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R Angel

Publications and source records attributed to R Angel.

At least 19 recordsLinked to original sources
PubMed2007

Characterization of the chicken small intestine type IIb sodium phosphate cotransporter.

Intestinal absorption and renal resorption play a critical role in overall phosphorus homeostasis in chickens. Using RNase-ligase-mediated rapid amplification of cDNA ends PCR, we obtained a cDNA from the broiler small intestine that encodes a type IIb Na-dependent phosphate transporter. The cDNA has an open reading frame of 2,022 bp and predicts a 674-amino acid protein with a molecular mass of approximately 74 kDa. Prediction of membrane spanning domains based on the hydrophilic and hydrophobic properties of the amino acids suggests 8 transmembrane domains, with both the NH(2) and COOH termini being intracellular. The Na-inorganic phosphate (Pi) IIb cotransporter has relative high homology with other type II Na-Pi cotransporters but low homology with the type I or type III Na-Pi cotransporters. Northern blot analysis demonstrated the presence of a single mRNA transcript present predominantly in the small intestine, with the highest expression in the duodenum, followed by the jejunum and ileum. In situ hybridization indicated that the Na-Pi cotransporter mRNA is expressed throughout the vertical cryptvillus axis of the small intestine. Reduction of P in the diet of chicks from hatch to 4 d of age resulted in a significant induction of Na-Pi cotransporter mRNA expression in the small intestine. Further study is needed to elucidate its physiological role in intestinal phosphate absorption in chickens.

Amino Acid Sequence↗
PubMed2006

Effect of dietary phosphorus, phytase, and 25-hydroxycholecalciferol on broiler chicken bone mineralization, litter phosphorus, and processing yields.

Three floor pen experiments (Exp) were conducted to evaluate low nonphytin P (NPP) concentrations and the NPP sparing effect of phytase (PHY) and 25-hydroxycholecalciferol (25D) on bone mineralization, bone breaking during commercial processing, litter P, and water-soluble P (WSP) concentrations. Tested treatments (TRT) were control, National Research Council NPP; University of Maryland (UMD) NPP; UMD + PHY, UMD NPP reduced by 0.064% NPP + 600 U of PHY/kg; UMD + PHY + 25D, UMD NPP reduced by 0.090% NPP + 600 U of PHY and 70 microg of 25D/kg; control + PHY mimicked the industry practice of diets by 0.1% when PHY is added; and negative control with 90% UMD NPP concentrations. UMD + PHY and control + PHY diets contained 600 U of PHY/kg, and UMD + PHY + 25D contained 600 U of PHY + 70 microg of 25D/kg. Performance results were presented separately. After each Exp, litter P and WSP were determined, and bone measurements were obtained on 8 or 10 broilers per pen. Tested TRT did not affect broiler BW. Femur ash weight of broilers fed the UMD and UMD + PHY + 25D was lower in all Exp compared with that of broilers fed the control diet. Femur ash was similar for control and UMD + PHY broilers, yet averaged over all Exp, UMD + PHY broilers consumed 39% less NPP and required less NPP per gram of femur ash than those on the control (4.87 and 7.77 g of NPP/g of ash, Exp 3). At the end of Exp 3, broilers were processed in a commercial facility. Despite reductions in NPP intake and bone mineralization, no differences were observed in measurements of economic importance (parts lost, carcass yield, and incidence of broken bones). The P excretion per bird was lowest for birds fed the UMD + PHY + 25D diet followed by those fed the UMD + PHY and negative control diets (10.44, 12.00, and 13.78 g of P/bird, respectively) and were highest for those fed the control diet (19.55 g of P/bird). These results suggest that feeding diets low in P together with PHY and 25D will not affect performance or increase losses at processing while resulting in improved P retention and reductions in P and WSP excreted.

6-Phytase↗
PubMed2006

Total and water-soluble phosphorus excretion from swine fed low-phytate soybeans.

