Pathogenesis of Experimental Infection of Nile Tilapia (Oreochromis niloticus) with Nucleospora Braziliensis Pathology and Proteomic of Microsporidia.

The recent discovery of disease caused by Nucleospora braziliensis in Nile tilapia (Oreochromis niloticus) is important as it has highlighted the high prevalence of infection and associated mortality in cultured fish. Thus, this study conducted an experimental infection of this microsporidium to evaluate pathological alterations and conduct proteomic analysis. For pathological observation, samples of brain, eyes, gall bladder, gut, heart, kidney, liver, muscle, skin, spleen, and stomach tissue, were collected, and liquid chromatography-mass spectrometry (LC-MS/MS) was performed for proteomic analysis. The most prevalent lesions were brownish color of the liver, gill filament fusion, gut ischemia, hemorrhage of the lips and fins, hepatomegaly, spleen atrophy, splenomegaly, and stomach congestion. The most common microscopic lesions were degeneration, hemorrhage, and inflammation in the brain, gills, gut, kidney, liver, muscle, spleen, and stomach. The digested peptides were identified by LC-MS/MS and the intersection of each group showed that in the spleen there were 121 exclusive proteins in the infected sample and 252 in the control, while in the kidney, 129 proteins were identified in the infected specimen compared to 83 in the control. In conclusion, this study demonstrates the proteome profile of O. niloticus kidney and spleen tissue in response to infection with N. braziliensis.

Doxycycline treatment modulates the immune response of tilapia and controls Aeromonas hydrophila infection

The objective of this study was to evaluate the immunopharmacological activity of doxycycline, administered orally in Nile tilapia (Oreochromis niloticus), during experimental infection by Aeromonas hydrophila, through the correlation between therapeutic efficacy and fish immune response. 160 Nile tilapia (±100 g) from the same spawning were distributed in 16 tanks (100 L, n = 10), constituting four treatments: control (infected and untreated); Infected and Treated with 20, 40 and 80 mg of doxycycline/Kg of b.w. Control fish and treated with the lowest dose of doxycycline (20 mg) exhibited typical signs of aeromonosis, including exophthalmos, fin erosion, hemorrhagic septicemia, corneal opacity and ascites. No clinical signs were observed in animals treated with 40 and 80 mg of doxycycline. There was a dose-response effect to the treatment with this tetracycline with relative percentage of survival (RPS) of 60, 73.3 and 93.3% for the treatments with 20, 40 and 80 mg/kg of b.w. when compared to control animals, as well as increased in the production of antibodies anti-A. hydrophila. Doxycycline treatment decreased monocytosis and reactive oxygen species (ROS) production observed in tilapia during A. hydrophila infection. Therefore, doxycycline administered orally to O. niloticus revealed the potential of this antimicrobial for use in tilapia farming, providing convincing results of the therapeutic efficacy against A. hydrophila. These results confirm the hypothesis that the antimicrobial action of doxycycline favored the defense mechanisms of tilapia treated mainly at a dose of 80 mg/kg. Although the exact mechanism of increased antibody response remains to be elucidated, the present observations demonstrate important practical significance for the sanitary management of tilapia farming.

First report of tilapia lake virus emergence in fish farms in the department of Córdoba, Colombia.

BACKGROUND AND AIM: In 2016, the tilapia-producing farms in the department of Córdoba, Colombia, had witnessed outbreaks of disease with clinical signs compatible with those caused by the tilapia lake virus (TiLV). This study was conducted to confirm the presence of TiLV in some fish farms in the department of Córdoba. MATERIALS AND METHODS: A descriptive cross-sectional study was conducted in seven farms using a non-random sampling method from July 2016 to December 2017. A total of 66 fish, including 33 healthy fish and 33 fish with clinical signs, were caught, from which 178 tissue samples of spleen, liver, and brain were collected. RNA was extracted from each organ using TRIzol®. cDNA was synthesized using a retrotranscriptase and a universal amplification primer. The polymerase chain reaction was performed using primers specific to TiLV, in which the primers were amplified in a 491 bp region in segment 3 of TiLV, and the amplicons were sequenced using the Sanger method. RESULTS: Of the seven farms surveyed, 3 (42.85%) had TiLV in the collected fish. Of the 66 collected fish, 18 (27.27%) were infected with TiLV. The virus was detected in the brain (64.3%, 18/28), spleen (61.9%, 13/21), and liver (35.7%, 10/28). The sequences were recorded in GenBank with the codes MH338228, MH350845, and MH350846. Nucleotide homology analyses revealed that this study's circulating strains exhibited 97% identity with the Israeli strain (GenBank KU751816.1). CONCLUSION: This is the first official report of TiLV in the department of Córdoba, Colombia. The circulating strains detected in this study exhibited 97% identity with the Israeli strain.

Investigation of the effects of some phytochemicals on Yersinia ruckeri and antimicrobial resistance / Investigação dos efeitos de alguns fitoquímicos em Yersinia ruckeri e resistência antimicrobiana

In this study, it is aimed to investigate the effects of Moringa oleifera and Sorbus domestica plant extracts on bacterial disease agents Yersinia ruckeri in aquaculture. Morphological and biochemical properties of 2 different Y. ruckeri isolates were determined. Then, Real-Time PCR analysis and gene sequencing of the isolates were identified. Phytochemicals (M. oleifera and S. domestica) and antibiotics (Oxytetracycline (OX) and Enrofloxacin (ENR)) were used together in the antibiogram test of antibiotics compared to the effect status of antibiotics. Also, the effects of phytochemicals on Y. ruckeri growth was examined comparatively by spectrophotometrically measuring at 600 nm wavelength every 2 hours according to bacterial growth densities with 10 different groups formed on TSB medium. As a result of the study, it was observed that the isolates formed Gram negative, catalase positive, oxidase negative, mobile and typical Y. ruckeri colonies. After the biochemical tests performed with Microgen ID panel, 99.85% similarity was determined. The isolates overlap with the 16S rRNA gene region after sequence analysis, and 99% of the isolates were similar in phylogenetic analysis. After the antibiogram test, Oxytetracycline and Enrofloxacin antibiotics were resistant to Y. ruckeri but the effects of phytochemicals were less on solid medium (MHA). As a result of the measurements carried out in liquid medium (TSB), it was observed that phytochemicals such as M. oliefera and S. domestica inhibit the growth of bacteria by 40-50%. As the importance of antibiotic resistance is increasing day by day, we believe that these phytochemicals will give positive results in treatment instead of using antibiotics.(AU)

