14C-Cobalamin Absorption from Endogenously Labeled Chicken Eggs Assessed in Humans Using Accelerator Mass Spectrometry.

Traditionally, the bioavailability of vitamin B-12 (B12) from in vivo labeled foods was determined by labeling the vitamin with radiocobalt (57Co, 58Co or 60Co). This required use of penetrating radioactivity and sometimes used higher doses of B12 than the physiological limit of B12 absorption. The aim of this study was to determine the bioavailability and absorbed B12 from chicken eggs endogenously labeled with 14C-B12 using accelerator mass spectrometry (AMS). 14C-B12 was injected intramuscularly into hens to produce eggs enriched in vivo with the 14C labeled vitamin. The eggs, which provided 1.4 to 2.6 µg of B12 (~1.1 kBq) per serving, were scrambled, cooked and fed to 10 human volunteers. Baseline and post-ingestion blood, urine and stool samples were collected over a one-week period and assessed for 14C-B12 content using AMS. Bioavailability ranged from 13.2 to 57.7% (mean 30.2 ± 16.4%). Difference among subjects was explained by dose of B12, with percent bioavailability from 2.6 µg only half that from 1.4 µg. The total amount of B12 absorbed was limited to 0.5-0.8 µg (mean 0.55 ± 0.19 µg B12) and was relatively unaffected by the amount consumed. The use of 14C-B12 offers the only currently available method for quantifying B12 absorption in humans, including food cobalamin absorption. An egg is confirmed as a good source of B12, supplying approximately 20% of the average adult daily requirement (RDA for adults = 2.4 µg/day).

Use of metabolomics and lipidomics to evaluate the hypocholestreolemic effect of Proanthocyanidins from grape seed in a pig model.

SCOPE: This work aims to evaluate changes in the fecal metabolomic profile due to grape seed extract (GSE) intake by untargeted and targeted analysis using high resolution mass spectrometry in conjunction with multivariate statistics. METHODS AND RESULTS: An intervention study with six crossbred female pigs was performed. The pigs followed a standard diet for 3 days, then they were fed with a supplemented diet containing 1% (w/w) of MegaNatural® Gold grape seed extract for 6 days. Fresh pig fecal samples were collected daily. A combination of untargeted high resolution mass spectrometry, multivariate analysis (PLS-DA), data-dependent MS/MS scan, and accurate mass database matching was used to measure the effect of the treatment on fecal composition. The resultant PLS-DA models showed a good discrimination among classes with great robustness and predictability. A total of 14 metabolites related to the GSE consumption were identified including biliary acid, dicarboxylic fatty acid, cholesterol metabolites, purine metabolites, and eicosanoid metabolites among others. Moreover, targeted metabolomics using GC-MS showed that cholesterol and its metabolites fecal excretion was increased due to the proanthocyanidins from grape seed extract. CONCLUSION: The results show that oligomeric procyanidins from GSE modifies bile acid and steroid excretion, which could exert a hypocholesterolemic effect.

Phenolic metabolites and substantial microbiome changes in pig feces by ingesting grape seed proanthocyanidins.

Proanthocyanidin (PAC) consumption has been linked to better colonic health, but PACs are poorly absorbed, making them a target for colonic metabolism. The resulting metabolites are low molecular weight and could potentially be absorbed. To understand the effects of dietary PACs it would be important to resolve the metabolic issue and link these changes to microbial population changes in a suitable model for human digestion. Here, six crossbred female pigs were fed a diet containing 1% (w/w) of MegaNatural® Gold grape seed extract (GSE) daily for 6 days. Fecal samples were analyzed by normal phase LC coupled to fluorescence detection and LC-MS/ToF. DNA was extracted from pig fecal samples and the V3/V4 region of the 16S rRNA gene was sequenced using an Illumina MiSeq. Intact parent PACs (dimer-pentamer) were observed in the feces on days 3 and 6 at similar high levels (∼400 mg kg(-1) total) during ingestion of GSE but were absent 48 h post-feeding. The major phenolic metabolites were 4-hydroxyphenylvaleric acid and 3-hydroxybenzoic acid which increased by ∼30 and 3 mg kg(-1) respectively. The GSE diet also caused an ecological shift in the microbiome, dramatically increasing Lachnospiraceae, Clostridales, Lactobacillus and Ruminococcacceae. The relationship between dietary PACs and colon health may be attributable to the altered bacterial populations or phenolic compounds in the colon.

