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1.
Br Poult Sci ; 62(3): 452-458, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33511863

RESUMO

1. In recent times the use of food waste in animal diets has gained considerable attention because of the increasing demand to cover the needs of human population and the high prices of conventional, arable based, animal feeds.2. The aim of the present study was to investigate the effect of adding dried human food waste to the diet of meat-type chickens (broilers). Two hundred, one-day-old broilers were divided into two treatment groups, with 10 replicate pens containing 10 birds per pen. The duration of the study was 42 days. In the control (C), the diet did not contain any food waste, whereas in the second treatment (T) food waste residues from hotels made up 15% of the diet. Diets had similar crude protein and metabolisable energy content.3. Feed intake and body weight were recorded in order to calculate weight gain and feed conversion ratio (FCR). Carcase and breast muscle yield, the weight of selected internal organs and the level of selected biochemical and haematological parameters were determined. Quality of breast muscle meat was assessed.4. Broilers fed the control treatment consumed more feed and gained more weight compared to broilers fed waste; however, the FCR was similar. No major differences were seen for internal organ weights and haematological parameters, although some differences were observed in colour traits and shear force of meat. It was concluded that there is a potential for use of food waste in broiler diets.


Assuntos
Galinhas , Eliminação de Resíduos , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dieta/veterinária , Carne/análise
2.
J Anim Physiol Anim Nutr (Berl) ; 102(1): e288-e298, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28508581

RESUMO

Twenty-four dairy sheep and goats, respectively, were assigned each to three homogenous subgroups per animal species and fed the same diet in quantities which met 70% (underfeeding), 100% (control) and 130% (overfeeding) of their energy and crude protein requirements. The results showed that the underfed sheep in comparison with the control had significantly lower glutathione reductase (GR), superoxide dismutase (SOD), catalase and glutathione peroxidase (GPX) activities and total antioxidant capacity (measured with Ferric Reducing Ability of Plasma [FRAP] assay) in their blood plasma. A significant increase in the glutathione transferase (GST) and GPX activities, malondialdehyde content and total antioxidant capacity (measured with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) [ABTS] assay) in the blood plasma of underfed goats compared with controls was observed, while the opposite happened for the GR and SOD activities. The underfeeding in both animal species caused a significant increase in the protein carbonyls (PC) content of their blood plasma. The overfeeding, compared with the control, caused a significant decline in the GPX activity and total antioxidant capacity (measured with FRAP) in the blood plasma of sheep while the opposite happened for the GPX and GST activities in the case of goats. The overfed animals, of both species, compared with the respective controls, had higher PC content in their blood plasma. The feeding level had no noticeable impact on the antioxidants' enzymes activities of milk in both animal species. Moreover, the underfeeding in the blood plasma and the overfeeding in milk of both animal species resulted into a significant increase in the PC content. Finally, only in sheep milk, the underfeeding, compared with the respective control, and overfeeding reduced significantly the total antioxidant capacity (measured with ABTS). The feeding level caused oxidative stress in both organism and milk but the response was different in animal species and needs further investigation.


Assuntos
Ração Animal/análise , Cabras/sangue , Leite/química , Ovinos/sangue , Animais , Antioxidantes/metabolismo , Peso Corporal , Dieta/veterinária , Peroxidação de Lipídeos , Estresse Oxidativo/efeitos dos fármacos
3.
J Anim Physiol Anim Nutr (Berl) ; 102(1): 142-151, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28447361

RESUMO

The impact of dietary supplementation with microalgae on goat's milk chemical composition, fatty acids (FA) profile and enzymes activities related to antioxidant mechanism has not been well documented. Thus, this study aimed to investigate the effects of dietary inclusion of Chlorella vulgaris on the following: (i) milk yield, chemical composition and FA profile, (ii) the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione transferase (GST) and glutathione peroxidase (GSH-Px) in blood plasma and (iii) the activities of SOD, GR and lactoperoxidase (LPO) in milk of goats. Furthermore, the oxidative stress indicators for measuring total antioxidant and free radical scavenging activity [ferric reducing ability of plasma (FRAP) and 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays] and oxidative stress biomarkers [malondialdehyde (MDA) and protein carbonyls (PC)] were also determined in blood plasma and milk of the animals. For this purpose, 16 cross-bred goats were divided into two homogenous groups. Each goat of both groups was fed individually with alfalfa hay and concentrates separately. The concentrates of the control group (Control) had no microalgae, while those of the Chlorella group were supplemented with 10 g lyophilized Chlorella vulgaris/kg concentrates (Chlorella). Thus, the average intake was 5.15 g Chlorella vulgaris/kg DM. The results showed that the dietary inclusion of Chlorella vulgaris had not noticeable impact on goat's milk yield, chemical composition and FA profile. Significantly higher SOD (by 10.31%) and CAT (by 18.66%) activities in the blood plasma of goats fed with Chlorella vulgaris compared with the control were found. Moreover, the dietary supplementation with Chlorella vulgaris caused a significant increase in SOD (by 68.84%) activity and a reduction in PC (by 24.07%) content in goat's milk. In conclusion, the Chlorella vulgaris inclusion in goat's diets improved the antioxidant status of both animals and milk.