A study was conducted to evaluate the impact of feeding soybean meal (SBM) from low-phytate (LP) or traditional phytate (TP) soybeans on performance and excretions from growing swine. Ninety-six crossbred barrows (initial BW = 18 +/- 0.3 kg) were allocated by BW to 24 pens and fed 1 of 4 treatment diets: TP SBM without supplemental phytase; TP SBM plus 500 phytase units of phytase/kg, as-fed basis [Ronozyme P (CT) 2500; DSM Nutritional Products, Basel, Switzerland]; LP SBM (USDA-ARS breeding line CX1834-1) without supplemental phytase, and LP SBM plus phytase. All diets within a feeding phase were formulated to be isocaloric and have similar available Lys and nonphytin P content. Pens were assigned randomly to treatments at the beginning of each of the 4 feeding phases. An indigestible marker was added to the mash feed. Individual pig weights and fecal samples were collected, and feed disappearance by pen was recorded weekly. No phytase inclusion or SBM source effects were observed for pen ADG, ADFI, or G:F (P > 0.05). Total tract apparent digestibility of DM and OM was not different among treatment groups (P > 0.05). Apparent digestibility of P was greater for pigs fed diets containing the LP SBM (48.9 vs. 42.4%; P < 0.01) and less when diets included phytase (44.3 vs. 47.0%; P < 0.0001). Total P (tP) and water-soluble P (WSP) excreted were affected by dietary treatment (tP: 20.0, 18.0, 16.8, and 13.8 g/kg of feces DM, P < 0.01; and WSP: 10.9, 10.1, 9.1, and 8.5 g/kg, P < 0.01, for TP SBM without supplemental phytase, TP SBM plus 500 phytase units of phytase/kg, LP SBM without supplemental phytase, and LP SBM plus phytase diets, respectively). Inclusion of phytase decreased tP and WSP excreted (P < 0.01), as did use of LP SBM (P < 0.01). Diet effects on the fraction of excreted tP that was WSP were observed (P < 0.01); however, there was not a significant effect of SBM source. Inclusion of exogenous phytase in diets increased the proportion of tP that was excreted as WSP from 55% in diets without phytase to 59% in diets containing phytase. The findings suggest that there is a need for LP soybeans as a dietary component to minimize environmental impacts.

Animal Feed↗
PubMed2005

Effects of dietary phosphorus, phytase, and 25-hydroxycholecalciferol on performance of broiler chickens grown in floor pens.

Three 49-d experiments (Exp 1, 2, and 3) with broilers in floor pens were conducted to test the applicability of nonphytin phosphorus (NPP) requirements and the NPP-sparing effect of phytase (PHY) and 25-hydroxycholecalciferol (25D) determined previously in battery Exp. Six dietary NPP treatments were tested using a 4-phase feeding program. Treatments 1 to 6 were NRC (1994) NPP (C); University of Maryland (UMD) NPP; UMD NPP - 0.064% (UMD+PHY); UMD NPP - 0.09% (UMD+PHY+25D); NRC - 0.10% (C+PHY), and 90% UMD NPP (NC), respectively. Treatments 3, 4, and 5 had 600 U of PHY/kg of diet. Treatment 4 also had 70 microg of 25D/kg of diet; NPP concentrations were reduced to account for the sparing effect of these additives. No differences in hatch to 49 d BW were observed between treatments in Exp 1 and 2, and only in Exp 3 were the BW of the NC broilers (2.86 kg) different (P < 0.05) from those fed the C, UMD, and UMD+PHY treatments (2.96, 2.94, and 2.98 kg, respectively). Cumulative NPP consumption per bird was lowest (P < 0.05) for broilers fed the UMD+PHY+25D treatment (8.65 g in Exp 3) compared with those fed the C, NC, UMD, and UMD+PHY treatments (18.19, 10.60, 13.63, and 11.01 g, respectively for Exp 3). Application of any of these treatments reduced total P and NPP consumption compared with C. The results of this series of floor pen Exp validate the UMD NPP recommendations for a 4-phase feed program and the PHY and 25D NPP-sparing effects observed in battery trials without negatively affecting broiler performance.

6-Phytase↗
PubMed2005

Performance of broiler chickens fed diets supplemented with a direct-fed microbial.

