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The essential oil of alfavaca (Ocimum gratissimum) contains important compounds, such as 1.8-cineol and eugenol. This study evaluated the effects of diets containing alfavaca essential oil on the zootechnical performance, plasma glucose, leukocyte respiratory activity, haematology, and intestinal histomorphometry in “cachara” (Pseudoplatystoma reticulatum) challenged with Aeromonas hydrophila. A total of 300 juvenile fish, with an average total length of 14.98 ± 0.28 cm and average weight of 18.84 ± 1.22 g, distributed in 20 tanks of 80 L, were fed twice a day with a diet containing essential oil at 0.5, 1.0, or 1.5% or without its inclusion in five replicates. After 45 days, blood collection and mid-intestinal bowel were sampled, before a challenge with Aeromonas hydrophila was performed. The fish supplemented with 1.0% of essential oil presented better weight gain, mean corpuscular volume, concentration of thrombotic and neutrophils, respiratory activity of leukocytes, and height of villi (p < 0.05) when compared to other groups. The cumulative mortality response was lower for fish fed 1.5% essential oil of alfavaca diets. Thus, the use of alfavaca essential oil is recommended in the diet of cachara catfish (P. reticulatum) at the level of up to 1.0% for 45 days for improvements in the zootechnical, haematological, and intestinal histomorphometric parameters. O óleo essencial de alfavaca (Ocimum gratissimum) contém componentes importantes, como por exemplo o 1.8-cineol e o eugenol. Este estudo avaliou os efeitos de dietas contendo óleo essencial de alfavaca sobre o desempenho zootécnico, glicose plasmática, atividade respiratória leucocitária, hematologia e histomorfometria intestinal em cachara (Pseudoplatystoma reticulatum) desafiado com Aeromonas hydrophila. Um total de 300 peixes juvenis, com comprimento total médio de 14,98 ± 0,28 cm e peso médio de 18,84 ± 1,22 g, distribuídos em 20 tanques de 80 L, alimentados duas vezes ao dia com dieta contendo o óleo essencial a 0,5, 1,0 ou 1,5 % ou sem inclusão de óleo em cinco repetições. Após 45 dias, foi realizada a biometria final, coleta de sangue, amostra do intestino médio e desafio com Aeromonas hydrophila. Após o período experimental, a dieta suplementada com 1,0% do óleo essencial apresentou melhor ganho de peso, volume corpuscular médio, concentração de trombóticos e neutrófilos, atividade respiratória de leucócitos e altura de vilosidades (p < 0,05) quando comparada aos demais grupos. A resposta de mortalidade cumulativa foi menor para peixes alimentados com dietas com o óleo essencial de alfavaca a 1,5%. Assim, o uso de óleo essencial de alfavaca é recomendado na dieta do bagre cachara (P. reticulatum) no nível de até 1,0% por 45 dias para melhorias nos parâmetros zootécnicos, hematológicos e histomorfométricos intestinais.

The aim of the present study was to investigate the influence of dietary supplementation with Bacillus subtilis C-3102 on the productive, intestinal histomorphometry, haemato-immunological aspects, as well as evaluated the resistance of juvenile Pseudoplatystoma sp. after challenge with Aeromonas hydrophila. Inclusion levels of the commercial probiotic were set at 0 (control), 1, 2, 3 and 4% of CALSPORIN® kg feed−1 with six replicates. Blood samples were collected on day 0, 10 and 20 for hematological analysis, and on the 20th day, samples were collected for intestinal histomorphometry, zootechnical and survival analyses. The results showed that probiotic supplementation with B. subtilis significantly improved intestinal morphology in fish from groups 1% and 2% and phagocytic activity in all supplemented groups, regardless of the applied dose. In addition, on the 20th day, improvements in non-specific immunity were observed, such as an increase in the number of monocytes (groups 2, 3 and 4%), eosinophils (group 3%), leukocytes (1%) and lymphocytes (group 4%) of the fish that received the supplemented feed. It was also possible to verify that the probiotic caused significant changes in the haemogram between the sampling periods on 0, 10th and 20th day, showing activation of specialized cells of the fish’s non-specific defense mechanism. At the end of the experimental period, supplementation of B. subtilis improved the productive indexes and survival of Pseudoplatystoma sp. after bacterial challenge.

The almond Terminalia catappa leaf extract has been used to prevent diseases and improve breeding in various fishes; however, their effects on the leaf fish Monocirrhus polyacanthus larviculture are unknown. We evaluated the effect of almond leaf extract on growth performance and survival of leaf fish larvae submitted to handling stress. Five concentrations of aqueous extract of almond leaf (0.25, 0.50, 0.75, 1.00 and 1.25 g/L) were evaluated with five replicates. Leaf fish larvae (15 larvae/L 0.1 cm and 0.001 g) were fed 100 Artemia nauplii per larvae twice a day along 15 days and then submitted to handling stress of total water exchange and T. catappa extract replacement. Untreated fish were used as control. The stressful management caused lower survival rate for larvae in the control group (22.2Â ± 3.14%, p

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.

The aim of this study was to evaluate the influence of the chelating mineral on propionic acid, calcium or sodium on the composition, dynamics and richness of the intestinal microbiota of a native silver catfish Rhamdia quelen through high-throughput sequencing (HTS). A total of 225 fish (8.43 ± 0.18 g) were distributed in tanks, 15 fish per tank in five groups with three replicates each: Control, Ca-propionate 0.25% (Ca0.25%) Ca-propionate 1% (Ca1%), Na-propionate 0.25% (Na0.25%) and Na-propionate 1% (Na1%). The feed was provided four times a day for 60 days. After experimental period, the fish were fasted for 24 h and the intestine was aseptically collected, pooled by treatment, and fixed in pure absolute ethanol for subsequent DNA extraction and HTS. The HTS showed that the supplementation of the propionic acid chelated to the mineral calcium or sodium in the different concentrations increased the operational taxonomic units and richness in comparison to control group. The main phyla found were Fusobacteria, Firmicutes, Proteobacteria and Bacteroides. Both the fusobacteria and the genus Cetobacterium, especially C. somerae, were positively modulated with Ca0.25% and Na1% supplementation. It can be emphasized that supplementation with calcium or sodium propionate at different concentrations changed the natural microbiota of R. quelen.

Acanthocephalosis in tambaqui Colossoma macropomum culture is a limiting factor for the production of the species, being the most recurrent, which makes it necessary to develop strategies to control parasitosis even in the early stages of parasite development. This study aimed to elucidate the morphological characteristics of eggs of the acanthocephalan Neoechinorhynchus buttnerae and the ovicidal effect of the essential oils of Lippia alba, Lippia sidoides, and Lippia gracilis. The parasites were collected from hosts naturally infected with N. buttnerae, and the eggs obtained from the female 'parasites' abdominal cavity were added to 12-well plates containing the essential oils at different dilutions. After the eggs (N = 300) were separated and measured (length and width) with the aid of an optical microscope coupled to a digital program, the viability of the treated eggs was monitored 24 h after treatments, L. gracilis essential oil was 100% effective at the highest concentration, whereas L. sidoides essential oil showed over 50% efficacy at 2 mg/ml, reaching 100% efficacy at all higher concentrations. Lippia. alba essential oil did not show satisfactory efficacy in preventing N. buttnerae egg hatching.

