Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

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    We will mail you new results for this query: keywords==Digestibility
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Effects of high hydrostatic pressure (HHP) on protein structure and digestibility of red abalone (Haliotis rufescens) muscle
Cepero-Betancourt, Yamira ; Opazo-Navarrete, Mauricio ; Janssen, Anja E.M. ; Tabilo-Munizaga, Gipsy ; Pérez-Won, Mario - \ 2020
Innovative Food Science and Emerging Technologies 60 (2020). - ISSN 1466-8564
Abalone - Digestibility - Fourier transform infrared spectroscopy - High hydrostatic pressure - Protein secondary structure

The protein secondary structure modifications and digestibility of red abalone muscle subjected to high hydrostatic pressure (HHP) treatments (200, 300, 400, and 500 MPa for 5 min) were evaluated. The protein structure was analysed by Fourier-Transformed Infrared spectroscopy. Protein digestibility was evaluated based on the degree of hydrolysis (DH) and peptide size distributions under in vitro gastrointestinal conditions. The intermolecular β-sheet structure was disrupted at 200 MPa, compensated by the formation of the intramolecular β-sheet. At 300 and 400 MPa, the β-sheet structure can fold on itself from the interactions that stabilize the protein structure. The 310-helix structure was significantly looser at 300 MPa. Structural modifications were accompanied by β-turn formation at 300, 400, and 500 MPa. In vitro gastrointestinal digestion is improved by HHP independently of pressure level. The results suggest that high pressure improve the DH of red abalone as a consequence of β-sheet and β-turn conformations changes. Industrial relevance: The seafood industry uses high hydrostatic pressure (HHP) technology to reduce undesirable sensory changes and preserve the functional and nutritional properties of compounds. The HHP experiments contributed to unravel the impact of the different level pressure on digestibility. HHP treatment can change the secondary structures of proteins and improve the protein digestibility as function the pressure level. The results of this study provide valuable information for the potential application of HHP on the development of red abalone with high-nutritional value.

Effect of dietary viscosity on digesta characteristics and progression of digestion in different segments of the gastrointestinal tract of striped catfish (Pangasionodon hypophthalmus)
Tran-Tu, L.C. ; Bosma, R.H. ; Verstegen, M.W.A. ; Schrama, J.W. - \ 2019
Aquaculture 504 (2019). - ISSN 0044-8486 - p. 114 - 120.
Chyme characteristics - Digestibility - Striped catfish - Viscosity

The physical and chemical characteristics of chyme have been shown to relate to apparent faecal nutrient digestibility, also in fish. This study assessed the effect of dietary viscosity on chyme characteristics in different segments of the gastrointestinal tract (GIT) of striped catfish (Pangasianodon hypophthalmus, Sauvage, 1878). Moreover, its effect on the progression of nutrient digestion throughout the GIT was studied. Six diets were produced, that had moderate differences in dietary viscosity by exchanging carboxymethylcellulose for guar gum (0, 0.25, 0.5, 1, 2, or 3 g kg−1 of diet). Eighteen tanks, each stocked with 20 fish of 95 g, were used (three replicate tanks per diet). Diets were randomly assigned to tanks and fed for 29 days. Thereafter fish were euthanized for the collection of chyme from four different segments of the GIT: stomach, proximal, mid and distal intestine. The chyme characteristics, dry matter content, viscosity and osmolarity were affected by the interaction effect of diet and GIT-segment. This implies that the impact of dietary viscosity on chyme characteristics differs between GIT-segments. Chyme viscosity increased with increasing dietary viscosity, but this mainly occurred in the stomach and distal intestine. Dry matter content of chyme was mainly affected (increased with rising dietary viscosity) in the stomach. The digestibility of both dry matter and crude protein was different between GIT-segments and increased from stomach towards distal intestine. Moreover, these nutrient digestibilities were influenced by dietary viscosity being negatively related. Already in the stomach increased dietary viscosity reduced the disappearance of nutrients (i.e., digestibility). These differences in digestibility were persistent and constant throughout the total GIT. In conclusion, moderate increases in dietary viscosity: alter predominantly stomach and distal chyme viscosity; increases chyme DM content in distal intestine; and reduces protein and DM digestibility, which are already different between diets from the stomach onward.

