• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 9
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 28
  • 23
  • 12
  • 12
  • 10
  • 8
  • 5
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

The effects of barley on starter- and finishing- pig performance

Goodband, Robert D. January 1986 (has links)
Call number: LD2668 .T4 1986 G66 / Master of Science / Animal Science and Industry
22

Rações farelada, peletizada e extrusada na alimentação e produção de vacas leiteiras / Meal, pelleted and extruded concentrates in the fed and milk yield in dairy cows

Wernersbach Filho, Humberto Luiz 09 May 2003 (has links)
Made available in DSpace on 2015-03-26T13:55:30Z (GMT). No. of bitstreams: 1 texto completo.pdf: 211270 bytes, checksum: 1d453950af1b6efd3aa6a33b18fb16a7 (MD5) Previous issue date: 2003-05-09 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work was carried out at the dairy cows Teaching, Research and extension unit at the Department of Animal Science of the Federal University of Viçosa with the objective of evaluating: the intake and apparent digestibility of nutrients, milk production and composition, ruminal pH and ammonia, ruminal degradability of dry matter and crude protein, urea concentration in the plasma in cows fed ration processed by different methods. Sixteen dairy holstein cows, purebreds and crossbred, in two milk production levels: 30.0 kg/day and 20.0 kg/day, were distributed equitatively in two latin squares balanced for each production level. The experiment was constituted of four periods with duration of 15 days each. The experimental diets were isoproteic, based on corn silage with forage: concentrate ratio of 50:50 to the level of 30.0 kg/day and 60:40 to the level of 20.0 Kg/day, in dry matter basis. The treatments were constituted of four concentrate rations: meal form (MR), pelleted (PR) and extruded (ER), with 27% and 84% of crude protein (CP) and total digestible nutrients(TDN), respectively and high energy ration with part of extruded elements (HER), with 27% and 86% of crude protein and TDN, respectively. The animals were housed in individual stalls like Tie Stall and fed ad libitum. The excretion of fecal dry matter was estimated by indigestible acid detergent fiber (ADFi). Rumen fluid was collected by esophagian tube. The urine collection was made by spot test . Blood was collected four hours after the morning feeding, being used heparin as anticoagulant. The in situ degradability was estimated with nylon pockets inside the animal rumen. The dry matter (DM) intake was not different among the experimental diets. Digestibility of the DM there was no difference, but the digestibility of the neutral detergent fiber (44,35%) was lower (P<0,05) to ER (extruded) and digestibility of the crude protein was lower (P<0,05) to ER (72,36%), compare to the MR meal). The milk production was larger (P<0,05) for the extruded diet (ER) (29.0 kg/day), in higher level production, however, in lower level there was no difference. The milk composition was not different among the diet to higher level production. Inside each time (before and three hours after the morning feeding) there was no difference in the pH values and amoniacal nitrogen compounds (N-NH3) among the experimental diets. There was no difference in ruminal N-NH3 concentration on time 0, however, at three hours after feeding, ER presented lower (P<0,05) ruminal N-NH3 concentration. The ruminal