Site Of Digestion Research Articles

The function of Apostichopus japonicas catalase in sea cucumber intestinal immunity

Catalase is an important oxidoreductase enzyme that catalyzes the conversion of hydrogen peroxide molecules into water and oxygen and regulates the homeostasis of ROS in animals and humans. Catalase functions in host immune defense, cellular apoptosis, aging, inflammation, and tumor formation. The intestine is not only an important site of nutrient digestion and absorption but also an important site of innate immunity against microbial infection in invertebrates. Catalase can participate in intestinal immune responses. However, the role of catalase in intestinal immunity in the sea cucumber (Aj-catalase) has not been elucidated. In this study, we showed that Aj-catalase plays a key role in intestinal immunity and microbiota homeostasis. The expression level of Aj-catalase was upregulated, and its enzymatic activity was increased in the Apostichopus japonicus intestine after challenge with Vibrio splendidus via oral infection. When Aj-catalase was knocked down by RNA interference (RNAi), the survival rate of sea cucumbers declined; microbiota homeostasis was disturbed in the intestine compared with that in the control group, and the intestinal villi protruding from the epithelial lining of the intestinal wall were damaged. Further study results demonstrated that the ROS level was increased for a long period in Aj-catalase-knockdown sea cucumbers, which is likely the main mechanism by which catalase is involved in regulating intestinal immunity. These results suggest that Aj-catalase participates in intestinal immunity and microbiota homeostasis by regulating ROS levels.

Effect of processing methods (Rolling, steam-flaking, pelleting) on protein molecular structure profile, rumen degradation, and intestinal digestion of cool-climate adapted oats grain in comparison with barley grain in western Canada

Processing cereal grains can lead to an improvement in nutrient digestibility and have an impact on the rate and site of grain nutrients digestion. There are several methods of processing and it is important to understand which processing method is better recommended for dairy cows ration with cool-climate adapted oat grain. The main objective of this study was to determine the impact of processing methods (Rolling, Steam-Flaking, Pelleting) on the nutritional and digestive characteristics and the protein related molecular spectral profiles of cool-climate adapted oats grain in comparison to barley grain. Results showed that heat treating oats (steam-flaking and pelleting) did not alter SCP of cool-climate adapted oats grain. Steam-flaking increased the intermediate degradable protein fraction PB1 (+13.68% CP), while reduced PA2 (−17.19% CP) fraction when compared to rolled oats. Steam-flaking also increased bypass CP (+14.71%BCP) while decreasing the EDCP in the rumen (−14.71%). In the DVE/OEB system, steam-flaked oats and pelleted oats presented lower values of OEB when compared to rolled oats, but they were higher than the value for rolled barley. Univariate analysis of the protein molecular structure features showed only changes in the protein beta-sheet height, with flaked oats presenting the higher value, pelleted oats showing the lowest value and rolled barley and oats showing intermediate values. There was overlap among the treatments when analyzed with PCA, implying similar molecular structure among the treatments.

Histomorphology of gastrointestinal tract in bullfrog Rana ( Lithobates ) catesbeiana and evaluation of the changes induced by a soybean meal‐based diet

Two studies were carried out to (a) characterize the gastrointestinal (GI) tract of bullfrog Rana (Lithobates) catesbeiana and (b) to evaluate the effects of total replacement of fish meal (FM) with soybean meal (SBM) on GI tract health. For characterization of the GI tract, oesophagus, stomach and intestine sections were sampled from 20 bullfrogs (80 g) fed a FM-based diet. The results revealed that the GI tract of bullfrog is consisted of four tissue layers including mucosa, submucosa, muscularis and serosa, and that the intestine could be divided into duodenum, jejunum, ileum and rectum. Furthermore, the abundance and length of mucosal folds suggested that jejunum is the primary site of digestion and absorption of nutrients. In the second study, a diet containing 44% fish meal (FM) was formulated and used as a FM-based diet, and a SBM-based diet was prepared by entire substitution of FM with SBM. Sixty bullfrogs (35 ± 1 g) were divided into three replicates of the two groups and were fed the test diets to apparent satiation twice daily for 8 weeks. The changes in pH and morphology of GI tract in response to the shift in dietary protein source were evaluated. The results showed the enhancement of pH values in GI tract of the SBM group excluding cardia, jejunum and rectum. Also, SBM diet triggered significant decreases in the number, height and width of mucosal folds, while an opposite trend was observed for thickness of lamina propria. Moreover, the entire replacement of FM with SBM led to the separation of submucosa from muscularis and incidence of lesion in mucous epithelium. The findings in this study showed that jejunum is the main site of nutrients digestion and absorption. Also, it was demonstrated that entire replacement of FM with SBM adversely influenced the GI tract health in bullfrog.

