Recent findings regarding calcium and phytase in poultry nutrition

2017 ◽  
Vol 57 (11) ◽  
pp. 2311 ◽  
Author(s):  
M. Bedford ◽  
X. Rousseau
Keyword(s):  
Low Cost ◽  
Essential Element ◽  
Dependent Manner ◽  
Maximum Value ◽  
Mild Deficiency ◽  
High Doses ◽  
And Performance ◽  
Dose Dependent ◽  
Hydrolysis Of ◽  
Very High

Calcium (Ca) is an essential element for poultry and even a mild deficiency can lead to significant welfare and performance issues. As a result, it is often fed at levels in excess of requirement, partly as an insurance policy and, to some degree, because of its relatively low cost compared with other feed ingredients. However, when diets meet but do not exceed the phosphorus (P) requirements of the bird, a marginal Ca excess can interfere with P digestibility. This problem is exacerbated when phytases are used to provide some of the required P because Ca decreases the efficiency of phytate (IP6) hydrolysis in a dose-dependent manner. More recently, phytases have been used at very high doses (1500 FyTase units (FTU); ‘superdosing’) in commercial diets, to improve bird performance by removing as much of the dietary IP6 and lower esters of phytate (IP5, IP4, IP3 and IP2) as possible, all of which are considered anti-nutrients, and concomitantly producing as much inositol, a nutrient, as possible. In such a regimen, the ability of the phytase to degrade the lower phytate esters, namely IP4, IP3 and IP2, takes on greater importance than does simply releasing phytate P. Calcium has recently been shown to reduce the efficacy of hydrolysis of the lower phytate esters to a greater degree than the extent to which it decreases IP6 hydrolysis. As a result, Ca concentrations in the diet should be monitored frequently if the maximum value of a phytase is to be realised.

Cannabinoids Reveal Separate Controls for Whisking Amplitude and Timing in Rats

2010 ◽  
Vol 104 (5) ◽  
pp. 2532-2542 ◽  
Author(s):  
Maciej Dominik Pietr ◽  
Per Magne Knutsen ◽  
David I. Shore ◽  
Ehud Ahissar ◽  
Zvi Vogel
Keyword(s):  
Cannabinoid Receptor ◽  
Spectral Power ◽  
Cycle Duration ◽  
Dependent Manner ◽  
Timing Channels ◽  
Amplitude Control ◽  
High Doses ◽  
Dose Dependent ◽  
Very High

Whisking is controlled by multiple, possibly functionally segregated, motor sensory-motor loops. While testing for effects of endocannabinoids on whisking, we uncovered the first known functional segregation of channels controlling whisking amplitude and timing. Channels controlling amplitude, but not timing, were modulated by cannabinoid receptor type 1 (CB1R). Systemic administration of CB1R agonist Δ9-tetrahydrocannabinol (Δ9-THC) reduced whisking spectral power across all tested doses (1.25–5 mg/kg), whereas whisking frequency was affected at only very high doses (5 mg/kg). Concomitantly, whisking amplitude and velocity were significantly reduced in a dose-dependent manner (25–43 and 26–50%, respectively), whereas cycle duration and bilateral synchrony were hardly affected (3–16 and 3–9%, respectively). Preadministration of CB1R antagonist SR141716A blocked Δ9-THC–induced kinematic alterations of whisking, and when administered alone, increased whisking amplitude and velocity but affected neither cycle duration nor synchrony. These findings indicate that whisking amplitude and timing are controlled by separate channels and that endocannabinoids modulate amplitude control channels.