Assuntos
Ração Animal/análise , Chlorella vulgaris , Dieta/veterinária , Cabras/fisiologia , Leite/enzimologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Antioxidantes , Biomarcadores , Suplementos Nutricionais , Enzimas/sangue , Enzimas/metabolismo , Ácidos Graxos/química , Feminino , Lactação , Peroxidação de Lipídeos , Oxirredução , Estresse Oxidativo , Carbonilação Proteica
4.
J Anim Physiol Anim Nutr (Berl) ; 101(4): 733-742, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27040180

RESUMO

This study investigated the effects of dietary inclusion of soya bean oil combined with fish oil (SFO) on the activities of a) superoxide dismutase (SOD), glutathione reductase (GR), catalase (CAT) and glutathione transferase (GST) in blood plasma and b) SOD, GR, CAT and lactoperoxidase (LPO) in the milk of sheep and goats. Furthermore, the oxidative stress indicators for measuring total antioxidant activity and free radical scavenging activity [ferric reducing ability of plasma (FRAP) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays] and oxidative stress biomarkers [malondialdehyde (MDA) and protein carbonyl (PC)] were also determined in the blood plasma and milk of the animals. For this purpose, twelve dairy sheep and twelve dairy goats were assigned each to two homogenous subgroups. Treatments in both animal species involved a control diet without added oil and a diet supplemented with 5% soya bean oil and 1% fish oil. The results showed that the inclusion of SFO in the diets of sheep and goats increased significantly the activities of CAT and GR in their blood plasma. The same effect was observed for the activities of GST and FRAP in the blood plasma of goats. Moreover, the fact that the goats had significantly higher average daily PUFA intake (3.62 g/kg BW0.75 ) compared to sheep (2.51 g/kg BW0.75 ) resulted in an enhancement in the MDA content in their plasma. A significant increase in CAT activity in the milk in both animal species fed with SFO diets was also found. Finally, due to the higher apparent transfer rate of n-3 FA from the diet to the milk in sheep, the PC concentrations were found to be enhanced in their plasma and milk. In conclusion, the impact of dietary SFO supplementation on the oxidative status of body and/or on the milk of small ruminants depends not only on the daily PUFA intake, but also on the amount of n-3 FA that reach their milk.


Assuntos
Enzimas/sangue , Óleos de Peixe/farmacologia , Cabras/fisiologia , Leite/química , Ovinos/fisiologia , Óleo de Soja/farmacologia , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dieta/veterinária , Enzimas/metabolismo , Feminino , Óleos de Peixe/administração & dosagem , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Cabras/sangue , Ovinos/sangue , Óleo de Soja/administração & dosagem
5.
J Anim Physiol Anim Nutr (Berl) ; 101(2): 275-283, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27184296

RESUMO

Microalgae might be considered as an alternative source of fat and/or protein for ruminant's diets. However, changes in populations of ruminal micro-organisms associated with biohydrogenation process, methane and ammonia production in response to microalgae dietary supplementation have not been well characterized. Thus, 16 cross-bred goats were divided into two groups. Each goat of both groups was fed individually with alfalfa hay and concentrates separately. The concentrates of the control group had no microalgae while those of the treated group were supplemented with 10 g lyophilized Chlorella vulgaris/kg concentrate (chlor). On the 30th experimental day, samples of rumen fluid were collected for microbial DNA extraction, fatty acid profile and enzyme activity analyses. The results showed that the chlor diet compared with the control increased significantly the populations of Methanosphaera stadtmanae, Methanobrevibacter ruminantium and Methanogens bacteria and protozoa in the rumen of goats. A significant reduction in the cellulase activity and in the abundance of Ruminococcus albus, and a significant increase in the protease activity and in the abundance of Clostridium sticklandii in the rumen liquid of goats fed with the chlor diet, compared with the control, were found. Chlorella vulgaris supplementation promoted the formation of trans C18:1 , trans-11 C18:1 and monounsaturated fatty acids (MUFA), while the proportions of C18:0 and long-chain fatty acids (LCFA) reduced significantly in the rumen liquid of goats. This shift in ruminal biohydrogenation pathway was accompanied by a significant increase in Butyrivibrio fibrisolvens trans C18:1 -producing bacteria. In conclusion, the supplementation of diets with microalgae needs further investigation because it enhances the populations of methane-producing bacteria and protozoa.