169 Increasing levels of sorghum dried distillers grains with solubles in feedlot diets: effects on nutrient digestibility, ruminal degradability and fermentation

Abstract The objective of this study was to determine the effect of increasing levels of sorghum dry distillers grains with solubles (DDGS) in high concentrate feedlot diets in the nutrient digestibility (%), ruminal degradability (%), pH, NH4 (µg N-NH4/ml) and volatile fatty acid (VFA, mM/l) concentration. Four ruminally cannulated steers (450 ± 63 kg) were used in a 4x4 Latin square design, evaluating four treatments in four periods of 19 days each, with 14 days of adaptation and 5 days of measurements. Animals received a TMR, 92% concentrate (63% sorghum grain, 25% soybean meal, 4% mineral commercial premix), with DDGS (90% DM, 29% CP, 51% NDF, 9% EE) in increasing levels generating 4 treatments: 0, 15, 30, or 45%. Replacing a combination of sorghum grain and soybean meal to maintain diets isoproteic. The TMR was offered ad-libitum to each animal in individual pens. Greater levels of DDGS increased the consumption of NDF (P = 0.0001) and EE (P = 0.0004), and NDF total tract apparent digestibility (linear; P = 0.038), but it decreased quadratically EE total tract apparent digestibility (P = 0.017). The DM (84.2 ± 0.17) and the CP total tract apparent digestibility (85.3 ± 2.0) was not affected by increasing levels of DDGS. Nevertheless, the ruminal degradability of total DM (P = 0.01) and CP decreased linearly (P = 0.01), without affecting NDF degradability (65.6 ± 4.3). Increasing levels of DDGS did not change ruminal pH (5.6 ± 0.14), acetate (45.1 ± 6.3), propionate (24.8 ± 3.6), and butyrate (5.2 ± 0.7) concentration, but NH4 concentration decreased linearly (P < 0.0001) directly related to the decreased CP ruminal degradability. Increasing levels of DDGS inclusion in a high concentrate diet reduce the CP ruminal degradability, without changes in total CP digestibility, what indicates a change of the site of digestion.

Plasma suPAR in differentiating malignant and benign pancreatic masses.

A number of studies were devoted to understanding an immunological effect of pressure-treated β-lactoglobulin. In our previous work we have proved that high pressure significantly modifies β-lactoglobulin conformation and consequently its physicochemical properties. Here, structure of β-lactoglobulin complex with myristic acid determined at the highest accepted by the crystal pressure value of 550 MPa is reported. Our results structurally prove that pressure noticeably modifies positions of the major β-lactoglobulin epitopes. Considering the biological impact of observed changes in epitope regions, high pressure β-lactoglobulin structure presents a step forward in understanding the pressure modification of food protein allergenicity. The conformational changes of pressurized β-lactoglobulin did not support the hypothesis that proteolytic digestion facilitated by pressure is caused by an exposure of the digestive sites. Our findings demonstrate that high pressure protein crystallography can potentially identify the most pressure-sensitive fragments in allergens, and can therefore support development of hypoallergenic food products.

Characterization of temporal relationships of comorbidities developed following cancer diagnoses in veterans.