Comparative effects of arginine vasopressin and oxytocin in cell culture systems

1992 ◽  
Vol 263 (2) ◽  
pp. F222-F227
Author(s):  
V. A. Briner ◽  
P. Tsai ◽  
H. L. Choong ◽  
R. W. Schrier
Keyword(s):  
Arginine Vasopressin ◽  
Mesangial Cells ◽  
Dependent Manner ◽  
Glomerular Mesangial Cells ◽  
Cell Culture Systems ◽  
Antagonist Binding ◽  
High Concentrations ◽  
High Doses ◽  
Dose Dependent ◽  
Very High

Arginine vasopressin (AVP) and oxytocin (OXT) induced contraction in cultured vascular smooth muscle cells (VSMC) and glomerular mesangial cells (GMC). The contractile response of AVP and OXT was paralleled by Ca2+ mobilization as assessed by 45Ca2+ efflux in a dose-dependent manner. The effects of AVP were blocked by pretreating VSMC and GMC with a V1 antagonist. OXT-stimulated effects, however, were not affected by preexposure of VSMC and GMC to an OXT antagonist but were inhibited by the V1 antagonist. Competition studies demonstrated displacement of [3H]AVP from its receptors by unlabeled AVP, the V1 antagonist, and high doses of OXT. The OXT antagonist was the least effective in displacing [3H]AVP. Thus occupancy of the V1 receptor by OXT may initiate signal transduction and contraction in VSMC and GMC in a manner qualitatively similar to that of the AVP agonist. Cultured myometrium cells (MMC) also contracted in response to AVP and OXT. Moreover, 45Ca2+ efflux increased in response to both hormones in a dose-dependent manner. AVP-stimulated contraction and 45Ca2+ efflux were blocked in MMC by pretreatment with V1 antagonist. OXT-induced effects were inhibited by the OXT antagonist but not by the V1 antagonist. Binding experiments showed that [3H]AVP was displaced equally by unlabeled AVP and V1 antagonist. Very high concentrations of OXT antagonist also demonstrated displacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Melatonin actions in the heart; more than a hormone

2018 ◽  
Vol 1 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Darío Acuña-Castroviejo ◽  
Maria T Noguiera-Navarro ◽  
Russel J Reiter ◽  
Germaine Escames
Keyword(s):  
Cell Membranes ◽  
Myocardial Cell ◽  
Rat Tissues ◽  
Dependent Manner ◽  
Broad Distribution ◽  
Multiple Organs ◽  
High Doses ◽  
Extrapineal Melatonin ◽  
Dose Dependent ◽  
Different Doses

Due to the broad distribution of extrapineal melatonin in multiple organs and tissues, we analyzed the presence and subcellular distribution of the indoleamine in the heart of rats. Groups of sham-operated and pinealectomized rats were sacrificed at different times along the day, and the melatonin content in myocardial cell membranes, cytosol, nuclei and mitochondria, were measured. Other groups of control animals were treated with different doses of melatonin to monitor its intracellular distribution. The results show that melatonin levels in the cell membrane, cytosol, nucleus, and mitochondria vary along the day, without showing a circadian rhythm. Pinealectomized animals trend to show higher values than sham-operated rats. Exogenous administration of melatonin yields its accumulation in a dose-dependent manner in all subcellular compartments analyzed, with maximal concentrations found in cell membranes at doses of 200 mg/kg bw melatonin. Interestingly, at dose of 40 mg/kg b.w, maximal concentration of melatonin was reached in the nucleus and mitochondrion. The results confirm previous data in other rat tissues including liver and brain, and support that melatonin is not uniformly distributed in the cell, whereas high doses of melatonin may be required for therapeutic purposes.

Intracerebroventricular injection of prostaglandin E2 increases splenic sympathetic nerve activity in rats

1995 ◽  
Vol 269 (3) ◽  
pp. R662-R668 ◽  
Author(s):  
T. Ando ◽  
T. Ichijo ◽  
T. Katafuchi ◽  
T. Hori
Keyword(s):  
Prostaglandin E2 ◽  
Sympathetic Nerve ◽  
Time Course ◽  
Sympathetic Nerve Activity ◽  
Dependent Manner ◽  
Central Administration ◽  
Nerve Activity ◽  
High Doses ◽  
Alpha Chloralose ◽  
Dose Dependent

