Simulated Gastrointestinal System Research Articles

Quantitative Analysis of Bioaccessible Phenolic Compounds in Aegean Bee Bread Using LC-HRMS Coupled with a Human Digestive System Model.

Bee bread, a valuable bee product that has recently attracted significant public interest as a nutritional supplement. The aim of this study was to evaluate the presence of phenolic compounds in bee bread samples from the Aegean Region and assess their bioaccessibility using a simulated human digestion model. Various extraction techniques, such as maceration, ultrasound-assisted extraction, and supercritical fluid extraction were employed to obtain extracts of bee bread. The antioxidant capabilities of these extracts were carried out using assays like DPPH⋅, ABTS⋅+ , CUPRAC, and β-carotene linoleic acid bleaching, and their effectiveness was quantified through IC50 values. The bioaccessibility of phenolic compounds was analysed by using LC-HRMS in a simulated human digestive system using ethanol extracts obtained from bee bread samples of each season by ultrasound-assisted extraction, which has the highest antioxidant activity. In the Aegean bee bread, a total of 25 phenolic compounds which were major phenolics including quercetin, ascorbic acid, isorhamnetin, kaempferol, and hyperoside were identified and quantified. Also, ascorbic acid was the one of the most bioaccessible compounds with the bioaccessibility index 35.38 % for 2021, 16.79 % for 2022. These findings underscore the substantial transformation of the phenolic profile of bee bread as it traverses the human digestive system.

In vitro fermentation characteristics of polysaccharides from coix seed and its effects on the gut microbiota

Coix seed polysaccharides had received increasing attention due to their diverse biological activities. In this study, a homogeneous polysaccharide (CSPW) was extracted and purified from coix seed. Furthermore, the saliva-gastrointestinal digestion and fecal fermentation behavior of CSPW were simulated in vitro. The results showed that CSPW was mainly composed of glucose. It cannot be degraded by the simulated salivary and intestinal digestive system, but can be degraded by the simulated gastric digestive system. After fermentation for 24 h, CSPW promoted the production of short-chain fatty acids (SCFAs), with acetic acid, propionic acid and n-butyric acid being the main metabolites. In addition, CSPW could significantly regulate the composition and microbial diversity of gut microbiota by increasing the relative abundance of beneficial bacteria, such as Limosilicactobacillus, Bifidobacterium and Collinsella. Finally, further analysis of functional prediction revealed that amino acid metabolism, nucleotide metabolism and carbohydrate metabolism were the most important pathways for CSPW to promote health. In summary, our findings suggested that CSPW could potentially be used as a good source of prebiotics because it can be used by gut microbiota to produce SCFAs and regulate the gut microbiota.

Vitro bioactivities and simulated gastrointestinal digestion studies on Guras-based traditional fermented drinks collected from Singalila ridge of the Himalayas

Guras or Rhododendron wine and its distilled form (Raksi) are popular traditional and therapeutic drinks served in the Rhododendron growing regions of the Himalayas, mainly in the northern and northeastern part of India, Nepal and Indo-Nepal Singalila ridge. In this research, lali Guras (Rhododendron arboreum Sm.) based traditional beverages such as unfermented decoction (as control), fermented Guras wine and distilled spirit Guras ko Raksi were collected from Singalila ridge of the Himalayas for analysis. In vitro experiments such as physicochemical and qualitative and quantitative biochemical tests; antioxidant assays (DPPH and iodometric assay); antibacterial assay; and simulated gastrointestinal digestion were carried out. Phytochemically rich unfermented decoction exhibited the best results in total phenolic content assay (82.18±1.13 mg/100 mL gallic acid equivalent) and fatty acid quantification (1.86±0.08%) test while the wine was found to be the most potential sample in all bioactivity tests. The wine was found to contain high amounts of glycoside and fermented distilled liquor Guras Raksi showed high presence of glycerol. Both the fermented samples exhibited high rate of digestion in simulated human digestion system compared to the phenolic rich unfermented decoction. This research validated the therapeutic potential of these Guras-based beverages in high-altitude conditions like Singalila by focusing on their biochemistry.