e18049 Background: Understanding patient trajectories and common sequences of comorbidity accrual among those newly diagnosed with cancer is critical for precision approaches to care and prevention. The Veterans Affairs (VA) Cooperative Studies Program (CSP) #380 cohort includes 3,121 healthy asymptomatic veterans who underwent screening colonoscopy and were followed for at least ten years. The current analysis leverages computational approaches to characterize the temporal relationships of diagnoses in CSP #380 participants following diagnosis of colorectal or other cancers. Methods: Patients enrolled in CSP #380 with at least 5 years of linked electronic health record data from the VA Corporate Data Warehouse (October 1999-December 2015) were included. Cancer diagnoses and their most common subsequent new diagnoses were identified per patient by the first instance of each three-digit ICD-9 diagnosis affecting at least 50 patients. Pairwise chronological relative risks (RR) between subsequent diagnoses were represented as a directed network graph, which maps the probability of developing a diagnosis following a prior diagnosis. Results: A total of 2,210 patients were included. The most common cancer diagnoses were prostate (436), thoracic (169), bladder (120), colon (72), and kidney cancers (65). Most first diagnoses following a cancer diagnosis were related to progressive cancer or acute/subacute treatment toxicity. For prostate cancer, comorbidities with greatest RR were carcinoma in situ (RR 6.85), unspecified (NOS) metastases (2.75), and urethral stricture (2.53). For lung cancer, they were metastases of respiratory and digestive sites (12.24), lymph nodes (6.47), and NOS (5.68), pneumothorax and air leak (4.16), and convalescence and palliative care (3.07). In bladder cancer, they were carcinoma in situ (9.00), cystitis (6.78), kidney or other urinary cancer (6.19), attention to artificial openings (3.40), and urethral stricture (2.78). These and other results were visualized with network graphs. Conclusions: Computational techniques can identify and visualize future health concerns following cancer diagnoses. In this cohort of initially healthy and asymptomatic veterans on a prospective screening colonoscopy study, most subsequent diagnoses were related to cancer or toxicities of therapy, as might be expected in an aging cohort. Future work may focus on streamlining in-clinic identification of potential high likelihood comorbidities.

Differentiation of Rickettsia felis and Rickettsia felis-Like Organisms via Restriction Fragment Length Polymorphism Analysis.

Rickettsia typhi and Rickettsia felis are flea-borne pathogens, which cause murine typhus and flea-borne spotted fever, respectively. Recently, two other flea-borne rickettsiae (phylogenetically similar to R. felis) have been discovered-Rickettsia asembonensis and Candidatus Rickettsia senegalensis. Currently, species-specific identification of detected organisms requires sequencing- or probe-based PCR assays. Our aim was to develop an efficient and inexpensive method to differentiate R. felis and R. felis-like organisms through restriction fragment length polymorphism (RFLP) analysis. Outer membrane protein B sequences of the aforementioned flea-borne rickettsiae were analyzed using DNASTAR Lasergene Core software to focus on the region amplified by the primers 120.2788 and 120.3599. Restriction enzyme digestion sites were identified, and in silico digestions of each species were compared through simulated agarose gels. The enzyme NlaIV was determined to be the most effective at creating a unique banding pattern within the area of interest. To confirm the predicted performance of NlaIV digestion, we tested the DNA of known PCR positive Ctenocephalides felis fleas collected from cats and opossums within Galveston, Texas. DNA from these fleas was amplified using the sca5 primer set 120.2788 and 120.3599. The PCR products were then digested with NlaIV, subjected to polyacrylamide gel electrophoresis, and visualized through ethidium bromide staining. The banding patterns were then compared with the computer-generated digestion patterns. All samples demonstrated a banding pattern consistent with the predicted pattern for the known species, as confirmed by previous sequencing. This RFLP assay was developed to be an efficient and cost-effective method to screen samples for R. felis, R. asembonensis, and Candidatus R. senegalensis. We believe this assay can aid in the epidemiological and ecological studies of flea-borne rickettsiae.

Diseases Producing Malabsorption and Maldigestion

Malabsorption refers to the impaired intestinal absorption of nutrients. It can result from congenital defects in absorption and the transport of ions and nutrients, defects in hydrolysis within the intestinal lumen, acquired defects in the intestinal absorptive cells that line the surface of the intestine, impaired bile production, or interruption of enterohepatic circulation or secondary to pancreatic insufficiency. Maldigestion, another factor in nutrient absorption, refers to the impaired digestion of nutrients within the intestinal lumen or at the terminal digestive site of the brush border membrane of mucosal epithelial cells. Although malabsorption and maldigestion are pathophysiologically distinct, they are interdependent, and in clinical practice, malabsorption has come to signify derangements in either or both processes. This chapter discusses the clinical manifestations of malabsorption and tests for suspected malabsorption. The diseases that can cause malabsorption, their diagnosis, and treatment recommendations are included. Figures illustrate the diagnosis and management of celiac disease; an approach to gluten challenge for the diagnosis or exclusion of celiac disease in patients maintained on a gluten-free diet without previous definitive diagnostic testing; and the histologic features of celiac disease, Crohn disease, collagenous sprue, autoimmune enteropathy, eosinophilic gastritis, and intestinal lymphangiectasia. This review contains 9 figures, 25 tables, and 116 references. Keywords: Malabsorption, maldigestion, Crohn disease, celiac disease, tropical sprue, diarrhea, endoscopy, short bowel syndrome, bacterial overgrowth

