed LF-WDG show greater weight gain (1.94 ± 0.09 kg/day) and final body weight (620 ± 18.8 kg) when compare to control (1.8 ± 0.09 kg/day and 602 ± 18.8 kg, respectively). Here, we conclude that inclusion of 15 to 30% LF-WDG in feedlot diets improved feeding behavior without impairing ruminal health and blood parameters, driving performance and weigh gain of crossbred bulls. However, bulls fed 45% LF-WDG had greater severity of liver abscesses.

Automatic assessment of human gastric motility and emptying from dynamic 3D magnetic resonance imaging.

BACKGROUND: Time-sequenced magnetic resonance imaging (MRI) of the stomach is an emerging technique for non-invasive assessment of gastric emptying and motility. However, an automated and systematic image processing pipeline for analyzing dynamic 3D (ie, 4D) gastric MRI data has not been established. This study uses an MRI protocol for imaging the stomach with high spatiotemporal resolution and provides a pipeline for assessing gastric emptying and motility. METHODS: Diet contrast-enhanced MRI images were acquired from seventeen healthy humans after they consumed a naturalistic contrast meal. An automated image processing pipeline was developed to correct for respiratory motion, to segment and compartmentalize the lumen-enhanced stomach, to quantify total gastric and compartmental emptying, and to compute and visualize gastric motility on the luminal surface of the stomach. KEY RESULTS: The gastric segmentation reached an accuracy of 91.10 ± 0.43% with the Type-I error and Type-II error being 0.11 ± 0.01% and 0.22 ± 0.01%, respectively. Gastric volume decreased 34.64 ± 2.8% over 1 h where the emptying followed a linear-exponential pattern. The gastric motility showed peristaltic patterns with a median = 4 wave fronts (range 3-6) and a mean frequency of 3.09 ± 0.07 cycles per minute. Further, the contractile amplitude was stronger in the antrum than in the corpus (antrum vs. corpus: 5.18 ± 0.24 vs. 3.30 ± 0.16 mm; p < 0.001). CONCLUSIONS & INFERENCES: Our analysis pipeline can process dynamic 3D MRI images and produce personalized profiles of gastric motility and emptying. It will facilitate the application of MRI for monitoring gastric dynamics in research and clinical settings.

Gastrointestinal Digestion Model Assessment of Peptide Diversity and Microbial Fermentation Products of Collagen Hydrolysates.

Osteoarthritis (OA), the most common form of arthritis, is associated with metabolic diseases and gut microbiome dysbiosis. OA patients often take supplements of collagen hydrolysates (CHs) with a high peptide content. Following digestion, some peptides escape absorption to induce prebiotic effects via their colonic fermentation to generate short-chain fatty acids (SCFAs), branched-chain fatty acids (BCFAs) and colonic gases (NH4 and H2S). The capacity of CHs to generate microbial metabolites is unknown. Proteomic analysis of two CHs (CH-GL and CH-OPT) demonstrated different native peptide profiles with increased peptide diversity after in vitro gastric and small intestinal digestion. Subsequent 24 h fermentation of the CH digests in a dynamic gastrointestinal (GI) digestion model containing human fecal matter showed that CH-OPT increased (p < 0.05) H2S, SCFAs (propionic, butyric and valeric acids), BCFAs, and decreased NH4 in the ascending colon reactor with no major changes seen with CH-GL. No major effects were observed in the transverse and descending vessels for either CH. These findings signify that CHs can induce prebiotic effects in the ascending colon that are CH dependent. More studies are needed to determine the physiological significance of CH-derived colonic metabolites, in view of emerging evidence connecting the gut to OA and metabolic diseases.

Sex differences feed into nuclear receptor signaling along the digestive tract.

Sex differences in physiology are noted in clinical and animal studies. However, mechanisms underlying these observed differences between males and females remain elusive. Nuclear receptors control a wide range of physiological pathways and are expressed in the gastrointestinal tract, including the mouth, stomach, liver and intestine. We investigated the literature pertaining to ER, AR, FXR, and PPAR regulation and highlight the sex differences in nutrient metabolism along the digestive system. We chose these nuclear receptors based on their metabolic functions, and hormonal actions. Intriguingly, we noted an overlap in target genes of ER and FXR that modulate mucosal integrity and GLP-1 secretion, whereas overlap in target genes of PPARα with ER and AR modulate lipid metabolism. Sex differences were seen not only in the basal expression of nuclear receptors, but also in activation as their endogenous ligand concentrations fluctuate depending on nutrient availability. Finally, in this review, we speculate that interactions between the nuclear receptors may influence overall metabolic decisions in the gastrointestinal tract in a sex-specific manner.