Simultaneous determination of typical toxic aldehydes formed during food frying and digestion using isotope dilution UHPLC-QqQ-MS/MS

An isotope dilution ultra-performance liquid chromatography–triple quadrupole mass spectrometry method was developed to simultaneously detect two typical kinds of α,β-unsaturated aldehydes, namely 4-hydroxy-2-hexenal (4-HHE) and 4-hydroxy-2-nonenal (4-HNE), in foods. The proposed method exhibited a linear range of 10–1000 ng/mL with a limit of detection of 0.1–2.0 ng/g and a limit of quantification of 0.3–5.0 ng/g. The recovery rates of these typical toxic aldehydes (i.e., 4-HHE, 4-HNE) and their d3-labeled analogues were 91.54%–105.12% with a low matrix effect. Furthermore, this proposed method was successfully applied to a real frying system and a simulated digestion system, wherein the contents of 4-HHE and 4-HNE were determined for both. Overall, the obtained results provide strong support for further research into the production of 4-HHE and 4-HNE resulting from foods during oil digestion and frying.

A comprehensive study of diverse techniques for enhanced physicochemical and structural properties of bio-calcium from hybrid catfish bone

This research examined the impact of various comparative preparation methods on enhanced physicochemical, and structural properties of bio-calcium (BC) from hybrid catfish bone. Raw hybrid catfish bones (RB) were used to make bio-calcium in four steps. High-pressure water jet processing produced washed bone (WB), soaking the bone in an alkaline solution to remove proteins (PR), immersing it in ethanol to remove lipids (LR), then bleaching, and grinding it to make bio-calcium powder. The BC had greater lightness values (L*) (p < 0.05), and contained significant calcium, and phosphorus. The SDS-PAGE showed three significant protein bands with molecular weights of 250, 133, and 116 kDa. The crystalline structure of hydroxyapatite in BC was confirmed using X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. The percentage of crystallinity of BC had a notable rise, increasing from the RB to BC of 36.25%–45.32%. The BC powder exhibited a consistent distribution of particle sizes, ranging from 2 to 10 μm. Additionally, the analysis of elemental profiles, and mappings using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) revealed that BC exhibits a significant concentration of calcium, and phosphorus. BC showed superior %bioavailability of calcium (18.94%) in an in vitro simulated gastrointestinal system (GIMs) compared to RB (10.58%), and calcium carbonate (11.19%). Hence, the BC production process proved to be a viable method for acquiring premium-grade BC, which holds potential for further development as a calcium dietary supplement.

Prediction equations of the metabolizable energy in corn developed by chemical composition and enzymatic hydrolysate gross energy for roosters

Two experiments were conducted to establish the prediction equations for AME and TME of corn based on chemical composition and enzymatic hydrolysate gross energy (EHGE) in roosters. In experiment 1, eighty 32-wk-old Hy-line Brown roosters with an average body weight of 2.55 ± 0.21 kg were randomly assigned to 10 diet treatments in a completely randomized design to determine AME and TME by the force-feeding method. Each treatment had 8 replicates with 1 bird per replicate. The 10 test diets used in the experiment were formulated with corn (including 96.10%) as the sole source of energy. In experiment 2, the EHGE of 14 corn samples was measured by the computer-controlled simulated digestion system (CCSDS) with 5 replicates of each sample. The average AME and TME values of corn were 14.58 and 16.46 MJ/kg DM, respectively. The EHGE of 14 corn samples ranged from 14.66 to 15.89 (the mean was 15.24) MJ/kg DM. The best-fit equations for corn based on chemical composition were AME (MJ/kg DM) = 14.5504 + 0.1166 × ether extract (EE) + 0.5058 × Ash - 0.0957 × neutral detergent fiber (NDF) (R2 = 0.8194, residual standard deviation (RSD) = 0.0860, P < 0.01) and TME (MJ/kg DM) = 16.0625 + 0.1314 × EE + 0.4725 × Ash - 0.0872 × NDF (R2 = 0.7867, RSD = 0.0860, P < 0.01). The best-fit equations for corn based on EHGE were AME (MJ/kg DM) = 7.8883 + 0.4568 × EHGE (R2 = 0.8587, RSD = 0.0693, P < 0.01) and TME (MJ/kg DM) = 10.0099 + 0.4228 × EHGE (R2 = 0.8720, RSD = 0.0608, P < 0.01). The differences between determined and predicted values from equations established based on EHGE were lower than those observed from chemical composition equations. These results indicated that EHGE measured with CCSDS could predict the AME and TME of corn for roosters with high accuracy.