Neste estudo, objetiva-se investigar os efeitos dos extratos de plantas de Moringa oleifera e Sorbus domestica sobre agentes bacterianos Yersinia ruckeri na aquicultura. Foram determinadas as propriedades morfológicas e bioquímicas de 2 isolados diferentes de Y. ruckeri. Em seguida, a análise de PCR em tempo real e o seqüenciamento genético dos isolados foram identificados. Fitoquímicos (M. oleifera e S. domestica) e antibióticos (Oxitetraciclina e Enrofloxacina) foram usados juntos no teste de antibiograma dos antibióticos em comparação com o status de efeito dos antibióticos. Além disso, os efeitos dos fitoquímicos no crescimento de Y. ruckeri foram examinados comparativamente por medição espectrofotométrica no comprimento de onda de 600 nm a cada 2 horas de acordo com as densidades de crescimento bacteriano com 10 grupos diferentes formados no meio TSB. Como resultado do estudo, observou-se que os isolados formaram colônias Gram-negativas, catalase-positivas, oxidase-negativas, móveis e típicas de Y. ruckeri. Após os testes bioquímicos realizados com o painel Microgen ID, foi determinada uma similaridade de 99,85%. Os isolados se sobrepõem à região do gene 16S rRNA após a análise da sequência e 99% dos isolados foram semelhantes na análise filogenética. Após o teste do antibiograma, os antibióticos Oxitetraciclina e Enrofloxacina foram resistentes a Y. ruckeri, mas os efeitos dos fitoquímicos foram menores no meio sólido (MHA). Como resultado das medições realizadas em meio líquido (TSB), observou-se que os fitoquímicos inibem o crescimento de bactérias em 40-50%. Como a importância da resistência aos antibióticos está aumentando dia a dia, acreditamos que as plantas que são mais alternativas e mais adequadas para o uso de antibióticos hoje em dia darão resultados positivos no tratamento.(AU)

Investigation of the effects of some phytochemicals on Yersinia ruckeri and antimicrobial resistance / Investigação dos efeitos de alguns fitoquímicos em Yersinia ruckeri e resistência antimicrobiana

Abstract In this study, it is aimed to investigate the effects of Moringa oleifera and Sorbus domestica plant extracts on bacterial disease agents Yersinia ruckeri in aquaculture. Morphological and biochemical properties of 2 different Y. ruckeri isolates were determined. Then, Real-Time PCR analysis and gene sequencing of the isolates were identified. Phytochemicals (M. oleifera and S. domestica) and antibiotics (Oxytetracycline (OX) and Enrofloxacin (ENR)) were used together in the antibiogram test of antibiotics compared to the effect status of antibiotics. Also, the effects of phytochemicals on Y. ruckeri growth was examined comparatively by spectrophotometrically measuring at 600 nm wavelength every 2 hours according to bacterial growth densities with 10 different groups formed on TSB medium. As a result of the study, it was observed that the isolates formed Gram negative, catalase positive, oxidase negative, mobile and typical Y. ruckeri colonies. After the biochemical tests performed with Microgen ID panel, 99.85% similarity was determined. The isolates overlap with the 16S rRNA gene region after sequence analysis, and 99% of the isolates were similar in phylogenetic analysis. After the antibiogram test, Oxytetracycline and Enrofloxacin antibiotics were resistant to Y. ruckeri but the effects of phytochemicals were less on solid medium (MHA). As a result of the measurements carried out in liquid medium (TSB), it was observed that phytochemicals such as M. oliefera and S. domestica inhibit the growth of bacteria by 40-50%. As the importance of antibiotic resistance is increasing day by day, we believe that these phytochemicals will give positive results in treatment instead of using antibiotics.

Resumo Neste estudo, objetiva-se investigar os efeitos dos extratos de plantas de Moringa oleifera e Sorbus domestica sobre agentes bacterianos Yersinia ruckeri na aquicultura. Foram determinadas as propriedades morfológicas e bioquímicas de 2 isolados diferentes de Y. ruckeri. Em seguida, a análise de PCR em tempo real e o seqüenciamento genético dos isolados foram identificados. Fitoquímicos (M. oleifera e S. domestica) e antibióticos (Oxitetraciclina e Enrofloxacina) foram usados ​​juntos no teste de antibiograma dos antibióticos em comparação com o status de efeito dos antibióticos. Além disso, os efeitos dos fitoquímicos no crescimento de Y. ruckeri foram examinados comparativamente por medição espectrofotométrica no comprimento de onda de 600 nm a cada 2 horas de acordo com as densidades de crescimento bacteriano com 10 grupos diferentes formados no meio TSB. Como resultado do estudo, observou-se que os isolados formaram colônias Gram-negativas, catalase-positivas, oxidase-negativas, móveis e típicas de Y. ruckeri. Após os testes bioquímicos realizados com o painel Microgen ID, foi determinada uma similaridade de 99,85%. Os isolados se sobrepõem à região do gene 16S rRNA após a análise da sequência e 99% dos isolados foram semelhantes na análise filogenética. Após o teste do antibiograma, os antibióticos Oxitetraciclina e Enrofloxacina foram resistentes a Y. ruckeri, mas os efeitos dos fitoquímicos foram menores no meio sólido (MHA). Como resultado das medições realizadas em meio líquido (TSB), observou-se que os fitoquímicos inibem o crescimento de bactérias em 40-50%. Como a importância da resistência aos antibióticos está aumentando dia a dia, acreditamos que as plantas que são mais alternativas e mais adequadas para o uso de antibióticos hoje em dia darão resultados positivos no tratamento.

