Fecal Fraction Research Articles

Post-breeding waste from Zophobas morio for biogas and energy generation via anaerobic methane fermentation

Zophobas morio is one of the most widely bred insect species in commercial farms around the world, however Z. morio post-breeding waste has never been tested for its biogas and biomethane potential. The unseparated waste (M) was sieved to separate it into fractions of feces (F) and remaining wheat bran (W) in order to investigate whether isolated feces can have higher biomethane potential. Mesophilic (37 °C ± 1 °C) anaerobic digestion was performed in glass bioreactors (2 l total volume) for 24 days. The substrate loading was 8 g of the air-dried sample and the inoculum-to-substrate total mass was 125:1. The physicochemical parameters of the wastes and sludges after fermentation were investigated. The biogas potential of the feces was only approximately 3% higher than other tested materials and reached 650 ml of biogas · g−1VS. The average methane concentration was 52% (vol.). The calculation of theoretical electric and heat energy recovery in a co-generation system reached (per 1 Mg of waste VS) 1.3–1.4 MWh and 1.4–1.5 MWh, respectively. Post-breeding waste from Z. morio can be successfully used for energy recovery in the form of biogas.

A skew in poo: Biases in primate fecal isotope analysis and recommendations for standardized sample preparation.

Feces are a treasure trove in the study of animal behavior and ecology. Stable carbon and nitrogen isotope analysis allows to assessthe dietary niches of elusive primate species and primate breastfeeding behavior. However, some fecal isotope data may unwillingly be biased towardthe isotope ratios of undigested plant matter, requiring more consistent sample preparation protocols. We assess the impact of this potential data skew in 114 fecal samples of wild bonobos (Pan paniscus) by measuring the isotope differences (Δ13 C, Δ15 N) between bulk fecal samples containing larger particles (>1 mm) and filtered samples containing only small particles (<1 mm). We assess the influence of fecal carbon and nitrogen content (ΔC:N) and sample donor age (subadult, adult) on the resulting Δ13 C, Δ15 N values (n = 228). Additionally, we measure the isotope ratios in three systematically sieved fecal samples of chimpanzees (Pan troglodytes verus), with particle sizes ranging from 20 μm to 8 mm (n = 30). We found differences in fecal carbon and nitrogen content, with the smaller fecal fraction containing more nitrogen on average. While the Δ13 C values were small and not affected by age or ΔC:N, the Δ15 N values were significantly influenced by fecal ΔC:N, possibly resulting from the differing proportions of undigested plant macroparticles. Significant relationships between carbon stable isotope ratios (δ13 C) values and %C in large fecal fractions of both age groups corroborated this assessment. Δ15 N values were significantly larger in adults than subadults, which should be of concern in isotope studies comparing adult females with infants to assess breastfeeding. We found a random variation of up to 3.0‰ in δ13 C and 2.0‰ in nitrogen stable isotope ratios within the chimpanzee fecal samples separated by particle sizes. We show that particle size influences isotope ratios and propose a simple, cost-effective filtration method for primate feces to exclude larger undigested food particles from the analysis, which can easily be adopted by labs worldwide.

Combined models of growth, waste production, dispersal and deposition from cage-cultured Atlantic salmon to predict benthic enrichment

Models of particulate waste production and deposition can be used in performance-based management approaches as cost-effective tools to assess environmental effects of open-pen finfish aquaculture. XLDEPMOD is an MS Excel® spreadsheet-based depositional model for predicting particulate organic carbon (POC) waste production and sedimentation from net-pen cultured finfish. Calculations are based on temperature-dependent fish growth and mass-balance calculations of feed input, growth, respiration and 3 size classes of feces. Depth-average and near-bottom directional currents are used to determine waste dispersion by fitted Gaussian distribution functions. Near-bottom velocity and substrate-based resuspension thresholds and loss of deposited waste due to decomposition and consumption by wild fish and invertebrates are used to calculate net POC sedimentation. The model was applied to 2 Atlantic salmon farms in southwestern Bay of Fundy, Canada. Sensitivity analysis showed that reduction in waste flux due to resuspension depends on the magnitude of current and wave-driven bottom shear and mass fractions of feces with different settling velocities. Depending on depth, current speed, substrate type and fecal mass fractions, resuspension can remove up to 80% of deposited waste from under net-pens. Steep gradients with high rates (&gt;5 g POC m-2 d-1) of sedimentation predicted under and close to cages and lower rates (&lt;1 g POC m-2 d-1) &gt;50 m away are consistent with published DEPOMOD results and sediment trap observations at the farm sites. The model can be used by regulators to determine if acceptable environmental standards for benthic impacts due to waste deposition from salmon aquaculture are being maintained.