Effects of inclusion rate of high fiber dietary ingredients on apparent ileal, hindgut, and total tract digestibility of dry matter and nutrients in ingredients fed to growing pigs
Navarro, D.M.D.L. ; Bruininx, E.M.A.M. ; Jong, L. de; Stein, H.H. - \ 2019
Animal Feed Science and Technology 248 (2019). - ISSN 0377-8401 - p. 1 - 9.
Digestibility - Fiber - Pigs

An experiment was conducted to determine if values for the coefficient of ileal apparent digestibility (CIAD), the coefficient of hindgut apparent disappearance (CHAD), and the coefficient of total tract apparent digestibility (CTTAD) of dry matter (DM) and nutrients in high-fiber ingredients measured at 150 g/kg inclusion are also accurate if measured at 300 g/kg inclusion in diets fed to pigs. The second objective was to confirm that most of the insoluble dietary fiber (IDF) is not fermented by growing pigs. Twenty ileal-cannulated pigs (BW: 30.64 ± 2.09 kg) were allotted to a replicated 10 × 4 incomplete Latin Square design with 10 diets and four 26-d periods. There were 2 pigs per diet in each period for a total of 8 replications per diet. A corn and soybean meal (SBM) basal diet and a corn-SBM diet with 300 g/kg corn starch were formulated. Six diets were formulated by replacing 150 or 300 g/kg corn starch by 150 or 300 g/kg corn germ meal (CGM), sugar beet pulp (SBP), or wheat middlings (WM). Two additional diets were formulated by adding 150 or 300 g/kg canola meal (CM) to the diet containing corn, SBM, and 300 g/kg corn starch at the expense of corn and SBM. Effects of inclusion rate of each fiber source in the diet on CIAD, CHAD, and CTTAD of DM and nutrients were analyzed using orthogonal contrasts. Independent t-tests were used to compare inclusion rates within each ingredient. Results indicated that CIAD and CHAD of CP, acid hydrolyzed ether extract (AEE), and most fiber fractions in CM decreased (P<0.05) as inclusion level increased from 150 to 300 g/kg, but that was not the case for CGM, SBP, or WM. The CTTAD of DM, organic matter (OM), AEE, and soluble dietary fiber (SDF) in CGM increased (P<0.05) if 300 g/kg rather than 150 g/kg was included in the diet and CTTAD of DM, OM, acid detergent fiber, and SDF in WM increased (P<0.05) as inclusion level increased. No differences in CTTAD of DM and nutrients in CM and SBP were observed between inclusion rates. The CTTAD of IDF ranged from 0.529 in WM included at 150 g/kg to 0.862 in SBP included at 300 g/kg in the diet. In conclusion, CIAD, CHAD, and CTTAD of most nutrients in test ingredients is not different between 150 and 300 g/kg inclusion rate. Under the conditions of this experiment, there was relatively high digestibility of IDF.

Role of the food matrix and digestion on calculation of the actual energy content of food
Capuano, Edoardo ; Oliviero, Teresa ; Fogliano, Vincenzo ; Pellegrini, Nicoletta - \ 2018
Nutrition Reviews 76 (2018)4. - ISSN 0029-6643 - p. 274 - 289.
Digestibility - Energy content of food - Food structure - Nutrition fact - Processing

The energy content of food is calculated on the basis of general factors for fat, protein, and carbohydrates. These general factors were derived by W.O. Atwater in the late 19th century, while additional factors for dietary fiber, polyols, and organic acids were introduced more recently. These factors are applied indiscriminately to all types of foods, yet the same nutrient may be digested to different extents to generate energy, depending on the characteristics of the food matrix, the processing methods applied to foods, and the meal composition. As a consequence, the actual energy content of food may differ from what is theoretically calculated with the Atwater factors. In this review, the relationship of macronutrient digestibility with food structure, macronutrient structure, and food composition is examined, and the implications for the amount of energy achievable through diet are highlighted. Estimates of the discrepancy between calculated energy content and actual energy content are provided for different diets. The findings may have implications for consumer purchasing decisions as well as for the design of dietary interventions.

Characterization and in vitro digestibility of by-products from Brazilian food industry : Cassava bagasse, orange bagasse and passion fruit peel
Bussolo de Souza, Carlota ; Jonathan, Melliana ; Isay Saad, Susana Marta ; Schols, Henk A. ; Venema, Koen - \ 2018
Bioactive Carbohydrates and Dietary Fibre 16 (2018). - ISSN 2212-6198 - p. 90 - 99.
Bagasse - By-product - Digestibility - Fibre - Peel - Sustainability