The study aimed to evaluate the oral infected-feed, intragastric-gavage, and intraperitoneal routes of the Streptococcus agalactiae infection in Nile tilapia (Oreochromis niloticus). For this purpose, 270 juveniles of Nile tilapia, with an average weight of 2 g, were distributed in 18 experimental units of 90 L, acclimatized, and raised for 55 days, until reaching 50 g (median weight). The experimental design was entirely randomized in six treatments, three of which were composed by bacterial infection routes: intraperitoneal 100 μL fish

Ascocotyle (Phagicola) longa is an etiological agent of human phagicolosis. Mugilids are the second intermediate host, the first being Heleobia australis, and mugilids predatory birds and mammals are its definitive hosts. The occurrence of cysts holding A. longa metacercariae is described in mugilids with a prevalence of up to 100%. The wide geographical distribution of A. longa and its intermediate hosts coupled with the rise in the consumption of raw or poorly cooked fish may elevate the risk of human infection. Therefore, in this study, we aimed to verify the distribution pattern of cysts holding A. longa in mugilids. The tissue and organ samples of these fish were processed in a domestic blender and examined under a stereoscopic microscope to identify the cysts holding the digenetic metacercariae. Of the 24 (100%) fish samples that were analyzed, 12 of Mugil curema and 12 of Mugil liza possessed cysts holding A. longa metacercariae. Digenetic cysts were identified to be present in the gills, heart, stomach, liver, intestines, mesentery, and muscular tissues collected from M. curema and M. liza. Conclusively, in M. curema, the cysts holding A. longa metacercariae were found to be distributed randomly throughout the fish body in almost every tissue and organ that was examined. Resumo Ascocotyle (Phagicola) longa é o agente etiológico da fagicolose humana. Os mugilídeos são os segundos hospedeiros intermediários. O primeiro é Heleobia australis e pássaros e mamíferos predadores de mugilídeos, os hospedeiros definitivos. A ocorrência de cistos contendo metacercárias de A. longa é descrita em mugilídeos, com até 100% de prevalência. A ampla distribuição geográfica de A. longa e seus hospedeiros intermediários, acompanhado do aumento do consumo de peixe cru ou mal cozido, pode aumentar o risco de infecção humana, portanto o objetivo do presente estudo foi verificar o padrão de distribuição de cistos, contendo metacercárias de A. longa, em mugilídeos. Amostras de tecidos e órgãos desses peixes foram processadas em liquidificador doméstico e observadas em microscópio estereoscópico à procura de cistos contendo metacercárias do digenético. Todos os 24 (100%) mugilídeos, 12 Mugil curema e 12 Mugil liza examinados apresentaram cistos contendo metacercária de A. longa. Foram observados cistos do digenético nas brânquias, coração, estômago, fígado, intestino, mesentério e tecido muscular de M. curema e de M. liza. Em M. curema, os cistos contendo metacercárias de A. longa estão distribuídos de forma aleatória por praticamente todos os tecidos e órgãos dos mugilídeos examinados.

Mugil curema e um peixe teleosteo, abundante em regioes costeiras, estuarinas e lagunares, em todo o litoral brasileiro. Os parâmetros sanguineos podem ser usados como indicadores da saude e do bem-estar dos peixes, bem como do ambiente onde estes vivem. O objetivo deste estudo foi verificar o perfil hematologico de M. curema ao longo de 18 meses, em aguas estuarinas, no Litoral norte do estado de Santa Catarina, sul do Brasil. Um total de 133 peixes foram capturados, entre marco de 2016 e agosto de 2017, para realizacao de eritrograma, leucograma, trombocitograma, porcentagem de hematocrito, dosagem de hemoglobina, dosagem de proteina plasmatica total, volume corpuscular medio (VCM), hemoglobina corpuscular media (HCM) e concentracao de hemoglobina corpuscular media (CHCM). Nao houve diferenca significativa (P>0,05) entre o numero total de eritrocitos entre machos e femeas. No entanto, houve diferenca no hematocrito, entre machos e peixes de sexo indeterminado. As influencias do espaco temporal e geografico, entre os valores dos parâmetros hematologicos, nos diferentes estudos do litoral brasileiro sao discutidas. A presente investigacao e importante contribuicao para o estabelecimento de um padrao hematologico para M. curema. A populacao local de peixes estudada tem comportamento proprio em descritores hematologicos, diferenciado de outros estudos no litoral brasileiro para a mesma especie.

Nile tilapia is an exotic species produced in Brazilian aquaculture. The aim of this study was to constitute a pathological diagnosis in Oreochromis sp. with a noticeable presence in a river in southern Brazil, and to verify the origin of these fish in this natural habitat, an environment with high sanitary precariousness due to discharges of industrial effluents. A total of 30 fish were collected during three sampling events and their health status was assessed by parasitological fauna survey, parasitological indices and histopathological examination of the gills, liver, spleen and kidney. Five species of monogenea were identified infesting gills and stomach: Cichlidogyrus sclerosus, C. halli, C. thurstonae, Scutogyrus longicornis and Enterogyrus cichlidarum; and 4 species of trichodinidae infesting the body surface and gills: Trichodina magna, T. compacta, T. centrostrigeata and Paratrichodina africana. The results showed differences according to the seasonality of the collection, with higher parasite count and larger tissue alterations in summer. Histopathological analysis fluctuated from moderate to severe, but necrosis prevailed in all organs and in all fish, indicating that these fish did not enjoy full health.

Intensive fish farming has resulted in an increased concern for disease outbreaks. Probiotic use is one of the strategies being developed to improve fish health and productivity. Measures of probiotic colonization, growth performance, haematological characteristics and parasite load were used to evaluate the effect of diets supplemented with Enterococcus faecium on growth and health of Arapaima gigas juveniles. A completely randomized design with four treatments (diet with E. faecium at 1 × 10⁶ CFU/g and 1 × 10⁸ CFU/g, control diet and diet with the culture medium MRS) and three replicates was used. Ninety‐six Arapaima juveniles were distributed in 12 cages fed with the specified diet for 68 days. Colonization of the intestinal tract by lactic acid bacteria reduced the total number of heterotrophic bacteria in fish fed with probiotics compared to controls. Fish fed a supplemented diet containing 1 × 10⁸ CFU/g presented higher values of weight gain, survival and fish growth uniformity, and lower values of feed conversion ratio. The prevalence of Trichodina sp. could have affected the survival of fish in the control group. Reduction in parasite load and an increase in haematocrit, the number of erythrocytes, thrombocytes, neutrophils and monocytes were also observed in fish fed the diet containing 1 × 10⁸ CFU/g. Enterococcus faecium presented a probiotic effect in A. gigas juveniles and can be recommended for use at a concentration of 1 × 10⁸ CFU/g to modify the gut microbiota, improve growth performance and haematology and reduce parasitic load.