Experimental transmission of Caligus rogercresseyi between two different fish species.

Caligus rogercresseyi is the dominant sea louse parasite affecting the salmon and trout industry in southern Chile. This parasite has a wide range of native and endemic fish hosts. The Patagonian blenny Eleginops maclovinus, which is parasitized mostly by the caligid species Lepeophtheirus spp. and C. rogercresseyi, is presumably responsible for the transmission of C. rogercresseyi to salmonids. The aim of this study was to characterize the transmission of parasites between different fish species and parasite cohort development under laboratory conditions. Parasite abundances and intensities were quantified. Transmission of parasites from Patagonian blenny to Atlantic salmon Salmo salar was lower (~9%, mainly corresponding to C. rogercresseyi) than from salmon to Patagonian blenny (14.7-26.9%, where only C. rogercresseyi were observed). This suggests that the transmission of C. rogercresseyi from salmon individuals is higher than the transmission from a native fish. Parasite cohorts developed successfully on both fish species, but apparently under different developmental rates. Water temperature, oxygen, and juvenile abundances were the variables that better explained cohort development success and variation in C. rogercresseyi adult abundances over time.

Can histology and haematology explain inapparent Streptococcus agalactiae infections and asymptomatic mortalities on Nile tilapia farms?

The aim of this study was to characterise possible histopathological and haemato-immunological changes after subclinical infection by S. agalactiae S13 serotype Ib. One hundred juveniles of Nile tilapia with average weight of 45 g were distributed in ten 90 L experimental units. After the acclimation period 25 fish were euthanised, and fragments of liver, spleen and posterior mid-intestine tissue were sampled to verify the integrity of the organs and blood samples taken to check the haematological profile. Fifty animals were used to verify the optimal dosage for the challenge. The remaining 25 fish were infected with S. agalactiae S13. After 96 h, tissue fragments from the liver, spleen and posterior mid-intestine and blood samples were collected. The analyses revealed that, 96 h after contagion, S. agalactiae S13 serotype Ib caused subclinical lesions in the liver and spleen that are not commonly described as pathognomonic, in addition to haematological alterations. These results allow a better understanding of sudden recurrent mortalities in Brazilian tilapia farms, since the serotype Ib of S. agalactiae causes inapparent infections and can remain lodged in internal organs and cause irreversible lesions and haemato-immunological alterations, therefore compromising physiological functions vital for the health of fish without revealing external clinical signs in the animals.

Investigation of the effects of some phytochemicals on Yersinia ruckeri and antimicrobial resistance

Abstract In this study, it is aimed to investigate the effects of Moringa oleifera and Sorbus domestica plant extracts on bacterial disease agents Yersinia ruckeri in aquaculture. Morphological and biochemical properties of 2 different Y. ruckeri isolates were determined. Then, Real-Time PCR analysis and gene sequencing of the isolates were identified. Phytochemicals (M. oleifera and S. domestica) and antibiotics (Oxytetracycline (OX) and Enrofloxacin (ENR)) were used together in the antibiogram test of antibiotics compared to the effect status of antibiotics. Also, the effects of phytochemicals on Y. ruckeri growth was examined comparatively by spectrophotometrically measuring at 600 nm wavelength every 2 hours according to bacterial growth densities with 10 different groups formed on TSB medium. As a result of the study, it was observed that the isolates formed Gram negative, catalase positive, oxidase negative, mobile and typical Y. ruckeri colonies. After the biochemical tests performed with Microgen ID panel, 99.85% similarity was determined. The isolates overlap with the 16S rRNA gene region after sequence analysis, and 99% of the isolates were similar in phylogenetic analysis. After the antibiogram test, Oxytetracycline and Enrofloxacin antibiotics were resistant to Y. ruckeri but the effects of phytochemicals were less on solid medium (MHA). As a result of the measurements carried out in liquid medium (TSB), it was observed that phytochemicals such as M. oliefera and S. domestica inhibit the growth of bacteria by 40-50%. As the importance of antibiotic resistance is increasing day by day, we believe that these phytochemicals will give positive results in treatment instead of using antibiotics.

Resumo Neste estudo, objetiva-se investigar os efeitos dos extratos de plantas de Moringa oleifera e Sorbus domestica sobre agentes bacterianos Yersinia ruckeri na aquicultura. Foram determinadas as propriedades morfológicas e bioquímicas de 2 isolados diferentes de Y. ruckeri. Em seguida, a análise de PCR em tempo real e o seqüenciamento genético dos isolados foram identificados. Fitoquímicos (M. oleifera e S. domestica) e antibióticos (Oxitetraciclina e Enrofloxacina) foram usados juntos no teste de antibiograma dos antibióticos em comparação com o status de efeito dos antibióticos. Além disso, os efeitos dos fitoquímicos no crescimento de Y. ruckeri foram examinados comparativamente por medição espectrofotométrica no comprimento de onda de 600 nm a cada 2 horas de acordo com as densidades de crescimento bacteriano com 10 grupos diferentes formados no meio TSB. Como resultado do estudo, observou-se que os isolados formaram colônias Gram-negativas, catalase-positivas, oxidase-negativas, móveis e típicas de Y. ruckeri. Após os testes bioquímicos realizados com o painel Microgen ID, foi determinada uma similaridade de 99,85%. Os isolados se sobrepõem à região do gene 16S rRNA após a análise da sequência e 99% dos isolados foram semelhantes na análise filogenética. Após o teste do antibiograma, os antibióticos Oxitetraciclina e Enrofloxacina foram resistentes a Y. ruckeri, mas os efeitos dos fitoquímicos foram menores no meio sólido (MHA). Como resultado das medições realizadas em meio líquido (TSB), observou-se que os fitoquímicos inibem o crescimento de bactérias em 40-50%. Como a importância da resistência aos antibióticos está aumentando dia a dia, acreditamos que as plantas que são mais alternativas e mais adequadas para o uso de antibióticos hoje em dia darão resultados positivos no tratamento.