Assuntos
Ração Animal/análise , Líquidos Corporais/enzimologia , Chlorella , Dieta/veterinária , Ácidos Graxos/metabolismo , Cabras/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Suplementos Nutricionais , Rúmen/fisiologia
6.
J Anim Physiol Anim Nutr (Berl) ; 101(5): 1004-1013, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27278119

RESUMO

This study investigated the effects of dietary inclusion of rumen-protected methionine alone or in combination with rumen-protected choline and betaine on: (i) milk yield, chemical composition and fatty acids (FA) profile and (ii) blood plasma glutathione transferase (GST) activity of periparturient ewes. Furthermore, the oxidative stress indicators for measuring total antioxidant and free radical scavenging activity [ferric reducing ability of plasma (FRAP) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays] were also determined in plasma and milk of ewes. Thus, 45 ewes were divided into three equal groups. Each animal of the control group fed daily with a basal diet. The same diet was offered also in each animal of the other two groups. However, the concentrate fed to M group was supplemented with 2.5 g/kg rumen-protected methionine, while the concentrate fed to MCB group with 5 g/kg of a commercial product which contained a combination of methionine, choline and betaine, all three in rumen-protected form. The results showed that the M diet, compared with the control, increased significantly the ewe's milk fat and the total solids content. Likewise, a tendency for higher milk fat and total solids content in ewes fed the MCB diet was also observed. Both M and MCB diets had not noticeable impact on ewes milk FA profile. Significantly higher FRAP values in the blood plasma of ewes fed the MCB and in the milk of ewes fed with the M diet compared with the control were found. Additionally, significantly higher GST activity in the blood plasma of ewes fed the M diet, compared with the control, was observed. Moreover, a significant increase (by 20%) and a tendency for increase (by 16.72%) in the growth rate of lambs nursing ewes fed with M and MCB diets, respectively, compared to controls, were found.


Assuntos
Betaína/administração & dosagem , Colina/administração & dosagem , Metionina/farmacologia , Leite/química , Rúmen/fisiologia , Ovinos/fisiologia , Ração Animal/análise , Animais , Antioxidantes/química , Betaína/farmacologia , Colina/farmacologia , Dieta/veterinária , Suplementos Nutricionais , Ácidos Graxos/química , Feminino , Lactação/efeitos dos fármacos , Metionina/administração & dosagem , Metionina/química , Gravidez , Ovinos/sangue
7.
Br Poult Sci ; 57(4): 551-8, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27172005

RESUMO

Concomitant presence of mycotoxins is more likely to appear than a single mycotoxicosis since many mycotoxigenic fungi grow and produce their toxic metabolites under similar conditions. The present study was designed to evaluate the efficacy of 4 mycotoxin binders to protect meat-type chickens against single and concomitant administration in the feed of two mycotoxins, namely aflatoxin B1 (AFB1) and ochratoxin A (OTA) both at concentration of 0.1 mg/kg. A total of 440 as hatched, d-old, Ross 308 broilers were reared for 42 d. There were 11 dietary treatments. Chickens were fed on either an uncontaminated basal diet, basal diet and AFB1, basal with concomitant presence of AFB1 and OTA, basal diet and three binders A, B and C (1%) with or without AFB1 or basal diet and binder D (0.5%) with or without concomitant presence of AFB1 and OTA. Performance, carcass yield and several biochemical parameters were examined. Mycotoxin concentration in liver and breast muscle samples was determined. Broiler performance under concomitant mycotoxin contamination was poorer than that under single mycotoxicosis. Mycotoxin presence increased relative heart weight compared to that of broilers fed on uncontaminated diets. Only OTA and not AFB1 was detected and only in the liver. OTA concentration was four-fold lower in broilers fed on a diet with binder compared to those fed on contaminated diets without binder. In conclusion, the study revealed that binder composition and presence or not of multiple toxins may be important factors for optimum broiler performance under mycotoxicosis.


