Low-Protein Diets Decrease Porcine Nitrogen Excretion but with Restrictive Effects on Amino Acid Utilization.

Reducing dietary crude protein (CP) intake effectively decreases nitrogen excretion in growing-finishing pigs but at the expense of poor growth when dietary CP content is reduced by ≥3%. In this study, we investigated the main disadvantages of low-protein diets supplemented with lysine, methionine, threonine, and tryptophan in pigs. First, changes in the nitrogen balance in response to differences in dietary CP content (18%, 15%, and 13.5%) were investigated in barrows (40 kg). Then, barrows (40 kg) surgically fitted with catheters in the mesenteric vein, portal vein, hepatic vein, and carotid artery were used to investigate changes in amino acid (AA) metabolism in the portal-drained viscera and liver in response to differences in dietary CP content. The results showed that low-protein diets reduced fecal and urinary nitrogen excretion ( P < 0.05) meanwhile resulted in significant decreases in nitrogen retention ( P < 0.05). Moreover, a reduction in the dietary CP content from 18% to 13.5% resulted in decreases in the net portal fluxes of NH3, glycine, and alanine as well as in the urea production in the liver ( P < 0.05), whereas their values as a percentage of nitrogen intake did not decline ( P > 0.05). The net portal fluxes of nonessential AA (NEAA) were reduced in the low-protein diet groups ( P < 0.05), while essential AA consumption in the liver increased ( P < 0.05). Thus, low-protein diets result in reductions in both nitrogen excretion and retention, and NEAA deficiency may be a major disadvantage of low-protein diets.

Portal-drained viscera heat production in Iberian pigs fed betaine- and conjugated linoleic acid-supplemented diets.

BACKGROUND: Betaine and conjugated linoleic acid (CLA) may alter growth and body composition in pigs, although their mode of action is not well understood. Portal-drained viscera (PDV) have a disproportionate influence with respect to their masses, and this may affect the productivity of more profitable tissues. The objective of this study was to determine if the use of betaine and/or CLA in the diet affects PDV heat production. RESULTS: Postprandial portal blood flow (PBF) was greater (19.0%, P = 0.004) for control compared with the other three diets. The lowest (P < 0.001) value for postprandial PDV O2 consumption corresponded to betaine + CLA followed by betaine and CLA diets (32.7, 25.4 and 17.7% respectively with respect to control diet). Postprandial PDV heat production was greater (26.4%, P < 0.001) for control with respect to the other three diets, with the minimum value corresponding to betaine + CLA (34.1% lower than control). CONCLUSION: Supplementation with betaine and/or CLA reduced the PBF, O2 consumption and therefore PDV heat production with respect to control diet. This effect was more pronounced when betaine and CLA were supplemented together, potentially increasing the energy availability for other body tissues. © 2016 Society of Chemical Industry.

Assessment of metabolism-dependent drug efficacy and toxicity on a multilayer organs-on-a-chip.

Pharmaceutical development is greatly hindered by the poor predictive power of existing in vitro models for drug efficacy and toxicity testing. In this work, we present a new and multilayer organs-on-a-chip device that allows for the assessment of drug metabolism, and its resultant drug efficacy and cytotoxicity in different organ-specific cells simultaneously. Four cell lines representing the liver, tumor (breast cancer and lung cancer), and normal tissue (gastric cells) were cultured in the compartmentalized micro-chambers of the multilayer microdevice. We adopted the prodrug capecitabine (CAP) as a model drug. The intermediate metabolites 5'-deoxy-5-fluorocytidine (DFUR) of CAP that were metabolized from liver and its active metabolite 5-fluorouracil (5-FU) from the targeted cancer cells and normal tissue cells were identified using mass spectrometry. CAP exhibited strong cytoxicity on breast cancer and lung cancer cells, but not in normal gastric cells. Moreover, the drug-induced cytotoxicity on cells varied in various target tissues, suggesting the metabolism-dependent drug efficacy in different tissues as exisits in vivo. This in vitro model can not only allow for characterizing the dynamic metabolism of anti-cancer drugs in different tissues simultaneously, but also facilitate the assessment of drug bioactivity on various target tissues in a simple way, indicating the utility of this organs-on-chip for applications in pharmacodynamics/pharmacokinetics studies, drug efficacy and toxicity testing.

Structure and antioxidative property of a polysaccharide from an ammonium oxalate extract of Phellinus linteus.