The main objective of this study was to evaluate the histological and hematological alterations of silver catfish Rhamdia quelen (Quoy & Gaimard, 1824) against intense parasitism by anchor worm Lernaea cyprinacea Linnaeus, 1758. Thirteen fish specimens were collected at the Fish Genetic Improvement Unit (EPAGRI/CEDAP), Brazil. After acclimatization, the fish were anesthetized for blood collection, and the samples were used for counting thrombocytes, total leukocytes, differential leukocytes and for quantification of total erythrocytes. Afterwards, the animals were euthanized, the parasites removed and quantified, and the portions of the affected tegument fixed in 10% buffered formalin. All the analyzed animals were parasitized by L. cyprinacea with mean intensity of 192 specimens per fish. The hematological profile of the animals was different from that reported for healthy fish. Immature leukocytes were the most abundant cells, followed by monocytes, lymphocytes, neutrophils, and periodic acid-Schiff-positive granular leukocytes. A small number of neutrophils were present in the bloodstream of parasitized fish, while histological examination evidenced the accumulation of this cell type near the place of infection by the parasite. Total leukocytes correlated significantly and positively (r = 0.6, p = 0.030) with the intensity of L. cyprinacea infection and the fish weight. Histological changes included hemorrhage, liquefactive necrosis and connective tissue disarrangement, necrosis, granulomatous inflammation, mononuclear and polynuclear inflammation, as well as hyperplasia and hypertrophy of the alarm and mucous cells. The L. cyprinacea infection intensity caused deleterious changes both in the hematological profile and the integument of R. quelen, confirming the pathogenic potential of this parasite to the affected fish species.

This study evaluated the effects of dietary supplementation of organic acids blend (OAB) alone or in combination with essential oil, Lippia origanoides (OAE) for Nile tilapia fed supplemented diets for 30 days. Fish (1.1 ± 0.04 g) were fed control (Control), or OAB 0.5% or OAB 0.5% + essential oil 0.125% (OAE) respectively. At the end of the experiment, samples were collected for de hemato‐immunological, histological analysis of the intestine and liver, as well as microbiology of the intestine. The pH of the diets supplemented with OAB and OAE reduced 0.92 and 0.19 respectively. The growth and FCR were unaffected by the treatments, but survival was significantly higher in the OAB treatment. Fish fed the OAB diet showed reduced concentration of total heterotrophic bacteria and Pseudomonas sp. in the intestine. Increased glucose in fish fed OAB and high number of circulating monocytes in fish fed OAE diet were observed. The anterior intestine of fish fed OAE diet showed larger number of goblet cells and increased villi height. The diet supplemented with OAB, mainly, improved the intestinal health and survival of tilapia juveniles and can be used in juvenile production.

The aims of this study were to evaluate the inclusion of different concentrations of Lactobacillus plantarum in Nile tilapia diet and to verify histological effects on tissues of the animal organs, as well as to verify its effects on growth parameters and possible increase in the immune system. A total of 240 juveniles were distributed in 16 tanks arranged in a recirculation system. One control group and three treated groups (104, 106, and 108 colony-forming unit (CFU) g −1L. plantarum kg feed−1) were established in quadruplicate. After 35 days of supplementation, it was not possible to observe differences in growth rates and hematological parameters. However, in the kidney, there was a reduction in the presence of PAS-positive granular leukocytes (PAS-GL) between the collections (15 and 35 days). The liver had lower number of lesions related to loss of cordonal aspects of fish fed 108 CFU g−1 on day 15. Fish fed 104 and 108 CFU g−1 showed lower degree of congestion at day 35. The probiotic also provided a reduction in the number of melanomacrophage centers in the splenic tissue and an increase in the amount of goblet cells in the gut. The concentration 108 CFU g−1 of probiotic in diets increased the number of goblet cells, improved cordonal aspects, and reduced hepatic congestion, and indicated a possible improvement in the immunophysiological conditions of the fish.

This study aimed to evaluate the hematological profile and relative condition factor of naturally parasitized Nile tilapia from 12 fish farms in southern Brazil. A total of 240 fish were collected from four regions of the state of Santa Catarina. They were anesthetized, and the blood was collected by puncturing the caudal vein. Subsequently, the fish were necropsied for parasitological analysis. The results were compared with the Kruskal-Wallis test, and the correlations were verified with the Spearman test ( P < 0.05). The parasitological analysis revealed high infestations by Ichthyophthirius multifiliis on the fish gills of the south and west regions. The presence of Trichodina magna and Trichodina compacta was observed in low intensity on the body surface of fish from all facilities. Trichodina spp. was found in high intensity parasitizing the fish gills of northern, Itajai valley and western regions, nonetheless, in those regions, the presence of Monogenea, Cichlidogyrus sclerosus , and Cichlidogyrus halli , on fish gills was observed. The hematological profile presented altered parameters, featuring monocytosis and thrombocytopenia, possibly associated with high parasitic intensities. The observed correlations suggest that neutrophils and monocytes are directly involved in an organic defense against parasites. Monocytes are mainly targeted in the defense against I. multifiliis .

The present study aimed to contribute to the monogenean dactylogyrids that occur in C. auratus from an ornamental fish farm in southern Brazil. Samples of goldfish were obtained from a fish farm and the gills were removed and analysed to identify the species of Dactylogyrus to determine the levels of infestation. Three species of Dactylogyrus were found in the gills: Dactylogyrus anchoratus, Dactylogyrus baueri and Dactylogyrus formosus. The most prevalent species was D. baueri [prevalence (P) = 70%, mean intensity (MI) = 2.14 ± 1.21, mean abundance (MA) = 1.5 ± 1.43], followed by D. anchoratus (P = 60%, MI = 1.67 ± 0.81, MA = 1.00 ± 1.05) and D. formosus (P = 30%, MI = 1.66 ± 1.15, MA = 0.5 ± 1.64). Dactylogyrus anchoratus shares morphological characteristics with D. arcuatus by the similarity in shape of the haptor parts. Dactylogyrus baueri shows similarity to D. dulkeiti in relation to the pair of anchors and accessory piece of the male copulatory complex. Dactylogyrus formosus presents an accessory piece with branch and total length of the anchors smaller than D. anchoratus. This study reports the occurrence of D. anchoratus, D. baueri and D. formosus in goldfish cultured in southern Brazil. These monogenean species have been described in cyprinid fishes that have a wide geographic distribution with the result of the dissemination of the host in the world.

