Com o objetivo de utilizar o Capim-de-rhodes como ferramenta de remediação de um Argissolo, textura média, irrigado com efluente industrial, um ensaio foi realizado em condições de campo no município de Matão (Estado de São Paulo), a fim de se verificar a capacidade de exportação de Na pelo Capim, sob diferentes doses de fertilizantes, nitrogenado e potássico. O experimento foi instalado no final da estação seca, em parcelas de 6 X 7 m, com desenho experimental de blocos totalmente casualizados. Os tratamentos foram: testemunha total (solo nu) e cultivo de capim com 0, 50, 100 e 200 kg de N e K2O . ha-1, aplicados a cada corte do capim (40 dias de intervalo). Foram realizadas coletas de solo em três profundidades, antes da aplicação dos tratamentos e depois, juntamente com as duas colheitas de capim; estas últimas visando a avaliação do rendimento agrícola e diagnose foliar. Os resultados indicaram uma nítida resposta em termos de produção de massa seca e teor de sódio na parte aérea quando o capim foi submetido às doses de 50, 100 e 200 kg de N e K2O.ha-1, comparado com o tratamento sem fertilizante. Esta resposta levou o capim a uma capacidade total de exportação de sódio de 120 kg.ha-1, quantidade esta, maior do que a aplicada pela irrigação no período do ensaio (75 kg.ha-1), levando à redução do teor no solo. O Capim-de-Rhodes demonstrou sua utilidade potencial como remediador de solos solódicos. Os resultados indicaram que é possível a prática da irrigação com o efluente, manejando-se adequadamente o capim, principalmente com fertilizantes nitrogenados, indicando também melhoria das características químicas do solo. / With the objective of using Chloris gayana (a grass specie) as a tool on the remediation of a tipic Hapludult, medium texture, irrigated with industrial waste water, a field trial was installed in Matão (state of São Paulo, Brazil) in order to assess the total exportation capacity of sodium by the grass, under different rates of nitrogen and potassium. The experiment was carried out at the end of the dry season, on 6 x 7 meters plot on a randomized complete block design. The treatments were: untreated (nude soil), and grass fertilized with 0, 50, 100 & 200 kg of N and K2O.ha-1, applied at each grass harvesting event (40 days interval). Soil was collected at three depths, before treatment application, and after, together with both grass harvesting; those, with the objective of evaluating yield and foliar analysis. The results indicated a clear response of yield and leaf sodium content when the grass was submitted to 50, 100 & 200 kg.ha-1 of N and K2O, compared to the zero fertilizer treatment. The grass achieved 120 kg.ha-1 exportation capacities in 80 days, which is more than the amount of sodium applied by the irrigation (75 kg.ha-1). Chloris gayana, showed its utility as a potential bio remediator of sodic soils. Also, the results confirmed that is possible to use the soil as a tool to treat waste water containing sodium, by managing adequately the mentioned grass specie, mainly with nitrogen fertilizer, maintaining quality for production.

The capital maintenance rules stem from the English company law and were primarily aimed at protecting the rights of a company’s creditors. Before the introduction of the Companies Amendment Act 37 of 1998, a company was prohibited from purchasing its own shares. After this legislation was passed, a company was able to do so, provided that it satisfied the solvency and liquidity test and also complied with the new statutory provisions set out by sections 85 to 89 of the Companies Act 61 of 1973. Section 48 of the Companies Act 71 of 2008 now regulates the acquisition by a company of its own shares, as well as the acquisition of shares in its holding company by a subsidiary company. The above actions also fall under the ambit of a “distribution” as defined in the Act and therefore need to satisfy the requirements of section 46 of the Act as well. Unlike its predecessor, the provisions in the new Act are very broad and devoid of guidelines. The emphasis is placed on companies satisfying the principles of solvency and liquidity. Non-adherence to these provisions gives rise to the personal liability of the company’s directors. The provisions of section 48 do not apply where a dissenting shareholder exercises his appraisal rights in terms of section 164 of the new Act, or where a company redeems redeemable securities. These exceptions do, however, still amount to “distributions” and will accordingly need to satisfy