The effects of central administration of prostaglandin E2 (PGE2) and its selective agonists on splenic sympathetic nerve activity (SNA) were investigated in urethan- and alpha-chloralose-anesthetized rats. An intra-third-cerebroventricular (13V) injection of PGE2 (0.1-10 nmol/kg) increased splenic SNA in a dose-dependent manner. An I3V injection of an EP1 agonist, 17-phenyl-omega-trinor PGE2 (1-30 nmol/kg), also resulted in a dose-dependent increase in splenic SNA, with a time course similar to that of PGE2-induced responses. In contrast, EP2 agonists, butaprost (10-100 nmol/kg I3V) and 11-deoxy-PGE1 (10-100 nmol/kg I3V), had no effect on splenic SNA. An I3V injection of M & B-28767 (an EP3/EP1 agonist, EP3 >> EP1) increased splenic SNA only at high doses (10-100 nmol/kg). Pretreatment with an EP1 antagonist, SC-19220 (200 and 500 nmol/kg), completely blocked the responses of splenic SNA to PGE2 (0.1 nmol/kg) and M & B-28767 (10 nmol/kg), respectively. These findings indicate that brain PGE2 increases splenic SNA through its action on EP1 receptors.

Bradykinin stimulates ceramide production by activating specific BK-B1receptor in rat small artery

2002 ◽  
Vol 282 (1) ◽  
pp. H175-H183 ◽  
Author(s):  
Leonard Kleine ◽  
Gele Liu ◽  
Normand Leblanc ◽  
Richard L. Hébert
Keyword(s):  
Vascular Tone ◽  
Functional Change ◽  
Mesenteric Arteries ◽  
Dependent Manner ◽  
Small Artery ◽  
Mediated Effects ◽  
Ceramide Generation ◽  
Dose Dependent ◽  
Hydrolysis Of ◽  
Ceramide Production

Bradykinin (BK), a proinflammatory factor and vasodilator, causes functional change of the small artery. However, it is not clear whether any of these changes induced by BK are mediated by N-acetyl-d-sphingosine (ceramide). Therefore, we investigated whether BK affects the hydrolysis of sphingomyelin and generation of ceramide in the intact rat small artery. Our results suggest that BK induces sphingomyelin hydrolysis and increases ceramide production in a time- and dose-dependent manner. Relative to controls, BK causes a 50% decrease in sphingomyelin levels. Ceramide levels increase in response to BK with the highest level being obtained with 10−8M BK as well as similar amounts of ceramide are generated when exogenous sphingomyelinase (SMase) is added. We then determined which of the two BK receptors (BK-B1antagonist Lys-Des-Arg9-Leu8-BK or the BK-B2antagonist HOE-140) are implicated in the BK-induced generation of ceramide. The BK-B2antagonist did not alter the effect of BK on ceramide generation, whereas the BK-B1antagonist blocked the BK-induced production of ceramide. Although ceramide had no effect on KCl-induced constrictions, ceramide dilated preconstricted (phenylephrine) small pressurized rat mesenteric arteries by ∼40%. These results suggest that the activation of the BK-B1receptor mediates the BK-induced activation of SMase and of the production of ceramide. In conclusion, BK-mediated effects on vascular tone may be due, at least in part, to the increased production of ceramide.

Effect of ethyl alcohol on motor function in canine stomach

1992 ◽  
Vol 262 (2) ◽  
pp. G223-G230
Author(s):  
L. C. Knight ◽  
A. H. Maurer ◽  
R. Wikander ◽  
B. Krevsky ◽  
L. S. Malmud ◽  
...  
Keyword(s):  
Gastric Emptying ◽  
Solid Food ◽  
Blood Levels ◽  
Lag Phase ◽  
Dependent Manner ◽  
Solid Meal ◽  
The Mean ◽  
High Doses ◽  
Mean Time ◽  
Dose Dependent