In this paper, the novel polysaccharide PL-A11 was purified from an ammonium oxalate extract of Phellinus linteus mycelia. Its physicochemical properties, structural characteristics, and antioxidant activities were investigated. Results showed that PL-A11 had a weight-average molecular weight (Mw) of 13.8kDa and was mainly composed of arabinose, xylose, mannose, and glucose in a molar ratio of 1.1:1.3:1.0:6.6. The backbone of PL-A11 was composed of (1→4)-α-d-glucopyranosyl, (1→2)-α-d-xylopyranosyl, and (1→3)-α-d-arabinofuranosyl residues, whereas the (1→6)-α-d-mannopyranosyl residues formed branches at the O-2 position with 1-linked-α-d-glucopyranosyl terminal residues. From the antioxidative activity tests in vivo, the administration of PL-A11 obviously enhanced the activity of antioxidant enzymes and significantly reduced the level of malondiadehyde (MDA) in the serum and liver of d-galactose-treated aging mice in a dose-dependent manner, as well as effectively stimulated the immune system of aging mice. These findings implied that PL-A11 could be developed as a potential antioxidant for applications in the functional food, pharmaceutical, cosmetic or nutraceutical industries.

Splanchnic extraction of phenylalanine in mature mares was not affected by threonine supplementation.

This study determined splanchnic extraction of phenylalanine at two intakes of threonine. Six Thoroughbred mares were supplemented with isonitrogenous amounts of either threonine or glutamate. Dietary threonine intakes were 119 (+Thr) and 58 (Basal) mg/kg/day, respectively. Each horse received each diet twice and each was studied once with an oral and once with an intravenous (IV) infusion of [1-(13)C]phenylalanine. A 2-h primed, constant IV infusion of [(13)C]sodium bicarbonate and a 4-h primed, constant infusion of [1-(13)C]phenylalanine, either orally or IV, were used to measure isotopic enrichments. Phenylalanine kinetics were not affected by diet (P > 0.05). Values for the splanchnic extraction of phenylalanine were 26 ± 5% and 27 ± 3% for the +Thr and Basal supplemented diets, respectively. These values will improve the accuracy of future equine indicator amino acid oxidation studies.

Acupuncture Meridian of Traditional Chinese Medical Science: An Auxiliary Respiratory System.

The acupuncture meridian system (AMS) is the key concept of Traditional Chinese Medical Science (TCMS). It is a natural network formed by the tissue space that connects human viscera and skin. In this article, a new hypothesis that the AMS is an auxiliary respiratory system is presented. The AMS collects the CO2 that is produced by tissue supersession and that cannot be excreted via blood circulation, and discharges the CO2 through the body's pores, thus preventing a pressure increase in the internal environment. Thus, local blood circulation will not be blocked, and the body will remain healthy. In addition to neuroregulation and humoral regulation, AMS regulation is an important method of physiological regulation. Furthermore, the pathological principle of the AMS, therapies of TCMS, and the excellent future of the AMS are discussed.

Abomasal amino acid infusion in postpartum dairy cows: Effect on whole-body, splanchnic, and mammary glucose metabolism.

