The objective of this study was to evaluate the viability of Campylobacter jejuni and quantify indicator microorganisms (mesophilic bacteria, total coliforms and E. coli) in initial and final broiler feed artificially contaminated with 103 and 105 CFU of C. jejuni per gram of ration, kept at two different temperatures of storage (25 and 370C) and analyzed on four different storage periods 0, 24, 72 and 120 hours. C. jejuni survived throughout the study period and multiplied when inoculated with 103UFC, with the highest counts observed when the feed was kept at a temperature of 370C. Overall, there was a multiplication of mesophilic microorganisms, but the amount of coliforms didn´t increase with time. This work shows that the importance of feed in the epidemiology of C. jejuni in broilers should be better assessed and instigates other studies to verify the possible symbiotic relationship between C. jejuni and mesophilic. / O objetivo desse estudo foi avaliar a viabilidade de Campylobacter jejuni e quantificar microrganismos indicadores (bactérias mesófilas, coliformes totais e E. coli) em rações inicial e final de frangos de corte artificialmente contaminadas com 103 e 105 UFC de C. jejuni por grama de ração, mantidas em duas diferentes temperaturas de armazenamento (25 e 370C) e analisadas em quatro períodos de armazenamento distintos 0, 24, 72 e 120 horas. A C. jejuni sobreviveu durante todo o período avaliado e se multiplicou quando inoculada 103 UFC, sendo observadas as maiores contagens quando a ração foi mantida na temperatura de 370C. Houve multiplicação de microrganismos mesófilos, mas a quantidade de coliformes não aumentou com o tempo. Este trabalho alerta para a necessidade de melhores investigações sobre a importância da ração na epidemiologia da C. jejuni em frangos de corte e a relação mesófilo e Campylobacter. / Mestre em Ciências Veterinárias

A bacteriospermia pode prejudicar a qualidade das doses de sêmen suíno. Desta forma, a adição de antimicrobianos (ATM) aos diluentes de sêmen é imprescindível para a manutenção da qualidade das doses inseminantes. Contudo, a crescente ocorrência de resistência bacteriana tem impulsionado a redução do uso de ATM na suinocultura. Nesse sentido, o armazenamento das doses inseminantes em baixas temperaturas pode ser uma alternativa para a remoção dos ATM dos diluentes comerciais. Sendo assim, no presente estudo, foram realizados dois experimentos para avaliar a qualidade espermática e a contagem de unidades formadoras de colônias (UFC/mL) de doses de sêmen suíno submetidas a baixas temperaturas de armazenamento, na ausência ou presença de ATM. No experimento 1, as motilidades (total e progressiva) das doses com ATM foram maiores conforme aumentou a temperatura de armazenamento (P<0,01). Nas doses sem ATM, as motilidades foram inferiores nas mantidas a 5 °C do que nas demais (P<0,05). O número de UFC/mL foi menor nas doses sem ATM mantidas a 5 e 10 °C do que a 17 °C (P<0,05), mas não houve diferença entre as temperaturas de armazenamento nas doses com ATM (P>0,05). As integridades de acrossoma e de membrana plasmática não foram afetadas (P>0,05) pelo uso de ATM, mas foram influenciadas pela temperatura de armazenamento (P<0,0001) No experimento 2, os machos foram categorizados em BONS e RUINS de acordo com a motilidade progressiva das doses com ATM armazenadas a 5 °C nas 120 h, sendo investigado o efeito dessas categorias sobre as variáveis estudadas. A motilidade total das doses armazenadas a 17 °C foi superior à das mantidas a 5 °C diluídas sem ATM (P<0,05). Os percentuais de motilidade progressiva e de acrossomas normais foram superiores nas doses mantidas a 17 °C do que nas mantidas a 5 °C, com ou sem ATM (P<0,05). O número de UFC/ml foi maior nas doses diluídas sem ATM do que nas demais (P<0,05). Após a categorização dos machos, as motilidades (total e progressiva) foram maiores nos machos BONS do que nos RUINS (P<0,05), sem diferença significativa (P>0,05) nas integridades (acrossomal e de membrana plasmática). Apesar de a qualidade espermática ter sido afetada negativamente pelas baixas temperaturas, o armazenamento das doses de sêmen suíno a 5 °C é possível, uma vez que foi mantida a viabilidade espermática in vitro, por até 5 dias, acima do nível mínimo considerado adequado para a inseminação artificial. Contudo, o uso de doses sem antimicrobianos ainda precisa de otimização, posto que que as baixas temperaturas de armazenamento reduzem, mas não inibem por completo o crescimento bacteriano. / Bacteriospermia can impair boar semen dose quality. Thus, the addition of antibiotics (ATB) is indispensable for maintaining semen doses quality. Nevertheless, growing bacterial resistance occurrence have had driven to a reduction in use of ATB in pig industry. In this sense, storage of semen doses at low temperature may be an alternative to removal ATB of commercial semen extenders. Therefore, the aim of the present study was to assess sperm quality and number of colony-forming units (CFU mL-1) in boar semen doses stored at low storage temperatures with or without ATB, in two experiments. In experiment 1, in semen doses with ATB, total and progressive motility increased as the storage temperature increased (P<0.01). In semen doses without ATB, total and progressive motility were observed to be lower when stored at 5 °C than at 10 and 17 °C (P<0.05). The number of CFU mL-1 was lower in semen doses without ATB stored at 5 and 10 °C than at 17 °C (P<0.05), but there was no difference among storage temperatures in doses with ATB (P>0.05). Acrosome and sperm membrane integrity were not influenced (P>0.05) by using ATB, but they were influenced by storage temperature (P<0,0001) In experiment 2, boars were grouped in GOOD and POOR according to progressive motility in doses stored for up to 120 h at 5 °C. So, the effect of this classification on assessed variables, was investigated. Total motility was higher in doses stored at 17 °C than in doses without ATB stored at 5 °C (P<0.05). The percentages of progressive motility and normal acrosomes were higher in doses stored at 17 °C than in doses stored at 5 °C, with or without ATB (P<0.05). The number of CFU mL-1 was higher in doses without ATB than in remaining ones (P<0.05). Total and progressive motility were observed to be higher in GOOD than in POOR boars (P<0.05). There was no difference between groups of boars in acrosome and membrane integrity (P>0.05). Despite sperm quality was negatively affected by low temperatures, the storage of boar semen doses at 5 °C is possible, since sperm viability in vitro was maintained for up to 5 days, fulfilling the requirements of semen quality to be used in artificial insemination. Nevertheless, the use of semen doses without ATB will need optimization, since low storage temperatures decreased bacterial growth, but not completely inhibit it.

A bacteriospermia pode prejudicar a qualidade das doses de sêmen suíno. Desta forma, a adição de antimicrobianos (ATM) aos diluentes de sêmen é imprescindível para a manutenção da qualidade das doses inseminantes. Contudo, a crescente ocorrência de resistência bacteriana tem impulsionado a redução do uso de ATM na suinocultura. Nesse sentido, o armazenamento das doses inseminantes em baixas temperaturas pode ser uma alternativa para a remoção dos ATM dos diluentes comerciais. Sendo assim, no presente estudo, foram realizados dois experimentos para avaliar a qualidade espermática e a contagem de unidades formadoras de colônias (UFC/mL) de doses de sêmen suíno submetidas a baixas temperaturas de armazenamento, na ausência ou presença de ATM. No experimento 1, as motilidades (total e progressiva) das doses com ATM foram maiores conforme aumentou a temperatura de armazenamento (P<0,01). Nas doses sem ATM, as motilidades foram inferiores nas mantidas a 5 °C do que nas demais (P<0,05). O número de UFC/mL foi menor nas doses sem