Diseases Producing Malabsorption and Maldigestion

Malabsorption refers to the impaired intestinal absorption of nutrients. It can result from congenital defects in absorption and the transport of ions and nutrients, defects in hydrolysis within the intestinal lumen, acquired defects in the intestinal absorptive cells that line the surface of the intestine, impaired bile production, or interruption of enterohepatic circulation or secondary to pancreatic insufficiency. Maldigestion, another factor in nutrient absorption, refers to the impaired digestion of nutrients within the intestinal lumen or at the terminal digestive site of the brush border membrane of mucosal epithelial cells. Although malabsorption and maldigestion are pathophysiologically distinct, they are interdependent, and in clinical practice, malabsorption has come to signify derangements in either or both processes. This chapter discusses the clinical manifestations of malabsorption and tests for suspected malabsorption. The diseases that can cause malabsorption, their diagnosis, and treatment recommendations are included. Figures illustrate the diagnosis and management of celiac disease; an approach to gluten challenge for the diagnosis or exclusion of celiac disease in patients maintained on a gluten-free diet without previous definitive diagnostic testing; and the histologic features of celiac disease, Crohn disease, collagenous sprue, autoimmune enteropathy, eosinophilic gastritis, and intestinal lymphangiectasia. This review contains 9 figures, 25 tables, and 116 references. Keywords: Malabsorption, maldigestion, Crohn disease, celiac disease, tropical sprue, diarrhea, endoscopy, short bowel syndrome, bacterial overgrowth

In vitro pepsin digestion of silver carp (Hypophthalmichthys molitrix) surimi gels after cross-linking by Microbial Transglutaminase (MTGase)

The addition of microbial transglutaminase (MTGase) in surimi gel protein promote cross-linking and improvement of textural properties. In this study, the effects of cross-linking by MTGase on digestibility by pepsin were investigated using different methods, including, scanning electron microscopy (SEM), particle size, dry matter digestibility, Tricine SDS-PAGE, LC-MS/MS, and analysis of amino acids. Gel properties and cross-linking of surimi gels increased significantly (P < 0.05) when surimi was induced by MTGase. Gels with MTGase prohibited the hydrolysis at the beginning because enhanced cross-linking reduced the accessibility of pepsin to the hydrolytic site and the hydrolysis rate increased more rapidly once the network was destroyed during the first 30 min of digestion. The amounts of peptides and amino acids reached their maximum at the end of digestion and showed slight difference to the control gels. The digestion sites and the quantities of peptides from myosin heavy chain also differed between two kinds of surimi gels. This research can help explore the impact of structure on surimi foods, which will improve elastic texture, nutritional value, and provide a delayed reaction in digestion that potentially enhances the feeling of satiety; this delay could control caloric intake without affecting food value.

Fluorescent Gene Tagging of Transcriptionally Silent Genes in hiPSCs.

SummaryWe describe a multistep method for endogenous tagging of transcriptionally silent genes in human induced pluripotent stem cells (hiPSCs). A monomeric EGFP (mEGFP) fusion tag and a constitutively expressed mCherry fluorescence selection cassette were delivered in tandem via homology-directed repair to five genes not expressed in hiPSCs but important for cardiomyocyte sarcomere function: TTN, MYL7, MYL2, TNNI1, and ACTN2. CRISPR/Cas9 was used to deliver the selection cassette and subsequently mediate its excision via microhomology-mediated end-joining and non-homologous end-joining. Most excised clones were effectively tagged, and all properly tagged clones expressed the mEGFP fusion protein upon differentiation into cardiomyocytes, allowing live visualization of these cardiac proteins at the sarcomere. This methodology provides a broadly applicable strategy for endogenously tagging transcriptionally silent genes in hiPSCs, potentially enabling their systematic and dynamic study during differentiation and morphogenesis.