Nine Holstein cows fitted with rumen cannulas and indwelling catheters in splanchnic blood vessels were used to study the effects of supplementing AA on milk lactose secretion, whole-body rate of appearance (WB-Ra) of glucose, and tissue metabolism of glucose, lactate, glycerol, and ß-OH-butyrate (BHBA) in postpartum dairy cows according to a generalized randomized incomplete block design with repeated measures in time. At calving, cows were blocked according to parity (second and third or greater) and were allocated to 2 treatments: abomasal infusion of water (n=4) or abomasal infusion of free AA with casein profile (AA-CN; n=5) in addition to the same basal diet. The AA-CN infusion started with half the maximal dose at 1 d in milk (DIM) and then steadily decreased from 791 to 226 g/d from DIM 2 to 29 to cover the estimated essential AA deficit. On DIM 5, 15, and 29, D[6,6-(2)H2]-glucose (23.7 mmol/h) was infused into a jugular vein for 5h, and 6 blood samples were taken from arterial, portal, hepatic, and mammary sources at 45-min intervals, starting 1h after the initiation of the D[6,6-(2)H2]glucose infusion. Trans-organ fluxes were calculated as veno-arterial differences times plasma flow (splanchnic: downstream dilution of deacetylated para-aminohippurate; mammary: Fick principle using Phe+Tyr). Energy-corrected milk and lactose yields increased on average with AA-CN by 6.4 kg/d and 353 g/d, respectively, with no DIM × treatment interaction. Despite increased AA supply and increased demand for lactose secretion with AA-CN, net hepatic release of glucose remained unchanged, but WB-Ra of glucose tended to increase with AA-CN. Portal true flux of glucose increased with AA-CN and represented, on average, 17% of WB-Ra. Splanchnic true flux of glucose was unaltered by treatments and was numerically equivalent to WB-Ra, averaging 729 and 741 mmol/h, respectively. Mammary glucose utilization increased with AA-CN infusion, averaging 78% of WB-Ra, and increased gradually as lactation advanced. Net portal, hepatic, splanchnic, and mammary fluxes of lactate, glycerol, and BHBA were not affected by AA infusion. Increasing the supply of AA in postpartum dairy cows elevated the WB-Ra of glucose without affecting the true liver glucose release. The greater WB-Ra of glucose with abomasal AA infusion seemed to originate mainly from greater true portal-drained viscera release of glucose. Glucose utilization by the portal-drained viscera was unaffected by abomasal AA infusion, but the exact mechanism behind the greater true portal glucose release could not be assessed in the current study. The increased mammary glucose uptake was in line with the increased milk lactose yield. In early postpartum lactation, the demand for AA seems to be so high that even with increased AA supply, cows have metabolic priorities for AA other than hepatic gluconeogenesis.

Abomasal amino acid infusion in postpartum dairy cows: Effect on whole-body, splanchnic, and mammary amino acid metabolism.

Nine Holstein cows with rumen cannulas and indwelling catheters in splanchnic blood vessels were used in a generalized randomized incomplete block design with repeated measures to study the effect of increased early postpartum AA supply on splanchnic and mammary AA metabolism. At calving, cows were blocked according to parity (second and third or greater) and allocated to 2 treatments: abomasal infusion of water (CTRL; n=4) or free AA with casein profile (AA-CN; n=5) in addition to a basal diet. The AA-CN infusion started with half of the maximal dose at the calving day (1 d in milk; DIM) and then steadily decreased from 791 to 226 g/d until 29 DIM. On 5, 15, and 29 DIM, 6 sample sets of arterial, portal, hepatic, and mammary blood were taken at 45-min intervals. Over the whole period, increasing AA supply increased milk (+7.8 ± 1.3 kg/d) and milk protein yields (+220 ± 65 g/d) substantially. The increased milk yield was not supported by greater dry matter intake (DMI) as, overall, DMI decreased with AA-CN (-1.6 ± 0.6 kg/d). Arterial concentrations of essential AA were greater for AA-CN compared with CTRL. The net portal-drained viscera (PDV) release of His, Met, and Phe was greater for AA-CN compared with CTRL, and the net PDV recovery of these infused AA ranged from 72 to 102% once changes in DMI were accounted for. The hepatic removal of these AA was increased equivalently to the increased net PDV release, resulting in an unaltered net splanchnic release. The net PDV release of Ile, Leu, Val, and Lys tended to be greater for AA-CN, and the net PDV recovery of these infused AA ranged from 69 to 73%, indicating increased PDV metabolism with AA-CN. The fractional hepatic removal of these AA did not differ from zero and was unaffected by the increased supply. Consequently, the splanchnic release of these AA was approximately equivalent to their net PDV release for both CTRL and AA-CN. Overall, greater early postpartum AA supply increased milk and milk protein yields substantially based on increased mammary AA uptake. The PDV metabolism of branched-chain AA and Lys were increased, whereas it seemed to be unaffected for other essential AA when the intestinal AA supply was increased. On a net basis, the liver removed more group 1 AA (His, Met, Phe, and Trp) for anabolism and catabolism when the early postpartum AA supply was increased. Thus, increasing the postpartum AA supply increased splanchnic and mammary consumption of AA; hence, the protein deficiency persisted.

Changes in tissue lipid and fatty acid composition of farmed rainbow trout in response to dietary camelina oil as a replacement of fish oil.