First report of Lernaea cyprinacea (Crustacea: Lernaeidae) parasiting Rhamdia quelen (Pisces: Heptapteridae) in Santa Fe (Argentina) under hatchery conditions / Primer reporte de Lernaea cyprinacea (Crustacea: Lernaeidae) parasitando Rhamdia quelen (Pisces: Heptapteridae) bajo condiciones de cultivo en Santa Fe (Argentina) / Primeiro registro de Lernaea cyprinacea ( Crustacea: Lernaeidae ) em Rhamdia quelen ( Pisces: Heptapteridae ), em condições de cultura em Santa Fe (Argentina)

Abstract Background: Lernaea cyprinacea was introduced in South America with cyprinids. To the best of our knowledge, this ectoparasite has not been reported in Santa Fe province (Argentina). Objective: To report Lernaea cyprinacea presence in Rhamdia quelen under hatchery conditions in Santa Fe province (Argentina). Methods: In May 2014, samples of L. cyprinacea attached to the fins and flanks of R. quelen were obtained in the Chronobiology Laboratory of the Veterinary Sciences School at Esperanza (Santa Fe, Argentina) where they were collected and identified. Results: A description of L. cyprinacea is presented along with detailed records previously reported in this and other regions. Conclusions: Presence of this parasite constitutes evidence of the introduction of exotic species through commercialization of their natural hosts and the potential pathogen colonization of natural environments, which constitutes a threat to the integrity of aquatic ecosystems.

Resumen Antecedentes: la Lernaea cyprinacea fue introducida en América del Sur a través de los ciprínidos, no habiendo siendo previamente registrada en la provincia de Santa Fe (Argentina). Objetivo: reportar la presencia de Lernaea cyprinacea en Rhamdia quelen en condiciones de acuicultivo. Método: en mayo de 2014, se obtuvieron ejemplares de L. cyprinacea, parasitando aletas y flancos de R. quelen en el laboratorio de Cronobiología de la Facultad de Ciencias Veterinarias, en Esperanza (Santa Fe, Argentina), donde fueron colectados e identificados. Resultados: se brinda una descripción de L. cyprinacea y se detallan antecedentes del ectoparasito en ésta y otras regiones. Conclusiones: la presencia de este parásito constituye evidencia de introducción de una especie exótica mediante la comercialización de sus hospedadores naturales y de la potencial colonización por patógenos introducidos en ambientes naturales, lo cual amenaza la integridad de estos ecosistemas.

Resumo Antecedentes: Lernaea cyprinacea foi introduzido na América do Sul através de ciprinídeos, não sendo registrado na província de Santa Fe. Objetivo: relatar a sua presença no Rhamdia quelen, em condições de crescimento. Método: em maio de 2014, foram obtidas individuos de L. cyprinacea, parasitando nadadeiras e flancos em R. quelen, no Cronobiologia Laboratório da Faculdade de Ciências Veterinárias, Esperanza (Santa Fe, Argentina), que foram coletados e identificados. Resultados: uma descrição de L. cyprinacea é relatada, e detalhes prévios da presença deste parasito na região. Conclusões: a presença neste parasito é evidência de introdução de espécies exóticas através da comercialização de seus hospedeiros naturais. O potencial de colonização de patógenos introduzidos em ambientes naturais é uma ameaça à integridade dos ecossistemas.

Surto de infecção por Piscinoodinium pillulare e Trichodina spp. em tambaquis (Colossoma macropomu), pirapitingas (Piaractus brachypomus) e tilápias (Oreochromis niloticus) no Distrito Federal / Outbreak of Infection by Piscinoodinium pillulare and Trichodina spp. in Tambaquis (Colossoma macropomu), Pirapitingas (Piaractus brachypomus) and Tilapias (Oreochromis niloticus) in the Federal District, Brazil

Background: Piscinoodinium pillulare is a mandatory mastigophore protozoan with no parasitic specificity, and an important ectoparasite of tropical and temperate psiculture. This parasite is responsible for serious health problems in Brazilian native fish. Another important pathogenic protozoan in psciculture belongs to the genus Trichodina spp., which is commonly found on the surface of fish, gills, fins, and integument. The aim of the present study was to describe an outbreak of P. pillulare and Trichodina spp. in three species of fish intensively created, emphasizing the anatomopathological and epidemiological aspects.Cases: Five animals were necropsied, among them three tambaquis (Colossoma macropomu), one pirapitinga (Piaractus brachypomus) and one tilapia (Oreochromis niloticus) from an intensive psciculture in the Federal District. Out of 1500 fishes, 18 (1.2%) became ill and died. It was reported that the animals showed decreased feed intake, discomfort, dyspnea, opercular movements, red skin lesions and consequent death. In the direct examination of scraping of the body surface of a fish, prepared between lamina and coverslip, a ciliated ectoparasite, with a circular bell shape, measuring approximately 20-180 μm, adhered, with morphology consistent with Trichodina spp. was evidenced. During necropsy, fragments of different organs were collected and fixed in 10% formalin, routinely processed for histology, embedded in paraffin, cut to five microns thick and stained with hematoxylin and eosin (HE).Macroscopically, there were pale scaly areas in the medial-lateral regions, moderate increase amount of mucus with brown to green lumps on the body surface, partial loss of the fins, swollen gills with whitish mucus and multifocal hemorrhagic areas on the skin and between the scales.[...](AU)

Surto de infecção por Piscinoodinium pillulare e Trichodina spp. em tambaquis (Colossoma macropomu), pirapitingas (Piaractus brachypomus) e tilápias (Oreochromis niloticus) no Distrito Federal / Outbreak of Infection by Piscinoodinium pillulare and Trichodina spp. in Tambaquis (Colossoma macropomu), Pirapitingas (Piaractus brachypomus) and Tilapias (Oreochromis niloticus) in the Federal District, Brazil