degradability of crude protein and DM were higher to PR and especiallly in ER. There was no difference in the concentration of plasmatic urea and fractional urine excretions. / O presente trabalho foi realizado na Unidade de Ensino, Pesquisa e Extensão em Gado de Leite do Departamento de Zootecnia, na Universidade Federal de Viçosa, objetivando avaliar: o consumo e a digestibilidade aparente dos nutrientes, a produção e composição do leite, o pH e a amônia ruminal, a degradabilidade ruminal da matéria seca e proteína bruta, e concentração de uréia no plasma e excreções urinárias de vacas leiteiras alimentadas com diferentes formas de processamento da ração concentrada. Foram utilizadas 16 vacas da raça holandesa, puras e mestiças, em dois níveis de produção de leite: 30,0 kg/dia e 20,0 kg/dia, que foram distribuídas equitativamente em dois quadrados latinos balanceados para cada nível de produção. O Experimento foi constituído por quatro períodos, com duração de 15 dias cada. As dietas experimentais foram isoprotéicas, constituídas à base de silagem de milho (Zea mays) com relação volumoso: concentrado de 50:50 para o nível de 30,0 kg/dia e 60:40 para o nível de 20,0 kg/dia, com base na matéria seca. Os tratamentos foram constituídos de quatro rações concentradas sendo: ração farelada (RF); ração peletizada (RP) e ração extrusada (RE), com 27% com de proteína bruta (PB) e 84% de nutrientes digestíveis totais (NDT) e ração de alta energia parcialmente processada (RAE), com 27% de PB e 86% de NDT. Os animais foram mantidos em baias individuais do tipo Tie Stall , onde receberam alimentação ad libitun. A excreção de matéria seca fecal foi estimada através da fibra em detergente ácido indigestível (FDAi). O líquido ruminal foi coletado, utilizando-se sonda esofágica. A coleta de urina foi feita através do 4 h após a alimentação. Foi coletado sangue quatro horas após a alimentação matinal, utilizando-se heparina como anticoagulante. A degradabilidade foi estimada através da técnica in situ utilizando-se sacos de náilon incubados no rúmen animal. O consumo de matéria seca (CMS) não diferiu entre os tratamentos RF, RP e RE. A digestibilidade da matéria seca (DMS) não foi afetada pelo processamento, enquanto a digestibilidade da proteína bruta para vacas alimentadas com ração extrusada (RE) (72,36%), foi menor (P<0,05), comparada a ração farelada (RF), no nível de 50 % de concentrado. A digestibilidade da fibra em detergente neutro para vacas alimentadas com RE (44,35%) foi menor (P<0,05) no nível de 50 % de concentrado. A produção de leite foi maior (P<0,05) para os animais consumindo ração extrusada (29,9 kg/dia), no nível de 50 % de concentrado, contudo, o menor nível não apresentou diferença significativa. A composição do leite não diferiu entre os tratamentos, para ambos os níveis de produção. Dentro de cada tempo (antes e três horas após a alimentação matinal), não houve diferenças nos valores de pH. Para as concentrações de N - NH3 ruminal, imediatamente antes da alimentação, as concentrações não diferiram entre si. Contudo, a ração extrusada apresentou menor (P<0,05) concentração de N - NH3 ruminal três horas após a alimentação. A degradabilidade ruminal da proteína bruta e da matéria seca foi numericamente maior para o tratamento peletizado e, principalmente, para o tratamento extrusado. As concentrações de uréia plasmática as excreções urinárias não diferiram entre os tratamentos.
23