The aim of the present study was to characterize selected by-products from Brazilian food industry and their in vitro digestibility. These by-products (cassava and orange bagasses and passion fruit peels) are potentially rich sources of dietary fibres, but currently they are mostly disposed. Their analysis revealed differences in composition for the same by-product type from different suppliers. Cassava bagasses were mainly composed of starch, with high variability among tested by-products (45–77.5% starch). In vitro experiments indicated that cassava bagasses had ~ 12% of resistant starch. The orange bagasses had free glucose and highly methyl esterified pectin as the main constituents (~23.5% of total pectin). Seventy-seven % of digestible glucose present in the orange bagasse were absorbed within 3 h experimental run. Passion fruit peels were a good source of fibres, especially pectin (~19%) and (hemi)cellulose (~16%). These in vitro experiments indicated that passion fruit peel had slower absorption of glucose than the other by-products, with 80% of digestible glucose absorbed within 5 h. In conclusion, the tested by-products are good sources of diverse types of fibres and have a great potential to be incorporated into different food products, decreasing food waste and contributing to a sustainable food system.

Effects of physicochemical characteristics of feed ingredients on the apparent total tract digestibility of energy, DM, and nutrients by growing pigs
Navarro, Diego M.D.L. ; Bruininx, Erik M.A.M. ; Jong, Lineke de; Stein, Hans H. - \ 2018
Journal of Animal Science 96 (2018)6. - ISSN 0021-8812 - p. 2265 - 2277.
Correlation - Digestibility - Energy - Physicochemical characteristics - Pigs - Total dietary fiber

Effects of physicochemical characteristics of feed ingredients on DE and ME and apparent total tract digestibility (ATTD) of GE, DM, and nutrients were determined in growing pigs using ingredients with different ratios between insoluble dietary fiber (IDF) and soluble dietary fiber (SDF). Eighty growing barrows (BW: 48.41 ± 1.50 kg) were allotted to a randomized complete block design with 10 diets and eight replicate pigs per diet. Dietary treatments included a corn-based diet, a wheat-based diet, a corn–soybean meal (SBM) diet, and seven diets based on a mixture of the corn–SBM diet and canola meal, distillers dried grains with solubles (DDGS), corn germ meal (CGM), copra expellers, sugar beet pulp (SBP), synthetic cellulose, or pectin. Values for the ATTD of DM and nutrients were also compared with the in vitro digestibility of GE, DM, and nutrients. Results indicated that the ATTD of GE was greater (P < 0.05) in wheat than in canola meal, DDGS, CGM, copra expellers, SBP, and synthetic cellulose, but not different from corn, SBM, or pectin. SBM had greater (P < 0.05) DE and ME (DM basis) compared with all other ingredients. The concentration of ME (DM basis) was greater (P < 0.05) in wheat than in canola meal, DDGS, CGM, copra expellers, SBP, synthetic cellulose, and pectin, but not different from corn. Stronger correlations between total dietary fiber (TDF) and DE and ME than between ADF or NDF and DE and ME were observed, indicating that TDF can be used to more accurately predict DE and ME than values for NDF or ADF. The DE, ME, and the ATTD of DM in ingredients were positively correlated (P < 0.05) with in vitro ATTD of DM, indicating that the in vitro procedure may be used to estimate DE and ME in feed ingredients. Swelling and water-binding capacity were positively correlated (P < 0.05) with the ATTD of IDF, TDF, non-starch polysaccharides (NSP), and insoluble NSP, and viscosity was positively correlated (P < 0.05) with the ATTD of NDF, IDF, and insoluble NSP, indicating that some physical characteristics may influence digestibility of fiber. However, physical characteristics of feed ingredients were not correlated with the concentration of DE and ME, which indicates that these parameters do not influence in vivo energy digestibility in feed ingredients. It is concluded that the DE and ME in feed ingredients may be predicted from some chemical constituents and from in vitro digestibility of DM, but not from physical characteristics.

The contribution of digestible and metabolizable energy from high-fiber dietary ingredients is not affected by inclusion rate in mixed diets fed to growing pigs
Navarro, D.M.D.L. ; Bruininx, E.M.A.M. ; Jong, L. de; Stein, H.H. - \ 2018
Journal of Animal Science 96 (2018)5. - ISSN 0021-8812 - p. 1860 - 1868.
Digestibility - Energy - Fiber - Inclusion rate - Passage rate - Pigs

