Mannan oligosaccharides (MOS) have shown to stimulate immune response in different fish species, but the results may appear contradictory and have not been tested in conjunction with vaccination. We ...hypothesized that dietary MOS supplementation could enhance efficacy and immune responses after immunization with a novel hydrogen peroxide‐inactivated vaccine. Nile Tilapia, Oreochromis niloticus, fingerlings were distributed into four groups (supplemented or not, vaccinated or not) and were used to determine immune and hematological parameters and somatic indexes. For the bacterial challenge and vaccine efficacy test, fish were assigned to five experimental groups. Twenty‐eight days after the feeding trial and vaccination, the groups were challenged intraperitoneally and monitored for 21 days. The relative percent survival of the groups basal diet‐vaccinated and MOS diet‐vaccinated were 98.1% and 100.0%, respectively. The dietary inclusion of MOS after vaccination for 28 days had no influence on vaccine efficacy, which could be explained because of the high efficacy of the vaccine itself. Therefore, we suggest that the contribution of MOS supplementation to immune responses after vaccination in fish would be greater for vaccines with lower efficacy, or when tested for heterologous challenges or for crossed protection.
ABSTRACT The objective of this work was to assess the performance of two aeration types, splash and blower, used on a commercial biofloc technology (BFT) farm of red tilapia, Oreochromis sp., and ...their effect on growth performance and water quality parameters. For this, red tilapia juveniles were randomly distributed into twelve tanks. Each tank had an independent aeration system, and two experimental groups were characterized: six tanks used splash aerators (SPL group; one per tank, 1 hp), and the remaining tanks used a blower aerator (BLW group) with the same potency (1 hp). Water quality parameters were registered daily, and after 90 days of commercial culture, we obtained final growth parameters for each batch (tank). We observed no statistical differences on growth parameters, while water quality parameters showed that dissolved oxygen and oxygen saturation were significantly higher for the SPL group. Therefore, this field study corroborated indications from prior research at laboratory conditions that, at a commercial scale, splash aerators are more adequate for the production of red tilapia in BFT conditions.
•Skin integrity plays a crucial role on infection with Aeromonas hydrophila in Brazilian native fish Astyanax altiparanae.•Polyethylene or polypropylene rather than nylon are more appropriate net ...materials for handling of Astyanax altiparanae.•There are no differences on the course of infection with A.hydrophila between females or males of Astyanax altiparanae.
Farmed fish are permanently exposed to management procedures such as netting that can result in stress, skin injuries and subsequent secondary infections. The type of mesh material can modulate the magnitude of netting injury, yet there is scarce information on this topic for aquaculture species. The aim of this study was to evaluate the influence of net material on experimental infection by Aeromonas hydrophila using male and female Astyanax altiparanae, yellowtail tetra, as an infection model. Two hundred and fifty six A. altiparanae were distributed into 16 groups considering sex, types of net material (nylon, polypropylene, polyethylene, and a control group handled without net), and immersion challenge with A. hydrophila. Prior to infection, fish were anesthetized and submitted to netting for 30 s. Immediately, a fluorescein bath was applied under UV light to detect skin lesions. Later, fish were infected by immersion challenge in diluted bacterial solution, while control groups were immersed in sterile PBS. It was verified that the fish handled with nylon net mesh showed more extensive lesions than groups handled with polypropylene and polyethylene nets. Survival after infection was significantly lower in fish previously handled with nylon net when compared to all other groups, while no differences were found between polypropylene, polyethylene nets or fish handled by hand. There was no gender influence on lesions or mortality. It was concluded that yellowtail tetra is sensitive to netting and polypropylene and polyethylene capture nets should be used for handling this species. Additionally, nylon hand nets should be banned to avoid injuries that could serve as gateways for opportunist pathogens such as A. hydrophila
Se describen dos casos de caninos infectados con Hepatozoon canis en la ciudad de Cúcuta, Colombia. La primera paciente de 18 meses de edad llegó a consulta con vómitos, anorexia y pérdida progresiva ...de peso. En el segundo caso se pretendía realizar ovariohisterectomía preventiva, pero en los exámenes clínicos prequirúrgicos presentó anemia. Para los dos casos, el diagnóstico fue mediante extendido sanguíneo, observado a 100X. Para el segundo caso, el diagnóstico se confirmó con la prueba de PCR. El tratamiento instaurado fue sintomático, usando fármacos como oxitetraciclina y doxiciclina. Este es el primer reporte de hepatozoonosis en la ciudad de Cúcuta.