Bioreduction of selenite and tellurite by Phanerochaete chrysosporium / Applications de la bioréduction du sélénite et/ou de la tellurite par Phanerochaete chrysosporium

Espinosa Ortiz, Erika 10 December 2015 (has links)
Le sélénium et le tellurium partagent des propriétés chimiques communes et appartiennent à la colonne des éléments chalcogènes de la classification périodique des éléments. Ces métalloïdes ont des propriétés physico-chimiques remarquables et ils ont été utilisés dans un grand nombre d'applications dans le domaine des hautes technologies (électronique, semi-conducteurs, alliages). Ces éléments, qui se retrouvent généralement sous formes d'oxyanions, sont extrêmement solubles dans l'eau et présentent une forte toxicité. Leur libération dans l'environnement est donc d'un enjeu capital. Différentes méthodes physico-chimiques ont été développées pour la récupération de ces metalloïdes, en particulier pour le sélénium. Néanmoins, ces méthodes requièrent un équipement lourd et couteux et ne sont pas très recommandables sur le plan écologique. Le traitement biologique est donc une bonne alternative pour la récupération de Se et de Te provenant des effluents pollués. Cette approche réside dans la bioréduction des différents oxyanions sous formes métalliques. Ceux-ci sont moins toxiques et d'intérêts commerciales notables surtout lorsqu'ils se présentent sous forme nanométrique. L'utilisation de micro-champignons comme microorganismes catalyseur de la réduction de Se et de Te a été démontrée dans cette étude. La réactivité du champignon responsable de la pourriture blanche, Phanerochaete chrysosporium en présence de sélénite et de tellurite a été évaluée, ainsi que son application potentielle pour le traitement des eaux contaminées et la production de nanoparticules. La présence de Se et de Te a une influence importante sur la croissance et la morphologie du champignon. Il s'avère que P. chrysosporium est très sensible à la présence de sélénites. La synthèse de Se° et de Te° sous forme de nanoparticules piégées dans la biomasse fongique a été observée, ainsi que la formation de nano-composites Se-Te lorsque le champignon était cultivé simultanément en présence des deux métalloïdes. L'usage potentiel de biofilm fongiques pour le traitement des effluents semi-acides (pH 4.5) contenant du Se et du Te a été suggéré. De plus, le traitement en mode continu de sélénite dans un réacteur à biofilm fongique granulaire a été évalué. Le réacteur a montré un rendement d'élimination du sélénium en régime permanent de 70% pour differentes conditions opératoires. Celui-ci s'est montré efficace pendant une période supérieure à 35 jours. La bonne sédimentation du biofilm granulaire facilite la séparation du sélénium de l'effluent traité. L'utilisation du biofilm granulaire contenant du sélénium élémentaire comme bio-sorbant a également été étudiée. Cet adsorbant hybride s'est montré prometteur pour l'immobilisation du zinc présent dans les effluents semi-acides. La plupart des recherches effectuées se sont focalisées sur l'utilisation des biofilms granulaires. Toutefois, la croissance du champignon suite à l'exposition à des concentrations différentes de sélénites a également été étudiée. Des micro-électrodes à oxygène et un microscope confocal à balayage laser ont été utilisées pour évaluer l'effet du sélénium sur la structure des biofilms fongiques. Quel que soit le mode de croissance de P. chrysosporium, le mécanisme de réduction du sélénite semble être toujours le même tout en menant à la formation de sélénium élémentaire. Cependant, l'architecture des biofilms et l'activité en oxygène sont influencées par la présence de sélénium / Selenium (Se) and tellurium (Te) are particular elements, they are part of the chalcogens (VI-A group of the periodic table) and share common properties. These metalloids are of commercial interest due to their physicochemical properties, and they have been used in a broad range of applications in advanced technologies. The water soluble oxyanions of these elements (i.e., selenite, selenate, tellurite and tellurate) exhibit high toxicities, thus their release in the environment is of great concern. Different physicochemical methods have been developed for the removal of these metalloids, mainly for selenium. However, these methods require specialized equipment, high costs and they are not ecofriendly. The biological treatment is a green alternative to remove Se and Te from polluted effluents. This remediation technology consists on the microbial reduction of Se and Te oxyanions in wastewater to their elemental forms (Se0 and Te0), which are less toxic, and when synthesized in the nano-size range, they can be of commercial value due to their enhanced properties. The use of fungi as potential Se- and Te-reducing organisms was demonstrated in this study. Response of the model white-rot fungus, Phanerochaete chrysosporium, to the presence of selenite and tellurite was evaluated, as well as their potential application in wastewater treatment and production of nanoparticles. The presence of Se and Te had a clear influence on the growth and morphology of the fungus. P. chrysosporium was found to be more sensitive to selenite. Synthesis of Se0 and Te0 nanoparticles entrapped in the fungal biomass was observed, as well as the formation of unique Se-Te nanocomposites when the fungus was cultivated concurrently in the presence of Se and Te. Potential use of fungal pellets for the removal of Se and Te from semi-acidic effluents (pH 4.5) was suggested. Moreover, the continuous removal of selenite in a fungal pelleted reactor was evaluated. The reactor showed to efficiently remove selenium at steady-state conditions (~70%), and it demonstrated to be flexible and adaptable to different operational conditions. The reactor operated efficiently over a period of 35 days. Good settleability of the fungal pellets facilitated the separation of the selenium from the treated effluent. The use of elemental selenium immobilized fungal pellets as novel biosorbent material was also explored. This hybrid sorbent was promising for the removal of zinc from semi-acidic effluents. The presence of selenium in the fungal biomass enhanced the sorption efficiency of zinc, compared to Se-free fungal pellets. Most of the research conducted in this study was focused on the use of fungal pellets. However, the response of the fungus to selenite in a different kind of growth was also evaluated. Microsensors and confocal imaging were used to evaluate the effects of selenium on fungal biofilms. Regardless of the kind of fungal growth, P. chrysosporium seems to follow a similar selenite reduction mechanism, leading to the formation of Se0. Architecture of the biofilm and oxygen activity were influenced by the presence of selenium
24