Effects of inclusion rate of fiber-rich ingredients on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of GE and on the concentration of DE and ME in mixed diets fed to growing pigs were determined. The hypothesis was that increasing the inclusion rate of fiber decreases digestibility of GE, and thus, the contribution of DE and ME from hindgut fermentation because greater concentrations may reduce the ability of microbes to ferment fiber. Twenty ileal-cannulated pigs (BW: 30.64 ± 2.09 kg) were allotted to a replicated 10 × 4 incomplete Latin Square design with 10 diets and four 26-d periods. There were 2 pigs per diet in each period for a total of 8 replications per diet. A basal diet based on corn and soybean meal (SBM) and a corn-SBM diet with 30% corn starch were formulated. Six additional diets were formulated by replacing 15% or 30% corn starch by 15% or 30% corn germ meal, sugar beet pulp, or wheat middlings, and 2 diets were formulated by including 15% or 30% canola meal in a diet containing corn, SBM, and 30% corn starch. Effects of adding 15% or 30% of each fiber source to experimental diets were analyzed using orthogonal contrasts and t-tests were used to compare inclusion rates within each ingredient. The AID and ATTD of GE and concentration of DE and ME in diets decreased (P < 0.05) with the addition of 15% or 30% canola meal, corn germ meal, sugar beet pulp, or wheat middlings compared with the corn starch diet. However, inclusion rate did not affect the calculated DE and ME or AID and ATTD of GE in any of the ingredients indicating that concentration of DE and ME in ingredients was independent of inclusion rate and utilization of energy from test ingredients was equally efficient between diets with 15% and 30% inclusion. Increased inclusion of fiber in the diet did not influence transit time in the small intestine, but reduced the time of first appearance of digesta in the feces indicating that transit time was reduced in the hindgut of pigs fed high-fiber diets. However, this had no impact on DE and ME or ATTD of GE in test ingredients. In conclusion, fiber reduced the DE and ME in the diet. However, inclusion rate of fiber-rich ingredients in diets did not affect calculated values for DE and ME in feed ingredients indicating that microbial capacity for fermentation of fiber in pigs is not overwhelmed by inclusion of 30% high-fiber ingredients in the diets.

The repeatability of individual nutrient digestibility in pigs
Ouweltjes, W. ; Verschuren, L.M.G. ; Pijlman, J. ; Bergsma, R. ; Schokker, D. ; Knol, E.F. ; Aar, P.J. van der; Molist, F. ; Calus, M.P.L. - \ 2018
Livestock Science 207 (2018). - ISSN 1871-1413 - p. 63 - 67.
Digestibility - Pigs - Repeatability
Digestibility of nutrients in pig diets is an important component of overall feed efficiency. Targeted improvement of digestibility is currently mainly achieved by optimization of pig diets, based on information generated from digestibility trials that aim to establish fecal digestibility coefficients of different nutrients across a variety of ingredients. Genetic selection for nutrient digestibility is hampered by shortage of data on individual digestibility, but might help to further improve efficiency of pork production. The present study aimed to estimate the repeatability of fecal digestibility in pigs, as a first step to judge the perspectives for a breeding approach of nutrient digestibility. To achieve this, data was accumulated across nine digestibility trials, containing 1150 digestibility records of 416 growing pigs, measured across the trials. The data was analyzed with a model estimating variances for trial, diet, common litter, and individual animal effect for digestibility of Dry Matter, Ash, Organic Matter, Crude Protein, Crude fat and Non-Starch Polysaccharides. The factors diet and trial together explained the majority of the phenotypic variance, due to the design of the trials. Within diet and trial, common litter and individual animal effect contributed 0–10% of the phenotypic variance. The repeatability estimates ranged from 7% for Ash to 16% for Crude Protein, which suggests there may be genetic variation between pigs in digestibility. In conclusion, the repeatability estimates indicate it is worthwhile to collect phenotypic data that enable the estimation of genetic parameters for digestibility, if these data can be obtained at reasonable cost.
Digestibility and intestinal fermentability of canola meal from Brassica juncea and Brassica napus fed to ileal-cannulated grower pigs
Le, M.H.A. ; Buchet, A.D.G. ; Beltranena, E. ; Gerrits, W.J.J. ; Zijlstra, R.T. - \ 2017
Animal Feed Science and Technology 234 (2017). - ISSN 0377-8401 - p. 43 - 53.
Canola meal - Digestibility - Energy - Pig - Volatile fatty acid
Yellow-seeded Brassica (B.) juncea is a novel canola species. Therefore, its meal co-product requires feed quality evaluation and comparison to conventional, dark-seeded B. napus canola meal for pigs. The B. juncea canola meal contains less fibre than B. napus canola meal (190 vs. 260 g NDF/kg, as is), but also less lysine (20.3 vs. 22.1 g/kg). Nutrient digestibility and fermentibility of B. juncea and B. napus canola meal were assessed in a 2 × 2factorial arrangement. Six ileal-cannulated pigs (47 kg BW) were fed six diets in a 6 × 6 Latin square: basal diet (460 g wheat/kg and corn starch), 4 diets with 460 g wheat/kg and either B. juncea or B. napus canola meal at 250 or 500 g/kg replacing corn starch, sugar and canola oil, and an N-free diet based on corn starch. The B. juncea canola meal had greater (P < 0.05) CATTD of gross energy than B. napus canola meal (0.70 vs. 0.63) most likely due to its lower fibre content. Ileal total VFA concentration was lower (P < 0.001) in pigs fed B. juncea than B. napus canola meal diets (15.2 vs. 20.8 μmol/g of wet digesta). In pigs fed B. juncea canola meal instead of B. napus canola meal diets, the molar ratio was greater (P < 0.01) for digesta propionate and faecal acetate, but lower (P < 0.05) for digesta and faecal butyrate. Canola meal species did not affect the CAID of gross energy, CSID of amino acid and faecal VFA content. The digestible energy (DE) value was greater (P < 0.01; 12.1 vs. 10.9 MJ/kg, standardised to 100 g/kg moisture) for B. juncea than B. napus canola meal. Increasing dietary inclusion of canola meal up to 500 g/kg reduced (P < 0.01) diet digestibility of gross energy but not amino acids and decreased (P < 0.05) intestinal fermentability of B. napus but not B. juncea. In conclusion, B. juncea canola meal had greater fermentability and ATTD of gross energy than B. napus canola meal, but digestibility of amino acids did not differ. Increasing dietary inclusion of canola meal up to 500 g/kg reduced digestibility of gross energy but not digestibility of AA. Fermentability of B. napus canola meal but not B. juncea canola meal decreased in the pig intestine with increased dietary inclusion. Hence, yellow-seeded B. juncea canola meal had a greater DE value, similar amino acid digestibility as conventional dark-seed B. napus canola meal and may limit protein fermentation in the pig intestine.
Determination of pre-cecal phosphorus digestibility of inorganic phosphates and bone meal products in broilers
Harn, J. van; Spek, J.W. ; Vuure, C.A. van; Krimpen, M.M. van - \ 2017
Poultry Science 96 (2017)5. - ISSN 0032-5791 - p. 1334 - 1340.
Bone meal - Broilers - Digestibility - Phosphorus