Bioavailability and bioaccessibility of food bioactive compounds; overview and assessment by in vitro methods.

Oral bioavailability is the key to the bioefficiency of food bioactive ingredients; it evaluates the relationship between foods and their health benefits. The analysis of the main factors limiting the oral bioavailability (bioaccessibility, absorption, and transformation) has led to the proposal of classification systems for pharmaceuticals and nutraceuticals (Biopharmaceuticals Classification System and Nutraceutical Bioavailability Classification Scheme). Based on the relevant studies published in the last decade, this review presents the essential aspects regarding the factors limiting the oral bioavailability of the biocomponents and different in vitro methods used to investigate the mechanisms involved in the digestion, absorption, and metabolism of biocomponents, particularly encapsulated bioactive compounds. Oral bioavailability investigated by in vitro studies provides the food and drug manufacturers with information to formulate delivery systems more efficiently and to determine the dosage of biocomponents for increase the health benefits and avoid or reduce the risk of toxicity.

Assessment of the effect of lactic acid fermentation on the gastroduodenal digestibility and immunoglobulin E binding capacity of soy proteins via an in vitro dynamic gastrointestinal digestion model.

Fermentation by lactic acid bacteria is helpful in reducing soy protein immunoreactivity. However, how lactic acid fermentation influences the gastroduodenal digestibility and immunoglobulin E (IgE) binding capacity of soy proteins remains unclear. In this study, the protein digestion of a fermented soybean protein isolate (FSPI) was investigated and compared with that of a soybean protein isolate (SPI). The effect on their respective IgE binding capacities at the gastric and duodenal phases was also explored by using a novel in vitro dynamic gastrointestinal digestion model (Bionic Rat Model II+). Medium pH was measured, microstructural analysis was performed, peptide distribution and free amino acid content were determined, and SDS-PAGE analysis was performed to assess the differences between SPI and FSPI. The results showed that FSPI had lower pH (3.76), larger protein aggregates (>60 µm), and higher low-molecular-weight peptides than SPI. During the first 30 min of gastric and duodenal digestion, the extent of hydrolysis of FSPI was higher than that of SPI, and the gastric transition time of the former was longer than that of the latter. Conversely, differences tended to be narrower in the next 30-180 min of gastric and duodenal digestion. As a result, the IgE binding capacity of FSPI was significantly lower than that of SPI at 30 min of gastric and duodenal digestion. Therefore, fermentation by lactic acid bacteria affected the digestibility rate of soy proteins, especially at the initial phases of gastric and duodenal digestion, thereby reducing the exposure of intact epitopes in the duodenum. This study helped to elucidate how lactic acid fermentation affected the digestive behavior of soy proteins and its implication in IgE immunoreactivity reduction.

Assessment of in situ techniques to determine indigestible components in the feed and feces of cattle receiving supplemental condensed tannins1.

Reliable assessments of indigestible dietary components are required when using internal markers to estimate diet digestibility and determine the potentially digestible portion of the fiber. The lack of a standardized methodology and understanding of how antinutritional factors influence indigestible residues can result in erroneous estimates with inconsistent variation across trials and among studies. Previous studies have detailed suitable bag porosity and sample size (SS) with incubation length (IL) varying from 96 to 504 h, with many assuming that 288-h IL yields truly indigestible components. Recent studies have primarily investigated the variation that exists among feedstuffs, but most have failed to account for possible effects of secondary compounds. Using 2 similar concentrate diets, one of which contained supplemental condensed tannins (CT), we investigated the effect of bag type (BT; 10 and 25 µm), SS (20 and 40 mg/cm2), and IL (288 and 576 h) on in situ indigestible DM (iDM) and neutral detergent fiber (iNDF) residues of feed and feces, and resultant DM and NDF digestibilities. There were no 3-way interactions (P > 0.05), but 2-way interactions were present for iDM and iNDF residues with BT × SS influencing the control (no CT) ration (P < 0.01), SS × IL impacting feed containing CT (P < 0.01), and BT × IL affecting both feedstuffs (P ≤ 0.01). For the control diet, only BT × SS affected DM and NDF digestibilities. Whereas the CT diet did not demonstrate any significant interactions for digestibilities. Values of iDM were largely influenced by contamination that varied greatly based on intrinsic factors associated with the bag and incubation duration. The presence of CT influenced iDM and iNDF to varying degrees due to possible trapping of CT-substrate complexes. For the control diet, the use of 25-µm bags resulted in lower fecal recoveries relative to the 10 µm (P < 0.01). However, there appears to be a dynamic relationship among BT, SS, and IL within respective diets and sample types that can affect indigestible components and resultant digestibility estimates. Based on simulations from these data, the sample size required to attain 90% power when utilizing 2 incubation animals exceeds the triplicate and quadruplicate replications commonly utilized. Further emphasizing the necessity for a more complete understanding of incubation dynamics to design biologically and statistically valid investigations.