Predicting energetic values of cereal grains and byproducts using a computer-controlled simulated digestion system for growing pigs

The objective of this study was to predict the apparent total tract digestibility (ATTD) of gross energy (GE), digestible energy (DE), and metabolizable energy (ME) of cereals and byproducts using an in vitro digestion procedure automatically progressed in a computer-controlled simulated digestion system (CCSDS) for growing pigs. In in vivo test to determine the ATTD of GE, DE and ME of feed ingredients, 15 barrows (30.2 ± 2.4 kg of initial body weight) were allotted to a 15 × 6 Youden square design with 15 experimental diets in 6 periods to give 6 replicates per diet. Diets included a corn-soybean meal-based basal diet and 14 test diets formulated with 14 samples of cereals and byproducts. The in vitro digestible energy (IVDE) and IVDE/GE were determined using CCSDS with 5 replicates for each sample. Principal components analysis showed that similar positions of samples were observed on a two-dimensional plot of PC1 and PC2 extracted from chemical composition and each of DE, ME, or IVDE. The ratios of IVDE to DE or ME among 14 samples ranged from 87.7–110.4 % and 91.1–112.9 %, but ranged from 97.8–103.5 % or 100.2–105.7 % when both paddy rice and wheat shorts were excluded in consideration of lever effect. Models to predict DE and ME from IVDE were DE = 0.7428 × IVDE + 945 (R² = 0.71, root mean square error (RMSE) = 157 kcal/kg DM, P < 0.01), ME = 0.7465 × IVDE + 839 (R² = 0.76, RMSE=139 kcal/kg DM, P < 0.01) when 14 samples were included, but regression equations were DE = 0.6924 × IVDE + 1173 (R² = 0.91, RMSE = 49 kcal/kg DM, P < 0.01) and ME = 0.6876 × IVDE + 1098 (R² = 0.95, RMSE = 34 kcal/kg DM, P < 0.01) when paddy rice and wheat shorts were excluded. Our results indicate that IVDE determined with a novel CCSDS can precisely predict the DE and ME of cereals and byproducts with lower fiber content (ADF < 6.01 % DM) for growing pigs.

Developing garlic polysaccharide-Fe (III) complexes using garlic pomace to provide enhanced iron-supplementing activity in vivo

This study investigated the potential of garlic polysaccharides (GPs) from garlic pomace as iron carriers. The obtained GP-Fe (III) complexes had a higher molecular weight (5646 Da) and more fructose (90.46 %) than the GPs did and contained 9.7 % Fe (III). GPs were mainly composed of → 2)-β-d-Fruf (1 → and → 2)-β-d-Fruf (6 → residues, and their interactions with Fe (III) reduced the crystallinity, increased the thermal stability, and altered the morphological features through targeting the OH stretching vibrations of the hydroxyl groups and affecting the COC and OCO structures. The GP-Fe (III) complexes had high stability under simulated gastrointestinal digestion system and showed better therapeutic effects on iron deficiency anemia in mice than FeSO4 did, evidenced by improved hematological parameters, restored iron levels, and attenuated oxidative damage. Thus, GP-Fe (III) complexes are promising as novel Fe (III) supplements for Fe-deficient individuals, and promote the high-value utilization of garlic pomace.