Essential oils are obtained from vegetal material and present antibacterial activities, antioxidant, antiviral, antifungal properties and may replace the use of chemotherapeutics for treating and prophylaxis in fish farm. The objective of this study was to verify the influence of essential oil of Mentha piperita in the prevention of Streptococcus in Nile tilapia. A total of 300 fish with approximately 5 g were divided into 20 tanks with 15 fish each were fed diet supplemented with essential oil at concentrations of Mentha 0.075%; Mentha 0.125%; Mentha 0.25% and two controls (commercial feed and feed+cereal alcohol) in quadruplicate, during 50 days. At the end of the supplementation period, four fish from each experimental unit were collected for hemato-immunological analysis and the rest of the animals were challenged against Streptococcus agalactiae intraperitoneally. During seven days after infection, the fish were monitored every three hours for mortality registration. Zootechnical performance indexes were measured based in the biometries each 15 days along the experimente and did not present significant difference as well as the hematological parameters. Total plasmatic protein was higher in fish fed Mentha 0.125% than those fed Mentha 0.25%. After the challenge, unlike the animals whose diet did not contain essential oil, the animals that received supplemented ration maintained their alimentary activity. The supplementation with the essential oil increased the resistance of the fish after the challenge with S. agalactiae and survival was significantly higher in fish fed with Mentha 0.25%.

The aim of the present study was to verify the effect of sodium butyrate in protected and unprotected forms at two different concentrations of diet inclusion (0.25% or 0.5%) on the digestive enzyme's activity, integrity and structure of the intestinal tract and liver, in juveniles of Oreochromis niloticus, during the period of sexual reversion. In the experimental period, 3150 newly hatched post-larvae were randomly distributed in 21 experimental units of 100 L, divided into six treatments and one control, with three replicates each. The treatments were: fish fed with feed without supplementation (Control); fed with pure Na-butyrate (Pure 0.25% and Pure 0.5%), fed with palm oil-protected Na-butyrate (Oil 0.25% and Oil 0.5%) and fed with protected Na-butyrate with buffer solution (Buffer 0.25% and Buffer 0.5%). At the end of the experimental period, a decrease in alkaline protease activity was observed in the Oil 0.25%, Oil 0.5% and Buffer 0.5% groups when compared to the control. Fish fed Buffer 0.5% supplemented diet for 28 days had a longer length, perimeter and villus area of the anterior region of the intestinal tract when compared to Pure 0.25%. The Control, Pure 0.25% and Oil 0.5% groups had a reduction in villus width when compared to the other groups. In the posterior region, the group Oil 0.25% had a longer villus length when compared to the Pure 0.25% and Control, in addition to a greater area of villi when compared to the same groups and also to the Oil 0.5%. In this same intestinal portion, the Buffer 0.5% presented greater perimeter of intestinal villi when compared to the Control and Pure 0.25%. The Pure 0.25% and Buffer0.25% presented higher number of goblet cells per villi when compared to Oil 0.5%. The control group and those supplemented with sodium butyrate, in the different concentrations and forms, presented the intact intestine and without the presence of lesions. Regarding the liver, the Pure 0.5% group presented the highest macroesteatosis indexes when compared to the Control group, besides a higher necrosis index when compared to the Pure 0.25%. Thus, it can be observed that the supplementation of protected forms of sodium butyrate in the diet of juvenile Nile tilapia during the period of sexual reversion was effective in maintaining intestinal health, because Oil 0.5% contributed to the intestinal health of the animals, and the Oil 0.25%, Buffer 0.25% and Buffer 0.5%, increased the development of the intestine.

Annually, more than 2500 ornamental fish species are traded worldwide. Forty percent of these are from marine water. Some 98% of marine species are wild-caught from their natural habitat, and the majority subsequently exported. Wild fish frequently carry pathogens, which could induce diseases after the stress of capture. Neobenedenia melleni is a platyhelminth that mainly attaches to the skin and eyes of the host. It provokes dermal inflammation, epidermal loss, skin depigmentation, reduction in the number of mucous cells, and, consequently, decreased mucus protection, and declining immunological barriers. This makes fish susceptible to secondary infections. A total of 47 wild reef fish from a retailer were examined, suspected to be infected with ectoparasites. The morphological identification revealed N. melleni as a monogenean agent. One monogenean specimen was collected from the eye of each of the 40 fish analyzed to evaluate possible bacterial secondary infections using the matrix-assisted laser desorption ionization–time-of-flight mass spectrometry (MALDI-TOF MS) technique. The MALDI-TOF MS identified that 59% of monogenean collected from the eyes had bacteria, including some pathogenic to fish. This led us to believe that the ectoparasite can be a possible mechanical vector of pathogenic bacteria for fish culture and maintenance. The use of praziquantel as an antiparasitic agent is also discussed.

This study evaluated the potential of alternative treatments against larval stages of Lernaea cyprinacea. For in vitro test, the nanoemulsified oils of Pinus sp. acicule and oleoresin were evaluated, along with Biogermex® (commercial product based on citrus biomass). For this, the motility of five larvae of the same stage (nauplii or copepodite) were evaluated in a 96-well microplate. Using the best results, on the in vivo test, fries of Rhamdia quelen were submitted to a long-term immersion bath (96 h) containing different concentrations of the product diluted directly in the water. It was possible to notice the antiparasitic potential of the oleoresin and the acicule of Pinus sp., as well as the citrus biomass extract against the parasites. The nanoemulsified oils successfully inhibited the development of nauplii (10 mg L(−1) in 24 h) and the fries showed to be tolerant to the presence of the compound (LC(50) 96 h—16.74 mg L(−1)). The concentration of 30.5 mg L(−1) of Biogermex® eliminated the copepodites within 24 h, being more efficient than Pinus sp. when tested at the same stage, at the times analyzed. The results obtained indicate a potential use of these compounds as prophylactic agents against L. cyprinacea.

El presente estudio reporta la presencia de Enterogyrus cichlidarum Paperna, 1963 (Monogenoidea: Ancyrocephalidae) en el estomago de tilapia del Nilo, Oreochromis niloticus Linnaeus, 1758, de cautiverio en el Estado de Santa Catarina, Sur de Brasil. Un total de 98 peces de cautiverio en Joinville, Santa Catarina fueron examinados. Los peces fueron colectados en invierno del 2007, en primavera, otoño, invierno y primavera del 2008. Después de la anestesia y muerte en benzocaina, sus estómagos fueron removidos, bañados en agua caliente a 55oC, fijados en formalina 5% para el conteo y evaluación de las tasas de prevalencia, intensidad de infección, abundancia media y montaje en Hoyer. La tasa total de prevalencia por todo el periodo fue 94%. Las más altas intensidades de infección ocurrieron en agosto 2008 y noviembre 2008 seguidas de julio 2007, enero y mayo 2008. La mayor parte de Monogenoidea habitan las branquias y cuerpo de los peces, pero pocos son los encontrados en otros órganos. Este estudio es el primer caso de Enterogyrus en tilapia del Nilo en Brasil.