the requirements contained in section 46 of the Act. Redeemable securities were initially not exempted from the provisions of section 48. This would potentially have given rise to a situation where a company could approach a court in terms of section 48(6) to reverse a redemption of its securities. It would have had dire consequences for financing by way of redeemable securities. In terms of the Companies Amendment Act 3 of 2011 redeemable securities are now specifically exempted from the provisions of section 48. In terms of the new Act a subsidiary company is allowed to purchase shares in its holding company to a maximum of 10% in the aggregate of the issued shares of any share class, provided that no voting rights attached to such shares may be exercised. The new Act fails to properly address some of the issues regarding the “round-tripping” of dividends and the declaration of a dividend in specie that were already identified as far back as 2001. Where the consideration for a repurchase constitutes a “dividend” as defined in the Income Tax Act 58 of 1962, the company will be liable to pay secondary tax on companies in respect thereof. If a distribution does not constitute a dividend, capital gains tax is payable with regard to it. Share repurchases are allowed in terms of Canadian corporate law after the legislative reform which occurred in that country during the 1970’s. The Canadian Business Corporations Act contains provisions that bear a striking resemblance to the provisions of the new Act adopted in South Africa. Whilst the basis and rationale behind the new corporate legislation cannot be faulted, a host of issues and concerns still remain. The unfortunate consequence is that the new Act lacks transparency and is fraught with clumsy errors. Copyright / Dissertation (LLM)--University of Pretoria, 2012. / Mercantile Law / unrestricted

Text in Afrikaans / During the last few decades the need existed for a new framework to give direction to development and ecological thought in respect of the sustaining of nature in order to place development and ecological thought within the limits of nature. However, development thought and the debate relating to nature are to some extent still treated in theory and practice as two separate entities. One of the current challenges for sustainable development is to reconcile the development and ecological branches of this debate. The thesis firstly explains the origin and characteristics of sustainable development. Secondly, the crisis in nature is discussed, followed by a discussion of the most important ecological views relating to sustainable development. Then issues in development thought that relates to sustainable development is discussed, as well as the changing emphasis in development thought that stimulated the growth of sustainable development. The mainstream development view, as the other main branch of sustainable development thinking, is then discussed. In conclusion, some issues relating to the operationalisation of sustainable development is discussed. / Development Studies / D. Litt. et Phil. (Ontwikkelingstudies)

Text in Afrikaans / During the last few decades the need existed for a new framework to give direction to development and ecological thought in respect of the sustaining of nature in order to place development and ecological thought within the limits of nature. However, development thought and the debate relating to nature are to some extent still treated in theory and practice as two separate entities. One of the current challenges for sustainable development is to reconcile the development and ecological branches of this debate. The thesis firstly explains the origin and characteristics of sustainable development. Secondly, the crisis in nature is discussed, followed by a discussion of the most important ecological views relating to sustainable development. Then issues in development thought that relates to sustainable development is discussed, as well as the changing emphasis in development thought that stimulated the growth of sustainable development. The mainstream development view, as the other main branch of sustainable development thinking, is then discussed. In conclusion, some issues relating to the operationalisation of sustainable development is discussed. / Development Studies / D. Litt. et Phil. (Ontwikkelingstudies)