Background: Piscinoodinium pillulare is a mandatory mastigophore protozoan with no parasitic specificity, and an important ectoparasite of tropical and temperate psiculture. This parasite is responsible for serious health problems in Brazilian native fish. Another important pathogenic protozoan in psciculture belongs to the genus Trichodina spp., which is commonly found on the surface of fish, gills, fins, and integument. The aim of the present study was to describe an outbreak of P. pillulare and Trichodina spp. in three species of fish intensively created, emphasizing the anatomopathological and epidemiological aspects.Cases: Five animals were necropsied, among them three tambaquis (Colossoma macropomu), one pirapitinga (Piaractus brachypomus) and one tilapia (Oreochromis niloticus) from an intensive psciculture in the Federal District. Out of 1500 fishes, 18 (1.2%) became ill and died. It was reported that the animals showed decreased feed intake, discomfort, dyspnea, opercular movements, red skin lesions and consequent death. In the direct examination of scraping of the body surface of a fish, prepared between lamina and coverslip, a ciliated ectoparasite, with a circular bell shape, measuring approximately 20-180 μm, adhered, with morphology consistent with Trichodina spp. was evidenced. During necropsy, fragments of different organs were collected and fixed in 10% formalin, routinely processed for histology, embedded in paraffin, cut to five microns thick and stained with hematoxylin and eosin (HE).Macroscopically, there were pale scaly areas in the medial-lateral regions, moderate increase amount of mucus with brown to green lumps on the body surface, partial loss of the fins, swollen gills with whitish mucus and multifocal hemorrhagic areas on the skin and between the scales.[...]

Enterococcus, Myroides Y Exiguobacterium: GÉNEROS BACTERIANOS CON POTENCIAL PROBIÓTICO PARA EL CULTIVO DE TILAPIA NILÓTICA (Oreochromis niloticus) / Enterococcus, Myroides, and Exiguobacterium: Bacterial Genus with Probiotic Potential for Nile Tilapia (Oreochromis niloticus) Culture

RESUMEN Se aislaron 120 morfotipos bacterianos de intestino de tilapia y se seleccionaron según su actividad antibacteriana contra patógenos como Aeromonas hydrophila, Streptococcus agalactiae y Edwardsiella tarda, su capacidad de adherencia a mucus intestinal y cinética de crecimiento. Las bacterias seleccionadas se identificaron mediante secuenciación de 16S rRNA y se identificaron como Exigobacterium sp. l9, Enterococcus faecalis I15 y Myroides odoratimimus l19. Además, se evaluó su efecto in vivo sobre el crecimiento de los peces, mediante su adición al alimento de juveniles de Oreochromis niloticus (106 UFC / g, por 15 días). Se determinó la supervivencia luego de un desafío experimental con Edwardsiella tarda por inyección intraperitoneal (100 µL 105 UFC / mL). Las tres bacterias seleccionadas incrementaron la tasa de crecimiento específico, redujeron la mortalidad de los peces durante el desafío experimental con E. tarda y no causaron mortalidad durante la adición en el alimento. Los efectos positivos in vivo se relacionan posiblemente con actividad in vitro; sin embargo, por motivos de bioseguridad se recomienda efectuar estudios posteriores a Exigobacterium sp. l9y E. faecalis I15 dado que se han reportado miembros de este género como causantes de mortalidad en peces, mientras que en el caso de M. odoratimimus l19, es necesario efectuar futuros estudios para verificar su actividad positiva a mayor escala productiva.

ABSTRACT 120 bacteria were isolated from tilapia intestine and screened according to the antibacterial activity against pathogens such as Aeromonas hydrophila, Edwardsiella tarda and Streptococcus agalactiae, the ability to adhere to intestinal mucus and growth kinetics. The selected bacteria were identified by 16S rRNA sequencing of and were identified as Exigobacterium sp. I9, Enterococcus faecalis l15 and Myroides odoratimimus l19. Furthermore, the in vivo effect on fish growth was assessed by the addition of selected bacteria to juvenile Oreochromis niloticus feed (106 CFU / g, for 15 days). Survival was also determined after a challenge by intraperitoneal injection of E. tarda (100 µL of 105 UFC / mL). The three selected bacteria increased the specific growth rate, reduced mortality of fish during the experimental challenge with E. tarda and did not cause mortality during the addition in the feed. The positive effects observed in vivo are possibly associated with in vitro activity; however, for biosafety reasons, it is recommended that further studies of Exigobacterium sp. l9 and E. faecalis l15 may be carried out since this genus have been reported of as causative agents of fish mortality, whereas in the case of M. odoratimimus l19, verification of positive effects at a higher production scales is desirable.

Inter-laboratory ring trial to evaluate real-time reverse transcription polymerase chain reaction methods used for detection of infectious pancreatic necrosis virus in Chile

Background: Infectious Pancreatic Necrosis Virus (IPNV) is the etiological agent of a highly contagious disease that affects salmonids. In Chile, the second worldwide salmon producer, IPNV causes great economic loss and is one of the most frequently detected pathogens. Due to its high level of persistence and the lack of information about the efficiency of its diagnostic techniques, the National Reference Laboratory (NRL) for IPNV in Chile performed the first inter-laboratory ring trial, to evaluate the sensitivity, specificity and repeatability of the qRT-PCR detection methods used in the country. Results: Results showed 100% in sensitivity and specificity in most of the laboratories. Only three of the twelve participant laboratories presented problems in sensitivity and one in specificity. Problems in specificity (false positives) were most likely caused by cross contamination of the samples, while errors in sensitivity (false negatives) were due to detection problems of the least concentrated viral sample. Regarding repeatability, many of the laboratories presented great dispersion of the results (Ct values) for replicate samples over the three days of the trial. Moreover, large differences in the Ct values for each sample were detected among all the laboratories. Conclusions: Overall, the ring trial showed high values of sensitivity and specificity, with some problems of repeatability and inter-laboratory variability. This last issue needs to be addressed in order to allow harmonized diagnostic of IPNV within the country. We recommend the use of the NRL methods as validated and reliable qRT-PCR protocols for the detection of IPNV.