This study aimed to evaluate the effects of essential oil (EO) of Lippia sidoides, Ocimum gratissimum, and Zingiber officinale in the diet of tambaqui (Colossoma macropomum) growth, hematological and immunological parameters. The survival rate was also calculated after challenge with Aeromonas hydrophila. Seven diets containing 32 % crude protein were formulated as follows: control (0 g/kg of EO), 0.625 and 1.25 g/kg of L. sidoides EO; 1.25 and 5.0 g/kg of O. gratissimum EO; 1.25 and 5.0 g/kg of Z. officinale EO, in triplicate. Tambaqui fed diets supplemented with EO of L. sidoides, O. gratissimum, and Z. officinale did not present significant differences in the growth parameters. After 30 and 60 days of feeding, performance and hematological parameters were evaluated. Reductions in total thrombocytes number occurred after 30 days of feeding with 1.25 g/kg and 5.0 g/kg O. gratissimum EO. After 60 days of feeding, fish were challenged with A. hydrophila (1.6 × 108 UFC mL−1) and were observed for 10 days. Fish fed with diets supplemented with L. sidoides EO at 0.625 g/kg and 1.25 g/kg showed a higher nonspecific immune response through the increased respiratory activity of leukocytes after challenge. Additionally, there was a decrease in plasma glucose levels and no alteration of the total protein levels. Moreover, after the challenge, the highest survival rate occurred among fish fed 0.625 g/kg L. sidoides EO, while treatments with O. gratissimum and Z. officinale EO did not affect fish survival. This is the first report of L. sidoides EO in tambaqui diets. More studies are warranted to adjust the concentration and periods of treatment regarding diets supplemented with L. sidoides EO or thymol in treatment of bacterial fish diseases.

Made available in DSpace on 2021-06-25T10:36:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Graduate Program in Zootechny State University of Mato Grosso do Sul (UEMS) Zona Rural Graduate Program in Animal Science Federal University of Mato Grosso do Sul UFMS AQUOS - Aquatic Organisms Health Laboratory Aquaculture Department Federal University of Santa Catarina (UFSC) LAPAD - Biological Laboratory and Cultivation of Freshwater Fish Aquaculture Department UFSC UNESP Aquaculture Center São Paulo State University (CAUNESP) Zona Rural UNESP Aquaculture Center São Paulo State University (CAUNESP) Zona Rural CNPq: 119737/2017-5 CNPq: 306635/2018-6 CNPq: 552395/2011-0

This study evaluated the parasitic fauna of hybrids tambacu (Colossoma macropomum × Piaractus mesopotamicus) and patinga (P. mesopotamicus × Piaractus brachypomus) and their host-parasite-environment interaction during the warm and cold seasons in two fish farms located in the State of Mato Grosso do Sul, Brazil, South America. A total of 120 fish, being 60 fish for species (30 in the warm season and 30 in the cold season) were examined. Water quality was measured weekly to evaluate the interaction between environmental conditions and parasitism. Fifteen species of parasites were found: Ichthyophthirius multifiliis, Chilodonella hexasticha e Trichodina sp. (Protozoa), Henneguya piaractus, Myxobolus colossomatis and Myxobolus cuneus (Myxozoa); Anacanthorus penilabiatus, Mymarothecium boegeri, Mymarothecium viatorum, and Notozothecium janauachensis (Monogenoidea), Goezia spinulosa and Goezia sp. (Nematoda), Echinorhynchus jucundus (Acanthocephala), and Dolops carvalhoi, Lernaea cyprinacea (Crustacea). The ciliate protozoan I. multifiliis and monogenoids were the most prevalent parasites in the cold and warm seasons for both hybrids in the different culture systems intensive production and sportive fishing. It was observed that the serrasalmid hybrids are more susceptible to parasites and harbor high diversity of parasites in relation to the parental species C. macropomum, P. mesopotamicus and P. brachypomus, with a predominance of ectoparasites. -- Resumo: Este estudo avaliou a fauna parasitária de híbridos tambacu (Colossoma macropomum × Piaractus mesopotamicus) e patinga (P. mesopotamicus × Piaractus brachypomus) e a interação hospedeiro-parasito-ambiente durante as estações quente e fria em duas pisciculturas localizadas no estado de Mato Grosso do Sul, Brasil, América do Sul. Foram examinados um total de 120 peixes, sendo 60 peixes por espécie. A qualidade da água foi mensurada semanalmente para avaliar a interação entre condições ambientais e parasitismo. Foram encontradas quinze espécies de parasitos: Ichthyophthirius multifiliis, Chilodonella hexasticha e Trichodina sp. (Protozoa); Henneguya piaractus, Myxobolus colossomatis e Myxobolus cuneus (Myxozoa), Anacanthorus penilabiatus, Mymarothecium boegeri, Mymarothecium viatorum e Notozothecium janauachensis (Monogenoidea), Goezia spinulosa e Goezia sp. (Nematoda), Echinorhynchus jucundus (Acanthocephala), Dolops carvalhoi eLernaea cyprinacea (Crustacea). O protozoário ciliado I. multifiliis e helmintos monogenoides foram os parasitos mais prevalentes nas estações fria e quente para ambos os híbridos nos diferentes sistemas de cultivo, produção intensiva comercial e pesca esportiva. Observou-se que os híbridos de serrasalmídeos são mais suscetíveis aos parasitos e abrigam alta diversidade parasitária em relação às espécies parentais, C. macropomum, P. mesopotamicus e P. brachypomus em ambiente de cultivo com predominância de ectoparasitos. Made available in DSpace on 2020-12-01T09:01:52Z (GMT). No. of bitstreams: 1 Ishikawa-Parasitological-assessment-2020.pdf: 1471025 bytes, checksum: 89b7c82f070030733e07a087cf61c8f5 (MD5) Previous issue date: 2020

Resumo: Este estudo avaliou os parâmetros hematológicos de híbridos tambacu e patinga cultivados no Mato Grosso do Sul, Brasil, com ênfase na influência das épocas do ano. Duzentos e quarenta peixes híbridos, 120 tambacus e 120 patingas, foram coletados ao longo de 12 meses para análises hematológicas, comparando a estação quente (Outubro-Março) com a estação fria (Abril-Setembro). Os parâmetros de qualidade de água foram medidos semanalmente, para verificar sua influência sobre os parâmetros hematológicos. A estação quente mostrou tendência ao declínio nos níveis de oxigênio dissolvido, enquanto na estação fria ocorreu o inverso. Na estação quente, tambacus apresentaram valores mais altos (p

This study evaluated the potential of alternative treatments against larval stages of Lernaea cypriancea. For in vitro test, the nanoemulsified oils of Pinus sp. acicule and resin were evaluated, along with Biogermex® (commercial product based on citrus biomass). For this, the motility of five larvae of the same stage (nauplii or copepodite) were evaluated in a 96-well microplate. Using the best results, on the in vivo test, fries of Rhamdia quelen were submitted to a long-term immersion bath (96 h) containing different concentrations of the product diluted directly in the water. It was possible to notice the antiparasitic potential of the resin and the acicule of Pinus sp., as well as the citrus biomass extract against the parasites. The nanoemulsified oils successfully inhibited the development of nauplii (10 mg L− 1 in 24 h) and the fries showed to be tolerant to the presence of the compound (LC50 96h − 16.74 mg L− 1). The concentration of 30.5 mg L− 1 of Biogermex® eliminated the copepodites within 24 h, being more efficient than Pinus sp. when tested at the same stage, at the times analyzed. The results obtained indicate a potential use of these compounds as prophylactic agents against L. cyprinacea.