Intestinal Function of the Stomachless Fish, Ballan Wrasse (Labrus bergylta)

Little is known about the digestion of nutrients in stomachless (agastric) fishes with short intestines, such as wrasse. This study describes the digestion, absorption and evacuation rates in ballan wrasse (Labrus bergylta) fed either dry or pre-soaked diets. Ballan wrasse juveniles received either dry or pre-soaked diets containing inert markers to determine intestinal evacuation rates over a 4 to 14 h period after ingestion. The digestive tract evacuation was completed in 12 - 14 h, and was not affected by dietary moisture level. Within the different segments of the intestine, 90 % of the digesta moved from the foregut to the midgut after 4 - 8 h, and over 7 % of the digesta had arrived in the hindgut 4 h after feeding. The foregut was a major site of digestion, where 86 % of carbohydrates, 74 % of proteins, and 50 % of lipids, were absorbed from the diet. The absorption of carbohydrates and lipids increased until the hindgut (98 and 80 %, respectively). Protein absorption continued along the length of the intestine reaching 90 % absorption at the hindgut. Protein and carbohydrate absorption was slightly higher in the foregut for fish fed dry versus moist diets, but this difference disappeared in the midgut. The moisture levels of diet had no effect on the digesta moisture levels, expression of metabolic genes, the levels of nutrients in plasma, or intestinal health. Nine aquaporins were found to be expressed in the wrasse intestinal tissue. Vertebrate aquaporins are involved in water transport from the intestinal lumen into the body and may play a role in maintaining stable moisture level of the digesta in the intestine of ballan wrasse regardless of the initial dietary moisture levels.

Expression of milk-derived angiotensin I-converting enzyme-inhibitory peptides in Lactococcus lactis

ABSTRACTAngiotensin I-converting enzyme (ACE) plays a key role in the regulation of blood pressure. Currently, most single or tandem repeats of ACE-inhibitory (ACE-I) peptides have been expressed in Escherichia coli. However, in this study, a food-grade system was constructed using Lactococcus lactis (L. lactis) to simultaneously express four different milk-derived ACE-I peptides with antihypertensive activity. Mixed peptides (MPs) fused with green fluorescent protein (GFP) and eight histidines were synthesized. To ensure potent ACE inhibition by the MPs in human digestive juice, pepsin and trypsin cleavage sites were introduced among the four ACE-I peptides. The MP fusion gene was inserted into expression vector pSEC-E7 with nisin induction and expressed in L. lactis NZ9000, then purified by affinity chromatography. The transformants containing pSEC-MP:GFP were identified based on green fluorescence using Leica laser scanning confocal microscopy. The target proteins were detected by SDS-PAGE analysis and displayed obvious immunogenicity by western blot. After hydrolysis with digestive enzymes, the IC50 of the MPs was 118.63 μM. These results suggested that multiple milk-derived ACE-I peptides with antihypertensive properties could be produced using a food-grade lactococcal expression system.

A Self-Actuated Cellular Protein Delivery Machine.

Engineered bacterial cells have great promise to solve global problems, yet they are hampered by a lack of convenient strategy for controlled protein release. A well-controlled protein translocation through cellular membranes is essential for cell-based protein delivery. Here we have developed a controlled protein release system by programming a bacterial autotransporter system named Ag43. Ag43 protein is engineered by adding a protease digestion site between its translocation and cargo domains. Once it is displayed on the cell surface, we managed to release the cargo proteins in defined conditions by processing environmental signals. The protein release in terms of time and quantity can be controlled through changing the inducer conditions. We thought that the release system can be adopted for complex genetic circuitries due to its simplicity. We implemented the protein release system to develop a cellular device that is able to release proteins in a sequence response to ordered chemical signals. We envision that development of genetically controlled protein release systems will improve the applications of synthetic organisms in cell based therapies, especially for cases with a need for controlled protein release using the cues from the biological environment.

Optimizing Gastrointestinal Integrity in Poultry: The Role of Nutrients and Feed Additives.