Assuntos
Bentonita/metabolismo , Galinhas , Dieta/veterinária , Contaminação de Alimentos/análise , Micotoxicose/veterinária , Doenças das Aves Domésticas/prevenção & controle , Aflatoxina B1/metabolismo , Ração Animal/análise , Animais , Micotoxicose/microbiologia , Micotoxicose/prevenção & controle , Ocratoxinas/metabolismo , Doenças das Aves Domésticas/microbiologia , Distribuição Aleatória
8.
J Anim Physiol Anim Nutr (Berl) ; 100(3): 422-30, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26613803

RESUMO

Milk protein synthesis in the mammary gland involves expression of six major milk proteins' genes whose nutritional regulation remains poorly defined. In this study, the effect of long-term under- and overfeeding on the expression of as1-casein: CSN1S1, as2-casein: CSN1S2, ß-casein: CSN2, κ-casein: CSN3, α-lactalbumin: LALBA and ß-lactoglobulin: BLG gene in goat mammary tissue (MT) was examined. Twenty-four lactating dairy goat, at 90-98 days in milk, were divided into three homogenous subgroups and fed the same ration, for 60 days, in quantities which met 70% (underfeeding), 100% (control) and 130% (overfeeding) of their energy and crude protein requirements. The results showed a significant decrease in mRNA of CSN1S2, CSN2, CSN3 and LALBA genes in the MT of underfed goats compared with the overfed and on the CSN1S1 and BLG gene expressions in the MT of underfed goats compared with the respective control and overfed. CSN2 was the most abundant transcript in goat MT relative to the other milk proteins' genes. Significantly positive correlations were observed between the mRNA levels of caseins' and BLG genes with the milk yield. Moreover, a significant correlation was found between the mRNA levels of CSN1S2 with the milk protein, lactose content and lactose yield and also between the LALBA gene expression with the lactose content and lactose yield respectively. In conclusion, the feeding level and consequently the nutrients availability affected the milk lactose content, protein and lactose yield as well as the milk volume by altering the CSN1S1, CSN1S2, CSN2, CSN3, LALBA and BLG gene expression involved in their metabolic pathways.


Assuntos
Ração Animal/análise , Dieta/veterinária , Ingestão de Energia , Regulação da Expressão Gênica/efeitos dos fármacos , Cabras/fisiologia , Proteínas do Leite/metabolismo , Animais , Feminino , Glândulas Mamárias Animais/metabolismo , Leite/química , Proteínas do Leite/genética , Necessidades Nutricionais , Fatores de Tempo
9.
J Anim Physiol Anim Nutr (Berl) ; 99(1): 92-99, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24924522

RESUMO

The present study aimed to test the hypothesis that dietary protein source influences lipid metabolism-related parameters weaned piglets. The effects of soyabean meal (SB) and whey proteins (WP) on gene expression of several genes involved in the lipogenic process in liver, visceral (VAT) and subcutaneous (SAT) adipose tissues, plasma insulin concentration and fatty acid (FA) profile were investigated in 18 weaned piglets. Weaned piglets were fed one of two diets containing either SB or WP as the main protein source. Following a 10-h fasting period, plasma insulin concentration and FA profile were assessed at 56 and 72 days of age, whereas gene expression in liver, VAT and SAT was assessed at 72 days of age. Plasma insulin concentration was not affected by diet, although it was 40% lower in SB fed pigs. The SB pigs had lower 14:0 (p < 0.01) and higher 18:3n-3 (p < 0.001) levels in plasma in comparison with WP pigs. However, these changes were attributed to background differences in the dietary FA profile and not to a direct protein source effect. Gene expression of sterol regulatory element-binding protein 1 (SREBP-1) in liver and VAT were lower (p < 0.01 and p < 0.05, respectively) in SB compared to WP fed piglets, but no differences occurred in SAT. No changes were observed in sterol regulatory element-binding protein 2, liver X receptor, peroxisome proliferator-activated receptors α and γ and plasminogen activator inhibitor 1 mRNA levels, either in liver or in adipose tissues. In conclusion, dietary protein source, accompanied likely by side alterations in the dietary composition, affects lipid metabolism in pigs through the downregulation of SREBP-1, which is a crucial determinant of lipogenic process.