Camelina oil (CO) replaced 50 and 100 % of fish oil (FO) in diets for farmed rainbow trout (initial weight 44 ± 3 g fish(-1)). The oilseed is particularly unique due to its high lipid content (40 %) and high amount of 18:3n-3 (α-linolenic acid, ALA) (30 %). Replacing 100 % of fish oil with camelina oil did not negatively affect growth of rainbow trout after a 12-week feeding trial (FO = 168 ± 32 g fish(-1); CO = 184 ± 35 g fish(-1)). Lipid and fatty acid profiles of muscle, viscera and skin were significantly affected by the addition of CO after 12 weeks of feeding. However, final 22:6n-3 [docosahexaenoic acid (DHA)] and 20:5n-3 [eicosapentaenoic acid (EPA)] amounts (563 mg) in a 75 g fillet (1 serving) were enough to satisfy daily DHA and EPA requirements (250 mg) set by the World Health Organization. Other health benefits include lower SFA and higher MUFA in filets fed CO versus FO. Compound-specific stable isotope analysis (CSIA) confirmed that the δ(13)C isotopic signature of DHA in CO fed trout shifted significantly compared to DHA in FO fed trout. The shift in DHA δ(13)C indicates mixing of a terrestrial isotopic signature compared to the isotopic signature of DHA in fish oil-fed tissue. These results suggest that ~27 % of DHA was synthesized from the terrestrial and isotopically lighter ALA in the CO diet rather than incorporation of DHA from fish meal in the CO diet. This was the first study to use CSIA in a feeding experiment to demonstrate synthesis of DHA in fish.

Curcumin acts via transient receptor potential vanilloid-1 receptors to inhibit gut nociception and reverses visceral hyperalgesia.

BACKGROUND: An antinociceptive effect has been reported for curcumin in animal models and in humans, but the molecular mechanisms of curcumin's effect remain undefined. In this study, we explored the possibility that curcumin inhibit visceral nociception via antagonizing the transient receptor potential vanilloid-1 (TRPV1) receptor. METHODS: The effects of curcumin were explored using two experimental models: viscero-motor response (VMR) to colorectal distension (CRD) in rats and jejunal afferent firing in the ex vivo mouse jejunum preparations [TRPV1 knockout (KO) and wild-type mice, naive and trinitrobenzene sulfonic acid (TNBS)-treated Kunming mice]. In addition, capsaicin-induced calcium transients and whole-cell currents were examined in acutely dissociated dorsal root ganglia (DRG) neurons. KEY RESULTS: In the anesthetized rat, curcumin (4 mg kg(-1)  min(-1) for 3 min) caused a marked and rapidly reversible inhibition of CRD-induced VMRs. In the mouse jejunum, the mesenteric afferent nerve response to ramp distension was attenuated by curcumin (3, 10 µmol L(-1) ), an effect that was significantly reduced in TRPV1 KO mice compared with wild-type (WT) controls. Moreover, in WT mice, curcumin (1-30 µmol L(-1) ) was found to inhibit the afferent responses to capsaicin in a concentration-dependent manner. Trinitrobenzene sulfonic acid-induced hypersensitivity of jejunal afferents was also attenuated by curcumin. Curcumin potently inhibited capsaicin-induced rise in intracellular calcium and inward currents in mouse or rat DRG neurons. CONCLUSIONS & INFERENCES: Our results provide strong evidence that curcumin inhibit visceral nociception via antagonizing TRPV1 and may be a promising lead for the treatment of functional gastrointestinal diseases.

Bifidobacterium breve with α-linolenic acid and linoleic acid alters fatty acid metabolism in the maternal separation model of irritable bowel syndrome.

The aim of this study was to compare the impact of dietary supplementation with a Bifidobacterium breve strain together with linoleic acid & α-linolenic acid, for 7 weeks, on colonic sensitivity and fatty acid metabolism in rats. Maternally separated and non-maternally separated Sprague Dawley rats (n = 15) were orally gavaged with either B. breve DPC6330 (10(9) microorganisms/day) alone or in combination with 0.5% (w/w) linoleic acid & 0.5% (w/w) α-linolenic acid, daily for 7 weeks and compared with trehalose and bovine serum albumin. Tissue fatty acid composition was assessed by gas-liquid chromatography and visceral hypersensitivity was assessed by colorectal distension. Significant differences in the fatty acid profiles of the non-separated controls and maternally separated controls were observed for α-linolenic acid and arachidonic acid in the liver, oleic acid and eicosenoic acid (c11) in adipose tissue, and for palmitoleic acid and docosahexaenoic acid in serum (p<0.05). Administration of B. breve DPC6330 to MS rats significantly increased palmitoleic acid, arachidonic acid and docosahexaenoic acid in the liver, eicosenoic acid (c11) in adipose tissue and palmitoleic acid in the prefrontal cortex (p<0.05), whereas feeding B. breve DPC6330 to non separated rats significantly increased eicosapentaenoic acid and docosapentaenoic acid in serum (p<0.05) compared with the NS un-supplemented controls. Administration of B. breve DPC6330 in combination with linoleic acid and α-linolenic acid to maternally separated rats significantly increased docosapentaenoic acid in the serum (p<0.01) and α-linolenic acid in adipose tissue (p<0.001), whereas feeding B. breve DPC6330 with fatty acid supplementation to non-separated rats significantly increased liver and serum docosapentaenoic acid (p<0.05), and α-linolenic acid in adipose tissue (p<0.001). B. breve DPC6330 influenced host fatty acid metabolism. Administration of B. breve DPC6330 to maternally separated rats significantly modified the palmitoleic acid, arachidonic acid and docosahexaenoic acid contents in tissues. The effect was not observed in non-separated animals.