Effects of six different microbial strains on polyphenol profiles, antioxidant activity, and bioaccessibility of blueberry pomace with solid-state fermentation.

To explore the effect of different microbial strains on blueberry pomace with solid-state fermentation (SSF), three fungi strains and three lactic acid bacteria (LAB) strains were utilized to investigate with respect to polyphenol profiles, antioxidant capacities, and bioaccessibility. Different strains exhibited different capacities for metabolizing polyphenolic compounds in blueberry pomace. The contents of 10 phenolic acids and 6 flavonoids (except (+)-catechin) were increased in blueberry pomace fermented by Lactobacillus acidophilus (LA). A similar tendency was observed in blueberry pomace fermented by Aspergillus niger (AN) and Lactobacillus plantarum (LP), where the concentration of 8 phenolic acids and 5 flavonoids was enhanced, with the following exceptions: (+)-catechin, ferulic acid, vanillic acid, and quercitrin. Chlorogenic acid and quercetin were the maximum phenolic acids and flavonoids in blueberry pomace with SSF, upgraded at 22.96 and 20.16%, respectively. Contrary to the growth of phenolic acids and flavonoid compounds, all individual anthocyanins showed a decreased trend. Only in the blueberry pomace fermented by AN, all anthocyanidins exhibit a rising trend. After SSF, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenylpicrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) radical scavenging abilities were increased by up to 33.56, 59.89, and 87.82%, respectively. Moreover, the simulated gastrointestinal digestion system revealed that SSF improved the bioaccessibility of polyphenolic compounds. Compared with other strains, LA, LP, and AN showed better excellent capacities for metabolizing polyphenolic compounds, which led to a greater increase in antioxidant activity and bioaccessibility in fermented blueberry pomace.

Important Role and Properties of Granular Nanocellulose Particles in an In Vitro Simulated Gastrointestinal System and in Lipid Digestibility and Permeability.

This research evaluated the role and feasibility of the granular nanocellulose particles (GNC) from sugarcane bagasse obtained from enzymatic hydrolysis in reducing lipid digestibility and permeability in an in vitro simulated gastrointestinal (GI) system. GNC concentration (0.02%, w/v) had significantly affected the released free fatty acids (FFA), with a reduction of approximately 20%. Pickering emulsion of a GNC and olive oil simulation mixture revealed higher oil droplet size distribution and stability in the initial stage than the vortexed mixture formation. The difference in particle size distribution and zeta potential of the ingested GNC suspension and GNC-olive oil emulsion were displayed during the in vitro gastrointestinal simulation. GNC particles interacted and distributed surrounding the oil droplet, leading to interfacial emulsion. The GNC concentration (0.01-0.10%, w/v) showed low toxicity on HIEC-6 cells, ranging from 80.0 to 99% of cell viability. The release of FFA containing the ingested GNC suspension and GNC-olive oil emulsion had about a 30% reduction compared to that without the GNC digestion solution. The FFA and triglyceride permeability through the HIEC-6 intestinal epithelium monolayer were deceased in the digesta containing the ingested GNC and emulsion. This work indicated that GNC represented a significantly critical role and properties in the GI tract and reduced lipid digestion and absorption. This GNC could be utilized as an alternative food additive or supplement in fatty food for weight control due to their inhibition of lipid digestibility and assimilation.