A broiler study was performed to determine the pre-cecal phosphorus (P) digestibility of 5 P sources, 3 from animal (Delfos, Calfos, and porcine bone meal) and 2 of inorganic (monocalcium phosphate [MCP] and dicalcium phosphate [DCP]) origin. Delfos is processed from bones resulting in a dicalcium phosphate product, and Calfos is processed from bones in which part of the gelatin is removed but in which the hydroxy-apatite matrix is preserved. During the first 14 d, birds were housed in floor pens bedded with wood shavings and received a commercial starter diet. At d 14, broilers were randomly assigned to pens (0.9 m2, 10 birds/pen) with a slatted floor. From d 14 onwards, one of the 6 experimental diets (a basal diet, and 5 diets containing the P sources) was provided. Test diets were replicated 6 times, and the basal diet 8 times. Electron microscopy images of test products were made in order to verify whether the spatial structure of the test products could be related to the pre-cecal P digestibility of the same products. Diets met or exceeded CVB (2011) requirements for all nutrients except for P and were formulated to contain a calcium to total P ratio of between 1.4 and 1.6 and a minimal amount of phytate P. Diets contained 5 g/kg titanium oxide as a marker to determine digestibility of P. At d 24 all birds were euthanized, after which the content of the terminal part of the ileum was sampled. The P digestibility was calculated by linear regression according to World's Poultry Science Association (WPSA) protocol for determination of pre-cecal P digestibility. Pre-cecal P digestibility of MCP, DCP, Delfos, Calfos, and porcine bone meal was 88.5, 82.4, 94.5, 86.9, and 78.2%, respectively. Based on visual inspection of electron microscopy images of test products, the spatial structure of the test products might be related to P digestibility. It is concluded that processing of bone meal increases the pre-cecal P digestibility in broilers.

Effects of pectin on fermentation characteristics, carbohydrate utilization, and microbial community composition in the gastrointestinal tract of weaning pigs
Tian, Lingmin ; Bruggeman, Geert ; Berg, Marco van den; Borewicz, Klaudyna ; Scheurink, Anton J.W. ; Bruininx, Erik ; Vos, Paul de; Smidt, Hauke ; Schols, Henk A. ; Gruppen, Harry - \ 2017
Molecular Nutrition & Food Research 61 (2017)1. - ISSN 1613-4125
Autoclave soybean meal - Dietary fiber - Digestibility - Fermentation - Microbiota composition