Dentro de las enfermedades biológicas en la piscicultura, se encuentran las causadas por parásitos, principalmente por la clase monogenea, que provocan perdidas en la tasa de crecimiento y altas ...mortalidades, representando grandes pérdidas económicas en la acuicultura. Se reportó el diagnóstico clínico de parásitos monogeneos en peces producidos bajo sistemas intensivos, implementando tecnología biofloc (BFT) en dos municipios del Departamento de Arauca. El primer caso se dio en la Asociación Piscícola el Vergel, municipio de Arauquita, en alevinos de tilapia roja (Oreochromis spp.). En el municipio de Arauca, en la Granja Experimental Picure (GEP), se presentó la segunda infestación parasitaria en alevinos de yamú (Brycon siebenthalae). En los dos casos, los parámetros de calidad físico-químicas de agua fueron evaluados con equipos y metodologías establecidas, la evaluación macro y microscópica de los peces fueron realizadas en el laboratorio de especies dulce acuícolas de la Universidad Cooperativa de Colombia sede Arauca. Los parámetros de calidad de agua se encontraron en los rangos ideales para la producción de peces, el único valor por debajo de lo recomendado fueron los sólidos decantables. Las lesiones macroscópicas encontradas fueron exoftalmia, ascitis, hemorragias, aletas y piel erosionada, en la evaluación microscópica, se observaron microorganismos parasitarios y por características morfológicas se logró establecer la presencia de monogeneos. Se instauro tratamiento con sal blanca en dosis de 3 g/l de agua, se realizaron cambios del 50 % del volumen total con agua desinfectada tres días antes usando formol a razón de 10 ml/l de agua. La mortalidad fue del 95 % de la población total de tilapia roja y el 100% de los alevinos de yamú. La desinfección del agua y alevinos antes de la siembra es lo más recomendable para evitar problemas ictiopatológicos
Streptococcus agalactiae is considered the main bacterial pathogen in cultured Nile tilapia. Formaldehyde-inactivated vaccines are the most accepted method for prevention and control of the disease. ...However, alternative inactivation methods for S. agalactiae vaccines have not been fully explored. Recently, we developed a hydrogen peroxide-inactivated vaccine against S. agalactiae with moderate efficacy, with the possibility to improve vaccine efficacy by adding adjuvants. The current study compared the efficacy of aluminum hydroxide and Freund's incomplete adjuvant (FIA) incorporated into a novel hydrogen peroxide-inactivated intraperitoneal vaccine against S. agalactiae for Nile tilapia fingerlings. The relative percentage survival (RPS) for aluminum hydroxide-adjuvanted vaccine (59.3%), and FIA-adjuvanted vaccine (77.8%) were higher than the vaccine without adjuvant (40.7%). In addition, fish immunized with aluminum hydroxide-adjuvanted vaccine had significantly higher levels of specific antibodies than control fish at 4 weeks post vaccination (wpv). Blood lymphocytes counts showed a decrease in vaccinated groups when compared to control fish, suggesting white cells migration to the tissues where antigen presentation is ongoing. Fish that received FIA-adjuvanted vaccine exhibited persistence of adjuvant deposits on intraperitoneal surfaces for at least 4 wpv that may be related to its superior performance compared to aluminum hydroxide adjuvanted vaccine, which did not evidence any type of deposit at any sampling times. The results observed in this study demonstrate that hydrogen peroxide-inactivated vaccine administered with either aluminum hydroxide or FIA induce optimal levels of protection, with a superior performance for FIA vaccine, which could be a good alternative to conventional formaldehyde-inactivated vaccines against S. agalactiae, due to its shorter manufacture time, and less toxicity.