Introduction Oral delivery of proteins faces numerous challenges due to their enzymatic susceptibility and instability in the gastrointestinal tract. In recent years, the polyelectrolyte complexes have been explored for their ability to complex protein and protect them against chemical and enzymatic degradation. However, most of the conventional binary polyelectrolyte complexes (PECs) are formed by polycations which are associated with toxicity and non-specific bio-interactions. The aim of this thesis was to prepare a series of ternary polyelectrolyte complexes (APECs) by introduction of a polyanion in the binary complexes to alleviate the aforementioned limitations. Method Eight non-insulin loaded ternary complexes (NIL APECs) were spontaneously formed upon mixing a polycation [polyallylamine (PAH), palmitoyl grafted-PAH (Pa2.5), dimethylamino-1-naphthalenesulfonyl grafted-PAH (Da10) or quaternised palmitoyl-PAH (QPa2.5)] with a polyanion [dextran sulphate (DS) or polyacrylic acid (PAA)] at 2:1 ratio, in the presence of ZnSO4 (4μM). A model protein i.e., insulin was added to a polycation, prior to addition of a polyanion and ZnSO4 to form eight insulin loaded (IL) APECs. PECs were used as a control to compare APECs. The complexes were characterised by dynamic light scattering (DLS) and transmission electron microscope (TEM). In vitro stability of the complexes was investigated at pH (1.2-7.4), temperature (25˚C, 37˚C and 45˚C) and ionic strength (NaCl-68mM, 103mM and 145mM). Insulin complexation efficiency was assessed by using bovine insulin ELISA assay kit. The in vitro cytotoxicity was investigated on CaCo2 and J774 cells by MTT (3-4,5 dimethyl thialzol2,5 diphenyl tetrazolium bromide) assay. All complexes were evaluated for their haemocompatibility by using haemolysis assay, oxidative stress by reactive oxygen species (ROS) assay and immunotoxicity by in vitro and in vivo cytokine generation assay. The potential of the uptake of complexes across CaCo2 cells was determined by flow cytometry and fluorescent microscopy. The underlying mechanism of transport of complexes was determined by TEER measurement, assessment of FITC-Dextran and insulin transport across CaCo2 cells. 15 Results NIL QPa2.5 APECs (except IL QPa2.5-DS) exhibited larger hydrodynamic sizes (228-468nm) than all other APECs, due to the presence of bulky quaternary ammonium moieties. QPa2.5 APECs exhibited lower insulin association efficiency (≤40%) than other APECs (≥55%) due to a competition between the polyanion and insulin for QPa2.5 leading to reduced association of insulin in the complexes. DS based APECs generally offered higher insulin association efficiency (≥75%) than PAA based APECs (≤55%) due to higher molecular weight (6-10kDa) of DS. In comparison to other complexes, Pa2.5 PECs and APECs were more stable at varying temperature, ionic strength and pH due to the presence of long palmitoyl alkyl chain (C16) which reduced the chain flexibility and provided stronger hydrophobic association. The cytotoxicity of polycations on CaCo2 and J774 cells is rated as PAH>Da10=Pa2.5>QPa2.5. The introduction of PAA in Pa2.5 and Da10 brought most significant improvement in IC50 i.e., 14 fold and 16 fold respectively on CaCo2 cells; 9.3 fold and 3.73 fold respectively on J774 cells. In comparison to other complexes, Da10 (8mgml-1) induced higher haemolytic activity (~37%) due to a higher hydrophobic load of 10 percent mole grafting of dansyl pendants. The entire range of APECs displayed ≤12% ROS generation by the CaCo2 cells. The degree of in vitro TNFα production (QPa2.5≥Da10≥Pa2.5=PAH) and in vitro IL-6 generation (QPa2.5≥Pa2.5=PAH≥Da10) by J774 cells established an inverse relationship of cytotoxicity with the cytokine generation. Similar to MTT data, the introduction of PAA in APECs brought more significant reduction in in vitro cytokine secretion than DS based APECs. Pa2.5-PAA brought the most significant reduction in both in vitro and in vivo cytokine generation. All the formulations were able to significantly reduce original TEER, however did not demonstrate appreciable paracellular permeation of a hydrophilic macromolecular tracer of paracellular transport i.e., FITC Dextran. The uptake study revealed internalisation of APECs predominantly by a transcellular route. Transcellular uptake of IL QPa2.5 (≤73%), IL QPa2.5-DS (67%) was higher than their NIL counterparts, whereas the uptake of NIL Pa2.5 (≤89%), NIL Pa2.5-PAA (42%) was higher than their IL counterparts. Conclusion In essence, amphiphilic APECs have shown polyanion dependent ability to reduce polycation associated toxicity and they are able to facilitate transcellular uptake of insulin across CaCo2 cells.