Physical and chemical effects of pelleting feed on broiler growth and behavioral parameters

Combs, Stephen H. January 1985 (has links)
Barred Rock chickens were offered diets that had been pelleted at 55° or 85°C. In an 8-week feeding trial, the subjects receiving pellets processed at the higher temperature experienced significant (P ≤ .05) weight gain over those receiving the diet processed at 55°C. Although feed consumption for this treatment increased as well, the difference was not significant (P ≤ .05). Chemical investigation revealed that metabolizable energy and bioavailability of lysine of both heat treatments were similar. Starch availability as measured by in vitro enzyme susceptibility, however, was lowered by increased heat application. In a second experiment, the feeding behavior of 12-16 week old cockerels offered diets of varying particle size, resulted in significant (P ≤ .05) increases in feed consumption rate and therefore decreases in total feeding activity for birds offered pellets and crumbles as compared to mash and reground pellets. No differences were noted in meal size, meal frequency, interval between meals, or total consumption. In a parallel experiment, no differences were noted in the behavioral parameters of birds receiving diets pelleted at 55, 70, or 85°C of similar density and particle size. Mash controls, however, experienced significantly (P ≤ .05) decreased consumption rate and concurrent increase in feeding activity. The beneficial effects experienced with pelleting can therefore be attributed to the reduction in total feeding activity that allows an increased proportion of net energy to be utilized in support of growth. / M.S.
25

Desempenho zootécnico do camarão marinho Litopenaeus vannamei (Boone,1931) cultivado com ração peletizada e extrusada

PESSÔA, Maurício Nogueira da Cruz 01 October 2008 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2017-02-16T15:07:14Z No. of bitstreams: 1 Mauricio Nogueira da Cruz Pessoa.pdf: 716355 bytes, checksum: 41120b87fa94d8d978b32032793ede5f (MD5) / Made available in DSpace on 2017-02-16T15:07:14Z (GMT). No. of bitstreams: 1 Mauricio Nogueira da Cruz Pessoa.pdf: 716355 bytes, checksum: 41120b87fa94d8d978b32032793ede5f (MD5) Previous issue date: 2008-10-01 / The statistical evaluation of the use of extruded and pelleted ration in the Litopenaeus vannamei shrimp culture, under field conditions, were done with the objective of determinie the advantages of these diets on shrimp performance index. To perform the analyses were used 481 crops, from 8 commercial farms of northeastern Brazil. It was the technique used multiple linear regression to determine the parameters of handling variables that influenced the responses of crops such as production, productivity, the conversion factor of food (FCA), the weekly average growth, the average weight end, the quantity of feed consumed and survival. These responses were measured by the density of storage, but also in time of cultivation. It may be noted that there was no significant difference (P ≥ 0,05) between the use of feed on the variables average weight final and average weekly growth, as in other variables can be observed that for the storage density of 15 shrimps.m-2 there were differences of up to 20.1% in the FCA in favour of extruded ration, a production 9.7% higher when using pelleted ration of feed consumption and a 33.2% higher in pelleted feed. For densities of 60 shrimps.m-2 the difference in the FCA was 18.8% lower when you used to feed pelleted, production was 7.2% higher if using pelleted diet, consumption of feed was 8.5% lower when used if pelleted diet and productivity was 10.3% higher when the extruded feed was used for that density. / Avaliações estatísticas do uso de ração extrusada e peletizada, em cultivos do camarão Litopenaeus vannamei, nas condições de campo, foram realizadas com o objetivo de determinar as vantagens sobre os índices zootécnicos dos camarões. Análises foram feitas utilizando-se 481 cultivos, provenientes de oito fazendas comerciais do nordeste do Brasil. Foi utilizada a técnica de regressão linear múltipla para estimar os parâmetros de manejo que influenciaram nas variáveis respostas dos cultivos tais como produção, produtividade, fator de conversão alimentar (FCA), crescimento semanal, peso final, quantidade de ração administrada e sobrevivência. Essas variáveis foram avaliadas em função da densidade de estocagem e do tempo de cultivo. Não houve diferença significativa (P ≥ 0,05) entre o uso das rações sobre as variáveis, peso final e crescimento semanal. Nas demais variáveis observou-se que na densidade de estocagem de 15 camarões/m2 houve diferença de até 20,1% no FCA a favor da ração extrusada, uma produção 9,7% maior quando se utilizou ração peletizada e um consumo a mais de 33,2% de ração peletizada. Para densidades de 60 camarões/m2 a diferença no FCA foi de 18,8% menor quando se utilizou ração peletizada, a produção foi 7,2% maior utilizando-se ração peletizada, o consumo de ração foi 8,5% menor com ração peletizada e a produtividade foi 10,3% maior quando a ração extrusada foi utilizada.
26