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•H2O2 inactivated vaccines for S. agalactiae can be used as an alternative to formaldehyde-inactivated vaccines.•Inactivated vaccine by H2O2 provided moderate protection against S. agalactiae in Nile tilapia.•H2O2 inactivated vaccine against S. agalactiae when used with adjuvants showed high protection in Nile tilapia.
Inactivation by hydrogen peroxide and pH manipulation are two novel methods used recently in experimental vaccines against Streptococcus agalactiae in Nile tilapia. Here we describe in detail ...inactivation using novel methods as well as the classical method of inactivation. These vaccines showed similar moderate efficacy when compared to the conventional formaldehyde vaccine. In addition, we describe the inclusion of adjuvants in a hydrogen peroxide vaccine.
Orientador: Julieta Rodini Engrácia de Moraes
Resumo: A produção de lambaris (Astyanax sp.) tem destaque na piscicultura de peixes nativos no Brasil devido ao crescente uso como isca viva e consumo ...direto como petisco. As pesquisas nesta espécie ainda são insipientes, particularmente na área da sanidade. Relatos de casos e diagnósticos laboratoriais sugerem que a aeromoniose é a principal doença infecciosa nesta espécie. O presente trabalho teve como objetivo avaliar o papel de diversos fatores de manejo reprodutivo e da despesca na susceptibilidade de Astyanax altiparanae à infecção experimental por Aeromonas hydrophila pelo método de banhos de imersão. Foram avaliados o material das redes de despesca, o sexo, a reversão sexual, a temperatura e o pH da água. A infecção experimental foi induzida por imersão em solução diluída de uma cepa patógena de A. hydrophila. Os sinais clínicos, lesões anatomopatológicas, integridade da pele e a mortalidade foram avaliados durante 12 dias. Com respeito ao uso de diferentes tipos de rede de despesca, a sobrevivência foi significativamente menor e houve severas lesões cutâneas na pele dos peixes manipulados com rede de nylon quando comparados aos grupos com redes de polipropileno, polietileno ou peixes manejados sem rede. Por outro lado, a reversão sexual com estradiol evidenciou sobrevivência menor das fêmeas sobre os machos (ambos tratados com hormônios), e houve tendência ao incremento na mortalidade com a adição do hormônio na ração (2 vs 4 mgkg-1 ). Com relação à temperatura e o pH da ág... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Yellowtail tetra (Astyanax sp) production has a promissory future in native fish farming in Brazil due to the increased use of this species as live bait and for direct consumption. Research on this species is still incipient, particularly in aquatic health, where local reports suggest that aeromoniosis is the major infectious diseases in yellowtail tetra. The present work aimed to evaluate the role of several reproductive and handling factors on the susceptibility of Astyanax altiparanae to experimental infection with Aeromonas hydrophila by an immersion bath method. The effects of the net material used for handling, sex, sexual reversion, water temperature and pH were evaluated. Experimental infection was achieved by immersion in dilute solution of a pathogenic strain of A. hydrophila. Clinical signs, pathological lesions, skin integrity and mortality were evaluated for 12 days. Regarding the different types of net material, the study showed significant lower survival and more severe cutaneous lesions in fish manipulated with nylon net when compared to polypropylene, polyethylene net and managed by hand. In addition, sexual reversion with estradiol revealed lower survival for females over males (both treated with hormones), and there was a tendency to increased mortality rates with the incorporation of hormone in the diet. Regarding water temperature and pH, there was lower survival in the groups maintained at higher temperature and pH. It was concluded that the immersion ba... (Complete abstract click electronic access below)
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