Circulating estradiol suppresses luteinizing hormone pulse frequency during dietary restriction.

The influence of dietary restriction on the negative feedback potency of 17-beta-estradiol (E2) was evaluated in both castrated male (wethers) and female sheep (OVX ewes) during the breeding season. In study 1, OVX ewes received maintenance or restricted dietary energy for 7 weeks or maintenance energy for 6 weeks prior to a 5 day fast (n=12ewes/feeding group). Estradiol (0.31microg E2/50kg/h) or vehicle (10% EtOH-saline) was continuously infused into half the animals in each dietary treatment for the final 54h of the study. The dynamic pattern of LH secretion was assessed during the final 6h of infusion. Estradiol inhibited luteinizing hormone (LH) pulse amplitude independent of nutrition (P=0.02); fasting increased mean LH, LH peak height, and LH nadir in the absence of E2 (P=0.004, P=0.02, and P=0.02, respectively); while E2 inhibited pulse frequency (P=0.02) and increased peak width (P=0.04) in restricted ewes. Interestingly, despite uniform E2 delivery, serum concentrations of E2 differed with feeding status. Therefore, 12 wethers were infused with 0.31microg E2/50kg/h (6 fed, 6 fasted) and six wethers received 0.19microg E2/50kg/h (fasted) to establish similar serum concentrations of E2 in fed (0.31microg/50kg/h) and fasted (0.19microg/50kg/h) wethers. When fed and fasted wethers had uniform serum concentrations of E2 LH pulse frequency was suppressed (P<0.05) in fasted relative to fed animals, supporting the postulate that energy restriction enhances the E2 negative feedback potency. Collectively, these studies demonstrate that nutrition affects E2 feedback potency and clearance.

Weight gain in gonadectomized normal and lipoprotein lipase-deficient male domestic cats results from increased food intake and not decreased energy expenditure.

Gonadectomy predisposes domestic cats to undesired body weight gain and obesity. The disturbance responsible for this disregulation of energy balance has not been clearly identified. Energy intake and expenditure, body composition and plasma concentrations of leptin, insulin, glucose and triacylglycerol were determined during a 36-wk period in adult male (2-5 y) gonadectomized (n = 8) and intact (n = 8) normal cats and gonadectomized (n = 8) and intact (n = 8) lipoprotein lipase (LPL)-deficient cats. Cats were housed individually in temperature- and light-controlled rooms and continuously provided a commercial dry-type diet. In normal and LPL-deficient cats, body weight increased (P < 0.05) after gonadectomy by 27 to 29%, mostly as a result of fat accretion. There was a rapid increase (P < 0.05) in food intake of approximately 12% after gonadectomy of normal and LPL-deficient cats. The metabolic rate (kJ.kg(-1).d(-1)), determined in normal intact (319 +/- 20, n = 5) and gonadectomized (332 +/- 36, n = 5) cats, did not differ after gonadectomy. After gonadectomy, plasma concentrations of glucose and triacylglycerol did not change, whereas plasma insulin and leptin concentrations increased (P < 0.05), but not coincidentally with body weight gain. A stair-step increase in energy intake, and not decreased energy expenditure, appears to drive the weight gain associated with gonadectomy. Body fat mass appears to increase until the energy intake supports no further expansion. Adiposity signaling through insulin or leptin does not appear to mediate the energy intake effect. LPL deficiency did not preclude development of the overweight body condition. Therefore, gonadectomy-induced weight gain in cats is not a result of changed adipose LPL activity, as previously suggested.