Investigation of the effects of some phytochemicals on Yersinia ruckeri and antimicrobial resistance

Abstract In this study, it is aimed to investigate the effects of Moringa oleifera and Sorbus domestica plant extracts on bacterial disease agents Yersinia ruckeri in aquaculture. Morphological and biochemical properties of 2 different Y. ruckeri isolates were determined. Then, Real-Time PCR analysis and gene sequencing of the isolates were identified. Phytochemicals (M. oleifera and S. domestica) and antibiotics (Oxytetracycline (OX) and Enrofloxacin (ENR)) were used together in the antibiogram test of antibiotics compared to the effect status of antibiotics. Also, the effects of phytochemicals on Y. ruckeri growth was examined comparatively by spectrophotometrically measuring at 600 nm wavelength every 2 hours according to bacterial growth densities with 10 different groups formed on TSB medium. As a result of the study, it was observed that the isolates formed Gram negative, catalase positive, oxidase negative, mobile and typical Y. ruckeri colonies. After the biochemical tests performed with Microgen ID panel, 99.85% similarity was determined. The isolates overlap with the 16S rRNA gene region after sequence analysis, and 99% of the isolates were similar in phylogenetic analysis. After the antibiogram test, Oxytetracycline and Enrofloxacin antibiotics were resistant to Y. ruckeri but the effects of phytochemicals were less on solid medium (MHA). As a result of the measurements carried out in liquid medium (TSB), it was observed that phytochemicals such as M. oliefera and S. domestica inhibit the growth of bacteria by 40-50%. As the importance of antibiotic resistance is increasing day by day, we believe that these phytochemicals will give positive results in treatment instead of using antibiotics.

Resumo Neste estudo, objetiva-se investigar os efeitos dos extratos de plantas de Moringa oleifera e Sorbus domestica sobre agentes bacterianos Yersinia ruckeri na aquicultura. Foram determinadas as propriedades morfológicas e bioquímicas de 2 isolados diferentes de Y. ruckeri. Em seguida, a análise de PCR em tempo real e o seqüenciamento genético dos isolados foram identificados. Fitoquímicos (M. oleifera e S. domestica) e antibióticos (Oxitetraciclina e Enrofloxacina) foram usados juntos no teste de antibiograma dos antibióticos em comparação com o status de efeito dos antibióticos. Além disso, os efeitos dos fitoquímicos no crescimento de Y. ruckeri foram examinados comparativamente por medição espectrofotométrica no comprimento de onda de 600 nm a cada 2 horas de acordo com as densidades de crescimento bacteriano com 10 grupos diferentes formados no meio TSB. Como resultado do estudo, observou-se que os isolados formaram colônias Gram-negativas, catalase-positivas, oxidase-negativas, móveis e típicas de Y. ruckeri. Após os testes bioquímicos realizados com o painel Microgen ID, foi determinada uma similaridade de 99,85%. Os isolados se sobrepõem à região do gene 16S rRNA após a análise da sequência e 99% dos isolados foram semelhantes na análise filogenética. Após o teste do antibiograma, os antibióticos Oxitetraciclina e Enrofloxacina foram resistentes a Y. ruckeri, mas os efeitos dos fitoquímicos foram menores no meio sólido (MHA). Como resultado das medições realizadas em meio líquido (TSB), observou-se que os fitoquímicos inibem o crescimento de bactérias em 40-50%. Como a importância da resistência aos antibióticos está aumentando dia a dia, acreditamos que as plantas que são mais alternativas e mais adequadas para o uso de antibióticos hoje em dia darão resultados positivos no tratamento.

Ectocommensal and ectoparasites in goldfish Carassius auratus (Linnaeus, 1758) in farmed in the State of São Paulo / Ectocomensais e ectoparasitas em kinguios Carassius auratus (Linnaeus, 1758)criados em fazenda no Estado de São Paulo

Concomitant infections by several parasitic genera are rare, very debilitating and often lethal to fish reared under commercial breeding conditions. Were describe a multiple and concurrent parasite infestation in cultured goldfish Carassius auratus with skin damage (nodules and/or ulceration). Fish with skin lesions underwent necropsy, and the skin and gills were scraped and examined. Histopathological examination with Hematoxylin-Eosin and Giemsa stain, and an ultrastructure study using transmission and scanning electron microscopy were conducted. In the skin, we identified multiple-parasite infestations by Gyrodactylidae, Epistylis sp., Trichodina sp., Ichthyophthirius multifiliis, Tetrahymena sp. and Ichthyobodo necator,associated with epithelial cell hyperplasia and epidermal sloughing. Although no gross lesions were observed, were identified a large number of parasites in the gills (Epistylis sp., Piscinoodinium sp., Ichthyophthirius multifiliis, Trichodina sp., Apiosoma sp., Hexamitasp. and cysts of a trematode digenean). The observed trematodes were not identified. The associated microscopic lesions were epithelial hypertrophic and hyperplasic and exhibited fusion of secondary lamellae and epithelial cell detachment. This is the first description of a protozoan Vorticella sp. parasitizing goldfish in Brazil. Multiple ectoparasitism by protozoa and Platyhelminthes, with or without apparent tissue damage, can be fatal for goldfish raised on farms with poor management.(AU)