Effects of simulated gastrointestinal digestion/epithelial transport on phenolics and bioactivities of particles of brewer’s spent yeasts loaded with Brazilian red propolis

Red propolis from northeast Brazil contains mainly isoflavonoids as bioactive compounds, and its consumption may counteract unregulated and exacerbated formation of reactive oxygen species and inflammatory cytokines/chemokines. Moreover, the production of particles using sustainable carriers have been studied to increase the use of propolis as a functional food ingredient. Hence, the objective of this work was to investigate the effects of simulated gastrointestinal digestion followed by a cell-based epithelial transport on phenolic profile, anti-inflammatory and antioxidant activities of particles of brewer’s spent yeasts (BSY) loaded with ethanolic extract of Brazilian red propolis (EEP). As a result, the EEP phenolic diversity decreased throughout the simulated gastrointestinal system, and was modulated by the particle production, as detected by high-performance liquid chromatography – electrospray ionization – quadrupole-time-of-flight-mass spectrometry (HPLC-ESI-QTOF-MS). Concomitantly, the antioxidant activity, as assessed by the ability to scavenge peroxyl and superoxide radicals, hydrogen peroxide, and hypochlorous acid, generally decreased at a higher extent for the particles of EEP with BSY (EEP-BSY) throughout the experiments. Nonetheless, after epithelial transport through the Caco-2 cell monolayer, the basolateral fraction of both EEP-BSY and EEP decreased the activation of pro-inflammatory transcription factor NF-κB by 83% and 65%, respectively, as well as the release of TNF-α (up to 51% and 38%, respectively), and CXCL2/MIP-2 (up to 33% and 25%, respectively). Therefore, BSY may be an interesting carrier for EEP bioencapsulation, since it preserves its anti-inflammatory activity. Further studies should be encouraged to investigate the feasibility of adding it in formulations of functional foods, considering its effect on sensory attributes.

The adsorption of PAHs on microplastics and desorption in the simulated human digestive system

Plastic debris is widely distributed in the aquatic environment and interacts with other pollutants. Microplastics (MPs) have a stronger binding ability with pollutants and could unconsciously ingested by humans, thus becoming the carrier of pollutants into the human body and affecting human health. In this study, polycyclic aromatic hydrocarbons (PAHs) were selected as model pollutants, polyethylene (PE) and polymethyl methacrylate (PMMA) were selected as research objects. The adsorption of PAHs on different kinds of MPs and desorption behavior in a simulated human digestive system were systematically studied. The results indicated that PAHs with higher molecular weight were more easily adsorbed on MPs, and the adsorption efficiency of PAHs on PE was 1.4–3.8 times higher than PMMA. The desorption experiments were conducted in simulated gastrointestinal fluid, the activity of enzymes directly affected the desorption of PAHs, and the desorption efficiency of PAHs from the surfaces of PMMA (0.7–41.6 %) was significantly higher than PE (0.8–27.7 %). For 15 PAHs, the desorption efficiency from the surfaces of PE decreased gradually with the number of PAHs rings, which was opposite to PMMA. Molecular dynamics simulation showed that enzymes in digestive fluid attenuated the interaction energy between MPs and PAHs, resulting in substantial desorption of PAHs from the surfaces of MPs. The risk assessment demonstrated that the carcinogenic risk of PAHs desorption from PMMA was higher than PE. This study helps understand the adsorption of PAHs on MPs and the potential health risks of accidental ingestion by humans.

Lauroylated, Acetylated, and Succinylated Agave tequilana Fructans Fractions: Structural Characterization, Prebiotic, Antibacterial Activity and Their Effect on Lactobacillus paracasei under Gastrointestinal Conditions.

The effect of chemical modification of fractions of native agave fructans (NAF), high performance (HPAF), and a high degree of polymerization (HDPAF) by lauroylation, acetylation, and succinylation reactions on their prebiotic activity, antibacterial properties were evaluated and survival of L. paracasei in a simulated gastrointestinal system. The characterization of the reactions was confirmed by NMR and FTIR. The lauroylated and succinylated fructan fractions showed higher antibacterial activity against pathogenic bacteria such as Escherichia coli, Enterococcus faecalis and Staphylococcus aureus than the unmodified ones. Analyses with L. paracasei showed that the acetylated fructan fractions had a greater prebiotic effect, and simulated gastrointestinal tests demonstrated that the acetylated and succinylated fractions favored the survival of L. paracasei during the gastrointestinal phase. The effect of modifying the agave fructans fractions on the evaluated properties depended on the structure, size, and polarity of each incorporated functional group, as well as the degree of polymerization and substitution of each fraction. These results show that the chemical modification of the fructan fractions analyzed improves their functional properties, offering an alternative in the food and pharmaceutical industry.