Effects of electroacupuncture on expression of c-fos protein and N-methyl-D-aspartate receptor 1 in the rostral ventromedial medulla of rats with chronic visceral hyperalgesia.

OBJECTIVE: Acupuncture has been clinically proved to be effective in treating abdominal pain in patients with irritable bowel syndrome (IBS). However, its neurobiological mechanism remains largely unexplored. The aim of this study was to investigate the effect of electroacupuncture (EA) in relieving chronic visceral hyperalgesia and the possible involvement of N-methyl-D-aspartate receptor 1 (NR1) in rostral ventromedial medulla (RVM) of the brain in an IBS rat model. METHODS: To establish the IBS rat model, male Sprague-Dawley neonatal rats received colon mechanical irritation on a daily basis from the 9th to the 22nd day after their birth. After a resting period of another two to four weeks, behavioral tests of pain threshold pressure (PTP) and abdominal withdrawal reflex (AWR) responding to colorectal distention (CRD) stimuli were conducted to judge the colorectal sensitive situation. Then administration of EA at acupoints of Zusanli (ST36) and Shangjuxu (ST37) bilaterally in the hind limbs was repeated four times every other day, while sham-EA was done by inserting needles at similar acupoints without electrical stimulation. Immunohistochemical method was used to display the expression of proto-oncogene protein c-fos and NR1 in RVM of rats. RESULTS: The results demonstrated that the PTP values and AWR scores, in response to the CRD stimuli, significantly decreased and increased, respectively (P<0.01, P<0.01), while the number of immunoreactive neurons of c-fos protein and NR1 significantly increased in nucleus reticularis gigantocellularis (Gi), nucleus lateralis paragigantocellularis (LPGi), nucleus reticularis gigantocellularis pars alpha (GiA) and nucleus raphe magnus (NRM) of RVM in IBS model rats compared with the normal rats (P<0.05). After EA treatment, PTP values and AWR scores significantly increased and decreased, respectively (P<0.01, P<0.05); the number of immunoreactive neurons of c-fos and NR1 significantly decreased respectively in Gi, LPGi and GiA and in Gi, LPGi, GiA and NRM (P<0.05). No such effects on PTP values, AWR scores and the number of immunoreactive neurons of c-fos and NR1 were observed after sham-EA treatment. CONCLUSION: These data provide the evidence that EA can relieve chronic visceral hyperalgesia in rats with IBS, and such an effect may be correlated with inhibitory modulation of hyperactivity of neurons by means of down-regulating the high expression of NR1 in RVM of IBS model rats.

Absence of post-prandial gut anabolism after intake of a low quality protein meal.

BACKGROUND & AIMS: Gut health relates to a diet with a high digestibility and quality. Limited data are available on the acute effects of low quality foods on gut metabolism and the consequences for liver metabolism. METHODS: A meal with the low quality protein gelatin (tryptophan deficient and low amount of essential amino acids) was compared to a meal with the high quality protein Whey and a tryptophan supplemented gelatin meal (Gel + TRP) in healthy pigs with chronic implanted catheters. In a conscious state, amino acid, ammonia, urea, glucose and lactate fluxes across the portal drained viscera (PDV) and liver were studied for 6 h after administration of the protein meal. RESULTS: The average net portal appearance of amino acids was 99.8 ± 14.6% of the intake in the Gel group as compared to 61.4 ± 9.0% (p = 0.022) in the Whey group. In addition, a net portal appearance of tryptophan was observed in the Gel group (p = 0.005) of about 42% of tryptophan released in the Whey group. Intestinal energy metabolism and citrulline production was not affected. Adding tryptophan to the Gel meal diminished net portal AA appearance to 41.6 ± 24.0% of the intake (p = 0.012), but did not reduce the stimulated liver urea production. CONCLUSIONS: In the post-prandial phase after intake of a low protein quality meal, net anabolism in the healthy intestine is absent. It is likely that the intestine responds with a net breakdown of endogenous (labile) proteins to secure amino acid availability for the body. Addition of the first limiting essential amino acid to this meal improved protein anabolism in the intestine. Protein quality of a meal is related to the anabolic response of the intestine during the meal.