Métodos para superação de dormência em sementes de tabaco / Methods to release dormancy in tobacco seeds

Gmach, Janice Regina 20 August 2009 (has links)
Made available in DSpace on 2014-08-20T13:44:42Z (GMT). No. of bitstreams: 1 dissertacao_janice_regina_gmach.pdf: 2217576 bytes, checksum: 44546cca74b285343c5577b59d2b02c1 (MD5) Previous issue date: 2009-08-20 / The growing modernization in agricultural production and the use of small and high cost seeds, usually with the waste of sowing and the disposal seedlings recommend the use of techniques such as pelleting of seeds. However, the use of pelleted seeds may present some problems because the pellet formed around the seed can affect their performance during the germination. The cultivation of tobacco is in itself one of the major agricultural activities in the South Region of Brazil, due to the system of production that allows the cultivation in small areas, with profit to small farmers, giving it relevant socioeconomic role, besides providing raw material for a major industrial complex. Its planting is done through seeds, whose small size hinders its handling, these seeds have difficulties in germination, showing dormancy varying levels in pelleted seeds, a fact that is not seen in raw seeds. This study aimed to verify the efficiency of the use of GA3 and KNO3 as a method of overcoming dormancy in tobacco pelleted seeds, as well as use of two methods for evaluation of tobacco pelleted seeds germination. The results show that the potassium nitrate showed higher percentage of germination in pelleted seeds in both varieties and that the methodology UC (moisture continues) is more sensitive to responses of tobacco pelleted seeds. / A crescente modernização na produção agrícola, assim como a utilização de sementes pequenas e de alto custo, geralmente com desperdícios na semeadura e no descarte de mudas, recomendam o uso de técnicas como a peletização de sementes. No entanto, o uso de sementes peletizadas pode apresentar também alguns problemas, pois o pélete formado ao redor da semente pode afetar seu desempenho durante a germinação. O cultivo do tabaco constitui-se em uma das principais atividades agrícolas da região Sul do Brasil, devido ao sistema de produção que possibilita o cultivo em pequenas áreas, com boa remuneração para os pequenos agricultores, o que lhe confere relevante papel sócio-econômico, além de se constituir em matéria prima para um importante complexo industrial. Seu plantio é feito por meio de sementes, cujo tamanho reduzido dificulta o seu manuseio, essas sementes apresentam dificuldades na germinação, apresentando níveis variáveis de dormência em sementes peletizadas, fato este não observado em sementes nuas. O presente trabalho teve por objetivo verificar a eficiência do uso de AG3 e KNO3 como método de superação de dormência em sementes peletizadas de tabaco, bem como a utilização de duas metodologias para avaliação de germinação de sementes peletizadas de tabaco. Os resultados demonstram que o nitrato de potássio apresentou maiores percentuais de germinação em sementes peletizadas em ambos os cultivares e que a metodologia do UC (Umedecimento Contínuo) é mais sensível ás respostas de sementes de tabaco peletizadas.
27