Lipid Structure Influences the Digestion and Oxidation Behavior of Docosahexaenoic and Eicosapentaenoic Acids in the Simulated Digestion System.

Omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are essential for human health but prone to oxidation. While esterification location is known to influence the stability of omega-3 in triacylglycerols (TAGs) in oxidation trials, their oxidative behavior in the gastrointestinal tract is unknown. Synthesized ABA- and AAB-type TAGs containing DHA and EPA were submitted to static in vitro digestion for the first time. Tridocosahexaenoin and DHA as ethyl esters were similarly digested. Digesta were analyzed by gas chromatography, liquid chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy. Besides the formation of di- and monoacylglycerols, degradation of hydroperoxides was detected in ABA- and AAB-type TAGs, whereas oxygenated species increased in tridocosahexaenoin. Ethyl esters were mainly unaffected. EPA was expectedly less susceptible to oxidation prior to and during the digestion process, particularly in sn-2. These results are relevant for the production of tailored omega-3 structures to be used as supplements or ingredients.

Comparative Study on Hydrolysis, Physicochemical and Antioxidant Properties in Simulated Digestion System between Cooked Pork and Fish Meat.

Pork and grass carp are commonly consumed animal protein sources, classified as red meat and white meat, respectively. This study aimed to better understand the differences in digestive behavior, nutrition, and functionality during digestion between these two types of meat after fat removal. The results showed that grass carp was more easily digested than pork, with a higher degree of hydrolysis, a smaller protein particle size, and a greater release of oligopeptides and amino acids (p < 0.05). During gastric digestion, all α-helix structures were destroyed, and the effect of the whole digestion process on the secondary and tertiary structure of pork protein was greater than that of grass carp. The antioxidant properties of the digestive fluids from the two types of meat showed different strengths in various assays, but the correlation analysis revealed that TCA-soluble peptides, random coil content, and particle size significantly influenced both types of meat. These findings provide new insights into the structural state and antioxidant properties of protein in meat digestion, which contribute to our understanding of the nutritional value of pork and grass carp.

Antibacterial, simulated digestive system tolerance and colon cancer cell lines adhesion properties of selected lactic acid bacteria of food origin

Lactic acid bacteria (LAB) are widespread in nature and are one of the major microbial groups involved in the fermentation of different types of food. LAB possess a large number of metabolic properties that are responsible for the organoleptic characteristics of the final product including antioxidants, organic acids, antimicrobial compounds, modulating and improving microbial balance in the gut. Therefore, to determine the appropriate LAB for the development of functional food products, commercial LAB strain screening had been carried out. The antibacterial activity, tolerant to acids (pH 2, 3 and 4), bile salts (0.3%, 0.5% and 1.0%) and adhesion to colon cancer cell lines (HT29 and SW480) of several LABs (Lactobacillus paracasei UALpc-04™, Lactobacillus plantarum UALp-05™, Lactobacillus acidophilus DDS®-1, Bifidobacterium bifidum UABb-10™ and Streptococcus thermophilus UASt-09™) were performed. The studies indicated that Lb. plantarum UALp-05™ and B. bifidum UABb-10™ showed more than 106 CFU/mL viability when tested against acid and bile saline with higher adherence to cancer cell lines compared to other strains. The antibacterial activity showed that these two LAB strains also gave a higher inhibition zone of 13 to 17 mm against five strains of pathogens (Escherichia coli ATCC® 0157™, Salmonella enterica serovar Typhimurium ATCC® 53648™, Salmonella enterica serovar Enteritidis (MDC15), Streptococcus bovis ATCC® 9809™ and Listeria monocytogenes ATCC® 51772™). Our results indicated that Lb. plantarum UALp-05™ and B. bifidum UABb-10™ strains could be used as adjunct cultures for contributing to the health of gastrointestinal system and decreasing the risk factor of colon cancer.