Assuntos
Ração Animal/análise , Dieta/veterinária , Glycine max/química , Metabolismo dos Lipídeos/efeitos dos fármacos , Proteínas do Leite/química , Suínos/metabolismo , Fenômenos Fisiológicos da Nutrição Animal , Animais , Masculino , Proteínas do Soro do Leite
10.
Opt Express ; 22(3): 3638-47, 2014 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-24663655

RESUMO

We present results from the first demonstration of a fully integrated SDN-controlled bandwidth-flexible and programmable SDM optical network utilizing sliceable self-homodyne spatial superchannels to support dynamic bandwidth and QoT provisioning, infrastructure slicing and isolation. Results show that SDN is a suitable control plane solution for the high-capacity flexible SDM network. It is able to provision end-to-end bandwidth and QoT requests according to user requirements, considering the unique characteristics of the underlying SDM infrastructure.

11.
Opt Express ; 21(5): 5487-98, 2013 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-23482120

RESUMO

Software defined networking (SDN) and flexible grid optical transport technology are two key technologies that allow network operators to customize their infrastructure based on application requirements and therefore minimizing the extra capital and operational costs required for hosting new applications. In this paper, for the first time we report on design, implementation & demonstration of a novel OpenFlow based SDN unified control plane allowing seamless operation across heterogeneous state-of-the-art optical and packet transport domains. We verify and experimentally evaluate OpenFlow protocol extensions for flexible DWDM grid transport technology along with its integration with fixed DWDM grid and layer-2 packet switching.

12.
Opt Express ; 21(7): 8865-72, 2013 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-23571976

RESUMO

We present the first elastic, space division multiplexing, and multi-granular network based on two 7-core MCF links and four programmable optical nodes able to switch traffic utilising the space, frequency and time dimensions with over 6000-fold bandwidth granularity. Results show good end-to-end performance on all channels with power penalties between 0.75 dB and 3.7 dB.


Assuntos
Redes de Comunicação de Computadores/instrumentação , Tecnologia de Fibra Óptica/instrumentação , Dispositivos Ópticos , Processamento de Sinais Assistido por Computador/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento
13.
Br Poult Sci ; 53(6): 817-27, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23398427

RESUMO

1. The study was part of a project designed to investigate if organic selenium (Se) can ameliorate the toxic effects of cadmium (Cd). The main objective of the present study was to investigate, in the chicken, the interactions between Se, Cd and the following elements: Sb, Ca, Cr, Co, Cu, Fe, Pb, Mg, Mn, Mo, Ni, V and Zn. 2. A total of 300 1-d-old chickens (broilers) were randomly distributed among 4 dietary treatments with 5 replicate pens per treatment. In T1, chickens were fed on a diet with 0·3 mg/kg added Se, without added Cd. In T2, chickens were fed on a diet with 0·3 mg/kg Se and 10 mg/kg Cd. In T3, chickens were fed on a diet with 0·3 mg/kg Se and 100 mg/kg of Cd added and in T4 treatment, chickens were fed on a diet with 3 mg/kg Se and 100 mg/kg Cd added. Se was added as Se-yeast. Cd was added as cadmium chloride (CdCl2). On d 28 and 42, two chickens per replicate pen were killed for collection of whole blood, liver, kidney and breast muscle samples. Samples were analysed by ICP-MS. The data were analysed using a multivariate linear model. 3. While low Cd concentrations in the diet led only to an increase of Cd concentration in the examined tissues, addition of high concentrations of Cd increased the concentration of Cd, Cu, Sb and V and decreased that of Se, Mn and Fe. Addition of high Se concentrations did not significantly reduce Cd concentration. 4. Prior to model application, correlations of 78 elements were noted, while after model application 39 correlations were noted. Most notably, Cd was correlated with Ca, Co, Cu and Mg, while Se was correlated with Mn. 5. The present study revealed several correlations between essential, probably essential and toxic elements illustrating the importance of the balance between pro-oxidants and antioxidants.