Harnessing anaerobic digestion for combined cooling, heat, and power on dairy farms: An environmental life cycle and techno-economic assessment of added cooling pathways.

Anaerobic digestion coupled with combined heat and power production on dairy farms is environmentally advantageous; however, high capital and operating costs have limited its adoption, especially in the United States, where renewable electricity and heat production are under-incentivized. Biogas is also at a disadvantage because it has to compete with very low natural gas prices. The objective of this study was to evaluate the feasibility of integrating absorption refrigeration technology for combined cooling, heat, and power (CCHP) on the farm to help bridge this economic hurdle. A combined environmental life cycle and techno-economic assessment was used to compare 2 cooling pathways with and without co-digestion. We considered using CCHP to (1) displace electricity-driven refrigeration processes (e.g., milk chilling/refrigeration, biogas inlet cooling) or (2) mitigate heat stress in dairy cattle via conductive cow cooling. All cooling scenarios reduced environmental emissions compared with combined heat and power only, with an appreciable reduction in land use impacts when employing conductive cow cooling. However, none of the cooling scenarios achieved economically viability. When using cooling power to displace electricity-driven refrigeration processes, economic viability was constrained by low electricity prices and a lack of incentives in the United States. When used for conductive cow cooling, economic viability was constrained by (1) low waste heat-to-cooling conversion efficiency; (2) limited conductive cow cooling effectiveness (i.e., heat-stress mitigation); and (3) low heat stress frequency and limited severity. However, we predict that with minor improvements in conductive cow cooling effectiveness and in hotter climates, CCHP for conductive cow cooling would be economically viable even in current US energy markets.

Does lipidomic serum analysis support the assessment of digestive efficiency in chickens?

The increasing cost of conventional feedstuffs used in poultry diets has bolstered interest in genetic selection for digestive efficiency (DE) to improve the adaptation of the birds to various alternative feedstuffs. However, DE measurement through AMEn is time-consuming and constraining. To simplify selection for DE, the potential of serum composition to predict AMEn was evaluated based on 40 birds from two broiler lines (D+ and D-) divergently selected on the fecal AMEn of a difficult-to-digest wheat-based diet. Differences in serum coloration were suspected between the two lines, and thus a spectrophotometric analysis was carried out, revealing a significant difference in absorption between 430 nm and 516 nm, corresponding to the signature of orange-red lipophilic pigments such as xanthophylls. To go further, the liposoluble fraction of the serum was explored for its lipidome by mass spectrometry. Discriminant analysis revealed that a pattern of 10 metabolites, including zeaxanthin/lutein, can explain 82% of the lipidomic differences between the two lines. Colorimetry combined with lipidomics studies confirmed the relationship between digestive efficiency and serum composition, which opens up new possibilities for using it as a quick and easy proxy of digestive efficiency.

An in vivo stable isotope-based approach for assessment of absorbed amino acids from individual feed ingredients within complete diets.