From hatch to 18 d of age broilers were fed starter diets with (0.9 kg/ton) or without direct fed microbial (DFM). At 18 d, birds were weighed and, within DFM treatment (trt), randomly assigned to battery pens. In Exp 1, a 2 x 2 factorial arrangement of nutrient density [control (C, 19.3% protein (CP), 0.84%, Ca 0.37% nonphytin P (nPP); and 17.1% CP, 0.8% Ca, and 0.3% nPP in the grower (Gr) and finisher (Fn) diets, respectively) and moderate (M) (17% CP, 0.69% Ca, 0.30% nPP; 15% CP, 0.66% Ca, 0.25% nPP in the Gr and Fn diets, respectively)] and DFM concentration [0 or 0.9 kg/ton (++)] was used. Exp 2 was a 2 (DSM at 0 and 0.45 kg/ton) x 3 (nutrient densities) factorial. Exp 2 included a low (L) nutrient density that differed from diet M only in Ca and nPP concentrations and an added trt, diet M with 0.45 kg/ ton DFM as in Exp 1. At the end of the Gr and Fn weight, feed efficiency, apparent nutrient retention were determined, and 4 birds per pen were sampled for tibia ash. In Exp 2, gains in the Gr phase were 1,122.0, 983.7, 1,121.5, 930.7, and 1,151.5 g in birds fed the C, M, M+, L, and L+ diets, respectively. Addition of DFM to the M diet overcame the negative effect of nutrient concentration on performance but not when the L diet was fed. Nutrient level and DFM affected apparent protein, Ca, and P retention at 32 or 42 d of age with retention increasing as nutrient level decreased and with DFM added to the diet. Ca and P retention at 28 d (Exp 1) was higher in birds fed M++ (45.8 and 46%, respectively) than in those fed the C diet (38.7 and 40.0%, respectively). Feeding the M and L diets resulted in lower tibia ash than that of birds fed the C diet, but the addition of DFM to low nutrient diets overcame this negative effect.

Animal Feed↗
PubMed2005

Evaluation of the broiler's ability to adapt to an early moderate deficiency of phosphorus and calcium.

We studied the ability of broiler chickens to adapt to early moderate P and Ca deficiencies by evaluating the impact of feeding different concentrations of P and Ca, from 1 to 18 d, on performance, bone characteristics, and nutrient absorption in the grower (Gr) period (18 to 32 d). Two starter (St) diets were fed from 1 to 18 d: a control (C) diet [0.45% nonphytate P (nPP) and 0.9% Ca] and a low (L) diet (0.30% nPP and 0.6% Ca). On d 19, half of the birds fed the St C diet were switched to a Gr C diet (0.40% nPP and 0.8% Ca), and the other half were switched to a Gr L diet (0.30% nPP and 0.6% Ca), whereas those fed the L diet in the St phase were fed the L diet in the Gr phase, resulting in a total of 3 treatments. Broiler chickens fed the St L diet weighed less (P < 0.05) than those fed the St C diet at 18 d; however, by 23 d they had they caught up to the C-C birds, and no BW differences (P > 0.05) were observed at 28 and 32 d. Feeding the St L diet resulted in decreased (P < 0.05) tibia ash at 18 d, but by 32 d their tibia ash was not different from that of birds fed the St C and Gr L diets. Broilers subjected to P and Ca restriction from hatch to 18 d absorbed more P and Ca during all times sampled than birds fed the St C and Gr C diets or those fed the St C and the Gr L diet. These results demonstrated that modern broilers exhibited a high adaptive capacity when they were exposed to early dietary P or Ca restrictions.

Adaptation, Physiological↗
PubMed2004

Influence of dietary calcium and phytase on phytate phosphorus hydrolysis in broiler chickens.