Assuntos
Cloreto de Cádmio/farmacologia , Galinhas/fisiologia , Metais/metabolismo , Selênio/farmacologia , Envelhecimento , Animais , Antioxidantes/metabolismo , Cloreto de Cádmio/sangue , Cloreto de Cádmio/metabolismo , Galinhas/crescimento & desenvolvimento , Dieta/veterinária , Relação Dose-Resposta a Droga , Rim/metabolismo , Modelos Lineares , Fígado/metabolismo , Espectrometria de Massas/veterinária , Metais/sangue , Análise Multivariada , Músculos Peitorais/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Selênio/sangue , Selênio/metabolismo
14.
Opt Express ; 19(26): B191-6, 2011 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-22274018

RESUMO

This paper introduces a novel ingress node design which takes advantage of video data partitioning in order to deliver enhanced video streaming quality when using H.264/AVC codec over optical burst switching networks. Ns2 simulations show that the proposed scheme delivers improved video traffic quality without affecting other traffic, such as best effort traffic. Although the extra network load is comparatively small, the average gain in video PSNR was 5 dB over existing burst cloning schemes, with a maximum end-to-end delay of 17 ms, and jitter of less than 0.35 ms.

15.
Opt Express ; 19(26): B235-41, 2011 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-22274024

RESUMO

An adaptive gridless OXC is implemented using a 3D-MEMS optical backplane plus optical modules (sub-systems) that provide elastic spectrum and time switching functionality. The OXC adapts its architecture on demand to fulfill the switching requirements of incoming traffic. The system is implemented in a seven-node network linked by installed fiber and is shown to provide suitable architectures on demand for three scenarios with increasing traffic and switching complexity. In the most complex scenario, signals of mixed bit-rates and modulation formats are successfully switched with flexible per-channel allocation of spectrum, time and space, achieving over 1000-fold bandwidth granularity and 1.5 Tb/s throughput with good end-to-end performance.

16.
Opt Express ; 19(12): 11182-8, 2011 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-21716346

RESUMO

An experimental demonstration of gridless spectrum and time switching is presented. We propose and demonstrate a bit-rate and modulation-format independent optical cross-connect architecture, based on gridless spectrum selective switch, 20-ms 3D-MEMS and 10-ns PLZT optical switches, that supports arbitrary spectrum allocation and transparent time multiplexing. The architecture is implemented in a four-node field-fiber-linked testbed to transport continuous RZ and NRZ data channels at 12.5, 42.7 and 170.8 Gb/s, and selectively groom sub-wavelength RZ channels at 42.7 Gb/s. We also showed that the architecture is dynamic and can be reconfigured to meet the routing requirements of the network traffic. Results show error-free operation with an end-to-end power penalty between 0.8 dB and 5 dB for all continuous and sub-wavelength channels.

17.
Opt Express ; 19(26): B277-82, 2011 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-22274030

RESUMO

We present results from the first gridless networking field trial with flexible spectrum switching nodes and 620 km of installed fibre links. Signals at 10G, 12.25G, 42.7G, DP-QPSK 40G, DP-QPSK 100G and 555G are generated, successfully transported and switched using flexible, custom spectrum allocation per channel. Spectrum defragmentation is demonstrated using integrated SOA-MZI wavelength converters. Results show error-free end-to-end performance (BER<1e-9) for the OOK channels and good pre-FEC BER performance with sufficient margin to FEC limit for the 40G and 100G coherent channels as well as for the 555G super-channel.

18.
Reprod Domest Anim ; 44(4): 677-84, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19642222

RESUMO

A study was conducted to evaluate the effects of maternal undernutrition on the hypothalamic-pituitary-gonadal axis in female sheep offspring. Pregnant ewes were fed to 100% throughout pregnancy (Control) or to 50% from 0 to 30 (R1) or from 31 to 100 days of gestation (R2). Female lambs were selected and fed to appetite throughout the study. At 2, 5.5 and 10 months of age a GnRH challenge was conducted. At the age of 10 months lambs were synchronized and blood samples were collected at 3 h intervals for 72 h following sponge removal. At slaughter (10 months) ovaries were removed and examined macroscopically. Maternal undernutrition did not affect the time of the onset of puberty, defined as the first increase in plasma progesterone concentrations >or=1 ng/ml. The magnitude of the pre-ovulatory gonadotrophin surge and the time to surge were unaffected by treatment. The LH and FSH response to GnRH challenge did not differ between groups at 2 and 5.5 months but at 10 months of age a higher (p < 0.05) FSH response was found in R1 group. Although the total number of visible follicles and corpora lutea did not differ between groups, a significant higher (p < 0.05) number of small (2-3 mm diameter) follicles in R1 group and a significant lower number (p < 0.05) of corpora lutea with diameter 8-11 mm and not even one with diameter >12 mm were detected in the ovaries of R2 lambs. In conclusion, maternal undernutrition during the first month of pregnancy resulted in increased pituitary sensitivity to GnRH and increased number of small follicles in the ovary, while during mid to late gestation resulted in a reduction of large corpora lutea in female offspring.