ATM mantidas a 5 e 10 °C do que a 17 °C (P<0,05), mas não houve diferença entre as temperaturas de armazenamento nas doses com ATM (P>0,05). As integridades de acrossoma e de membrana plasmática não foram afetadas (P>0,05) pelo uso de ATM, mas foram influenciadas pela temperatura de armazenamento (P<0,0001) No experimento 2, os machos foram categorizados em BONS e RUINS de acordo com a motilidade progressiva das doses com ATM armazenadas a 5 °C nas 120 h, sendo investigado o efeito dessas categorias sobre as variáveis estudadas. A motilidade total das doses armazenadas a 17 °C foi superior à das mantidas a 5 °C diluídas sem ATM (P<0,05). Os percentuais de motilidade progressiva e de acrossomas normais foram superiores nas doses mantidas a 17 °C do que nas mantidas a 5 °C, com ou sem ATM (P<0,05). O número de UFC/ml foi maior nas doses diluídas sem ATM do que nas demais (P<0,05). Após a categorização dos machos, as motilidades (total e progressiva) foram maiores nos machos BONS do que nos RUINS (P<0,05), sem diferença significativa (P>0,05) nas integridades (acrossomal e de membrana plasmática). Apesar de a qualidade espermática ter sido afetada negativamente pelas baixas temperaturas, o armazenamento das doses de sêmen suíno a 5 °C é possível, uma vez que foi mantida a viabilidade espermática in vitro, por até 5 dias, acima do nível mínimo considerado adequado para a inseminação artificial. Contudo, o uso de doses sem antimicrobianos ainda precisa de otimização, posto que que as baixas temperaturas de armazenamento reduzem, mas não inibem por completo o crescimento bacteriano. / Bacteriospermia can impair boar semen dose quality. Thus, the addition of antibiotics (ATB) is indispensable for maintaining semen doses quality. Nevertheless, growing bacterial resistance occurrence have had driven to a reduction in use of ATB in pig industry. In this sense, storage of semen doses at low temperature may be an alternative to removal ATB of commercial semen extenders. Therefore, the aim of the present study was to assess sperm quality and number of colony-forming units (CFU mL-1) in boar semen doses stored at low storage temperatures with or without ATB, in two experiments. In experiment 1, in semen doses with ATB, total and progressive motility increased as the storage temperature increased (P<0.01). In semen doses without ATB, total and progressive motility were observed to be lower when stored at 5 °C than at 10 and 17 °C (P<0.05). The number of CFU mL-1 was lower in semen doses without ATB stored at 5 and 10 °C than at 17 °C (P<0.05), but there was no difference among storage temperatures in doses with ATB (P>0.05). Acrosome and sperm membrane integrity were not influenced (P>0.05) by using ATB, but they were influenced by storage temperature (P<0,0001) In experiment 2, boars were grouped in GOOD and POOR according to progressive motility in doses stored for up to 120 h at 5 °C. So, the effect of this classification on assessed variables, was investigated. Total motility was higher in doses stored at 17 °C than in doses without ATB stored at 5 °C (P<0.05). The percentages of progressive motility and normal acrosomes were higher in doses stored at 17 °C than in doses stored at 5 °C, with or without ATB (P<0.05). The number of CFU mL-1 was higher in doses without ATB than in remaining ones (P<0.05). Total and progressive motility were observed to be higher in GOOD than in POOR boars (P<0.05). There was no difference between groups of boars in acrosome and membrane integrity (P>0.05). Despite sperm quality was negatively affected by low temperatures, the storage of boar semen doses at 5 °C is possible, since sperm viability in vitro was maintained for up to 5 days, fulfilling the requirements of semen quality to be used in artificial insemination. Nevertheless, the use of semen doses without ATB will need optimization, since low storage temperatures decreased bacterial growth, but not completely inhibit it.