This study aimed to verify the effects of dietary supplementation with sodium butyrate and Lippia origanoides, combined and isolated, on the health and zootechnical performance of Nile tilapia juveniles Oreochromis niloticus. A total of 120 fish (5.38 ± 0.65 g) were randomly distributed in 12 experimental units and fed different experimental diets for 30 days, namely: commercial diet without supplementation (Unsupplemented); commercial diet supplemented with 0.5% sodium butyrate (Butyrate); commercial diet supplemented with 0.125% L. origanoides (Lippia) and commercial diet supplemented with a mixture of 0.5% sodium butyrate and 0.125% L. origanoides (Butyrate + Lippia). After preparing the experimental diets there was an increase in the pH of diet Butyrate when compared to the other diets. After 30 days the fish supplemented with Butyrate + Lippia showed reduction significate in the mean corpuscular haemoglobin, concentration of total heterotrophic bacteria in the intestine, and lymphocyte infiltrates in the liver. Besides that, the supplementation with Butyrate + Lippia promoted an increased number of intestinal villi compared to the fish Unsupplemented ones. Additionally, fish fed a diet containing only Lippia presented an increase in the villus perimeter in the posterior region of the gut and in the red blood cell number. Animals supplemented only with sodium butyrate demonstrated increased lactic acid bacterium in the gut and macrosteatosis in the liver, besides decreased melanomacrophages in the spleen. The use of sodium butyrate associated with essential oil had positive effects on the intestinal microbiota, intestinal structure, liver, and spleen integrity, suggesting a greater efficiency of the compounds when used together in the nutrition of Nile tilapia juveniles.

Pocos estudios han sido hechos para evaluar la preferencia por el microhabitat de monogenea. Este estudio evaluó la distribución y estacionalidad de monogenea entre los diferentes arcos branquiales de tilapia del Nilo. Un total de 89 peces fueron capturados en una laguna en la ciudad de Chapecó, Santa Catarina, para el análisis parasitológico. Después de la eutanasia de los peces, fueron extraídos los arcos branquiales separadamente a partir de la región externa hasta la interna y numerados como I, II, III e IV. Fueron evaluadas la transparencia del agua, el pH, el oxigeno disuelto, la temperatura, la alcalinidad, la conductividad, el amonio, el hierro, el ortofosfato, el sulfato, el nitrito y el nitrato. En la primavera de 2008 las abundancias promedio de monogenea (Scutogyrus longicornis, Cychlidogyrus sclerosus, C. thurstonae y C. tilapiae) en los arcos I, II, III y IV fueron, respectivamente, 11,45; 14,45; 13,8; 13,15; en el verano de 2008 de 13,12; 12,25; 14,94; 21,53; en el verano de 2009 de 2,75; 3,25; 2,45; 2,45; en el otoño de 2009 de 13,44; 18,78; 11,78; 9,22 y en el invierno de 2009 de 0,35; 0,5; 0,3; 0,5. No fue observada preferencia por monogenea por el microhabitat en las branquias de la tilapia del Nilo en cultivo. Fue observado un aumento significativo de los helmintos en la primavera y verano de 2008 y otoño de 2009. El mayor número de parásitos coincidió con las estaciones de mayor temperatura del agua. La falta de preferencia por microhabitat entre los arcos branquiales sugiere una distribución homogénea de los parásitos combinados con los parámetros de calidad de agua.

Los alevines de bagres del Sur de América en cautiverio están frecuentemente expuestos a muchos parásitos, pero poca información es evaluada para implementar programa de salud para control y prevención de enfermedades en criaderos. Este estudio evaluó la fauna de parásitos de alevines de cachara (Pseudoplatystoma reticulatum Eingenmann & Eingenmann, 1889) y la relación huésped-parásito durante las fases iníciales de cultivo. Un total de 302 alevines fueran sometidos a diagnóstico y análisis histopatológicos. Ichthyophthirius multifiliis y Trichodina heterodentata fueran diagnosticados como los parásitos mas prevalentes, seguidos de Cryptobia sp., Henneguya sp., Monogenea y Nematoda. Ha sido observada una correlación positiva entre la longitud de los peces y la intensidad promedio de I. multifiliis. Proliferación de células de moco, células club, áreas multifocales de degeneración, necrosis epitelial en la superficie del cuerpo, ulceración de piel, fusión de laminillas branquiales secundarias e infiltración inflamatoria fueron observados en peces infectados por I. multifiliis. Los protozoarios ciliados fueran los agentes etiológicos mas importantes y el cachara (P. reticulatum) es un nuevo huésped para T. heterodentata. En adición, la ictioftiriasis indujo un daño severo favoreciendo las infecciones oportunistas en los alevines.

Made available in DSpace on 2022-04-29T08:34:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) This study evaluated the dietary supplementation of ginger Zingiber officinale essential oil for the Neotropical catfish Pseudoplatystoma reticulatum, its effects on fish hematology, immunology, the response of these variables to induction of stress (exposition to air for 3 min), and a bacterial challenge with Aeromonas hydrophila, and the effects on liver histomorphometry. Three levels of the ginger essential oil were evaluated (0.5, 1.0 and 1.5%) in addition to a control group (0%) in a feeding trial for 65 days in triplicate. Fish hematology and immunology were assessed at five different moments: after the feeding trial (0), after the stress induction (stress), and three points after the bacterial challenge (3, 6 and 24 h post-challenge). Fish fed the ginger essential oil supplemented diets did not exhibit significant differences between the hematocrit at the 0-sample point and the 24 h post-challenge point (P ≥ 0.05), while fish fed the control diet presented significantly lower values for the hematocrit when comparing those same two moments (P < 0.05). The thrombocytes count for fish fed the 0.5% essential oil supplemented diet was significantly higher than all other groups after the feeding trial (P < 0.05), and their total leukocytes count after the stress induction was also significantly higher than the other treatments (P < 0.05). Although the results mentioned above indicate that the ginger essential oil had positive health effects on the fish, no significant differences in survival after the challenge with A. hydrophila were observed (P ≥ 0.05). Lastly, histomorphometry suggests that the essential oil did not negatively impact fish hepatocytes. Postgraduate Program in Animal Science Federal University of Mato Grosso do Sul (UFMS) AQUOS-Aquatic Organisms Health Laboratory Aquaculture Department Federal University of Santa Catarina (UFSC) Marine Shrimp Laboratory (LCM) Aquaculture Department Federal University of Santa Catarina (UFSC) State University of Mato Grosso do Sul (UEMS), Zona Rural Aquaculture Center São Paulo State University (CAUNESP) EMBRAPA Western Amazon Postgraduate Program in Zootechny State University of Mato Grosso do Sul (UEMS) Aquaculture Center São Paulo State University (CAUNESP) CNPq: 306635/2018-6