Assuntos
Hipotálamo/fisiologia , Desnutrição/veterinária , Ovário/fisiologia , Hipófise/fisiologia , Efeitos Tardios da Exposição Pré-Natal/veterinária , Ovinos , Envelhecimento , Animais , Corpo Lúteo/anatomia & histologia , Feminino , Hormônio Foliculoestimulante/sangue , Idade Gestacional , Hormônio Liberador de Gonadotropina/farmacologia , Hormônio Luteinizante/sangue , Folículo Ovariano/anatomia & histologia , Ovário/anatomia & histologia , Hipófise/efeitos dos fármacos , Gravidez , Maturidade Sexual
19.
J Endocrinol ; 192(3): 495-503, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17332519

RESUMO

Epidemiological and experimental data support the hypothesis of 'fetal programming', which proposes that alterations in fetal nutrition and endocrine status lead to permanent adaptations in fetal homeostatic mechanisms, producing long-term changes in physiology and determine susceptibility to later disease. Altered hypothalamic-pituitary-adrenal (HPA) axis function has been proposed to play an important role in programming of disease risk. The aim of the present study was to examine the effects of maternal nutrient restriction imposed during different periods of gestation on the HPA axis function in sheep, at different ages postnatal. Pregnant ewes were fed a 50% nutrient-restricted diet from days 0-30 (group R1, n = 7), or from days 31-100 of gestation (group R2, n = 7) or a control 100% diet throughout pregnancy, (Control, n = 8). Blood samples were collected at 10-day intervals from day 40 of gestation to term. Lambs were born naturally and fed to appetite throughout the study period. At 2, 5.5, and 10 months of age lambs were given an i.v. injection of corticotrophin-releasing hormone (CRH) and blood samples were collected at -15, 0, 15, 30, 60, 120, and 180 min postinjection. Maternal cortisol levels were significantly higher (P < 0.05) in group R1 compared with the other two groups, whereas maternal insulin levels were lower (P < 0.05) in group R2 compared with control. Birth weight of lambs was not affected by the maternal nutritional manipulation. The area under the curve for ACTH and cortisol response to CRH challenge was greater (P < 0.05) in lambs of group R1 at two months of age, whereas no difference was detected at the ages of 5.5 and 10 months. However, significantly higher (P < 0.01) basal cortisol levels were observed in lambs of R1 group at 5.5 months of age. There was no interaction between treatment and sex for both pituitary and adrenal responses to the challenge. A significant sex effect was evident with females responding with higher ACTH and cortisol levels at the age of 5.5 months (P < 0.01, P < 0.001 respectively) and with higher cortisol levels (P < 0.01) at 10 months of age than males. It is concluded that the HPA axis is programmable by altered nutrition in utero. The sensitivity of the axis to exogenous stimulation is enhanced during early postnatal life and attenuated with age, suggesting a role for the postnatal influences in resetting of the HPA axis and emphasizing the importance of identifying the impact of maternal undernutrition at several time points after birth.


Assuntos
Envelhecimento/fisiologia , Sistema Hipotálamo-Hipofisário/fisiologia , Desnutrição , Fenômenos Fisiológicos da Nutrição Materna , Sistema Hipófise-Suprarrenal/fisiologia , Hormônio Adrenocorticotrópico/sangue , Animais , Animais Recém-Nascidos , Peso ao Nascer , Hormônio Liberador da Corticotropina , Feminino , Idade Gestacional , Hidrocortisona/sangue , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Insulina/sangue , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Gravidez , Ovinos
20.
Opt Express ; 14(24): 11545-50, 2006 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-19529574

RESUMO

We experimentally demonstrate an optical node with time-space-and- wavelength domain contention resolution, deflection and dropping capability. The node is composed of an optical buffer based on an optical crossconnect and a wavelength converter. Although the experimental results are shown at 10 Gbit/s the bitrate can be increased substantially. Bit-error rate measurements are shown, sustaining only 3.5 dB power penalty after 10mus of optical buffering and agile wavelength conversion over 18nm span.

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