Testing the Functionality of Lipids from Feces in the Conspecific Recognition of the Weeping Lizard, Liolaemus chiliensis

Pheromones, a mix of proteins and lipids, are involved in lizards' conspecific recognition. In our study, we specifically address whether fecal lipids are involved in conspecific recognition of the Weeping Lizard, Liolaemus chiliensis. The feces of each sex were dissolved in n-hexane to isolate their lipidic fraction. We then exposed individuals of both sexes of L. chiliensis to the lipidic fractions of each sex and a control (n-hexane), recording their responses. Lizards of both sexes were more active when exposed to the lipids from male than from female feces or from the control, suggesting that the lipidic fraction of male feces conveys some information for conspecific recognition. There was, however, no further evidence of recognition, and herein we offer possible explanations for this low responsiveness to the fecal lipidic fractions.

Refining of the solid fraction of sheep feces digestates from an anaerobic digester

Anaerobic digestion is a technology used in the degradation of organic waste, with the possibility of obtaining products such as biogas and digestates, which have significant nutrient concentrations. However, using them without any prior treatment can cause various problems, due to the presence of unstabilized organic matter and excessive concentrations of nutrients reaching phytotoxic levels, as well as water and air contamination. Therefore, in this work, we present a refining process of solid digestates from a biodigester fed with sheep feces, by means of vermicomposting, in combination with plant waste, and using earthworms of the species E. andrei and E. fetida. The digestate values at the end of the vermicomposting showed to be within optimal ranges of electrical conductivity, with values ≤4 dS/m. The pH values were between 5,39 and 7. The percentage of organic matter was between 20 and 50%. It could be proven that the refining process increased the concentration of K for groups F 50:50, F 75:25, and A 75:25, with a value of P = 0,0001. Treatments with E. fetida showed the highest concentrations (g/L) of N = 2,71 ± 1,10, P = 0,89 ± 0,69 and K = 4,01 ± 1,57. The importance of giving added value to the products generated during anaerobic digestion processes contributes to better yields and quality in their use and commercialization.

Stability of Thermophilic Pig Manure Mono-digestion: Effect of Thermal Pre-treatment and Separation

Anaerobic pig manure digestion holds potential to contribute to a bio-based economy. This work assesses the stability of the thermophilic mono-digestion process. Thermophilic mono-digestion experiments with (i) fresh liquid pig manure and (ii) the fresh fecal fraction from source separation by a pig housing construction were conducted in semi pilot-scale continuous stirred tank reactors. The effect of separation on the digestion stability was studied by comparing thermophilic mono-digestion of fresh liquid (unseparated) and fresh source separated pig manure. Influencing factors and inhibitors were identified during the experiments. An unstable thermophilic mono-digestion process was observed for fresh liquid pig manure at a digester retention time of 60 days, due to high levels of ammonia and sulfur-containing components. Thermophilic mono-digestion of the fresh fecal fraction was more promising in terms of stability, provided enough time for digestion. In addition, the effect of low temperature (70 degrees C) thermal pre-treatment of manure on the digestion stability was investigated. In the case of liquid pig manure, no improvement in the digestion stability was noted upon thermal pre-treatment. For the fecal fraction, the stability of the thermophilic mono-digestion process did improve. Moreover, thermal treatment and subsequent thermophilic mono-digestion of the fresh fecal fractions from two different farms with a similar pig housing construction suggested an effect of the (organic) dry matter content on the process stability.