A bacteriospermia pode prejudicar a qualidade das doses de sêmen suíno. Desta forma, a adição de antimicrobianos (ATM) aos diluentes de sêmen é imprescindível para a manutenção da qualidade das doses inseminantes. Contudo, a crescente ocorrência de resistência bacteriana tem impulsionado a redução do uso de ATM na suinocultura. Nesse sentido, o armazenamento das doses inseminantes em baixas temperaturas pode ser uma alternativa para a remoção dos ATM dos diluentes comerciais. Sendo assim, no presente estudo, foram realizados dois experimentos para avaliar a qualidade espermática e a contagem de unidades formadoras de colônias (UFC/mL) de doses de sêmen suíno submetidas a baixas temperaturas de armazenamento, na ausência ou presença de ATM. No experimento 1, as motilidades (total e progressiva) das doses com ATM foram maiores conforme aumentou a temperatura de armazenamento (P<0,01). Nas doses sem ATM, as motilidades foram inferiores nas mantidas a 5 °C do que nas demais (P<0,05). O número de UFC/mL foi menor nas doses sem ATM mantidas a 5 e 10 °C do que a 17 °C (P<0,05), mas não houve diferença entre as temperaturas de armazenamento nas doses com ATM (P>0,05). As integridades de acrossoma e de membrana plasmática não foram afetadas (P>0,05) pelo uso de ATM, mas foram influenciadas pela temperatura de armazenamento (P<0,0001) No experimento 2, os machos foram categorizados em BONS e RUINS de acordo com a motilidade progressiva das doses com ATM armazenadas a 5 °C nas 120 h, sendo investigado o efeito dessas categorias sobre as variáveis estudadas. A motilidade total das doses armazenadas a 17 °C foi superior à das mantidas a 5 °C diluídas sem ATM (P<0,05). Os percentuais de motilidade progressiva e de acrossomas normais foram superiores nas doses mantidas a 17 °C do que nas mantidas a 5 °C, com ou sem ATM (P<0,05). O número de UFC/ml foi maior nas doses diluídas sem ATM do que nas demais (P<0,05). Após a categorização dos machos, as motilidades (total e progressiva) foram maiores nos machos BONS do que nos RUINS (P<0,05), sem diferença significativa (P>0,05) nas integridades (acrossomal e de membrana plasmática). Apesar de a qualidade espermática ter sido afetada negativamente pelas baixas temperaturas, o armazenamento das doses de sêmen suíno a 5 °C é possível, uma vez que foi mantida a viabilidade espermática in vitro, por até 5 dias, acima do nível mínimo considerado adequado para a inseminação artificial. Contudo, o uso de doses sem antimicrobianos ainda precisa de otimização, posto que que as baixas temperaturas de armazenamento reduzem, mas não inibem por completo o crescimento bacteriano. / Bacteriospermia can impair boar semen dose quality. Thus, the addition of antibiotics (ATB) is indispensable for maintaining semen doses quality. Nevertheless, growing bacterial resistance occurrence have had driven to a reduction in use of ATB in pig industry. In this sense, storage of semen doses at low temperature may be an alternative to removal ATB of commercial semen extenders. Therefore, the aim of the present study was to assess sperm quality and number of colony-forming units (CFU mL-1) in boar semen doses stored at low storage temperatures with or without ATB, in two experiments. In experiment 1, in semen doses with ATB, total and progressive motility increased as the storage temperature increased (P<0.01). In semen doses without ATB, total and progressive motility were observed to be lower when stored at 5 °C than at 10 and 17 °C (P<0.05). The number of CFU mL-1 was lower in semen doses without ATB stored at 5 and 10 °C than at 17 °C (P<0.05), but there was no difference among storage temperatures in doses with ATB (P>0.05). Acrosome and sperm membrane integrity were not influenced (P>0.05) by using ATB, but they were influenced by storage temperature (P<0,0001) In experiment 2, boars were grouped in GOOD and POOR according to progressive motility in doses stored for up to 120 h at 5 °C. So, the effect of this classification on assessed variables, was investigated. Total motility was higher in doses stored at 17 °C than in doses without ATB stored at 5 °C (P<0.05). The percentages of progressive motility and normal acrosomes were higher in doses stored at 17 °C than in doses stored at 5 °C, with or without ATB (P<0.05). The number of CFU mL-1 was higher in doses without ATB than in remaining ones (P<0.05). Total and progressive motility were observed to be higher in GOOD than in POOR boars (P<0.05). There was no difference between groups of boars in acrosome and membrane integrity (P>0.05). Despite sperm quality was negatively affected by low temperatures, the storage of boar semen doses at 5 °C is possible, since sperm viability in vitro was maintained for up to 5 days, fulfilling the requirements of semen quality to be used in artificial insemination. Nevertheless, the use of semen doses without ATB will need optimization, since low storage temperatures decreased bacterial growth, but not completely inhibit it.