The aim of this study was to elucidate the effects of ethanol on gastric emptying and the trituration of solid food. With the use of a noninvasive physiological imaging technique, gastric processing of a radiolabeled solid meal was evaluated in unanesthetized dogs which ingested 6-8% ethanol solutions or received intravenous alcohol before the meal. Oral alcohol (resulting in blood levels up to 174 mg/dl) decreased the amplitude of antral contractions or completely abolished them. Alcohol did not significantly affect the fundamental frequency of contractions except at high doses, at which contractions were abolished. Alcohol lengthened the mean time to 50% of gastric emptying in a dose-dependent manner, from 132 +/- 3 min without alcohol to 160 +/- 10 min with oral alcohol at blood levels of 80-120 mg/dl (P less than 0.05). This was manifested by a lengthening of the lag phase, but there was no effect on the terminal slope of emptying (emptying rate) of the processed meal. At equal blood levels up to 120 mg/dl, orally administered alcohol had a more pronounced effect than intravenous alcohol. These data suggest that even low doses of dilute alcohol affect the ability of the antrum to process solid food and thereby contribute to impairment of gastric emptying.

scholarly journals Biphasic Dose–Response Induced by PCB150 and PCB180 in HeLa Cells and Potential Molecular Mechanisms

Dose-Response ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 155932582091004
Author(s):  
Ainy Zehra ◽  
Muhammad Zaffar Hashmi ◽  
Abdul Majid Khan ◽  
Tariq Malik ◽  
Zaigham Abbas
Keyword(s):  
Hela Cells ◽  
Molecular Mechanisms ◽  
Dependent Manner ◽  
Genotoxic Effects ◽  
Species Formation ◽  
Low Concentrations ◽  
Extracellular Signal ◽  
High Concentrations ◽  
High Doses ◽  
Dose Dependent

The polychlorinated biphenyls (PCBs) are persistent and their dose-dependent toxicities studies are not well-established. In this study, cytotoxic and genotoxic effects of PCB150 and PCB180 in HeLa cells were studied. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that the cell proliferation was stimulated at low doses (10−3 and 10−2 µg/mL for 12, 24, 48, and 72 hours) and inhibited at high doses (10 and 15 µg/mL for 24, 48, and 72 hours) for both PCBs. Increase in reactive oxygen species formation was observed in the HeLa cells in a time- and dose-dependent manner. Malondialdehyde and superoxide dismutase showed increased levels at high concentrations of PCBs over the time. Glutathione peroxidase expression was downregulated after PCBs exposure, suggested that both PCB congeners may attributable to cytotoxicity. Comet assay elicited a significant increase in genotoxicity at high concentrations of PCBs as compared to low concentrations indicating genotoxic effects. PCB150 and PCB180 showed decrease in the activity of extracellular signal–regulated kinase 1/2 and c-Jun N-terminal kinase at high concentrations after 12 and 48 hours. These findings may contribute to understanding the mechanism of PCBs-induced toxicity, thereby improving the risk assessment of toxic compounds in humans.

Design and performance of a new generation, compact, low cost, very high Doppler precision and resolution optical spectrograph

2012 ◽  
Author(s):  
Jian Ge ◽  
Bo Zhao ◽  
Scott Powell ◽  
Ji Wang ◽  
Adam Fletcher ◽  
...  
Keyword(s):  
Low Cost ◽  
And Performance ◽  
New Generation ◽  
Very High

scholarly journals Effect of Noni (Morinda citrifoliaLinn.) Fruit and Its Bioactive Principles Scopoletin and Rutin on Rat Vas Deferens Contractility: AnEx VivoStudy

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Vijayapandi Pandy ◽  
Megala Narasingam ◽  
Thubasni Kunasegaran ◽  
Dharmani Devi Murugan ◽  
Zahurin Mohamed
Keyword(s):  
Vas Deferens ◽  
Contractile Response ◽  
Rat Vas Deferens ◽  
Morinda Citrifolia ◽  
Dependent Manner ◽  
Per Se ◽  
High Doses ◽  
Dose Dependent ◽  
Higher Doses ◽  
Agonistic Effect