A infestação concomitante por vários gêneros de parasitas é uma condição rara, debilitante e letal para os peixes e está geralmente associada aos problemas ambientais e de manejo. Com o objetivo de descrever os ectoparasitos presentes em kinguios Carassius auratus com lesões cutâneas, cultivados em fazenda comercial, foram analisados 30 exemplares de peixes por esfregaços de pele lesionada e de brânquias; exame histopatológico de tecidos corados pela técnica de Hematoxilina-Eosina e Giemsa e estudo ultraestrutural por microscopia eletrônica de transmissão e varredura de tecidos coletados após necropsia. Nas lesões cutâneas, foram observados os parasitos: Gyrodactylidae, Epistylis sp., Trichodina sp., Ichthyophthirius multifiliis, Tetrahymena sp. e Ichthyobodo necator, associados à hiperplasia epitelial, descamação epidérmica e presença de infiltrado inflamatório. A infestação das brânquias, mesmo sem lesão macroscópica, evidenciou Epistylissp., Piscinoodinium sp., I. multifiliis, Trichodina sp., Apiosoma sp., Hexamita sp. e cistos de trematódeo associados à hipertrofia e hiperplasia epitelial, fusão de lamelas secundárias, descamação epitelial e presença de infiltrado inflamatório. Os trematódeos observados não foram identificados. É a primeira descrição do protozoário Vorticella sp. parasitando kinguios no Brasil. O ectoparasitismo múltiplo por protozoários e platelmintos, com ou sem lesão aparente, pode ser fatal em peixes cultivados em condições ambientais precárias.(AU)

Ectocommensal and ectoparasites in goldfish Carassius auratus (Linnaeus, 1758) in farmed in the State of São Paulo / Ectocomensais e ectoparasitas em kinguios Carassius auratus (Linnaeus, 1758) criados em fazenda no Estado de São Paulo

Concomitant infections by several parasitic genera are rare, very debilitating and often lethal to fish reared under commercial breeding conditions. Were describe a multiple and concurrent parasite infestation in cultured goldfish Carassius auratus with skin damage (nodules and/or ulceration). Fish with skin lesions underwent necropsy, and the skin and gills were scraped and examined. Histopathological examination with Hematoxylin-Eosin and Giemsa stain, and an ultrastructure study using transmission and scanning electron microscopy were conducted. In the skin, we identified multiple-parasite infestations by Gyrodactylidae, Epistylis sp., Trichodina sp., Ichthyophthirius multifiliis, Tetrahymena sp. and Ichthyobodo necator,associated with epithelial cell hyperplasia and epidermal sloughing. Although no gross lesions were observed, were identified a large number of parasites in the gills (Epistylis sp., Piscinoodinium sp., Ichthyophthirius multifiliis, Trichodina sp., Apiosoma sp., Hexamitasp. and cysts of a trematode digenean). The observed trematodes were not identified. The associated microscopic lesions were epithelial hypertrophic and hyperplasic and exhibited fusion of secondary lamellae and epithelial cell detachment. This is the first description of a protozoan Vorticella sp. parasitizing goldfish in Brazil. Multiple ectoparasitism by protozoa and Platyhelminthes, with or without apparent tissue damage, can be fatal for goldfish raised on farms with poor management.

A infestação concomitante por vários gêneros de parasitas é uma condição rara, debilitante e letal para os peixes e está geralmente associada aos problemas ambientais e de manejo. Com o objetivo de descrever os ectoparasitos presentes em kinguios Carassius auratus com lesões cutâneas, cultivados em fazenda comercial, foram analisados 30 exemplares de peixes por esfregaços de pele lesionada e de brânquias; exame histopatológico de tecidos corados pela técnica de Hematoxilina-Eosina e Giemsa e estudo ultraestrutural por microscopia eletrônica de transmissão e varredura de tecidos coletados após necropsia. Nas lesões cutâneas, foram observados os parasitos: Gyrodactylidae, Epistylis sp., Trichodina sp., Ichthyophthirius multifiliis, Tetrahymena sp. e Ichthyobodo necator, associados à hiperplasia epitelial, descamação epidérmica e presença de infiltrado inflamatório. A infestação das brânquias, mesmo sem lesão macroscópica, evidenciou Epistylissp., Piscinoodinium sp., I. multifiliis, Trichodina sp., Apiosoma sp., Hexamita sp. e cistos de trematódeo associados à hipertrofia e hiperplasia epitelial, fusão de lamelas secundárias, descamação epitelial e presença de infiltrado inflamatório. Os trematódeos observados não foram identificados. É a primeira descrição do protozoário Vorticella sp. parasitando kinguios no Brasil. O ectoparasitismo múltiplo por protozoários e platelmintos, com ou sem lesão aparente, pode ser fatal em peixes cultivados em condições ambientais precárias.

Treatment of Mycobacterium marinum with lymecycline: new therapeutic alternative?

Skin infections by Mycobacterium marinum are quite rare in our environment and, therefore, little studied. The majority of the lesions appear three weeks after traumas in aquariums, beaches and fish tanks. Lymph node drainage and systematization of the disease are rare and most lesions disappear in about three years. This case aims to show the effectiveness of the treatment used (lymecycline 150 mg/orally/day). This medication may be a new therapeutic option for the treatment of Mycobacterium marinum.

Ectocommensal and ectoparasites in goldfish Carassius auratus (Linnaeus, 1758) in farmed in the State of São Paulo

Concomitant infections by several parasitic genera are rare, very debilitating and often lethal to fish reared under commercial breeding conditions. Were describe a multiple and concurrent parasite infestation in cultured goldfish Carassius auratus with skin damage (nodules and/or ulceration). Fish with skin lesions underwent necropsy, and the skin and gills were scraped and examined. Histopathological examination with Hematoxylin-Eosin and Giemsa stain, and an ultrastructure study using transmission and scanning electron microscopy were conducted. In the skin, we identified multiple-parasite infestations by Gyrodactylidae, Epistylis sp., Trichodina sp., Ichthyophthirius multifiliis, Tetrahymena sp. and Ichthyobodo necator,associated with epithelial cell hyperplasia and epidermal sloughing. Although no gross lesions were observed, were identified a large number of parasites in the gills (Epistylis sp., Piscinoodinium sp., Ichthyophthirius multifiliis, Trichodina sp., Apiosoma sp., Hexamitasp. and cysts of a trematode digenean). The observed trematodes were not identified. The associated microscopic lesions were epithelial hypertrophic and hyperplasic and exhibited fusion of secondary lamellae and epithelial cell detachment. This is the first description of a protozoan Vorticella sp. parasitizing goldfish in Brazil. Multiple ectoparasitism by protozoa and Platyhelminthes, with or without apparent tissue damage, can be fatal for goldfish raised on farms with poor management.