Expression of keratin 10 in rat organ surface primo-vascular tissues.

The primo-vascular system is described as the anatomical structure corresponding to acupuncture meridians and has been identified in several tissues in the body, but its detailed anatomy and physiology are not well understood. Recently, the presence of keratin 10 (Krt10) in primo-vascular tissue was reported, but this finding has not yet been confirmed. In this study, we compared Krt10 expression in primo-vascular tissues located on the surface of rat abdominal organs with Krt10 expression on blood and lymphatic vessels. Krt10 protein (approximately 56.5 kDa) was evaluated by western blot analysis and immunohistochemistry. Krt10 (IR) in the primo-node was visualized as patchy spots around each cell or as a follicle-like structure containing a group of cells. Krt10 IR was also identified in vascular and lymphatic tissues, but its distribution was diffuse over the extracellular matrix of the vessels. Thus Krt10 protein was expressed in all three tissues tested, but the expression pattern of Krt10 in primo-vascular tissue differed from those of blood and lymphatic vascular tissues, suggesting that structural and the regulatory roles of Krt10 in primo-vascular system are different from those in blood and lymphatic vessels.

Cysteine fluxes across the portal-drained viscera of enterally fed minipigs: effect of an acute intestinal inflammation.

Cysteine is considered as a conditionally indispensable amino acid. Its dietary supply should thus be increased when endogenous synthesis cannot meet metabolic need, such as during inflammatory diseases. However, studies in animal models suggest a high first-pass extraction of dietary cysteine by the intestine, limiting the interest for an oral supplementation. We investigated here unidirectional fluxes of cysteine across the portal-drained viscera (PDV) of multi-catheterized minipigs, using simultaneous intragastric L-[(15)N] cysteine and intravenous L-[3,3D2] cysteine continuous infusions. We showed that in minipigs fed with an elemental enteral solution, cysteine first-pass extraction by the intestine is about 60% of the dietary supply, and that the PDV does not capture arterial cysteine. Beside dietary cysteine, the PDV release non-dietary cysteine (20% of the total cysteine release), which originates either from tissue metabolism or from reabsorption of endogenous secretion, such as glutathione (GSH) biliary excretion. Experimental ileitis induced by local administration of trinitrobenzene sulfonic acid, increased liver and ileal GSH fractional synthesis rate during the acute phase of inflammation, and increased whole body flux of cysteine. However, cysteine uptake and release by the PDV were not affected by ileitis, suggesting an adaptation of the intestinal sulfur amino acid metabolism in order to cover the additional requirement of cysteine linked to the increased GSH synthesis. We conclude that the small intestine sequesters large amounts of dietary cysteine during absorption, limiting its release into the bloodstream, and that the other tissues of the PDV (colon, stomach, pancreas, spleen) preferentially use circulating methionine or cysteine-containing peptides to cover their cysteine requirement.

Net flux of nutrients across splanchnic tissues of lactating dairy cows as influenced by dietary supplements of biotin and vitamin B12.