Immunomodulation of the immune system by stimulating or suppressing one or both arms, is an emerging concept driven by the understanding of the host defense system. In particular, the gastrointestinal tract (GIT) functions not only as a site for digestion and absorption of nutrients but also acts as a metabolic and immunological organ. This serves as a barrier against abnormal presentation of luminal constituents, caused by dysfunctional intestinal epithelial barrier, to the mucosal immune system. Invasion by pathogens in the case of disease or stress or a massive influx of commensal bacteria overcomes the defensive mechanisms, resulting in the full activation of local dendritic cells and the expression of co-stimulatory molecules and pro-inflammatory cytokines. A growing body of literature demonstrates the immune benefits of increasing the intake of specific nutrients. This strategy involves formulating diets that encompass the bioavailability and utilization of nutrients from various food sources and understanding the dynamics of the macro and micronutrients to support all physiological functions as well as maintaining the function of the immune cells. The nature and type of feed ingredients may also play some roles on the integrity of the GIT of birds. Because dietary intake or nutritional status as well as nutrient requirements may be altered as a result of disease or stress, this may eventually alter the gut microflora and intestinal mucosal integrity, resulting in a compromised barrier of the intestinal epithelium. The weakening of the intestinal integrity could result in an increase in bacterial adherence to the mucosa, bacterial translocation, susceptibility to opportunistic bacterial infection, and mis-appropriation of nutrients. In this chapter, we will discuss the role of dietary energy and nutrients as substrates that have the potential to influence GIT's health and integrity and their roles, directly or indirectly, in modulating bird's ability to be resilient or resist infection.

Rabbit SLC15A1, SLC7A1 and SLC1A1 genes are affected by site of digestion, stage of development and dietary protein content

Peptide transporter 1 (SLC15A1, PepT1), excitatory amino acid transporter 3 (SLC1A1, EAAT3) and cationic amino acid transporter 1 (SLC7A1, CAT1) were identified as genes responsible for the transport of small peptides and amino acids. The tissue expression pattern of rabbit (SLC15A1, SLC7A1 and SLC1A1) across the digestive tract remains unclear. The present study investigated SLC15A1, SLC7A1 and SLC1A1 gene expression patterns across the digestive tract at different stages of development and in response to dietary protein levels. Real time-PCR results indicated that SLC15A1, SLC7A1 and SLC1A1 genes throughout the rabbits’ entire development and were expressed in all tested rabbit digestive sites, including the stomach, duodenum, jejunum, ileum, colon and cecum. Furthermore, SLC7A1 and SLC1A1 mRNA expression occurred in a tissue-specific and time-associated manner, suggesting the distinct transport ability of amino acids in different tissues and at different developmental stages. The most highly expressed levels of all three genes were in the duodenum, ileum and jejunum in all developmental stages. All increased after lactation. With increased dietary protein levels, SLC7A1 mRNA levels in small intestine and SLC1A1 mRNA levels in duodenum and ileum exhibited a significant decreasing trend. Moreover, rabbits fed a normal level of protein had the highest levels of SLC15A1 mRNA in the duodenum and jejunum (P<0.05). In conclusion, gene mRNA differed across sites and with development suggesting time and sites related differences in peptide and amino acid absorption in rabbits. The effects of dietary protein on expression of the three genes were also site specific.

Site and extent of digestion of nitrogen compounds and organic matter in steers fed a finishing diet with dried distillers grains plus solubles supplemented with urea

Four Holstein steers (266 ± 13 kg) with ruminal and duodenal cannulae were used to evaluate the effect of inclusion of different levels of urea (0%, 0.4%, 0.8% and 1.2%) in a steam-flaked, corn-based finishing diet containing dried distillers grains plus solubles (DDGS) on the site and extent of N compounds and organic matter (OM) digestion, and on the ruminal N-NH3 and blood concentrations of urea nitrogen. Increasing the urea levels linearly decreased the OM flow to the duodenum ( P <0.04) and increased the total N and non-ammoniacal N flow to the duodenum ( P <0.01), which resulted from linear increases in the flow of microbial N and NH3-N ( P <0.01) without affecting the feed residual N flow ( P ≥0.47). Increasing the urea levels linearly increased ruminal digestion of OM and dietary N (P≤0.03), and decreased protein efficiency ( P <0.01) without affecting microbial efficiency. The urea supplementation did not affect post-ruminal digestion. Urea supplementation linearly increased ( P <0.01) total tract digestion of N compounds without affecting total tract digestion of OM. Ruminal pH averaged 6.09 ± 0.03 and was not affected ( P ≥0.97) by the inclusion of urea. Ruminal NH3-N concentration increased with urea supplementation (linear component, P<0.01). The same effect was observed for blood urea concentrations and plasma urea ( P <0.01). On the basis of the results observed here, urea can be incorporated in finishing corn-based diets that include DDGS. However, this must done carefully to avoid exceeding the RDP concentration in the diets in order to optimise ruminal fermentation and reduce the risk of high N excretion in the faeces. This is relevant when higher levels of DDGS are included in the diets (i.e. 30%). Key words : fermentation, ruminal nitrogen solubility, DDGS, plasmatic ureic nitrogen

360 Feeding Saccharomyces cerevisiae fermentation product affected rumen pH and fermentation, and site of digestion in finishing beef heifers.