Ce travail présente les résultats dune étude menée sur la dépollution des tailings de Kipushi (RD Congo) par la valorisation des métaux contenus. Ce sont les rejets anciens dun concentrateur. Ils contiennent de la pyrite et des sulfures résiduels de cuivre et de zinc. Du fait du stockage à lair libre pendant plus de 40 ans, ces sulfures sont partiellement oxydés. Ces tailings présentent une certaine instabilité physique et chimique qui est à la base de la dégradation des milieux environnants les plus proches (rivières naturelles, sols sous-jacents, nappes souterraines, etc.) suite à la migration et à la dispersion dETM (éléments traces métalliques) tels que larsenic, le cadmium, le cobalt, le cuivre, le plomb, le zinc, Linstabilité physique se manifeste par des phénomènes dérosion par les eaux de ruissellement pendant la saison des pluies et par des phénomènes dérosion éolienne pendant la saison sèche. Leur stockage en surface saccompagne dune lente oxydation des sulfures avec production deaux acides qui dans leur neutralisation par la dolomie présente dans les rejets et celle des formations géologiques sur lesquelles ils reposent, contribuent à laccroissement des réseaux karstiques, au durcissement des eaux des nappes et parfois provoquent des phénomènes daffaissements, voire même deffondrements de terrains. Pour réduire les impacts environnementaux majeurs de ces tailings, nous avons effectué ce travail en recherchant un traitement qui combinerait dune part la dépollution par la réduction des ETM et du soufre sulfure et dautre part la valorisation du cuivre et du zinc contenus. Les deux voies qui ont été testées commencent par une flottation globale de tous les sulfures (désulfuration environnementale). Les résultats de nos expérimentations montrent quon peut obtenir un nouveau rejet de flottation dans lequel une majeure partie des ETM facilement mobilisables dans lenvironnement est éliminée ainsi que presque tout le soufre (95 %), ce qui écarte donc tout risque de DMA. Nous avons démontré que pour atteindre ces résultats, il suffit de ne broyer que la fraction la moins libérée de dimension supérieure à 75 μm et dactiver par un prétraitement à pH 6 les sulfures dont la collection par le xanthate est sinon inhibée par laltération superficielle avec formation doxydes ou par les complexes cyanométalliques formés lors de la flottation avec dépression de la pyrite par les ions cyanures ayant produit les tailings étudiés. Nous avons tenté denrichir le concentré global de la désulfuration environnementale par une flottation différentielle avec dépression de la pyrite à pH 11. Cet enrichissement est difficile à réaliser à cause de la finesse des grains et des caractéristiques minéralogiques du concentré global qui contient beaucoup de grains mixtes. Les essais ont alors porté sur la lixiviation chimique acide oxydante (avec Fe3+) et la lixiviation bactérienne du concentré global après son enrichissement en cuivre et en zinc dans un circuit de flottation avec deux finissages. Une étude approfondie des paramètres qui influencent le mécanisme des biolixiviations a été effectuée et les conditions de leur mise en pratique industrielle ont été déterminées. La lixiviation chimique doit être réalisée à des températures élevées (98°C) pour fragiliser la couche de passivation de soufre élémentaire qui se forme à la surface des grains et qui tend à freiner la diffusion des réactifs et des produits de la réaction. Par contre, la biolixiviation donne de bons résultats à température modérée. Elle est techniquement applicable aux tailings de Kipushi. Nous proposons de réaliser la biolixiviation en deux étapes successives, la première avec des bactéries thermophiles modérées (55°C) à une densité de pulpe de 15 % (poids/volume) et la deuxième avec des bactéries mésophiles (33°C) sur des pulpes à 4 % de solides. Dans ces conditions, on réussit à produire deux solutions de lixiviation (PLS : pregnant leach solution), lune à 3 g/l de cuivre et 7 g/l de zinc et lautre à 0,2 g/l de cuivre et 7 g/l de zinc, quon purifie et concentre facilement dans un circuit dextraction par solvant. Lextraction par solvant du cuivre est réalisée avec le LIX984N directement sans modifier le pH des PLS (1,7-1,9) et le zinc est extrait par le D2EHPA après précipitation dions Fe3+ du raffinat cuivre à des pH entre 3 et 3,5. On obtient ainsi des solutions aqueuses de cuivre et de zinc convenant aux installations délectrolyse industrielle. Nous avons proposé un schéma de traitement des tailings de Kipushi qui pourrait fonctionner pendant 