Biotin and vitamin B(12) are coenzymes in reactions that are essential to propionate metabolism in dairy cows. The objective of the present studies was to determine whether an increased dietary supply of these vitamins would change the net flux of nutrients through the rumen, the portal-drained viscera (PDV), the total splanchnic tissues (TSP), and the liver. Four lactating cows equipped with ultrasonic flow probes around the right ruminal artery and the portal vein and catheters in the right ruminal vein, the portal vein, one hepatic vein, and one mesenteric artery were fed 12 times per day a mixed ration at 95% of ad libitum dry matter intake. Daily supplements of 500 mg of vitamin B(12)+20mg of biotin or no vitamin supplement (study 1) or 500 mg of vitamin B(12) alone or with 20mg of biotin (study 2) were fed according to a crossover design with two 4-wk periods in each study. On the last day of each period, blood flow was recorded and blood samples were collected every 30 min for 4h. In study 1, biotin and vitamin B(12) given together increased milk production and milk protein yields compared with the control diet. The supplement increased appearance of the 2 vitamins across the PDV and TSP. It also reduced the net portal appearance of ammonia and total volatile fatty acids across the PDV. In study 2, compared with the 2 vitamins together, vitamin B(12) alone increased glucose flux across PDV and TSP as well as its arterial concentration and PDV flux of ammonia. With the diet used in the present experiment, the major effects of the vitamin supplements seem to be mediated through changes in ruminal fermentation and gastrointestinal tract metabolism rather than by effects on hepatic metabolism.

Influence of slow-release urea on nitrogen balance and portal-drained visceral nutrient flux in beef steers.

Two experiments were conducted to evaluate the effects of slow-release urea (SRU) versus feed-grade urea on portal-drained visceral (PDV) nutrient flux, nutrient digestibility, and total N balance in beef steers. Multi-catheterized steers were used to determine effects of intraruminal dosing (Exp. 1; n = 4; 319 +/- 5 kg of BW) or feeding (Exp. 2; n = 10; 4 Holstein steers 236 +/- 43 kg of BW and 6 Angus steers 367 +/- 46 kg of BW) SRU or urea on PDV nutrient flux and blood variables for 10 h after dosing. Intraruminal dosing of SRU (Exp. 1) prevented the rapid increase in ruminal ammonia concentrations that occurred with urea dosing (treatment x time P = 0.001). Although apparent total tract digestibilities of DM, OM, NDF, and ADF were not affected by treatment (P > 0.53, Exp. 2), SRU increased fecal N excretion (49.6 vs. 45.6 g/d; P = 0.04) and reduced apparent total tract N digestibility (61.7 vs. 66.0%; P = 0.003). Transfer of urea from the blood to the gastrointestinal tract occurred for both treatments in Exp. 1 and 2 at all time points with the exception for 0.5 h after dosing of urea in Exp. 1, when urea was actually transferred from the gastrointestinal tract to the blood. In both Exp. 1 and 2, both urea and SRU treatments increased arterial urea concentrations from 0.5 to 6 h after feeding, but arterial urea concentrations were consistently less with SRU (treatment x time P < 0.001, Exp. 1; P = 0.007, Exp. 2). Net portal ammonia release remained relatively consistent across the entire sampling period with SRU treatment, whereas urea treatment increased portal ammonia release in Exp. 1 and tended to have a similar effect in Exp. 2 (treatment x time P = 0.003 and P = 0.11, respectively). Urea treatment also increased hepatic ammonia uptake within 0.5 h (treatment x time P = 0.02, Exp. 1); however, increased total splanchnic release of ammonia for the 2 h after urea treatment dosing suggests that PDV ammonia flux may have exceeded hepatic capacity for removal. Slow-release urea reduces the rapidity of ammonia-N release and may reduce shifts in N metabolism associated with disposal of ammonia. However, SRU increased fecal N excretion and increased urea transfer to the gastrointestinal tract, possibly by reduced SRU hydrolysis or effects on digestion patterns. Despite this, the ability of SRU to protect against the negative effects of urea feeding may be efficacious in some feeding applications.

[Effect of changji'an on visceral hypersensitivity in rats with irritable bowel syndrome and its mechanism].

OBJECTIVE: To explore the mechanism and efficiency of Changji'an (CJA) in treating irritable bowel syndrome through studying the relationship between serotonin transporter (SERT) and visceral hypersensitivity in rats. METHODS: Male SD rats were randomly divided into 4 groups: the normal control group, the model group, the high-dosage and low-dosage CJA (CJAH and CJAL) groups. Visceral hypersensitivity model was established by colorectal distension. Normal saline and different doses of CJA were administrated to rats respectively, starting from the 10th day of modeling for 10 days. After then, the abdominal withdrawal reflex (AWR) was scored for semi-quantitative estimation of visceral sensitivity, and tissues of brain and colon were harvested for detecting expressions of SERT and serotonin (5-HT) with Western blot, real-time PCR and immunohistochemistry. RESULTS: As compared with the normal controls, in model rats, the AWR score and content of 5-HT in intestinal mucosa were higher (P < 0.05), protein and mRNA expressions of SERT in colon and nucleus raphes dorsalis (NRD) were lower (P < 0.05), but all these indexes were improved significantly after CJA treatment, either in the CJAH or CJAL group (all P < 0.05). Besides, the number of 5-HT energic neuron in the model group and CJA groups was lower than that in the normal control group (P < 0.05). CONCLUSION: CJA has therapeutic effect for improving visceral hypersensitivity in irritable bowel syndrome by way of regulating colonic expression of SERT and content of 5-HT.