360 Feeding Saccharomyces cerevisiae fermentation product affected rumen pH and fermentation, and site of digestion in finishing beef heifers.

Comparative effects of ‘solid’-fat sources as a substitute for yellow grease on digestion of diets for feedlot cattle

Five cannulated Holstein steers fed a steam-flaked corn-based growing diet containing 40% of alfalfa hay were used in a 5 × 5 Latin square design to examine the effect of ‘solid’ supplemental fats as a substitute for yellow grease (YG) on the extent and site of digestion. Treatments were (% of diet DM) as follows: (1) no supplemental fat; (2) 5% YG; (3) 5.88% calcium soaps (ML); (4) 5% flaked palmitic acid (RP10); and (5) 5% hydrogenated palm fatty acid distillate (HPFAD). Supplemental fats replaced the corn in the control diet. Supplemental fat decreased (P &amp;lt; 0.01) ruminal and total-tract digestion of organic matter and tended to decrease (P = 0.06) ruminal digestion of neutral detergent fibre, with no effects on ruminal digestion of feed N, microbial N efficiency, or total-tract digestion of N and neutral detergent fibre. With the exception of RP10, fat supplementation decreased (P &amp;lt; 0.03) postruminal digestion of C18:0. Compared with the original C16:0:C18:0 ratio of solid fats, the C16:0:C18:0 ratio of fatty acids (FAs) entering the small intestine markedly decreased for all solid-fat treatments. Ruminal biohydrogenation of YG and ML were 73% and 49% respectively. On the basis of FA intake, postruminal FA digestion of YG, ML, RP10 and HPFAD was 0.97, 0.94, 0.92 and 0.80 of expected respectively. This experiment confirmed that postruminal digestion of total FAs of conventional supplemental yellow grease is a predictable function of total FA intake per unit of bodyweight. However, in the case sources of the solids fats, this relationship (FA intake and postruminal digestion of FAs) was less consistent. This may be due to their physical and chemical nature (saturatedFA:unsaturated FA ratio). On the basis of the nutrient digestion and postruminal FA digestibility observed in the present experiment, solid supplemental fats do not afford appreciable advantages over conventional YG when supplemented in growing diets (forage level ~400 g/kg diet DM) for feedlot steers.

Micro-patterned endogenous stroma equivalent induces polarized crypt-villus architecture of human small intestinal epithelium

The small intestine is the major site for digestion, drug and nutrient absorption, as well as a primary site for many diseases. Current in vitro gut models fail in reproducing the complex intestinal extracellular matrix (ECM) network of the lamina propria and the peculiar architecture of the crypt-villus axis. Here we proposed a novel in vitro human intestine model that mimics the intestinal stromal topography and composition and strictly reproduces the tissue polarity with the crypt-villus architecture. First we developed a 3D human intestinal stromal equivalent (3D-ISE) composed of human intestinal subepithelial myofibroblasts (ISEMFs) embedded in their own extracellular matrix. Then, we seeded human colon carcinoma-derived cells (Caco-2) onto flat or patterned cell-synthetized stromal equivalent structure and cultured them until the formation of a well-oriented epithelium. We demonstrated that the patterned stroma increases the absorbing surface area, the epithelial proliferation rate, and the density of microvilli. In addition it induces changes in the biological functions of the epithelial cells such as enzymes and mucus production, polarization and tightness showing a physiological cell-lineage compartmentalization along the crypt/villi axes with the undifferentiated phenotypes at the base. At last, we reproduced an inflamed intestinal tissue model in which we identified the contribution of the stromal microenvironment by molecular (cytokines release and MMPs production) and immunofluorescence analyses and the effects of the epithelial-stromal cross-talk in the intestinal innate immunity by multiphoton investigation that revealed differences in the collagen network architecture. Statement of SignificanceThe intestinal stroma morphology and composition has a fundamental role in crypt-villus development and appropriate epithelial cell-lineage compartmentalization. On this base, here we develop an engineered organotypic model of human intestine equivalent in which a functional epithelial/ECM crosstalk is recapitulated. Due to its accessible luminal surface it provides a new platform for preclinical studies of mucosal immunology and bowel inflammation as well as the assessment of pharmaco-toxicity studies.