L’objectif des travaux de cette thèse concerne la caractérisation du germoplasme marocain du cactus Opuntia. Les études réalisées pour atteindre cet objectif ont portées sur le comportement phénologique, les caractéristiques génétiques et la composition physicochimique du cactus, ainsi que sur les molécules à fort potentiel thérapeutique, susceptibles d’avoir des effets bénéfiques pour les cellules du système nerveux central, dans les extraits de cactus (fruit, fleur, graine, huile, raquette et épine) et ceci en comparaison avec l’huile d’Argan. Les travaux ont été réalisés dans quatre laboratoires partenaires partageant des compétences dans les domaines d’analyses agronomique, biochimique et moléculaire. Les résultats de nos travaux sont présentés dans trois volets : (i) la caractérisation agronomique du cactus, (ii) la purification et la caractérisation des extraits et des molécules naturelles et (iii) l’évaluation des effets biologiques de ces molécules sur un modèle cellulaire. L’étude phénologique sur des écotypes âgées de 4 ans, issus du site expérimental de l’INRA d’Ain Nezagh, nous a permis de les classer selon le taux de fructification ou la production de biomasse de manière à mieux orienter leur utilisation en fonction de l’origine géographique et de l’espèce. L’étude de la diversité génétique, basée sur les traits morphologiques et les marqueurs moléculaires, a permis d’identifier sur le site d’Ain Nezagh sept espèces de cactus dont deux n’avait jamais été décrites au Maroc, O. leucotricha et O. inermis. Les analyses morpho-anatomique et physico-chimique de la fleur, du jus, du fruit et de la raquette d’écotypes âgées de 10 ans provenant du site de l’INRA de Jemâat Riah ont démontré la présence de deux espèces différentes de cactus du genre Opuntia, comportant quatre variétés non identifiées auparavant sur ce site. Nos travaux montrent donc l’existence d’une grande diversité génétique intra-espèces (variétés) et inter-espèces chez le cactus au Maroc. Paralèllement à ces études, les compositions chimiques des huiles essentielles de raquette et de graine de cactus ainsi que celle d’huile d’argan ont été déterminées. A partir de ces analyses, nous avons choisi d’étudier les effets de deux stérols, le spinastérol et le schotténol, ainsi que d’extraits de stérols sur l’activation du récepteur nucléaire LXR (Liver X receptor, impliqué dans la régulation du métabolisme du cholestérol) dans les cellules cérébrales de la microglie (lignée murine BV-2). Nos résultats montrent que le spinastérol et le schotténol, sans être cytotoxiques, peuvent moduler les expressions des deux isoformes de LXR, LXR-α et LXR-β, ainsi que de leurs gènes cibles ABCA1 et ABCG1. De plus, le schotténol provoque une activation spécifique de LXR-β. Ces résultats suggèrent que ces deux phytostérols pourraient avoir un rôle protecteur dans la modulation du métabolisme du cholestérol dans la microglie. / The objective of this PhD thesis is to characterize the Moroccan germplasm of the cactus Opuntia collected from different regions in Morocco, by studying the phenologic behavior, the genetic features and physicochemical composition, along with the molecules of high therapeutic potential which may have beneficial effects on the central nervous system cells from cactus extracts (fruit, flower, seed, oil, cladodes and spine) and compared to Argan oil. This work has been conducted in fours different laboratories sharing complementary analyses skills at agronomic, biochemistry, molecular levels. Our results are presented in three parts : (i) cactus agronomic characteristics, (ii) purification and characterization of natural extracts and molecules and (iii) the evalution of biological effects of these molecules using a cell model. Initially, the first experimental INRA site of cactus culture, located in Ain Nezagh and containing ecotypes older than 4 years, allowed us to achieve a phenological study with the classification of the ecotypes according to fruiting rate and to the biomass production in order to better guide their use according to geographical origin and species. The genetic diversity study based on morphological traits and molecular markers permited the identification, on the site of Ain Nezagh, of the presence of seven species of cactus among which two have never been described in Morocco: O. leucotricha and O. inermis. The morpho-anatomical and physicochemical analyses of cactus flower, juice, fruit and cladodes of 10 years old ecotypes issued from the Jemâat Riah INRA site, demonstrated the presence of two different species of the genus Opuntia including four varieties not previously identified on this site. Thus, our work indicates the existence of a large intra-species (varieties) and inter-species genetic diversity. Secondly, the chemical compositions of cladode essential oils or cactus seeds as well as argan oil were determined. From these analyzes, we have chosen to study the effects of two sterols, spinasterol and schottenol and also sterol extracts on the activation of the nuclear receptor LXR (Liver X receptor, involved in the regulation of cholesterol metabolism) in microglia brain cells (BV-2 murine cell line). Our results show that spinasterol and schottenol, without being cytotoxics, can modulate the expression of the two isoforms of LXR, LXR-α and LXR-β, as well as of their target genes ABCA1 and ABCG1. In addition, the schottenol causes LXR-β specific activation. These results suggest that these two phytosterols could have a protective role in the modulation of cholesterol metabolism in microglia.