This study examined the effect of methanolic extract ofMorinda citrifoliaLinn. (MMC) and its bioactive principles, scopoletin and rutin, on dopamine- and noradrenaline-evoked contractility in isolated rat vas deferens preparations. MMC (1–40 mg/mL), scopoletin (1–200 μg/mL), and rutin hydrate (0.6–312.6 μg/mL) dose-dependently inhibited the contractility evoked by submaximal concentrations of both dopamine and noradrenaline, respectively. Haloperidol and prazosin, reference dopamine D2, andα1-adrenoceptors antagonists significantly reversed the dopamine- and noradrenaline-induced contractions, respectively, in a dose-dependent manner. Interestingly, MMCper seat higher doses (60–100 mg/mL) showed dose-dependent contractile response in rat vas deferens which was partially inhibited by high doses of haloperidol but not by prazosin. These results demonstrated the biphasic effects of MMC on dopaminergic system; that is, antidopaminergic effect at lower concentrations (<40 mg/mL) and dopaminergic agonistic effect at higher concentrations (>60 mg/mL). However, similar contractile response at high doses of scopoletin (0.5–5 mg/mL) and rutin hydrate (0.5–5 mg/mL)per sewas not observed. Therefore, it can be concluded that the bioactive principles of MMC, scopoletin, and rutin might be responsible for the antidopaminergic and antiadrenergic activities of MMC.

scholarly journals Parathyroid Hormone (1-34) Counteracts the Suppression of Interleukin-11 Expression by Glucocorticoid in Murine Osteoblasts: A Possible Mechanism for Stimulating Osteoblast Differentiation Against Glucocorticoid Excess

Endocrinology ◽  
2013 ◽  
Vol 154 (3) ◽  
pp. 1156-1167 ◽  
Author(s):  
Rika Kuriwaka-Kido ◽  
Shinsuke Kido ◽  
Yuka Miyatani ◽  
Yuji Ito ◽  
Takeshi Kondo ◽  
...  
Keyword(s):  
Bone Formation ◽  
Gene Transcription ◽  
Osteoblast Differentiation ◽  
Mechanical Strain ◽  
Dependent Manner ◽  
Rapid Induction ◽  
Kinase C ◽  
High Doses ◽  
Interfering Rna ◽  
Dose Dependent

Abstract Glucocorticoid (GC) excess causes a rapid loss of bone with a reduction in bone formation. Intermittent PTH (1-34) administration stimulates bone formation and counteracts the inhibition of bone formation by GC excess. We have previously demonstrated that mechanical strain enhances interleukin (IL)-11 gene transcription by a rapid induction of ΔFosB expression and protein kinase C (PKC)-δ-mediated phosphorylation of phosphorylated mothers against decapentaplegic (Smad)-1. Because IL-11 suppresses the expression of dickkopf-1 and -2 and stimulates Wnt signaling, IL-11 appears to mediate at least a part of the effect of mechanical strain on osteoblast differentiation and bone formation. The present study was undertaken to examine the effect of PTH(1-34) and GCs on IL-11 expression in murine primary osteoblasts (mPOBs). PTH(1-34) treatment of mPOBs enhanced IL-11 expression in a time- and dose-dependent manner. PTH(1-34) also stimulated ΔFosB expression and Smad1 phosphorylation, which cooperatively stimulated IL-11 gene transcription. PTH(1-34)-induced Smad1 phosphorylation was mediated via PKCδ and was abrogated in mPOBs from PKCδ knockout mice. Dexamethasone suppressed IL-11 gene transcription enhanced by PTH(1-34) without affecting ΔFosB expression or Smad1 phosphorylation, and dexamethasone-GC receptor complex was bound to JunD, which forms heterodimers with ΔFosB. High doses of PTH(1-34) counteracted the effect of dexamethasone on apoptosis of mPOBs, which was blunted by neutralizing anti-IL-11 antibody or IL-11 small interfering RNA. These results demonstrate that PTH(1-34) and GCs interact to regulate IL-11 expression in parallel with osteoblast differentiation and apoptosis and suggest that PTH(1-34) and dexamethasone may regulate osteoblast differentiation and apoptosis via their effect on IL-11 expression.

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