Fecal sST2 correlates with the disease severity of ulcerative colitis

Background/Aim. Ulcerative colitis (UC) is a chronic, relapsing inflammatory disease affecting the distal colon and rectum with complex pathogenesis and diagnosis, indicating the need for new diagnostic and prognostic markers. The aim of this study was to determine the fecal values of TNF- ?, IL-17, IL-10 and soluble protein ST2 (sST2) in the patients with UC and their relationship with clinicopathological aspects. Methods. The samples of stool of 80 patients with UC were analyzed. Concentrations of TNF-?, IL-17, IL-10 and sST2 were measured by ELISA. Results. Concentrations of TNF-?, IL-17 and sST2 were significantly increased in the feces of patients with the higher endoscopic, clinical and total Mayo score, as well as in the patients with an intense crypt destruction, erosion of the mucous membranes, architectural changes, neutrophil infiltration and eosinophil infiltration. The local value of anti-inflammatory cytokine IL-10 in liquid fraction of feces was increased in the patients with an advanced endoscopic stage of UC. The moderate positive correlation between the fecal sST2/IL-17 and the clinical and histological parameters of disease severity and also the strong correlation between sST2 and IL-17 was also observed in the feces of patients with UC. The analysis of receiver operating characteristic (ROC) curves showed that the optimal cut-off value for sST2 of 624.0 pg/g allows the discrimination of clinical stages of UC. Conclusion. The increased fecal value of sST2 in the UC patients with a higher endoscopic, clinical and histological stage of disease may be considered as a sign of the disease severity. The fecal values of sST2 can be used as a valuable marker for UC severity.

Two Populations of Mites (Tyrophagus putrescentiae) Differ in Response to Feeding on Feces-Containing Diets.

Background: Tyrophagus putrescentiae is a ubiquitous mite species in soil, stored products and house dust and infests food and causes allergies in people. T. putrescentiae populations harbor different bacterial communities, including intracellular symbionts and gut bacteria. The spread of microorganisms via the fecal pellets of T. putrescentiae is a possibility that has not been studied in detail but may be an important means by which gut bacteria colonize subsequent generations of mites. Feces in soil may be a vector for the spread of microorganisms.Methods: Extracts from used mite culture medium (i.e., residual food, mite feces, and dead mite bodies) were used as a source of feces-inhabiting microorganisms as food for the mites. Two T. putrescentiae populations (L and P) were used for experiments, and they hosted the intracellular bacteria Cardinium and Wolbachia, respectively. The effects of the fecal fraction on respiration in a mite microcosm, mite nutrient contents, population growth and microbiome composition were evaluated.Results: Feces from the P population comprised more than 90% Bartonella-like sequences. Feces from the L population feces hosted Staphylococcus, Virgibacillus, Brevibacterium, Enterobacteriaceae, and Bacillus. The mites from the P population, but not the L population, exhibited increased bacterial respiration in the microcosms in comparison to no-mite controls. Both L- and P-feces extracts had an inhibitory effect on the respiration of the microcosms, indicating antagonistic interactions within feces-associated bacteria. The mite microbiomes were resistant to the acquisition of new bacterial species from the feces, but their bacterial profiles were affected. Feeding of P mites on P-feces-enriched diets resulted in an increase in Bartonella abundance from 6 to 20% of the total bacterial sequences and a decrease in Bacillus abundance. The population growth was fivefold accelerated on P-feces extracts in comparison to the control.Conclusion: The mite microbiome, to a certain extent, resists the acquisition of new bacteria when mites are fed on feces of the same species. However, a Bartonella-like bacteria-feces-enriched diet seems to be beneficial for mite populations with symbiotic Bartonella-like bacteria. Coprophagy on the feces of its own population may be a mechanism of bacterial acquisition in T. putrescentiae.

Effect of partitioning the nonfiber carbohydrate fraction and neutral detergent fiber method on digestibility of carbohydrates by dairy cows.