Accurate assessment of the nutritional content of feed ingredients is required for precise diet formulation. Characterizing ingredients in terms of absorption and digestibility of individual AA is challenging, and this information often relies on indirect methods. The purpose of this research was to evaluate an in vivo stable isotope-based method of determining plasma entry rates of individual AA from feather meal (FM), blood meal (BM), and a rumen-protected AA (RPMet). Abomasal infusions of unprotected Ile, Leu, Met, and sodium caseinate were used as control treatments to assess technique reliability and accuracy. Isotopic enrichment of plasma AA in response to a 2-h constant jugular infusion of a mixture of 13C labeled AA was measured and modeled using a dynamic 4-pool model, which was fitted to each AA by infusion to derive diet entry rates. The resulting entry rate matrix was used to derive plasma entry rates of individual AA from each ingredient by regression. The mean of plasma AA entry for abomasally infused Ile, Leu, and Met was 93.4 ± 7.35% of that infused, indicating that 6.6% was used by splanchnic tissues during first pass. The mean of the plasma essential AA entry for abomasally infused casein was 86.7 ± 4.81% of that present in the source protein, which represents a mean of 8.7% first-pass use assuming 95% digestibility. Individual AA appearances ranged from 86 to 93% of the source content except Ile, which was 73%. These fractional appearance percentages were similar to those previously reported when using a dietary regression approach. The mean plasma essential AA entry rate for FM was 52.7% of the AA in the source ingredient, with a range across AA of 48 to 58%. The mean plasma essential AA entry rate for BM was 47.5%, with a range of 30 to 61%. However, estimated Met availability from the RPMet was lower (9.9%) than expected (42%). This may be due to the relatively larger errors of measurement for Met entry rates and a small change in RPMet inclusion. Assuming that rumen-undegraded protein absorption is reflective of aggregated essential AA entry rates after correction for first-pass use, 52.6 and 61.2% of dietary FM and BM CP was absorbed from the intestine, respectively, which yielded an estimated intestinal digestibility of 70 and 66%, respectively. This method appears to provide an accurate and precise in vivo assessment of individual AA plasma entry rates that can be used to better characterize individual feed ingredients in ruminants. Such information will result in more robust economic assessments of feeds and increased precision of diet formulation.

Multilevel social structure and diet shape the gut microbiota of the gelada monkey, the only grazing primate.

BACKGROUND: The gelada monkey (Theropithecus gelada), endemic to the Ethiopian highlands, is the only graminivorous primate, i.e., it feeds mainly on grasses and sedges. In spite of known dental, manual, and locomotor adaptations, the intestinal anatomy of geladas is similar to that of other primates. We currently lack a clear understanding of the adaptations in digestive physiology necessary for this species to subsist on a graminoid-based diet, but digestion in other graminivores, such as ruminants, relies heavily on the microbial community residing in the gastrointestinal (GI) system. Furthermore, geladas form complex, multilevel societies, making them a suitable system for investigating links between sociality and the GI microbiota. RESULTS: Here, we explore the gastrointestinal microbiota of gelada monkeys inhabiting an intact ecosystem and document how factors like multilevel social structure and seasonal changes in diet shape the GI microbiota. We compare the gelada GI microbiota to those of other primate species, reporting a gradient from geladas to herbivorous specialist monkeys to dietary generalist monkeys and lastly humans, the ultimate ecological generalists. We also compare the microbiotas of the gelada GI tract and the sheep rumen, finding that geladas are highly enriched for cellulolytic bacteria associated with ruminant digestion, relative to other primates. CONCLUSIONS: This study represents the first analysis of the gelada GI microbiota, providing insights into the adaptations underlying graminivory in a primate. Our results also highlight the role of social organization in structuring the GI microbiota within a society of wild animals.

Evaluation of vegetable protein in canine diets: Assessment of performance and apparent ileal amino acid digestibility using a broiler model.

Recent technological advances in the human food industry with respect to meat processing have decreased the availability of animal proteins to the pet food industry which typically formulates diets with an excess of animal protein. In the long term, this is not sustainable; thus, alternative protein sources need to be investigated. This study examined three canine diets, comparing a typical animal protein-based diet (control) with two experimental diets where the animal protein was substituted in part with vegetable protein (formulated based either on total protein or amino acid content) using a broiler model. Each diet was fed to six cages each containing two birds from day 15, 18 cages in total (36 birds). Excreta were collected from days 19 to 21. On day 23, birds were euthanized and weighed, and their ileal digesta were collected and pooled for each cage. In addition, one leg per cage was collected for evaluation of muscle mass. Results showed no significant difference in animal performance (feed intake or live weight gain) or muscle to leg proportion across the diets. Birds fed the control diet and the diet balanced for amino acid content exhibited the greatest coefficients of apparent metabolizability for nitrogen (p < .001). Birds fed the diets that contained partial replacement of animal with vegetable protein generally had greater ileal digestibility of amino acids compared to birds fed the control (animal protein) diet. Analysis of excreta showed no dietary difference in terms of dry matter content; however, birds fed the diet balanced for total protein and the diet balanced for amino acid content had significantly greater excreta nitrogen than the control (p = .038). Overall, the study suggests vegetable proteins when formulated based on amino acid content are a viable alternative to animal proteins in canine diets.

Metabolic costs of the mechanical components of the apparent specific dynamic action in the Dungeness crab, Cancer magister.