This study identified the parasitic species in juvenile freshwater finfishes during the fattening stage, from a fish farm located in the Zona da Mata (MG), southeastern Brazil, and revealed both macro and microscopical lesions in fish gills. A total of 172 juvenile fishes of different species (Oreochromis niloticus, Ictalurus punctatus, Ctenopharyngodon idella, Cyprinus carpio, Astyanax bimaculatus and Brycon amazonicus) were transported to a laboratory in São Paulo city. The fish were sedated and then euthanized for parasitological analysis. All fish were infected by at least one parasite species. Ten different species of parasites were identified: Apiosoma sp., Epistylis sp., Ichthyobodo sp., trichodinids, Piscinoodinium pillulare, Ichthyophthirius multifiliis, Tetrahymena sp., monogeneans, Centrocestus formosanus metacercariae, and Dermocystidium sp. The best management practices and lack of sanitary control were also discussed. Resumo Este trabalho identificou espécies parasitas em peixes de produção juvenis de água doce, durante a fase de engorda, oriundos de uma piscicultura da Zona da Mata (MG), na região sudeste do Brasil, além das lesões de brânquias, causadas tanto macro quanto microscopicamente. Um total de 172 peixes juvenis de diferentes espécies (Oreochromis niloticus, Ictalurus punctatus, Ctenopharyngodon idella, Cyprinus carpio, Astyanax bimaculatus e Brycon amazonicus) foram transportados para um laboratório na cidade de São Paulo. Os peixes foram anestesiados e eutanasiados para análise parasitológica. Todos os peixes estavam acometidos por pelo menos uma espécie de parasito. Dez diferentes espécies de parasitos foram identificadas: Apiosoma sp., Epistylis sp., Ichthyobodo sp., tricodinídeos, Piscinoodinium pillulare, Ichthyophthirius multifiliis, Tetrahymena sp., monogeneas, metacercárias de Centrocestus formosanus e Dermocystidium sp. As boas práticas de manejo e inadequado controle sanitário também foram discutidos.

This study evaluated the in vitro and in vivo parasiticidal efficacy of the essential oils of Mentha piperita, Lippia alba and Zingiber officinale on Neoechinorhynchus buttnerae (acanthocephalan) and their effect when used as dietary supplementation on hematological parameters of Colossoma macropomum. For the in vitro assay, the parasites were exposed to five different concentrations (360, 540, 720, 1440, and 2880 mg L−1) of the essential oils diluted in 3% Tween 80, for incubation period of 24 hs observed each 15 min. The essential oil of M. piperita caused mortality of 100 % of the parasites in 2 h in the concentration (540 mg L−1), compared to the essential oils of L. alba and Z. officinale. For the in vivo tests, 210 juvenile tambaqui were used; they were fed for 30 days with either the control diet and experimental diets consisting of supplementation with essential oils: control, M. piperita 0.54 g kg−1 and 2.88 g kg−1, L. alba 1.44 g kg-1 and 2.88 g kg−1, Z. officinale 1.44 g kg−1 and 2.88 g kg−1, in triplicate, resulting in 21 experimental units (10 fish per tank). The anthelmintic activity in the animals treated using diets supplemented with M. piperita at 0.54 and 2.88 g kg−1 were 85.46 % and 70.03 %; with L. alba 1.44 and 2.88 g kg−1 were 67.10 % and 56.93 %, and with Z. officinale 1.44 and 2.88 g kg−1 were 11.70 % and 5.19 %, respectively. Total red blood cells count and thrombocytes were higher in fish treated with M. piperita at 0.54 g kg−1 and Z. officinale at 1.44 g kg−1. The supplementation with essential oil of M. piperita at 0.54 g kg−1 was effective in the control of N. buttnerae and presented better specific growth rate. However, despite these promising results, more research is needed to validate their use in commercial production.

Acanthostomum gnerii és un digenea frecuentemente reportado en el intestino de Siluriformes y bien distribuida en el centro y suramérica. El objetivo de este estudio es proporcionar información adicional sobre las características morfológicas de la A. gnerii por secciones histológicas y microscopio electrónico de barrido, así como para proporcionar mediciones comparativas de Acanthostomum spp.. Diferente de registros anteriores de este helminto en Rhamdia sp., los espécimes de presente estudio presentearon dos brazos en la porción anterior del cuerpo luego después de la faringe. Ellos se juntan en un poro lateral en el lado esquierdo del cuerpo semelhante al observado en A. proctophorum y A. minimum. Esta morfología no hay sido descripta como característica válida para Acanthostomidae. La variación morfológica podria estar asociada a diferentes poblaciones de la misma especie. Nuevos estudios usando tecnicas moleculares son recomendados para certificar se esta característica coresponde a la diversidad de A. gnerii encuentrada en otras especies de peces.

This study aimed to explore different substances (or cold sea water) as potential anesthetic agents to facilitate short-term handling in Octopus maya juveniles. We investigated oxygen consumption before (baseline), during (first 600 s of exposure) and after anesthesia (recovery) of octopuses (n = 98; 1.67 ± 0.5 g) exposed to cold sea water (SW; 11 and 13°C), ethanol (EtOH; 0.5; 1.5 and 3.0%), magnesium chloride (MgCl2; 0.75; 1.5 and 3.75%), ethanol combined with magnesium chloride (Mix; 1.5:0.75%; 0.75:1.13%; and 2.25:0.37%) and clove oil (0.15 mL L–1). After exposure, the animals were handled for 180 s (exposed to air) and weighted. Two experimental groups not exposed to anesthetics (with or without handling) were also evaluated. The criteria for general anesthesia were analysed. Times of induction and recovery, incidence of attack response after recovery and possible longer-term effects of repeated general anesthesia on growth and mortality of the octopuses were evaluated. During anesthesia, O. maya juveniles exposed to SW (11 and 13°C), EtOH (0.5; 1.5 and 3.0%), Mix (0.75:1.13%), and clove oil, presented a significant decrease on oxygen consumption. In animals exposed to different concentrations of EtOH and Mix 0.75:1.13%, this decrease was registered after an increase on oxygen consumption. Animals exposed to MgCl2 did not show significant changes on oxygen consumption, except for animals exposed MgCl2 3.75%, which showed a significant increase on oxygen consumption. At the end of recovery, except for octopuses exposed to clove oil and MgCl2 0.75%, the values of oxygen consumption observed were comparable to the ones registered during baseline. Animals exposed to SW 11°C, EtOH 3.0%, Mix 1.5:0.75% and MgCl2 3.75% fulfilled the criteria defined for general anesthesia. Exposure to MgCl2 (all concentrations), SW 13°C and clove oil reduced or inhibited the incidence of attack response after recovery. Except for animals exposed to clove oil, growth of the juveniles was not affected by the exposure to the different substances. Short-term handling (180 s) of O. maya juveniles can eventually be carried out without anesthesia. However, to facilitated handling, we suggest the use of EtOH 3.0% or cold sea water 11°C.