The aim of this study is to show how a possible philosophy of life can arise from Bergson&rsquo / s conception of time. In realizing this aim, I appeal to Hadot&rsquo / s description of the paradox of the human condition. I claim that in order to understand how a Bergsonian philosophy of life through Bergson&rsquo / s conception of time would arise we need to understand the paradox of the human condition. The reason for this is that there are a lot of dualities in Bergson&rsquo / s philosophy all of which, I claim, are based on this fundamental duality concerning the human condition. I believe that when this paradox and its possible resolution are restated in Bergsonian notions, a Bergsonian philosophy of life that consists of a life sub specie durationis, that is a life under the aspect of duration, would arise. Hadot considered the paradox within the context of phenomenology alone. This made me proceed by searching for other approaches to the paradox within Bergson&rsquo / s philosophy. I realized that the attempts in finding out possible solutions to this problem cannot be found in the context of phenomenology alone and that the vitalist and the existentialist aspects have to be considered in order to remain faithful to Bergson&rsquo / s philosophy as well as in order to construct a Bergsonian philosophy of life. The phenomenological aspect of the paradox arises around Bergson&rsquo / s notion of displacement of attention and when the notion of dur&eacute / e r&eacute / elle is considered with consciousness in the light of the notion of intensity. The vitalist aspect enters into our discussion when we analyze Bergson&rsquo / s notion of &eacute / lan vital around the consideration of true evolution. I believe that the existentialist aspect of the paradox of the human condition comes from Bergson&rsquo / s notion of freedom around the discussion of the superficial and the fundamental self. It emerges if the individual asks himself how to deal with this paradox that in turn defines his struggle to transform the tension the paradox involves and that tells him to bring his own attitude towards it.

A introdução de espécies exóticas é uma prática que acompanha a história da humanidade, sendo as espécies introduzidas a base da nutrição e economia em vários países. Porém, esse processo contínuo tem levado a uma homogeneização da flora e fauna global. Os ecossistemas aquáticos, que têm recebido menor atenção que os terrestres, têm sofrido perda de diversidade, hibridação, introdução de patógenos, degradação do habitat além da necessidade e alto custo de controle das espécies introduzidas. O desenvolvimento da aqüicultura tem acelerado a introdução de peixes exóticos, que são a base dessa produção em países como o Brasil. Além desta, entre as razões para a introdução citam-se o esporte, a manipulação ecológica com controle de organismos indesejáveis, o melhoramento dos estoques, a ornamentação ou ainda introduções acidentais. No Rio Grande do Sul, nos rios dos Campos de Cima da Serra estão ocorrendo introduções da espécie exótica truta arco- íris (Oncorhynchus mykiss) desde meados da década de 90 como forma de estímulo ao turismo rural. O objetivo dessa prática é a pesca esportiva, que atrai turistas de várias regiões. Porém, os rios da região possuem várias espécies de peixes endêmicas e as conseqüências dessa prática sobre a biota aquática são desconhecidas. O objetivo do presente trabalho é avaliar o efeito da introdução da truta arco-íris sobre o ecossistema de rios de baixa ordem no município de São José dos Ausentes – RS, Brasil. Para tanto foi descrita a biologia da truta arco- íris no novo ambiente, verificando sua alimentação, movimentação, presença e viabilidade da reprodução. A ictiofauna autóctone dos rios com ausência e presença de trutas foi comparada, bem como o efeito da predação sobre a macrofauna bentônica. A ictiofauna foi amostrada com o uso da pesca elétrica, sendo o conteúdo estomacal das trutas avaliado sazonalmente. Três trutas foram marcadas e acompanhadas por ii biotelemetria para determinação da sua área de vida. Um experimento com ninhos artificiais foi conduzido para verificação da sobrevivência de ovos de trutas nas condições dos rios de São José dos Ausentes. O experimento de exclusão de peixes foi feito a fim de avaliar o efeito da predação sobre a macrofauna bentônica, comparando a macrofauna em rios com e sem trutas. Os resultados indicaram que a truta arco- íris tem como alimento principal os invertebrados bentônicos, porém as maiores classes de tamanho incluem peixes em seus alimentos principais. Logo após sua introdução a movimentação é restrita, porém alguns exemplares foram capturados em um rio onde não foi feita introdução dessa espécie. Apesar de baixa, a sobrevivência dos adultos ocorre, assim como