Scope: We aimed to investigate the effects of three different soluble pectins on the digestion of other consumed carbohydrates, and the consequent alterations of microbiota composition and SCFA levels in the intestine of pigs. Methods and results: Piglets were fed a low-methyl esterified pectin enriched diet (LMP), a high-methyl esterified pectin enriched diet (HMP), a hydrothermal treated soybean meal enriched diet (aSBM) or a control diet (CONT). LMP significantly decreased the ileal digestibility of starch resulting in more starch fermentation in the proximal colon. In the ileum, low-methyl esterified pectin present was more efficiently fermented by the microbiota than high-methyl esterified pectin present which was mainly fermented by the microbiota in the proximal colon. Treated soybean meal was mainly fermented in the proximal colon and shifted the fermentation of cereal dietary fiber to more distal parts, resulting in high SCFA levels in the mid colon. LMP, HMP, and aSBM decreased the relative abundance of the genus Lactobacillus and increased that of Prevotella in the colon. Conclusion: The LMP, HMP, and aSBM, differently affected the digestion processes compared to the control diet and shaped the colonic microbiota from a Lactobacillus-dominating flora to a Prevotella-dominating community, with potential health-promoting effects.

Interaction between dissolved oxygen concentration and diet composition on growth, digestibility and intestinal health of Nile tilapia (Oreochromis niloticus)
Tran, N.T.K. ; Dinh, Ngu T. ; Tin, Nguyen Hong ; Roem, A.J. ; Schrama, J.W. ; Verreth, J.A.J. - \ 2016
Aquaculture 462 (2016). - ISSN 0044-8486 - p. 101 - 108.
Nile Tilapia - Oxygen level - Soybean meal - Intestial morphology - intestial health - Digestibility
The present study was undertaken to evaluate the individual and combined effects of oxygen concentration and diet composition on the growth, nutrient utilization and intestinal morphology of Nile tilapia (Oreochromis niloticus). Two recirculating aquaculture systems were used to create the difference in oxygen concentration: normoxia (6.9 mg·L− 1) and hypoxia (3.5 mg·L− 1). Two diets were formulated using a different soybean meal (SBM) content to create a contrast in the potential to affect the gut barrier function. Triplicate groups of 35 fish with initial mean body weight of 23 g were fed “Control” diet containing 20% fish meal and “Test” diet containing only plant protein source at normoxia and hypoxia for 8 weeks. Six fish per treatment were sampled for intestinal morphological analysis at the end of week 1, 4 and 8. The proximal, middle and distal intestine were processed for quantitative histology, in order to count goblet cells (GC) and eosinophilic granulocytes (EG); and to measure the thickness of lamina propria (LP) and sub-epithelial mucosa (SM). The study showed that growth was best in the “Control” diet under normoxia, while no interaction between oxygen and diet composition was found. Hypoxia reduced nutrient digestibility significantly (p < 0.05). For the “Test” diet, the decline in digestibility was larger than for “Control” diet over time. Both diet composition and oxygen level induced changes in intestinal morphology of Nile tilapia. We observed a thickening of the LP and SM caused by an increased infiltration of inflammatory cells, and an increased number of GC and EG among the enterocytes. The negative effect of increased soybean meal on intestinal morphology was enhanced at low oxygen level and aggravated in time. The SBM enteritis-like symptoms were more pronounced in the proximal than in the distal intestine of Nile tilapia.
In vitro digestibility and fermentability of selected insects for dog foods
Bosch, G. ; Vervoort, J.J.M. ; Hendriks, W.H. - \ 2016
Animal Feed Science and Technology 221 (2016). - ISSN 0377-8401 - p. 174 - 184.
Amino acid - Digestibility - Dog - Fermentation product - In vitro - Insect

Insects are considered as a sustainable protein source for future pet foods. Here we aimed to evaluate the protein quality of larvae of the black soldier fly (Hermetia illucens, BSF), housefly (Musca domestica, HF) and yellow mealworm (Tenebrio molitor, YMW) and to evaluate the fermentation characteristics of their indigestible fractions. Clean freeze-dried larvae were subjected to in vitro simulated canine gastric and small intestinal digestion. Undigested insect residues, shrimp chitin and fructooligosaccharides (positive control, FOS) were incubated for 48 h with inoculum with fresh feces from three dogs simulating large intestinal fermentation. The AA profiles differed among the larvae with proteins from BSF and YMW larvae containing more Val and less Met and Lys than HF larvae. The in vitro N digestibility of the HF (93.3%) and YMW (92.5%) was higher than BSF larvae (87.7%). The BSF larvae also had lower in vitro digestibility values for essential AA (92.4%) and non-essential AA (90.5%) compared to the larvae of the HF (96.6 and 96.5%) and YMW (96.9 and 95.3%). Gas production for FOS increased rapidly during the first 6 h. Low and similar amounts of gas were found for HF larvae and chitin whereas gas production slowly increased over 30 h and was slightly higher at 48 h for BSF than for chitin. Gas production for YMW increased considerably between 6 and 20 h. At 48 h, gas produced for undigested residues was comparable to shrimp chitin and lower than FOS (P