Integrating metabolomics, bionics, and culturomics to study probiotics-driven drug metabolism.

Many drugs have been shown to be metabolized by the human gut microbiome, but probiotic-driven drug-metabolizing capacity is rarely explored. Here, we developed an integrated metabolomics, culturomics, and bionics framework for systematically studying probiotics-driven drug metabolism. We discovered that 75% (27/36 of the assayed drugs) were metabolized by five selected probiotics, and drugs containing nitro or azo groups were more readily metabolized. As proof-of-principle experiments, we showed that Lacticaseibacillus casei Zhang (LCZ) could metabolize racecadotril to its active products, S-acetylthiorphan and thiorphan, in monoculture, in a near-real simulated human digestion system, and in an ex vivo fecal co-culture system. However, a personalized effect was observed in the racecadotril-metabolizing activity of L. casei Zhang, depending on the individual's host gut microbiome composition. Based on data generated by our workflow, we proposed a possible mechanism of interactions among L. casei Zhang, racecadotril, and host gut microbiome, providing practical guidance for probiotic-drug co-treatment and novel insights into precision probiotics.

In vitro release and in vivo growth-promoting effects of coated cysteamine in broilers

The purpose of this study was to investigate the effects of coating technology on the cysteamine (CSH) release in the digestive tract and the growth-promoting effect of enteric-coating CSH in broilers. First, using the self-developed computer-controlled simulated digestion system to mimic the digestion process in vitro, the release of 2 coated CSH (CSH-I and CSH-Ⅱ) were studied. The results showed that less than 10% of CSH-I was released after gastric digestion and 52.35% of CSH-I was released with additional 4 h of small intestinal digestion. In contrast, 83.62% of CSH-Ⅱ was released during the gastric digestion. In order to verify the growth-promoting effects of CSH-I, a feeding trial was conducted in a completely randomized block arrangement with 3 treatments in 6 blocks, 5 chickens per replicate. Broilers were fed with corn-soybean meal diet either supplemented with 0 (CON), 200 mg/kg uncoated CSH (CSH) or 200 mg/kg CSH-I from d 7 to 42, respectively. Body weight and FI was recorded at d 21 and 42. Excreta were collected from d 39 to d 42 to determine the total tract retention (TTR) of dietary nutrients. In comparisons with controls, birds fed with CSH-I had greater BW, ADG, and ADFI and increased TTR of DM, gross energy (GE), NDF and hemicellulose (P < 0.05). In addition, duodenal villi height and surface area were also greater in those CSH-I-fed birds. In contrast, the growth performance of birds fed with uncoated CSH did not significantly differ from controls. Although the TTR of DM and GE was higher in birds fed with CSH than controls, no differences in small intestine morphology were noted. Thus, the type I coating (CSH-I) could be good enteric-coating technology to increase CSH release in the duodenum, improve digestion and duodenal morphology, and therefore growth performance in broilers.

Predicting the metabolizable energy and metabolizability of gross energy of conventional feedstuffs for Muscovy duck using in vitro digestion method.