a reprodução. A sobrevivência dos ovos também é baixa, porém, uma pós-larva foi encontrada. A ictiofauna autóctone é diferenciada nos rios com presença de truta, apresentando menor riqueza e diversidade e uma tendência a diminuição da biomassa. A macrofauna bentônica também é diferenciada, apesar de não ser possível atribuir essa diferença somente à presença das trutas. / The introduction of exotic species is a practice that accompanies the humanity's history, being the introduced species the base of the nutrition and economy in several countries. Even so, that continuous process has been taking to a homogenization of the global flora and fauna. The aquatic ecosystems, that have been receiving smaller attention than the terrestrial ones, have been suffering diversity loss, hybridization, pathogens introduction, degradation of the habitat and costs of control of the introduced species. The development of aquaculture has been accelerating the introduction of exotic fish, that are the base of that production in countries as Brazil. Among the reasons for the introduction are the sporting fishing, the ecological manipulation with control of undesirable organisms, the improvement of the stocks, the ornamentation or still accidental introductions. In Rio Grande do Sul, in the rivers of Campos de Cima da Serra are occurring introductions of the species exotic rainbow trout (Oncorhynchus mykiss) from middles of the decade of 90 as incentive form to the rural tourism. The objective of that practice is the sporting fishing, which attracts tourists of several areas. Even so, the rivers of the area possess several endemic species of fish and the consequences of that practice on the aquatic biota have been ignored. The objective of the present work is to evaluate the effect of the introduction of the rainbow trout on rivers of low order in the municipal district of São José dos Ausentes - RS, Brazil. Thus the biology of the rainbow trout was described in the new environment, verifying its feeding, movement, presence and viability of reproduction. The autochthonous ictiofauna of the rivers with absence and presence of trouts was compared, as well as the effect of the predation on the benthic macrofauna. The ictiofauna was collected with the use of the electric fishing, being the stomacal content of the trouts evaluated seasonally. Three trouts were marked and accompanied by biotelemetry for determination of its life iv area. An experiment with artificial nests was driven for verification of the survival of eggs of trouts in the conditions of the rivers of São José dos Ausentes. The experiment of exclusion of fish was made in order to evaluate the effect of the predation on the benthic macrofauna, comparing the macrofauna in rivers with and without trouts. The results indicated that the rainbow trout has as main food benthic invertebrates, even so, in larger size classes it include fishes as main food. After its introduction the movement is restricted, even so trout s were found in a river where they were not introduced. Although low, have survival, as well as reproduction. The survival of the eggs is low, but it is happening in Silveira River, a post larvae being found. The autochthonous ictiofauna is differentiated in the rivers with trout presence, presenting smaller richness and diversity. The benthic macrofauna is also differentiated, in spite of not being possible to attribute that difference only to the presence of trouts.

A introdução de espécies exóticas é uma prática que acompanha a história da humanidade, sendo as espécies introduzidas a base da nutrição e economia em vários países. Porém, esse processo contínuo tem levado a uma homogeneização da flora e fauna global. Os ecossistemas aquáticos, que têm recebido menor atenção que os terrestres, têm sofrido perda de diversidade, hibridação, introdução de patógenos, degradação do habitat além da necessidade e alto custo de controle das espécies introduzidas. O desenvolvimento da aqüicultura tem acelerado a introdução de peixes exóticos, que são a base dessa produção em países como o Brasil. Além desta, entre as razões para a introdução citam-se o esporte, a manipulação ecológica com controle de organismos indesejáveis, o melhoramento dos estoques, a ornamentação ou ainda introduções acidentais. No Rio Grande do Sul, nos rios dos Campos de Cima da Serra estão ocorrendo introduções da espécie exótica truta arco- íris (Oncorhynchus mykiss) desde meados da década de 90 como forma de estímulo ao turismo rural. O objetivo dessa prática é a pesca esportiva, que atrai turistas de várias regiões. Porém, os rios da região possuem várias espécies de peixes endêmicas e as conseqüências dessa prática sobre a biota aquática são desconhecidas. O objetivo do presente trabalho é avaliar o efeito da introdução