Many nutrition models rely on summative equations to estimate feed and diet energy concentrations. These models partition feed into nutrient fractions and multiply the fractions by their estimated true digestibility, and the digestible mass provided by each fraction is then summed and converted to an energy value. Nonfiber carbohydrate (NFC) is used in many models. Although it behaves as a nutritionally uniform fraction, it is a heterogeneous mixture of components. To reduce the heterogeneity, we partitioned NFC into starch and residual organic matter (ROM), which is calculated as 100 - CP - LCFA - ash - starch - NDF, where crude protein (CP), long-chain fatty acids (LCFA), ash, starch, and neutral detergent fiber (NDF) are a percentage of DM. However, the true digestibility of ROM is unknown, and because NDF is contaminated with both ash and CP, those components are subtracted twice. The effect of ash and CP contamination of NDF on in vivo digestibility of NDF and ROM was evaluated using data from 2 total-collection digestibility experiments using lactating dairy cows. Digestibility of NDF was greater when it was corrected for ash and CP than without correction. Conversely, ROM apparent digestibility decreased when NDF was corrected for contamination. Although correcting for contamination statistically increased NDF digestibility, the effect was small; the average increase was 3.4%. The decrease in ROM digestibility was 7.4%. True digestibility of ROM is needed to incorporate ROM into summative equations. Data from multiple digestibility experiments (38 diets) using dairy cows were collated, and ROM concentrations were regressed on concentration of digestible ROM (ROM was calculated without adjusting for ash and CP contamination). The estimated true digestibility coefficient of ROM was 0.96 (SE = 0.021), and metabolic fecal ROM was 3.43 g/100 g of dry matter intake (SE = 0.30). Using a smaller data set (7 diets), estimated true digestibility of ROM when calculated using NDF corrected for ash and CP contamination was 0.87 (SE = 0.025), and metabolic fecal ROM was 3.76 g/100 g (SE = 0.60). Regardless of NDF method, ROM exhibited nutritional uniformity. The ROM fraction also had lower errors associated with the estimated true digestibility and its metabolic fecal fraction than did NFC. Therefore, ROM may result in more accurate estimates of available energy if integrated into models.

A novel approach to measuring macrophage-specific reverse cholesterol transport in vivo in humans

Reverse cholesterol transport (RCT) is thought to be an atheroprotective function of HDL, and macrophage-specific RCT in mice is inversely associated with atherosclerosis. We developed a novel method using 3H-cholesterol nanoparticles to selectively trace macrophage-specific RCT in vivo in humans. Use of 3H-cholesterol nanoparticles was initially tested in mice to assess the distribution of tracer and response to interventions known to increase RCT. Thirty healthy subjects received 3H-cholesterol nanoparticles intravenously, followed by blood and stool sample collection. Tracer counts were assessed in plasma, nonHDL, HDL, and fecal fractions. Data were analyzed by using multicompartmental modeling. Administration of 3H-cholesterol nanoparticles preferentially labeled macrophages of the reticuloendothelial system in mice, and counts were increased in mice treated with a liver X receptor agonist or reconstituted HDL, as compared with controls. In humans, tracer disappeared from plasma rapidly after injection of nanoparticles, followed by reappearance in HDL and nonHDL fractions. Counts present as free cholesterol increased rapidly and linearly in the first 240 min after nadir; counts in cholesteryl ester increased steadily over time. Estimates of fractional transfer rates of key RCT steps were obtained. These results support the use of 3H-cholesterol nanoparticles as a feasible approach for the measurement of macrophage RCT in vivo in humans.

Influence of omega-3 PUFAs on the metabolism of proanthocyanidins in rats

Studies of the bioavailability of proanthocyanidins usually consider them independently of other dietary constituents, while there is a tendency in the field of functional foods towards the combination of different bioactive compounds in a single product. This study examined the long-term effects of ω-3 polyunsaturated fatty acids of marine origin on the metabolic fate of grape proanthocyanidins. For this, female adult Wistar-Kyoto rats were fed (18weeks) with a standard diet supplemented or not with eicosapentaenoic acid/docosahexaenoic acid (1:1, 16.6g/kg feed), proanthocyanidin-rich grape seed extract (0.8g/kg feed) or both. A total of 39 microbial-derived metabolites and 16 conjugated metabolites were detected by HPLC-MS/MS either in urine or in the aqueous fraction of feces. An unexpected significant increase in many proanthocyanidin metabolites in urine and feces was observed in the group supplemented with ω-3 polyunsaturated fatty acids group as compared to the animals fed a standard diet, which contains a small amount of polyphenols. However, proanthocyanidin metabolites in rats given ω-3 polyunsaturated fatty acids and grape seed extract did not significantly differ from those in the group supplemented only with grape seed extract. It was concluded that ω-3 polyunsaturated fatty acids collaborate in the metabolism of polyphenols when present at low doses in the feed matrix, while the capacity of ω-3 polyunsaturated fatty acids to induce microbiota transformations when proanthocyanidins are present at high doses is not relevant compared to that of polyphenols themselves.

A high-fat high-sucrose diet affects the long-term metabolic fate of grape proanthocyanidins in rats.