In total, two experiments were conducted to evaluate the effectiveness of an in vitro digestion method for predicting the metabolizable energy (ME) and metabolizability of gross energy (ME/GE) values using in vitro digestible energy (IVDE) and the digestibility of gross energy (IVDE/GE) content, respectively, of conventional feedstuffs for Muscovy ducks. In experiment 1, the apparent metabolizable energy (AME), true metabolizable energy (TME), AME/GE, and TME/GE of eight-grain feedstuff samples (two corn samples, three sorghum samples, and three barley samples) and eight protein feedstuff samples (two soybean meal samples, three cottonseed meal samples, and three rapeseed meal samples) were determined by the tube-feeding method with six different ducks for each sample. In experiment 2, a computer-controlled simulated digestion system (CCSDS) contain simulated digestive fluid was used to determine the enzymatic hydrolysis energy value of feedstuffs, which was defined as IVDE in our study. The simulated gastric fluid containing pepsin and simulated small intestinal fluid containing amylase, trypsin, and chymotrypsin for the in vitro gastric and intestinal digestion, respectively. The IVDE and in vitro digestibility of GE (IVDE/GE) of 16 feedstuff samples were determined using the CCSDS with five replicates per sample. The results showed that the IVDE and IVDE/GE were positively correlated with ME and ME/GE of feedstuffs, respectively. The coefficient of determination of eight regression models in predicting ME (grain feedstuffs: AME = 1.050 × IVDE- 0.9293, TME = 1.032 × IVDE + 0.6478; protein feedstuffs: AME = 1.331 × IVDE- 6.685, TME = 1.269 × IVDE-3.490) and ME/GE (grain feedstuffs: AME/GE = 1.069 × IVDE/GE- 6.516, TME/GE = 1.068 × IVDE/GE + 0.7764; protein feedstuffs: AME/GE = 1.093 × IVDE/GE -19.21, TME/GE = 1.196 × IVDE/GE - 13.25) of feedstuffs for Muscovy ducks ranged from 0.8610 to 0.9921. The accuracy of the regression model was acceptable as the difference between measured and predicted ME and ME/GE values was less than 0.45 MJ/kg (100 kcal/kg) and 2.62% for 14 of the 16 feed samples, respectively. In conclusion, the in vitro digestion method can be used to predict the ME and ME/GE of conventional feedstuffs for Muscovy ducks with acceptable accuracy.

A comparative study on in vitro and in vivo stomach-small intestinal and large intestinal digestion of plant protein meals in growing pigs.

This experiment evaluated the difference between computer-controlled simulated digestion and in vivo stomach-small intestinal or large intestinal digestion for growing pigs. Five diets including a corn-soybean meal basal diet and four experimental diets with rapeseed meal (RSM), cottonseed meal (CSM), sunflower meal (SFM), or peanut meal (PNM) were assigned to each group of five barrows installed terminal ileal cannula or distal cecal cannula in a 5 × 5 Latin square design. Ileal digesta and feces were collected for the determination of digestibility of dry matter (DM) and gross energy (GE) as well as digestible energy (DE) at terminal ileum and total tract. The large intestinal digestibility and DE were calculated by the difference between measurements obtained at the terminal ileum and those obtained from total tract. In vitro stomach-small intestinal digestibility and DE for diets and plant protein meals were determined by stomach-small intestinal digestion in a computer-controlled simulated digestion system (CCSDS). The in vitro large intestinal digestibility and DE of diets were determined in a CCSDS using ileal digesta and enzymes extracted from cecal digesta of pigs. The in vitro large intestinal digestibility and DE of four plant protein meals were determined by the difference between stomach-small intestinal and total tract digestion in the CCSDS. For the experimental diets, the in vitro ileal digestibility and DE were not different from corresponding in vivo values in basal diet and PNM diet, but greater than corresponding in vivo values for diets with RSM, CSM, and SFM (P < 0.05). No difference was observed between in vitro and in vivo large intestinal digestibility and DE in five diets. For the feed ingredients, the in vitro ileal digestibility and DE did not differ from corresponding in vivo ileal values in RSM and PNM but were greater than the in vivo ileal values in CSM and SFM (P < 0.05). The in vitro large intestinal GE digestibility and DE were not different from in vivo large intestinal values in RSM, CSM, and PNM, but lower than in vivo large intestinal values in SFM. This finding may relate to the higher fiber content of plant protein meals resulting in shorter digestion time of in vivo stomach-small intestine thus lower digestibility compared to in vitro, indicating it is necessary to optimize in vitro stomach-small intestinal digestion time.