da truta arco-íris sobre o ecossistema de rios de baixa ordem no município de São José dos Ausentes – RS, Brasil. Para tanto foi descrita a biologia da truta arco- íris no novo ambiente, verificando sua alimentação, movimentação, presença e viabilidade da reprodução. A ictiofauna autóctone dos rios com ausência e presença de trutas foi comparada, bem como o efeito da predação sobre a macrofauna bentônica. A ictiofauna foi amostrada com o uso da pesca elétrica, sendo o conteúdo estomacal das trutas avaliado sazonalmente. Três trutas foram marcadas e acompanhadas por ii biotelemetria para determinação da sua área de vida. Um experimento com ninhos artificiais foi conduzido para verificação da sobrevivência de ovos de trutas nas condições dos rios de São José dos Ausentes. O experimento de exclusão de peixes foi feito a fim de avaliar o efeito da predação sobre a macrofauna bentônica, comparando a macrofauna em rios com e sem trutas. Os resultados indicaram que a truta arco- íris tem como alimento principal os invertebrados bentônicos, porém as maiores classes de tamanho incluem peixes em seus alimentos principais. Logo após sua introdução a movimentação é restrita, porém alguns exemplares foram capturados em um rio onde não foi feita introdução dessa espécie. Apesar de baixa, a sobrevivência dos adultos ocorre, assim como a reprodução. A sobrevivência dos ovos também é baixa, porém, uma pós-larva foi encontrada. A ictiofauna autóctone é diferenciada nos rios com presença de truta, apresentando menor riqueza e diversidade e uma tendência a diminuição da biomassa. A macrofauna bentônica também é diferenciada, apesar de não ser possível atribuir essa diferença somente à presença das trutas. / The introduction of exotic species is a practice that accompanies the humanity's history, being the introduced species the base of the nutrition and economy in several countries. Even so, that continuous process has been taking to a homogenization of the global flora and fauna. The aquatic ecosystems, that have been receiving smaller attention than the terrestrial ones, have been suffering diversity loss, hybridization, pathogens introduction, degradation of the habitat and costs of control of the introduced species. The development of aquaculture has been accelerating the introduction of exotic fish, that are the base of that production in countries as Brazil. Among the reasons for the introduction are the sporting fishing, the ecological manipulation with control of undesirable organisms, the improvement of the stocks, the ornamentation or still accidental introductions. In Rio Grande do Sul, in the rivers of Campos de Cima da Serra are occurring introductions of the species exotic rainbow trout (Oncorhynchus mykiss) from middles of the decade of 90 as incentive form to the rural tourism. The objective of that practice is the sporting fishing, which attracts tourists of several areas. Even so, the rivers of the area possess several endemic species of fish and the consequences of that practice on the aquatic biota have been ignored. The objective of the present work is to evaluate the effect of the introduction of the rainbow trout on rivers of low order in the municipal district of São José dos Ausentes - RS, Brazil. Thus the biology of the rainbow trout was described in the new environment, verifying its feeding, movement, presence and viability of reproduction. The autochthonous ictiofauna of the rivers with absence and presence of trouts was compared, as well as the effect of the predation on the benthic macrofauna. The ictiofauna was collected with the use of the electric fishing, being the stomacal content of the trouts evaluated seasonally. Three trouts were marked and accompanied by biotelemetry for determination of its life iv area. An experiment with artificial nests was driven for verification of the survival of eggs of trouts in the conditions of the rivers of São José dos Ausentes. The experiment of exclusion of fish was made in order to evaluate the effect of the predation on the benthic macrofauna, comparing the macrofauna in rivers with and without trouts. The results indicated that the rainbow trout has as main food benthic invertebrates, even so, in larger size classes it include fishes as main food. After its introduction the movement is restricted, even so trout s were found in a river where they were not introduced. Although low, have survival, as well as reproduction. The survival of the eggs is low, but it is happening in Silveira River, a post larvae being found. The autochthonous ictiofauna is differentiated in the rivers with trout presence, presenting smaller richness and diversity. The benthic macrofauna is also differentiated, in spite of not being possible to attribute that difference only to the presence of trouts.