The effect of Ca and phytase on phytate phosphorus (PP) hydrolysis was studied in vitro and in vivo. In vitro, PP hydrolysis by a 3-phytase and a 6-phytase was studied at pH 2.5 and 6.5 with Ca added at levels equivalent to 0, 0.1, 0.2, 0.4, 0.7, or 0.9% of the diet. Irrespective of enzyme, Ca at a level as low as 0.1% reduced (P < 0.05) PP hydrolysis at pH 6.5. To test these effects in vivo, 22-d-old male broilers were fed 1 of 6 diets (10 replicate pens of 4 birds per diet) for 30 h. The experimental design was a 3 x 2 factorial arrangement of 3 phytase treatments (0, 500 U of phytase A/kg of diet, and 500 U of phytase B/kg of diet) and 2 added Ca levels (0 and 0.5% from CaCO3) to a corn-soy basal diet. Adding Ca to the diet resulted in a reduction (P < 0.05) in ileal PP disappearance from 69.2 to 25.4% when the 0 and 0.5% added Ca diets were fed, respectively, and in apparent ileal Ca and P absorption (46.3 to 33.6% and 67.9 to 29.4% when 0 and 0.5% Ca were added, respectively). Inclusion of a 3-phytase improved (P < 0.05) ileal PP disappearance from 25.4 to 58.9% in diets containing 0 and 0.5% added Ca, but the improvement was less pronounced with a 6-phytase. Apparent ileal Ca absorption was improved (P < 0.05) when Ca, phytase, or both were added to the diet.

6-Phytase↗
PubMed2003

Ultrastructural patterns of secretory activity in poison cutaneous glands of larval and juvenile Dendrobates auratus (Amphibia, Anura).

A transmission electron-microscope study has been performed on larval and juvenile skin of the Central American arrow-frog Dendrobates auratus to investigate early secretory processes and maturational changes in the serous (poison) glands. Poison biosynthesis involves the endoplasmic reticulum (both smooth and rough types), as well as Golgi stacks which release early serous product as secretory vesicles (or pre-granules). These vesicles contain fine-grained material, along with single electron-opaque bodies, spheroidal in shape, that accompany the grained product throughout its post-Gogian, maturational change. The first steps of this process involve condensation and lead to the formation of secretory granules with a glomerular-like substructure, resulting from a thick, random aggregation of rods (secretory granule subunits). Advanced maturational activity causes the loss of peculiar granule substructure: the dense bodies split into fragments, whereas the thick glomerular arrangement becomes looser, until the secretory product changes into a dispersed material. This ultrastructural study revealed biosynthesis and maturation processes in close sequence, suggesting the poison of D. auratus contains proteins and/or peptides as well as lipophilic compounds. Molecules of both these classes are known to perform several roles relevant to survival strategies in extant anurans. Furthermore, the ephemeral granules with a glomerular-like substructure detected in tadpoles and froglets exhibit the complex patterns of mature poisons in adult specimens of other anurans: Hylidae and related families. This agrees with current trends in the taxonomy of these advanced frogs and underlines the pertinence of an ontogenetic approach in investigating anuran phylogenesis.

Amphibians↗
PubMed2003

Water-soluble phosphorus in fresh broiler litter is dependent upon phosphorus concentration fed but not on fungal phytase supplementation.

This experiment determined the effects of different phosphorus (P) feeding programs on total and water-soluble P excretion by broilers. Ross 308, male broilers were fed an industry (IND) diet (0.48, 0.35, 0.31, and 0.30% nonphytate P; NPP), an industry diet with reduced NPP and supplemental phytase [IND + PT; 600 phytase units (FTU)/kg; 0.36, 0.26, 0.20, and 0.19% NPP], a diet to more closely meet the birds' NPP requirements in which NPP was reduced further with supplemental phytase (REQ + P; 600 FTU/kg; 0.36, 0.26, 0.19, and 0.09% NPP), or a diet with low-phytate(lpa 1-1) corn with supplemental phytase (LPA + P; 600 FTU/kg; 0.37, 0.29, 0.19, 0.19% NPP). These diets were fed from hatch to 17 d, 17 to 31 d, 31 to 42 d, and 42 to 49 d of age, respectively. Fungal phytase was analyzed prior to diet formulation. Diets were fed to six replicate pens of 39 birds per pen. Litter samples were collected at 49 d of age and frozen prior to analyses. Diet did not significantly affect broiler performance (average BW at 49 d = 3.03 kg), tibia, or toe ash throughout the study (P > 0.05). Litter from broilers fed the IND diet was significantly higher (P < or = 0.05) in total and water-soluble P (1.11 and 0.22% of DM, respectively) compared with litter from broilers fed IND + PT (0.84 and 0.14% of DM, respectively), REQ + P (0.78 and 0.11% of DM, respectively), or LPA + PT (0.64 and 0.12% of DM, respectively). Litter total and water-soluble P were not significantly different among broilers fed IND + PT, REQ + PT, or LPA + PT. In conclusion, phytase supplementation did not affect the solubility of P in the litter regardless of P feeding program.