Polyphenol metabolites are key mediators of the biological activities of polyphenols. This study aimed to evaluate the long-term effects of a high-fat high-sucrose (HFHS) diet on the metabolism of proanthocyanidins from grape seed extract (GSE). Adult female Wistar-Kyoto rats were fed a standard (STD) or HFHS diet supplemented or not with GSE for 16weeks. PA metabolites were determined by targeted HPLC-MS/MS analysis. A lower concentration of total microbial-derived PA metabolites was present in urine and the aqueous fraction of faeces in the HFHS+GSE group than in the STD+GSE group. In contrast, a tendency towards the formation of conjugated (epi)catechin metabolites in the HFHS+GSE group was observed. These results show that a HFHS diet significantly modifies PA metabolism, probably via: (1) a shift in microbial communities not counteracted by the polyphenols themselves; and (2) an up-regulation of hepatic enzymes.

Effects of quebracho tannin extract (Schinopsis balansae Engl.) and activated charcoal on nitrogen balance, rumen microbial protein synthesis and faecal composition of growing Boer goats

ABSTRACTUnder irrigated arid conditions, organic fertiliser rich in slowly decomposable nitrogen (N) and carbon (C) is needed for soil fertility maintenance. Feeding ruminants with condensed tannins will lower ruminal protein degradation, reduce urinary N excretion and might increase the faecal fraction of slowly decomposable N. Supplementation with activated charcoal (AC) might enrich manure with slowly degrading C. Therefore, we investigated the effects of feeding quebracho tannin extract (QTE) and AC on the N balance of goats, the efficiency of microbial protein synthesis in the rumen (EMPS) and the composition of faeces. The feeding trial comprised three periods; in each period, 12 male Boer goats (28 ± 3.9 kg live weight) were assigned to six treatments: a Control diet (per kg diet 500 g grass hay and 500 g concentrate) and to further five treatments the Control diet was supplemented with QTE (20 g and 40 g/kg; diets QTE2 and QTE4, respectively), with AC (15 g and 30 g/kg, diets AC1.5 and AC3.0, respectively) and a mixture of QTE (20 g/kg) plus AC (15 g/kg) (diet QTEAC). In addition to the N balance, EMPS was calculated from daily excretions of purine derivatives, and the composition of faecal N was determined. There was no effect of QTE and AC supplementation on the intake of organic matter (OM), N and fibre, but apparent total tract digestibility of OM was reduced (p = 0.035). Feeding QTE induced a shift in N excretion from urine to faeces (p ≤ 0.001) without altering N retention. Total N excretion tended to decrease with QTE treatments (p = 0.053), but EMPS was not different between treatments. Faecal C excretion was higher in QTE and AC treatments (p = 0.001) compared with the Control, while the composition of faecal N differed only in concentration of undigested dietary N (p = 0.001). The results demonstrate that QTE can be included into diets of goats up to 40 g/kg, without affecting N utilisation, but simultaneously increasing the excretion of slowly decomposable N and C fractions. Feeding AC up to 30 g/kg of the diet increases slowly degradable faecal C concentration, without negative effects on N metabolism of goats.

Abstract 330: Ezetimibe Prevents Atherogenesis Through Increased Catabolism and Fecal Excretion of LDL-cholesterol and Reduced Atherosclerotic Plaque Inflammation in Apolipoprotein E Knock-out Mice Fed a Paigen Diet