Potenciál krmných směsí a obilovin jako nástroj pro udržení dobré produkce tržního kapra ve vztahu ke kvalitě vody. / The potential of compound feed and cereals as a tool for keeping the production of carp at a good level in relation to the water quality.

MELKA, Václav January 2017 (has links)
The aim of this diploma thesis was to test the production effectiveness of cereals and compound feed and at the same time, find out what influence they have on the water quality when applied in the semi-intensity carp farming. The feeding test was taking place in the period of 112 days in 10 experimental storage ponds. The feed which was tested, was cereals, extruded feed from the Aller Aqua company with 24% share of protein, pelleted feed glycid type feed with the 12,5% share of protein (KP) and pellet feed glycid type compound feed with 12,5% share of protein and reduced share of phosphorus (KPminus). A tested carp population of the same density was left without any additional feeding, to be fed only on the natural nutrition. Every one of these separated carp populations were fed three times a week in the morning and on the same spot of the fish tank. The testing was taking place twice.The measuring of the parametres of the water (temperature, oxygen, pH) took place once a fortnight, taking samples of the water once a month. At the end of the experiment, the level of phosphorus and the observed production parametres were evaluated.The highest production effectiveness was reached in the carps that were fed with cereals (FCR - Food Convertion Ration 2,41 - 0,46, SGR - Specific Growth Rate 0,54 - 0,07 %.d-1). The lowest production effectiveness was achieved with the pelleted feed KPminus (FCR - 3,72 - 0,30, SGR - 0,39 - 0,02 %.d-1). The highest retention of phosphorus (88%) in the fish biomass was reached with cereals. The lowest retention of phosphorus (60%) was reached in the carps fed with the pelleted feed KP. Feeding carps with tested feeds did not have any significant influence on the water quality. From both the economic and the environmental point of view, the best feed for carp pond farming is cereals.
28

Adaptace štiky obecné (Esox lucius L.) na umělé peletované krmivo v kontrolovaných podmínkách chovu / Adaptation of northern pike (Esox lucius L.) on artificial pelleted feed under controlled conditions

HAJÍČEK, Jiří January 2012 (has links)
The main objective of this thesis is to describe and experimentally evaluate the possibility of adaptation of pike (Esox lucius L.) in controlled housing conditions and income artificial pelleted feed. The thesis is mainly based on the effect of an initial larval density of pike for adaptation and survival and the growth of larvae reared in the rearing tanks. The experiment consisted of four different densities of larvae (10, 20, 40, 80 pc of the larvae l??, which were always repeated three times. Two experiments were performed (M, H), with a length of rearing of five days. Rearing itself was conducted in twelve circular tanks with a capacity of 180 l??, the recirculation system connected to the experimental rearing facility in Vodňany FROV JU. The temperature during rearing was constant. For the first experiment the temperature was 22.3 ? 03 °C. For the second one, the average temperature was 21.5 ? 0.6 °C. The frequency of feeding was continuous (24 h) with a combination of hand feeding and feeders with a timer (at night). The illumination of the aquarium tanks was provided by fluorescent lamps, for each tank individually. The light intensity was high (210 lux) and constant during the rearing. Both experiments showed the optimal density at the initial feeding from 20 to 40 units . l??. Also, we have implemented made out performed- the basic biometric analysis of W (g) and TL (mm), the body length, size of eyes, head, jaw length, prenatal length.

Page generated in 0.0291 seconds