6-Phytase↗
PubMed2003

Effect of dietary calcium, 25-hydroxycholecalciferol, or bird strain on small intestinal phytase activity in broiler chickens.

Broilers chickens have limited ability to utilize phytate phosphorus (PP), and the influence of nutrients on the activity and efficacy of intestinal phytase is unclear. Therefore in a 2 x 2 x 2 factorial experiment, male chicks were fed 0 or 0.21 mg/kg 25-hydroxycholecalciferol (25-OH D3), 4 or 9 g/kg Ca supplied from CaCO3 or Ca malate from 14 to 24 d of age (six pens/treatment, eight birds/pen). Source of Ca had no effect on tibia ash, intestinal phytase activity, or apparent ileal PP hydrolysis. Phytase activity (Vmax) within brush border vesicles prepared from small intestinal mucosa was greater in chicks fed 4 vs. 9 g/kg Ca (P < or = 0.05). Similarly, birds fed 4 vs. 9 g/kg Ca were able to hydrolyze an additional 24.36% PP (P < 0.01). Intestinal phytase activity and apparent ileal PP hydrolysis were not affected by 25-OH D3 supplementation, but tibia ash was improved by 2.7% (P < 0.01). A subsequent experiment validated the effect of dietary Ca (4 and 9 g/kg) and elucidated differences between strains (Ross 308 and Hubbard x Peterson) from 8 to 22 d of age (six pens/treatment, eight birds/pen). The strains responded similarly to dietary Ca in terms of intestinal phytase and apparent ileal PP hydrolysis. Intestinal phytase activity was 9% greater in birds fed 4 vs. 9 g/kg Ca (P < 0.05) and apparent ileal PP hydrolysis was 11.9% greater (P < 0.02). In conclusion, a typical dietary Ca concentration (9 g/kg) reduced intestinal phytase activity and apparent ileal PP hydrolysis.

6-Phytase↗
PubMed2003

Broiler nonphytin phosphorus requirement in the finisher and withdrawal phases of a commercial four-phase feeding system.

Two experiments were conducted to determine the nonphytin phosphorus (nPP) requirement for broilers, based on broken line analysis, in the finisher (32 to 42 d) and withdrawal phases (42 to 49 d) of a four-phase feeding program. The determined nPP concentrations used were 0.15, 0.19, 0.26, and 0.31% in the finisher phase, experiment 1 (Exp 1), and 0.10, 0.13, 0.22, and 0.27% in the withdrawal phase, experiment 2 (Exp 2). The analyzed calcium levels in the diets were 0.69 +/- 0.02% and 0.72 +/- 0.05% in Exp 1 and 2, respectively. In Exp 2, an additional treatment was included in which birds were fed NRC-recommended (1994) nPP levels from hatch to 49 d. There were no differences (P>0.05) among dietary treatments in weight gain, feed intake, and feed efficiency in either experiment. In Exp 1, tibia ash weight of birds fed the diets containing 0.15% nPP was lower (P<0.05) than that of birds fed diets containing 0.19, 0.26, or 0.31% nPP. A requirement of 0.20 +/- 0.01% nPP was determined for male broilers weighing between 1,541 to 2,194 g and from 32 to 42 d of age based on broken line analysis of tibia ash weight response to different dietary nPP levels. In Exp 2, the nPP requirement of male broilers weighing between 2,396 g at 42 d and 3,076 g at 49 d, based on tibia ash weight, was 0.16 +/- 0.02% nPP.

Animal Nutritional Physiological Phenomena↗
PubMed1998

[Placental histopathology in premature rupture of membranes. Its relationship with microbiological findings, maternal, and neonatal outcome].