Background: Intestinal cholesterol absorption inhibitor ezetimibe (EZE) added to a statin therapy has demonstrated benefits in the IMPROVE-IT trial by further reducing LDL-cholesterol levels than statin therapy alone. We investigated the mechanisms by which EZE could contribute to cardiovascular events reduction in apolipoprotein E knock-out (apoE ko) mice. Methods: ApoE ko mice were fed a Paigen diet without (control) or with EZE (7mg/kg/day) for 6 weeks. To evaluate the effects of EZE on LDL-cholesterol metabolism and excretion, a first set of mice was injected intravenously with 3 H-cholesteryl oleate labeled human LDL. A second set of mice was used for in vivo SPECT/CT imaging of 99m Tc-cAbVCAM1-5, a single domain antibody directed against the Vascular Cell Adhesion Molecule-1 (VCAM-1), which was used as a marker of inflamed atherosclerotic plaques. The same mice were sacrificed for autoradiography and histology of aortic atherosclerotic plaques. Results: Compared with control, EZE treatment for 6 weeks induced a significant 41% and 65% reduction in plasma total cholesterol levels and atherosclerotic plaque area, respectively. After injection of 3 H-cholesteryl oleate labeled human LDL, mice treated with EZE showed a 173% higher LDL-cholesteryl ester catabolism (p&lt;0.001 vs. control). At time 96 hours after radiolabeled LDL injection, 3 H-tracer hepatic recovery was reduced by 61% with EZE (p&lt;0.001). Meanwhile, LDL-derived 3 H-tracer excretion in the feces was increased by 107% in the fecal cholesterol fraction (p&lt;0.001). Similar trends were observed for hepatic cholesterol levels and fecal cholesterol mass excretion, with a 75% reduction and 99% increase with EZE, respectively (both p&lt;0.001). After intravenous injection of 99m Tc-cAbVCAM1-5, mice treated with EZE also showed a significant 52% reduction in aortic uptake, which was confirmed by significant reduction in tracer uptake in ex vivo biodistribution and autoradiography analysis. Conclusion: EZE promotes anti-atherosclerotic effects through increased LDL-cholesterol catabolism and LDL-derived cholesterol fecal excretion, and reduced inflamed atherosclerotic plaques. These mechanisms may contribute to the benefits of adding EZE to a statin therapy.

Gender-related pharmacokinetics and absolute bioavailability of diosbulbin B in rats determined by ultra-performance liquid chromatography-tandem mass spectrometry

Ethnopharmacological relevanceDiosbulbin B (DB) is the main constituent of furano-norditerpenes in Dioscorea bulbifera Linn., which is widely distributed in China and was usually used as a remedy for sore throat, struma and tumor. Owing to its potential antitumor activity, DB has been considered as a promising candidate for drug development. Aim of the studyTo study the pharmacokinetic properties and excretion of DB in rats by a sensitive UPLC–MS/MS method. Absolute bioavailability and gender-related pharmacokinetic properties, as well as excretion fractions of DB in urine and feces after oral and intravenous administrations would be addressed for the first time. Materials and methodsSprague–Dawley rats were administrated orally (32mg/kg) and intravenously (0.5mg/kg) of DB, respectively. The concentrations of DB in rat plasma were determined by a sensitive and well-validated LC–MS/MS method. Main pharmacokinetic parameters including area under the plasma concentration–time curve (AUC), elimination half time (t1/2), mean residence time (MRT), apparent volume of distribution (Vd) and clearance rate (CL) were estimated using a non-compartmental pharmacokinetics data analysis software. Urine and feces of rats were collected within 48h after oral administration (32mg/kg) and detected by UPLC–MS/MS and HPLC, respectively. ResultsThe standard curves of DB in rat plasma and urine showed good linearity in the concentration range of 1.0–515ng/mL in the method, with acceptable selectivity, precisions, recoveries, and stability. The oral absolute bioavailability of DB in female rats was 2.0%, significantly higher than that of males (0.3%) (p<0.05). Female rats demonstrated longer t1/2 and MRT (p<0.01), bigger Vd and higher CL (p<0.05) than males after intravenous administration of DB. Bigger but no significant difference in excretion fractions of urine and feces in female rats were observed, comparing to those in males. ConclusionA simple and sensitive UPLC–MS/MS method was developed to determine the pharmacokinetic profiles of DB in rats, as well as the excretion in rat urine. Gender exerted a significant influence on the pharmacokinetics and bioavailability of DB in rats. Female rats showed significantly better absorption of DB than males after oral administration.

Technical note: Use of near infrared reflectance spectroscopy to assess nitrogen and carbon fractions in dairy cow feces