Effects of pectin supplementation on the fermentation patterns of different structural carbohydrates in rats
Tian, Lingmin ; Scholte, Jan ; Borewicz, Klaudyna ; Bogert, Bartholomeus van den; Smidt, Hauke ; Scheurink, Anton J.W. ; Gruppen, Harry ; Schols, Henk A. - \ 2016
Molecular Nutrition & Food Research 60 (2016)10. - ISSN 1613-4125 - p. 2256 - 2266.
Digestibility - Gut microbiota - MiSeq sequencing - Pectin - SCFA

Scope: We aimed to investigate and compare the effects of four types of pectins on dietary fiber (DF) fermentation, microbiota composition, and short chain fatty acid (SCFA) production throughout the large intestine in rats. Methods and results: Male Wistar rats were given diets supplemented with or without 3% structurally different pectins for 7 weeks. Different fermentation patterns of pectins and different location of fermentation of pectin and diet arabinoxylans (AXs) in the large intestine were observed. During cecal fermentation, sugar beet pectin significantly stimulated Lactobacillus (p <0.01) and Lachnospiraceae (p <0.05). The stimulating effects of sugar beet pectin on these two groups of microbes are stronger than both other pectins. In the cecum, low-methyl esterified citrus pectin and complex soy pectin increased (p <0.05) the production of total SCFAs, propionate and butyrate, whereas high-methyl esterified pectin and sugar beet pectin did not. The fermentation patterns of cereal AXs in the cecum were significantly different upon supplementation of different pectins. These differences, however, became smaller in the colon due to an enhanced fermentation of the remaining DFs. Conclusion: Dietary supplementation of pectin is a potential strategy to modulate the location of fermentation of DFs, and consequently microbiota composition and SCFA production for health-promoting effects.

Effect of dietary nitrate level on enteric methane production, hydrogen emission, rumen fermentation, and nutrient digestibility in dairy cows
Olijhoek, D.W. ; Hellwing, A.L.F. ; Brask, M. ; Weisbjerg, M.R. ; Højberg, O. ; Larsen, M.K. ; Dijkstra, Jan ; Erlandsen, E.J. ; Lund, P. - \ 2016
Journal of Dairy Science 99 (2016)8. - ISSN 0022-0302 - p. 6191 - 6205.
Dairy cow - Digestibility - Hydrogen - Methane - Nitrate

Nitrate may lower methane production in ruminants by competing with methanogenesis for available hydrogen in the rumen. This study evaluated the effect of 4 levels of dietary nitrate addition on enteric methane production, hydrogen emission, feed intake, rumen fermentation, nutrient digestibility, microbial protein synthesis, and blood methemoglobin. In a 4 × 4 Latin square design 4 lactating Danish Holstein dairy cows fitted with rumen, duodenal, and ileal cannulas were assigned to 4 calcium ammonium nitrate addition levels: control, low, medium, and high [0, 5.3, 13.6, and 21.1 g of nitrate/kg of dry matter (DM), respectively]. Diets were made isonitrogenous by replacing urea. Cows were fed ad libitum and, after a 6-d period of gradual introduction of nitrate, adapted to the corn-silage-based total mixed ration (forage:concentrate ratio 50:50 on DM basis) for 16 d before sampling. Digesta content from duodenum, ileum, and feces, and rumen liquid were collected, after which methane production and hydrogen emissions were measured in respiration chambers. Methane production [L/kg of dry matter intake (DMI)] linearly decreased with increasing nitrate concentrations compared with the control, corresponding to a reduction of 6, 13, and 23% for the low, medium, and high diets, respectively. Methane production was lowered with apparent efficiencies (measured methane reduction relative to potential methane reduction) of 82.3, 71.9, and 79.4% for the low, medium, and high diets, respectively. Addition of nitrate increased hydrogen emissions (L/kg of DMI) quadratically by a factor of 2.5, 3.4, and 3.0 (as L/kg of DMI) for the low, medium, and high diets, respectively, compared with the control. Blood methemoglobin levels and nitrate concentrations in milk and urine increased with increasing nitrate intake, but did not constitute a threat for animal health and human food safety. Microbial crude protein synthesis and efficiency were unaffected. Total volatile fatty acid concentration and molar proportions of acetate, butyrate, and propionate were unaffected, whereas molar proportions of formate increased. Milk yield, milk composition, DMI and digestibility of DM, organic matter, crude protein, and neutral detergent fiber in rumen, small intestine, hindgut, and total tract were unaffected by addition of nitrate. In conclusion, nitrate lowered methane production linearly with minor effects on rumen fermentation and no effects on nutrient digestibility.