BACKGROUND: There is a close relationship between premature membrane rupture, bacterial infections and premature labor. AIM: To study placental histological changes in patients with preterm membrane rupture. To establish a relationship between pathological findings, amniotic fluid and lower genital tract microbiological studies, maternal and neonatal outcome. PATIENTS AND METHODS: Patients with premature membrane rupture of membranes between 24 and 34 weeks of gestation participated in this study. On admission, patients had no evidence of clinical chorioamnionitis, labor or fetal distress. Microbiological studies of the amniotic fluid and cervicovaginal secretions were performed and the placenta was sent for pathological study. RESULTS: Seventy one placentas were available for the study. The main pathological findings were acute chorioamnionitis in 58%, trophoblastic proliferation in 38%, funisitis in 37%, villitis in 16%, fetal vascular lesions in 14% and no findings in 17%. Microbial invasion of amniotic cavity was present in 89% of acute chorioamnionitis. Sixty one percent of trophoblastic proliferation and all fetal vascular lesions were associated with negative amniotic and cervical cultures. Newborns with acute funisitis had a higher frequency of neonatal death (29%), severe asphyxia (42%) and neonatal infections (29%). CONCLUSIONS: Acute chorioamnionitis is the most frequent finding in patients with preterm membrane rupture and microbial invasion of amniotic cavity. In the absence of intra amniotic infection, proliferation of the trophoblast and the presence of fetal vascular lesions predominate. Acute funisitis is strongly associated with adverse fetal outcome.

Amniotic Fluid↗
PubMed1995

Chronic treatment with thioctic acid does not protect against malonate toxicity in vivo.

We reported previously that short-term systemic pretreatment with thioctic acid is protective against NMDA and malonate lesions of the striatum. In the current study, we examined the effects of 3 weeks of pretreatment with various doses of thioctic acid (5-60 mg/kg per day) on malonate-induced striatal degeneration in adult rats. In this paradigm, we were unable to demonstrate protection against malonate toxicity. The reasons for the difference in efficacy between subacute and chronic treatment remain to be defined.

Animals↗
PubMed1995

Adaptive health behaviors among ethnic minorities.

Race, ethnicity, and cultural attitudes and practices are among the variables that influence health behaviors, including adaptive health behaviors. The following discussions highlight the important role of social conditions in shaping health behaviors and the central role of family in promoting health across the Asian, Hispanic, Native American, and African American ethnic groups. Factors that may lead to health-damaging behaviors are also discussed. The need for additional research that identifies correlations among physiological, social, and behavioral factors and health behaviors, as well as underlying mechanisms, is called for.

Adaptation, Psychological↗
PubMed1991

Risk and selection processes between the general and the specialty mental health sectors.

This paper examines risk, defined as the threat of danger or disruption, as a contextual concept important for understanding patterns of patient selection and referral. We explore the hypothesis that risks associated with mental disorder, as represented by factors such as thoughts about suicide or problems associated with drinking, increase the probability of referral of patients receiving mental health care from general medical practitioners to the specialty mental health sector. Interview and claims data from the RAND Health Insurance Experiment, a large experimental study of coinsurance, are used to examine referral processes over a five-year period. Risk, and especially a measure of suicide thoughts, increase the probability of referral to specialty care. Women and persons with higher education are more likely to use specialty services; older persons are less likely to use such services. Understanding referral requires attention to the behavioral contingencies and illness behavior surrounding the presentation of mental disorder.

Educational Status↗
PubMed1989

The factor structure of the CES-D in the Hispanic Health and Nutrition Examination Survey: the influences of ethnicity, gender and language.

In this paper, we examine the factor structure of the Center for Epidemiologic Studies-Depression Scale (CES-D) in the Hispanic Health and Nutrition Examination Survey (Hispanic HANES). The Hispanic HANES provides a unique opportunity to examine the patterning of depressive symptoms among the three major Hispanic groups in the U.S. and to compare the factor structures that emerge from the analysis to other studies using this approach. Different factor structures emerged for the Hispanic groups as compared to previous analyses of the CES-D with non-Hispanic populations. We also found significant intra-group differences among Mexican-Americans, Puerto Ricans, and Cuban-Americans which were strongly influenced by the gender of the respondent and the language in which the person was interviewed.

Cross-Cultural Comparison↗