The feasibility of using near infrared spectroscopy (NIRS) for rapid prediction of nitrogen and carbon fractions of dairy cow feces was investigated. Fecal samples were collected from different farms characterized by differences in milk performances and feeding regimes. Dried fecal samples were first analyzed by chemical analysis for fractions of carbon and nitrogen in terms of ammonium-N (NH4-N), water soluble nitrogen (WSN), undigested dietary nitrogen (UDN), bacterial and endogenous debris nitrogen (BEDN), organic matter (OM), total C, neutral detergent fiber (NDFom), acid detergent fiber (ADFom), and lignin(sa). After chemical analysis, the samples were scanned by near infrared reflectance spectroscopy. The fecal spectrum and reference data of the chemical analysis were calibrated and cross validated using the partial least squares regression method. In addition, 24 fecal samples were collected for external validation. The derived coefficient of determination (R2) for calibration and standard error of calibration (SEC) were measured for total N and for NH4-N, WSN, UDN, OM and also for total C as 0.97 and 0.07, 0.92 and 0.02, 0.91 and 0.13, 0.90 and 0.04, 0.95 and 0.51, and 0.97 and 0.29, respectively. The NDFom, ADFom and lignin(sa) showed high R2 values with 0.97, 0.85, and 0.92. However, SEC values were measured as 1.09, 1.49, and 0.77. The co-efficiency of determination in the cross validation (SECV) attained 3.16, 2.16, and 1.24, respectively, which were on a higher level in comparison to the other fractions. The lowest R2 was found for BEDN measured as 0.78, with lower SEC as 0.15 and SECV as 0.17. Ratio of SEC to SD concerning the nitrogen fractions ranged between 0.29 and 0.50 and between 0.15 and 0.45 regarding the carbon fractions. The coefficient of determination for external validation was similar to the result obtained from cross validation for all parameters. This study suggested that NIRS is a suitable method for the determination of carbon and nitrogen fractions in dairy cow feces. The inclusion of a higher number of samples is expected to further improve the calibration equations.

Abstract 71: Assessment of Reverse Cholesterol Transport in Vivo in Humans: A Novel Method

Aim: Reverse cholesterol transport (RCT) is one of the main atheroprotective functions of HDL; however no method exists to assess RCT in vivo in humans. We developed a macrophage-specific method using 3H-cholesterol/albumin complexes that has been validated in animal studies. We present the results of a feasibility study in humans. Methods: Thirty subjects received 3H-cholesterol/albumin complexes as i.v. bolus, followed by blood and stool sample collection up to 8 days. Tracer counts were assessed in plasma, non-HDL, HDL and fecal fractions. Data were analyzed using multi-compartmental modeling. Results: Figure 1 shows the tracer kinetics as free cholesterol (FC; panel A) and cholesteryl ester (CE; panel B) specific activity in plasma, HDL and non-HDL. 3H-cholesterol disappeared from plasma rapidly after injection (macrophage uptake of 3H-cholesterol/albumin complexes); nadir was reached by 60 min. Counts present as FC in the HDL fraction increase rapidly and linearly in the first 240 min after nadir (129.9±85.5 cpm/μmols per hour)(3H-cholesterol uptake from macrophages by HDL). Linearity is lost after ∼240 min, as FC is transformed to CE and exchanged with other fractions. In a subset of subjects (n=10), multi-compartmental analysis was used to calculate fractional transfer rates, including macrophage FC to HDL-FC (0.040 ± 0.014 fraction/hour), HDL-FC to HDL-CE (0.238 ± 0.083 fraction/hour), HDL-CE to nonHDL-CE (0.200 ± 0.113 fraction/hour) and fecal excretion (0.032 ± 0.006 fraction/hour). Conclusions: These preliminary data support the feasibility of this approach and suggest that it may be used to measure macrophage RCT in vivo in humans.

Horizontal Distribution of the Fecal Microbiota in Adolescents With Inflammatory Bowel Disease

The commensal microbiota of the gastrointestinal tract plays an important role in the pathogenesis of inflammatory bowel disease. We examined the horizontal structure of the fecal microbiota in the colon in adolescents with Crohn disease or ulcerative colitis and a control group. Fecal samples were collected in 3 fractions from patients with Crohn disease (n = 22), ulcerative colitis (n = 12), and controls (n = 24) during preparation for colonoscopy. Additionally, biopsies from colon tissue were taken. Samples were examined using a culture technique and a fluorescent in situ hybridization method. The mucin degradation assay was carried out. Quantitative composition of the microbiota was different in the consecutive 3 fecal fractions and in the colon tissue of the study groups, but in patients from the control group, the composition of microbiota in the consecutive fractions was similar. Statistical analyses showed that the total distribution of the studied bacterial taxons in the contents in all 3 fecal fractions and in the colon tissue in the given disease group, and in the control group was characteristic for the studied patient group. Differences in species distribution among the cohorts studied were highly significant (P < 0.0001). Moreover, it was shown that in the fecal fraction I and in the colon tissue samples, there is no significant difference for any of the analyzed bacterial groups, using the culture methods or fluorescent in situ hybridization, but significant results were demonstrated in the II and III fractions for specific bacterial groups. The bacterial flora attached to the mucus layer in the UC group had significantly more degraded mucus in comparison with the control group (P = 0.045). Distribution of the microbiota in the colon is layered, which can be called horizontal distribution of the fecal flora. Only in the ulcerative colitis group, the bacterial flora attached to the mucous layer exerts action on the mucin.