Repeated electro-acupuncture attenuates chronic visceral hypersensitivity and spinal cord NMDA receptor phosphorylation in a rat irritable bowel syndrome model.

Acupuncture has been used in clinical trials for the treatment of abdominal pain in patients with irritable bowel syndrome (IBS). However, scientific evidence is still lacking and the underlying mechanism remains largely unexplored. The aim of this study was to examine the effects of repeated administration of electro-acupuncture (EA) on chronic visceral hypersensitivity and on the phosphorylation of spinal cord N-methyl-D-aspartic acid (NMDA) receptors in a rat model of IBS. The results showed that repeated administration of EA at bilateral points of Zu-san-li (ST-36) and Shang-ju-xu (ST-37) significantly attenuated chronic visceral hypersensitivity induced in young adult rats by neonatal colon irritation. Such an effect was not seen in either of the two controls: sham-EA at ST-36 and ST-37 without electrical stimulation and EA at control points (BL-62 and tail). Furthermore, rats with chronic visceral hypersensitivity exhibited high-level expression of phosphorylated NMDA receptor subunit 1 (pNR1) in the spinal cord (L4-L5 segments), which was markedly attenuated by EA treatment. In addition, EA at ST-36 and ST-37 neither altered the pain threshold of normal rats nor affected the expression of pNR1 in the lumbosacral spinal cord. Altogether, these data indicate that the EA-mediated attenuation of chronic visceral hypersensitivity is correlated with the down-regulation of NMDA receptors phosphorylation at the spinal level.

Effects of level and source of dietary selenium on maternal and fetal body weight, visceral organ mass, cellularity estimates, and jejunal vascularity in pregnant ewe lambs.

Pregnant Targhee ewe lambs (n = 32; BW = 45.6 +/- 2.2 kg) were allotted randomly to 1 of 4 treatments in a completely randomized design to examine the effects of level and source of dietary Se on maternal and fetal visceral organ mass, cellularity estimates, and maternal jejunal crypt cell proliferation and vascularity. Diets contained (DM basis) either no added Se (control) or supranutritional Se from high-Se wheat at 3.0 ppm Se (SW) or from sodium selenate at 3 (S3) or 15 (S15) ppm Se. Diets were similar in CP (15.5%) and ME (2.68 Mcal/kg of DM) and were fed to meet or exceed requirements. Treatments were initiated at 50 +/- 5 d of gestation. The control, SW, S3, and S15 treatment diets provided 2.5, 75, 75, and 375 microg of Se/kg of BW, respectively. On d 134 +/- 10 of gestation, ewes were necropsied, and tissues were harvested. Contrasts, including control vs. Se treatments (SW, S3, and S15), SW vs. S3, and S3 vs. S15, were used to evaluate differences among Se levels and sources. There were no differences in ewe initial and final BW. Full viscera and liver mass (g/kg of empty BW and g/kg of maternal BW) and maternal liver protein concentration (mg/g) and content (g) were greater (P < 0.04) in Se-treated compared with control ewes. Maternal liver protein concentration was greater (P = 0.01) in SW vs. S3 ewes, and content was greater (P = 0.01) in S15 compared with S3 ewes. Maternal jejunal mucosal DNA concentration (mg/g) was greater (P = 0.08) in SW compared with S3 ewes. Total number of proliferating cells in maternal jejunal mucosa was greater (P = 0.02) in Se-fed compared with control ewes. Capillary number density within maternal jejunal tissue was greater (P = 0.08) in S3 compared with SW ewes. Selenium treatment resulted in reduced fetal heart girth (P = 0.08). Fetal kidney RNA (P = 0.04) and protein concentrations (mg/g; P = 0.03) were greater in Se-treated compared with control ewes. These results indicate that supranutritional dietary Se increases cell numbers in maternal jejunal mucosa through increased crypt cell proliferation. No indications of toxicity were observed in any of the Se treatments.