Denaturation and in Vitro Gastric Digestion of Heat-Treated Quinoa Protein Isolates Obtained at Various Extraction pH
Ruiz, Geraldine Avila ; Opazo-Navarrete, Mauricio ; Meurs, Marlon ; Minor, Marcel ; Sala, Guido ; Boekel, Tiny van; Stieger, Markus ; Janssen, Anja E.M. - \ 2016
Food Biophysics 11 (2016)2. - ISSN 1557-1858 - p. 184 - 197.
Denaturation - Digestibility - Extraction pH - Heat processing - Protein - Quinoa

The aim of this study was to determine the influence of heat processing on denaturation and digestibility properties of protein isolates obtained from sweet quinoa (Chenopodium quinoa Willd) at various extraction pH values (8, 9, 10 and 11). Pretreatment of suspensions of protein isolates at 60, 90 and 120 °C for 30 min led to protein denaturation and aggregation, which was enhanced at higher treatment temperatures. The in vitro gastric digestibility measured during 6 h was lower for protein extracts pre-treated at 90 and 120 °C compared to 60 °C. The digestibility decreased with increasing extraction pH, which could be ascribed to protein aggregation. Protein digestibility of the quinoa protein isolates was higher compared to wholemeal quinoa flour. We conclude that an interactive effect of processing temperature and extraction pH on in vitro gastric digestibility of quinoa protein isolates obtained at various extraction pH is observed. This gives a first indication of how the nutritional value of quinoa protein could be influenced by heat processing, protein extraction conditions and other grain components.

Inclusion of sainfoin (Onobrychis viciifolia) silage in dairy cow rations affects nutrient digestibility, nitrogen utilization, energy balance, and methane emissions
Huyen, N.T. ; Desrues, O. ; Alferink, S.J.J. ; Zandstra, T. ; Verstegen, M.W.A. ; Hendriks, W.H. ; Pellikaan, W.F. - \ 2016
Journal of Dairy Science 99 (2016)5. - ISSN 0022-0302 - p. 3566 - 3577.
Digestibility - Methane production - Nitrogen utilization - Sainfoin silage

Sainfoin (Onobrychis viciifolia) is a tanniniferous legume forage that has potential nutritional and health benefits preventing bloating, reducing nematode larval establishment, improving N utilization, and reducing greenhouse gas emissions. However, the use of sainfoin as a fodder crop in dairy cow rations in northwestern Europe is still relatively unknown. The objective of this study was to evaluate the effect of sainfoin silage on nutrient digestibility, animal performance, energy and N utilization, and CH4 production. Six rumen-cannulated, lactating dairy cows with a metabolic body weight (BW0.75) of 132.5 ± 3.6 kg were randomly assigned to either a control (CON) or a sainfoin (SAIN)-based diet over 2 experimental periods of 25 d each in a crossover design. The CON diet was a mixture of grass silage, corn silage, concentrate, and linseed. In the SAIN diet, 50% of grass silage dry matter (DM) of the CON diet was exchanged for sainfoin silage. The cows were adapted to 95% of ad libitum feed intake for a 21-d period before being housed in climate-controlled respiration chambers for 4 d, during which time feed intake, apparent total-tract digestibility, N and energy balance, and CH4 production was determined. Data were analyzed using a mixed model procedure. Total daily DM, organic matter, and neutral detergent fiber intake did not differ between the 2 diets. The apparent digestibility of DM, organic matter, neutral detergent fiber, and acid detergent fiber were, respectively, 5.7, 4.0, 15.7, and 14.8% lower for the SAIN diet. Methane production per kilogram of DM intake was lowest for the SAIN diet, CH4 production as a percentage of gross energy intake tended to be lower, and milk yield was greater for the SAIN diet. Nitrogen intake, N retention, and energy retained in body protein were greater for the SAIN than for the CON diet. Nitrogen retention as a percentage of N intake tended to be greater for the SAIN diet. These results suggest that inclusion of sainfoin silage in dairy cow rations reduces CH4 per kilogram of DM intake and nutrient digestibility. Moreover, sainfoin silage improves milk production and seems to redirect metabolism toward body protein accretion at the expense of body fat.

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