A infestação concomitante por vários gêneros de parasitas é uma condição rara, debilitante e letal para os peixes e está geralmente associada aos problemas ambientais e de manejo. Com o objetivo de descrever os ectoparasitos presentes em kinguios Carassius auratus com lesões cutâneas, cultivados em fazenda comercial, foram analisados 30 exemplares de peixes por esfregaços de pele lesionada e de brânquias; exame histopatológico de tecidos corados pela técnica de Hematoxilina-Eosina e Giemsa e estudo ultraestrutural por microscopia eletrônica de transmissão e varredura de tecidos coletados após necropsia. Nas lesões cutâneas, foram observados os parasitos: Gyrodactylidae, Epistylis sp., Trichodina sp., Ichthyophthirius multifiliis, Tetrahymena sp. e Ichthyobodo necator, associados à hiperplasia epitelial, descamação epidérmica e presença de infiltrado inflamatório. A infestação das brânquias, mesmo sem lesão macroscópica, evidenciou Epistylissp., Piscinoodinium sp., I. multifiliis, Trichodina sp., Apiosoma sp., Hexamita sp. e cistos de trematódeo associados à hipertrofia e hiperplasia epitelial, fusão de lamelas secundárias, descamação epitelial e presença de infiltrado inflamatório. Os trematódeos observados não foram identificados. É a primeira descrição do protozoário Vorticella sp. parasitando kinguios no Brasil. O ectoparasitismo múltiplo por protozoários e platelmintos, com ou sem lesão aparente, pode ser fatal em peixes cultivados em condições ambientais precárias.

Determinación y prevalencia de Mycobacterium spp., en tilapia nilótica (Oreochromis niloticus) cultivada en Campeche, México / Determination and prevalence of Mycobacterium spp., in Nile tilapia (Oreochromis niloticus) cultured in México

Objetivo. Determinar la presencia y prevalencia de Mycobacterium spp., en granjas de tilapia nilótica (Oreochromis niloticus) en el Municipio de Champotón, Campeche, México. Materiales y métodos. La colecta de organismos se realizó en tres granjas de cultivo de tilapia nilótica del municipio de Champotón, Campeche, México. Los organismos se examinaron externa e internamente y se tomó una muestra de riñón la cual fue sembrada en forma de estría en medios de cultivo: Lõwesntein-Jensen, TCBS, KF y en TSA; las placas fueron incubadas a 35°C de 24 a 48 horas, los órganos fueron fijados en formalina tamponada al 10% para ser procesados para histología de rutina para análisis posteriores. Asimismo, muestras de cultivo bacteriológico y de tejido fueron teñidas con la técnica de Ziel-Neelsen con el fin de observar la presencia de bacilos ácido-alcohol resistentes. Resultados. Los resultados obtenidos sugieren que la presencia de Mycobacterium spp., es constante y en alta prevalencia y puede ser un factor que este mermando la rentabilidad del cultivo. Conclusiones. La presencia de Mycobacterium spp., representa un riesgo para el cultivo de tilapia en el municipio de Champotón, por ser una enfermedad muy persistente y difícil de erradicar una vez ocurrido e brote de infección, por lo cual es importante llevar estudios más detallados de la presencia de este género bacteriano, así como, medidas de prevención y dispersión de este patógeno en los cultivos adyacentes.

Surtos de infecção por Piscinoodinium pillulare e Henneguya spp. em pacus (Piaractus mesopotamicus) criados intensivamente no Sudoeste de Goiás / Outbreaks of Piscinoodinium pillulare and Henneguya spp. infection in intensively raised Piaractus mesopotamicus in Southwestern Goiás, Brazil

Três surtos de infecção por Piscinoodinium pillulare e Henneguya spp. em Piaractus mesopotamicus criados intensivamente no Sudoeste de Goiás são descritos. Dois surtos ocorreram no inverno e um no verão. As taxas de morbidade (58,57%-90%) e mortalidade (100%) foram determinadas. Episódios de estresse ocorreram previamente em todos os casos. Sinais clínicos incluíam mudanças comportamentais e movimentos erráticos com perda de equilíbrio. Os principais achados macroscópicos foram tumefação das brânquias com exsudato mucoso esbranquiçado. Microscopicamente, as brânquias apresentaram inflamação linfoplasmocítica e necrosante, multifocal, leve a moderada, com hipertrofia e fusão de lamelas secundárias. Adicionalmente, numerosos trofontes intralesionais de P. pillulare e cistos de Henneguya spp. foram notados. Para o conhecimento dos autores, essa parece ser a primeira descrição de infecção por P. pillulare e Henneguya spp. em peixes criados no Sudoeste de Goiás.(AU)

Three outbreaks of infection by Piscinoodinium pillulare and Henneguya spp. in Piarac tus mesopotamicus intensively raised in Southwestern Goiás, Brazil, are described. Two outbreaks occurred in the winter and another one in summer. Morbidity (58.57%-90%) and mortality (100%) rates were determined. Stress episodes occurred previously in all cases. Clinical signs included behavior changes and erratic movements with loss of equilibrium. Main gross findings were swelling of the gills with white mucus exudate. Microscopically, gills had mild to moderate multifocal necrotizing and lympho-plasmocytic inflammation with hypertrophy and fusion of secondary lamellae. In addition, numerous intralesional trophonts of P. pillulare and cysts of Henneguya spp. were noted. According to our knowledge, this seems to be the first description of Piscinoodinium pillulare e Henneguya spp. infection in fishes reared in Southwestern Goiás, Brazil.(AU)