Pharmacokinetics, dosimetry and comparative efficacy of 188Re-liposome and 5-FU in a CT26-luc lung-metastatic mice model

The biodistribution, pharmacokinetics, dosimetry and comparative therapeutic efficacy of intravenously administrated (188)Re-N,N-bis(2-mercaptoethyl)-N',N'-diethylethylenediamine (BMEDA)-labeled pegylated liposome ((188)Re-liposome) and 5-FU were investigated in a CT26-luc lung-metastatic model. After intravenous administration of (188)Re-liposome, tumor accumulation from the radioactivity was observed. Levels of radioactivity in tumors were maintained at steady levels (from 5.40 to 5.67 %ID/g) after 4 to 24 h. In pharmacokinetics, the AUC((0→∞)), MRT((0→∞)) and Cl of (188)Re-liposome in blood via intravenous route were 998 h %ID/ml, 28.7 h and 0.1 ml/h, respectively. The total excreted fractions of feces and urine were 0.61 and 0.26, respectively. Absorbed doses for (188)Re-liposome in the liver and red marrow were 0.31 and 0.08 mSv/MBq, respectively. Tumor-absorbed doses for (188)Re-liposome ranged from 48.4 to 1.73 mGy/MBq at 10 to 300 g tumor spheres. In therapeutic efficacy, the survival times of mice after (188)Re-liposome [80% maximum tolerated dose (MTD); 29.6 MBq], 5-FU (80% MTD; 144 mg/kg), liposome or normal saline treatments were evaluated. Consequently, radiotherapeutics of (188)Re-liposome attained a longer lifespan (increase of 34.9%; P=.005) in mice than in the normal saline group. The increase in lifespan of the (188)Re-liposome group was 2.5-fold greater than that of the 5-FU group. Therefore, intravenous administration of (188)Re-liposome could provide a benefit and it is a promising strategy for delivery of passive nanotargeted radiotherapeutics in oncology applications.

Changes in fecal pellet characteristics with depth as indicators of zooplankton repackaging of particles in the mesopelagic zone of the subtropical and subarctic North Pacific Ocean

We investigated how fecal pellet characteristics change with depth in order to quantify the extent of particle repackaging by mesopelagic zooplankton in two contrasting open-ocean systems. Material from neutrally buoyant sediment traps deployed in the summer of 2004 and 2005 at 150, 300, and 500 m was analyzed from both a mesotrophic (Japanese time-series station K2) and an oligotrophic (Hawaii Ocean Time series—HOT station ALOHA) environment in the Pacific Ocean as part of the VERtical Transport In the Global Ocean (VERTIGO) project. We quantified changes in the flux, size, shape, and color of particles recognizable as zooplankton fecal pellets to determine how these parameters varied with depth and location. Flux of K2 fecal pellet particulate organic carbon (POC) at 150 and 300 m was four to five times higher than at ALOHA, and at all depths, fecal pellets were two to five times larger at K2, reflective of the disparate zooplankton community structure at the two sites. At K2, the proportion of POC flux that consisted of fecal pellets generally decreased with depth from 20% at 150 m to 5% at 500 m, whereas at ALOHA this proportion increased with depth (and was more variable) from 14% to 35%. This difference in the fecal fraction of POC with increasing depth is hypothesized to be due to differences in the extent of zooplankton-mediated fragmentation (coprohexy) and in zooplankton community structure between the two locations. Both regions provided indications of sinking particle repackaging and zooplankton carnivory in the mesopelagic. At ALOHA, this was reflected in a significant increase in the mean flux of larvacean fecal pellets from 150 to 500 m of 3–46m gCm � 2 d � 1 , respectively, and at K2 a large peak in