20 ans avec les 36 684 600 tonnes sèches de rejets stockés à la digue 1 et 2. Le traitement produirait un nouveau rejet plus ou moins dépollué qui représente 66 % en poids des tailings traités, 80 950 tonnes de cuivre et 631 750 tonnes de zinc. The work present results from research study devoted to de-pollution of the stocked tailings in Kipushi (DR Congo) via valorization of the metals contained in the tailings. Pyrite and copper and zinc sulfides present the principal mineral composition of the laid down tailings from the concentrator. Due to the fact that the sulphides have been stocked during more than 40 years, they are partly oxidized. These tailings present a constant risk from physical instability and spillage, which reflects in the deterioration of the surrounding environment (rivers, soil, underground water table, etc). Moreover the migration and dispersion of TEM (trace metal elements) such as arsenic, cadmium, cobalt, copper, lead, zinc, is leading to erosion and mine run-off phenomena during wet season and generate air-borne particles during dry season. The stocking of the tailings is accompanied by slow oxidation of the sulfides with concomitant production of acidic waters which are neutralized by the dolomite present, which finally reflects in hardening of the underground waters and even provoke soil subsidence and ground collapses. In order to reduce the major environmental impacts from the tailings, we have performed a study for their post-treatment which encompasses the cleanup from one side and the reduction of TEMs and sulphur on the other side. Apart from this, the aim was to economically extract the remaining non-ferrous metals, notably Zn and Cu. The approach which has been chosen to accomplish this task has been to re-float by bulk flotation the majority of the sulphides and thus by elimination of the nearly total sulphur (95 %) to eliminate the risk of AMD generation and metals immobilization. We have shown that this is possible to be achieved via grinding the 75 μm oversize fraction in order to facilitate minerals liberation, following by subsequent activation at pH 6 before flotation. Without this pretreatment step, the flotation by use of xanthates is impossible, due to the surface coatings of the grains, which are either of oxide nature or are cyano-metallic complexes formed from the use of potassium cyanide as pyrite depressor in the flotation circuit practiced at the times when the concentrator was operational. The further attempts to produce monometallic flotation concentrates via selective flotation with depression of the pyrite at pH 11 have been unsuccessful due to reasons of complex mineralogy. Therefore chemical (Fe3+) and bacterial leaching of the bulk concentrate enriched in Cu and Zn via two cleaning flotation circuits have been envisaged. The technological parameters for the both leaching options have been studied and the mechanisms of the bioleaching taking place have been proposed in view industrial scale up of the process. It has been found that the chemical leaching should be conducted at very high temperatures (98°C) in order to breakdown the passivation coatings (sulphur). In contrast, the bioleaching has shown good results at moderate temperatures. It has been found that bioleaching is technically feasible to the tailings of Kipushi. We have suggested a bioleaching in two successive stages: the first one with moderate thermophilic microorganisms (55 °C) at pulp density 15 % (weight / volume) and the second one with mesophilic microorganisms (33 °C) at pulp density of 4 % (w/v). Under these conditions two principal PLSs (pregnant leach solution) can be obtained - a one with 3 g/l Cu and 7 g/ l Zn and other one in 0.2 g/l Cu and 7 g/l Zn. The both PLSs could be further processed via solvent extraction. The solvent extraction of Cu is accomplished with LIX984N without modifying the pH of the PLS (1.7 - 1.9), while Zn is extracted using a D2EHPA at pH between 3 and 3,5, after elimination of the iron from the copper raffinate. The aqueous solutions thus obtained are suitable for Cu and Zn electrowinning. Finally, a flow sheet for re-treatment of the Kipushi tailings which could operate during 20 years has been proposed. It could treat about 37 mln tones of dry tailings stocked in the tailing ponds 1 and 2. Preliminary calculations estimate that such treatment would produce new tailings with low environmental risk which will represent about 66 % in weight of the original treated tailings and will yield about 80 950 tons of Cu and 631 750 tons of Zn.