A introdução de espécies exóticas é uma prática que acompanha a história da humanidade, sendo as espécies introduzidas a base da nutrição e economia em vários países. Porém, esse processo contínuo tem levado a uma homogeneização da flora e fauna global. Os ecossistemas aquáticos, que têm recebido menor atenção que os terrestres, têm sofrido perda de diversidade, hibridação, introdução de patógenos, degradação do habitat além da necessidade e alto custo de controle das espécies introduzidas. O desenvolvimento da aqüicultura tem acelerado a introdução de peixes exóticos, que são a base dessa produção em países como o Brasil. Além desta, entre as razões para a introdução citam-se o esporte, a manipulação ecológica com controle de organismos indesejáveis, o melhoramento dos estoques, a ornamentação ou ainda introduções acidentais. No Rio Grande do Sul, nos rios dos Campos de Cima da Serra estão ocorrendo introduções da espécie exótica truta arco- íris (Oncorhynchus mykiss) desde meados da década de 90 como forma de estímulo ao turismo rural. O objetivo dessa prática é a pesca esportiva, que atrai turistas de várias regiões. Porém, os rios da região possuem várias espécies de peixes endêmicas e as conseqüências dessa prática sobre a biota aquática são desconhecidas. O objetivo do presente trabalho é avaliar o efeito da introdução da truta arco-íris sobre o ecossistema de rios de baixa ordem no município de São José dos Ausentes – RS, Brasil. Para tanto foi descrita a biologia da truta arco- íris no novo ambiente, verificando sua alimentação, movimentação, presença e viabilidade da reprodução. A ictiofauna autóctone dos rios com ausência e presença de trutas foi comparada, bem como o efeito da predação sobre a macrofauna bentônica. A ictiofauna foi amostrada com o uso da pesca elétrica, sendo o conteúdo estomacal das trutas avaliado sazonalmente. Três trutas foram marcadas e acompanhadas por ii biotelemetria para determinação da sua área de vida. Um experimento com ninhos artificiais foi conduzido para verificação da sobrevivência de ovos de trutas nas condições dos rios de São José dos Ausentes. O experimento de exclusão de peixes foi feito a fim de avaliar o efeito da predação sobre a macrofauna bentônica, comparando a macrofauna em rios com e sem trutas. Os resultados indicaram que a truta arco- íris tem como alimento principal os invertebrados bentônicos, porém as maiores classes de tamanho incluem peixes em seus alimentos principais. Logo após sua introdução a movimentação é restrita, porém alguns exemplares foram capturados em um rio onde não foi feita introdução dessa espécie. Apesar de baixa, a sobrevivência dos adultos ocorre, assim como a reprodução. A sobrevivência dos ovos também é baixa, porém, uma pós-larva foi encontrada. A ictiofauna autóctone é diferenciada nos rios com presença de truta, apresentando menor riqueza e diversidade e uma tendência a diminuição da biomassa. A macrofauna bentônica também é diferenciada, apesar de não ser possível atribuir essa diferença somente à presença das trutas. / The introduction of exotic species is a practice that accompanies the humanity's history, being the introduced species the base of the nutrition and economy in several countries. Even so, that continuous process has been taking to a homogenization of the global flora and fauna. The aquatic ecosystems, that have been receiving smaller attention than the terrestrial ones, have been suffering diversity loss, hybridization, pathogens introduction, degradation of the habitat and costs of control of the introduced species. The development of aquaculture has been accelerating the introduction of exotic fish, that are the base of that production in countries as Brazil. Among the reasons for the introduction are the sporting fishing, the ecological manipulation with control of undesirable organisms, the improvement of the stocks, the ornamentation or still accidental introductions. In Rio Grande do Sul, in the rivers of Campos de Cima da Serra are occurring introductions of the species exotic rainbow trout (Oncorhynchus mykiss) from middles of the decade of 90 as incentive form to the rural tourism. The objective of that practice is the sporting fishing, which attracts tourists of several areas. Even so, the rivers of the area possess several endemic species of fish and the consequences of that practice on the aquatic biota have been ignored. The objective of the present work is to evaluate the effect of the introduction of the rainbow trout on rivers of low order in the municipal district of São José dos Ausentes - RS, Brazil. Thus the biology of the rainbow trout was described in the new environment, verifying its feeding, movement, presence and viability of reproduction. The autochthonous ictiofauna of the rivers with absence and presence of trouts was compared, as well as the effect of the predation on the benthic macrofauna. The ictiofauna was collected with the use of the electric fishing, being the stomacal content of the trouts evaluated seasonally. Three trouts were marked and accompanied by biotelemetry for determination of its life iv area. An experiment with artificial nests was driven for verification of the survival of eggs of trouts in the conditions of the rivers of São José dos Ausentes. The experiment of exclusion of fish was made in order to evaluate the effect of the predation on the benthic macrofauna, comparing the macrofauna in rivers with and without trouts. The results indicated that the rainbow trout has as main food benthic invertebrates, even so, in larger size classes it include fishes as main food. After its introduction the movement is restricted, even so trout s were found in a river where they were not introduced. Although low, have survival, as well as reproduction. The survival of the eggs is low, but it is happening in Silveira River, a post larvae being found. The autochthonous ictiofauna is differentiated in the rivers with trout presence, presenting smaller richness and diversity. The benthic macrofauna is also differentiated, in spite of not being possible to attribute that difference only to the presence of trouts.