The specific dynamic action (SDA) describes the postprandial increase in metabolism. It is a composite of mechanical and chemical digestion, nutrient transport and protein synthesis. How these individual events contribute to the overall SDA has not been worked out fully for any organism. The mechanical events associated with the SDA were investigated in Dungeness crabs, Cancer magister. Following consumption of a meal, oxygen consumption (MO2) remained elevated for several hours. When the crabs were presented with fish scent there was a 2 fold increase in MO2, which rapidly decreased once the stimulus was removed. Crabs were then offered fish in a perforated tube. There was a rapid increase in MO2 associated with handling which returned to pre-treatment levels within an hour of removal of the tube. Finally the crabs were fed a piece of foam that had been soaked in fish water to determine the costs of mechanical digestion. The mechanical breakdown of the meal accounted for 29.9±3.3% of the overall SDA. Since food handling produced a large increase in MO2, it was reinvestigated using crabs that had one or both claws removed. Although there were no statistically significant differences as a function of claw removal there was a consistent trend in the data. The maximum MO2, scope, duration and SDA increased from animals with 0 claws through 1 claw to 2 claws. The results showed that the mechanical portion of the SDA can account for a significant portion of the overall budget in decapod crustaceans.

Development of dietary soluble fibres by enzymatic synthesis and assessment of their digestibility in in vitro, animal and randomised clinical trial models.

The aim was to develop novel fibres by enzymatic synthesis, to determine their total dietary fibre by AOAC method 2009.01 and to estimate their potential digestibility and assess their digestibility in vivo using glycaemic and insulinaemic responses as markers in mice and randomised clinical trial models. We found that fibre candidates to which α-(1,2) branching was added were resistant to digestion in the mouse model, depending on the amount of branching. These results show that in vivo models are needed to reliably assess the digestibility of α-glycosidic-linked oligomeric dietary fibre candidates, possibly due to absence of brush border α-glucosidase activity in the current in vitro assessment. α-(1,3)-linked and α-(1,6)-linked glucose oligomers were completely digested in humans and mice. In conclusion, it is possible to develop dietary soluble fibres by enzymatic synthesis. Adding α-(1,2) branching increases their resistance to digestion in vivo and can thus improve their suitability as potential fibre candidates. Clinical Trial Registry: ClinicalTrials.gov, NCT02701270.

Uncoupling Basal and Summit Metabolic Rates in White-Throated Sparrows: Digestive Demand Drives Maintenance Costs, but Changes in Muscle Mass Are Not Needed to Improve Thermogenic Capacity.

Avian basal metabolic rate (BMR) and summit metabolic rate (Msum) vary in parallel during cold acclimation and acclimatization, which implies a functional link between these variables. However, evidence suggests that these parameters may reflect different physiological systems acting independently. We tested this hypothesis in white-throated sparrows (Zonotrichia albicollis) acclimated to two temperatures (-8° and 28°C) and two diets (0% and 30% cellulose). We expected to find an uncoupling of Msum and BMR where Msum, a measure of maximal shivering heat production, would reflect muscle and heart mass variation and would respond only to temperature, while BMR would reflect changes in digestive and excretory organs in response to daily food intake, responding to both temperature and diet. We found that the gizzard, liver, kidneys, and intestines responded to treatments through a positive relationship with food intake. BMR was 15% higher in cold-acclimated birds and, as expected, varied with food intake and the mass of digestive and excretory organs. In contrast, although Msum was 19% higher in cold-acclimated birds, only heart mass responded to temperature (+18% in the cold). Pectoral muscles did not change in mass with temperature but were 8.2% lighter on the cellulose diet. Nevertheless, Msum varied positively with the mass of heart and skeletal muscles but only in cold-acclimated birds. Our results therefore suggest that an upregulation of muscle metabolic intensity is required for cold acclimation. This study increases support for the hypothesis that BMR and Msum reflect different physiological systems responding in parallel to constraints associated with cold environments.

Development, Validation, and Verification of a Self-Assessment Tool to Estimate Agnibala (Digestive Strength).

According to Ayurveda, the traditional system of healthcare of Indian origin, Agni is the factor responsible for digestion and metabolism. Four functional states (Agnibala) of Agni have been recognized: regular, irregular, intense, and weak. The objective of the present study was to develop and validate a self-assessment tool to estimate Agnibala The developed tool was evaluated for its reliability and validity by administering it to 300 healthy volunteers of either gender belonging to 18 to 40-year age group. Besides confirming the statistical validity and reliability, the practical utility of the newly developed tool was also evaluated by recording serum lipid parameters of all the volunteers. The results show that the lipid parameters vary significantly according to the status of Agni The tool, therefore, may be used to screen normal population to look for possible susceptibility to certain health conditions.