The aim of this study was to determine the median lethal concentration LC50 24 h of formalin in Xiphophorus maculatus, Xiphophorus heleri, Oreochromis niloticus, Danio rerio, and Carassius auratus. The concentrations of 100, 150, and 200 mg L−1 were tested in each fish species separately. Fish behavior was observed in the first 6 h after exposure to formalin. The 200 mg L−1 concentration was the most lethal for all species in less than 24 h. Tilapia was the most resistant species with a LC50 24 h achieving 191.34 mg L−1. In the first 2 h, the behaviors of fish on the higher concentration were agglomeration near the aeration input in the tanks and agitated swimming with fast movement of opening and closing of both mouth and operculum. With more than 4 h exposure, an increase in mucus production was observed, promoting a change in water color, reduction of operculum beating, and slow swimming until the beginning of the first deaths. We recommend using 100 mg L−1 of formalin for prophylactic baths during 1 h or two baths with 50 mg L−1 for 30 min for juvenile fish, in two consecutive days to ensure the fish welfare post-bath, as well as the health of those who will manipulate the formalin.

The present study proposes to characterize the parasites isolated during the initial phase of production in fish farms located in Mato Grosso do Sul in the central-western region of Brazil, using histopathology analysis and molecular techniques. A total of 340 hybrid surubim fish (Pseudoplatystoma reticulatum × P. corruscans) from four farms were examined during the co-feeding phase. Histopathology analysis showed that 10.9% (n = 37) of the fish were infected with parasites. Branchitis, lifting epithelium, hypertrophy of epithelial cells, lamellar fusion, aneurisms and infection in the bone tissue of the gill filament was observed. The parasite species was determined by amplification of the 18S rRNA gene followed by sequencing. The phylogenetic analysis of nucleotide sequences indicates a close relationship (99.6%) with Henneguya pseudoplatystoma reported to be infecting the hybrid Pseudoplatystoma. This study demonstrates the occurrence of H. pseudoplatystoma in hybrid surubim (P. reticulatum × P. corruscans) during the co-feeding phase in fish farms in Mato Grosso do Sul. Also, molecular techniques provide a faster and sensitive method to identify fish parasites, and may assist in the development of new management techniques aimed at improving the sanitary conditions contributing to the reduction of mortality rates in these animals.

Fish may bioaccumulate contaminants from the aquatic environment and extend them to the food chain provoking risks to human health. This study evaluated the microbiological parameters of the pond´s water and trace elements concentrations in samples of water, sediment, feed and muscle of farmed Nile tilapia used for human consumption in southern Brazil. A total of 240 fish were collected from 12 tilapia farms. Sediment, tank water and dry ration used in the animals' diet were collected for analysis. Analysis were performed by Energy Dispersion X-ray Fluorescence (EDXRF), Inductively Coupled Plasma Mass Spectrometer (ICP-MS), Induced Coupled Plasma Optical Emission Spectrometer (ICP-OES), and Atomic Absorption Spectrometer (AAS-VGA). In addition, the microbiological analysis of the water was carried out. The concentrations of Se, I, Fe, Cu and Zn in fish muscle were higher than the recommended by the Brazilian legislation, considering the advised daily intake for adults. The arsenic element had concentrations above the limit stipulated by the present Brazilian legislation, observed in all samples of muscle, sediment and tank water highlighting a possible environmental and fish contamination by the toxic element. Moreover, the arsenic concentration in the water presented a positive correlation (ρ = 0.33) with arsenic in the muscle, suggesting that tilapia is a good environmental bioindicator, once they properly reflect the levels of arsenic in the water. It is suggested to perform an arsenic speciation for quantification of the inorganic form and accurate assessment of the degree of toxicity in the muscle samples and risks it can bring to human health. Regarding the other potentially toxic elements (Hg, Pb and Cd), and microbiological analysis of water it was verified that the consumption of the fish in question does not raise risks, since the values are within a quality benchmark established by law. The concentration of total and fecal coliforms in pond´s water in the facilities was in agreement with the microbiological indexes required by the legislation of CONAMA class II. Western region presented the lowest concentrations of fecal coliforms when compared to the other regions. There was no significant difference in the microbiological counts of total heterotrophic bacteria, Vibrio spp. and Pseudomonas spp. among the regions.

The present study evaluated the effect of pure and protected sodium butyrate with palm oil and buffered solution supplemented in the diet of Nile tilapia Oreochromis niloticus on the performance parameters, hematological parameters and disease resistance during sexual reversion. Initially, the minimum inhibitory concentration (MIC) of sodium butyrate (Na-butyrate) against Aeromonas hydrophila or Streptococcus agalactiae under three different pH to determine the concentration of inclusion of Na-butyrate in the diet were analyzed. After that a total of 3150 newly hatched post-larvae were distributed in 21 tanks with 100 L of capacity on six treatments and one control, in triplicate: fish fed unsupplemented diet (control); fish fed Na-butyrate supplemented diet (Pure 0.25% and Pure 0.5%); fish fed Na-butyrate coated with palm oil (Oil 0.25% and Oil 0.5%) and fish fed Na-butyrate coated with buffered solution (Buffer 0.25% and Buffer 0.5%). After 28 days of feeding, zootechnical parameters, hematological parameters and resistance against A. hydrophila were verified. The MIC results showed that Na-butyrate had a better inhibitory effect in vitro at pH 6 and 6.6 than at pH 7, regardless of the microorganism. The addition of Na-butyrate at different concentrations and forms did not influence the sexual reversal process of tilapia. Yield and biomass gain showed an increment in fish fed Buffer 0.5% and Oil 0.5%. Moreover, fish fed Oil 0.5% had a better feed conversion ratio than the other groups. An increase in the red blood cells (RBC) and monocytes were observed in fish fed Buffer 0.5% and Oil 0.25% when compared to control group, while those fed Pure 0.25% and Oil 0.5% showed the lowest monocytes number when compared to Buffer0.5% and Oil0.25%. After challenge by immersion in A. hydrophila solution, no difference was found among the treatments for 14 days of observation, except for the nonchallenged fish that showed no mortality ensuring the effectiveness of the experimental infection. The use of coated Na-butyrate either in buffer or oil showed to be feasible to improve the zootechnical parameters of Nile tilapia during the sexual reversion period.

Este estudo avaliou os parasitos endohelmí­­nticos do peixe nativo Gymnotus spp. coletados de diferentes isqueiros comerciais na bacia do Pantanal, Mato Grosso do Sul, Brasil Central. De 99 peixes coletados para análise parasitológica, todos estavam parasitados por pelo menos um parasito por hospedeiro. Um total de 4504 parasitos foi coletado compreendendo os seguintes táxons: Digenea, Nematoda, Pentastomida e Acanthocephala. Rondonia rondoni e Goezia sp. bem como Alofia sp. foram registrados pela primeira vez em Gymnotus spp. A diversidade de espécies de parasitos no hospedeiro é discutida neste estudo.

The toxicity of formalin on Cyprinus carpio var. koi and its anti-parasite effects against Dactylogyrus minutus (Monogenea) in in vitro tests is analyzed. Specimens of D. minutus were submitted to eight concentrations of formalin: 50, 75, 100, 125, 150, 175, 200, 250 mg L−1, in triplicate. Concentrations of formalin 100, 150 and 200 mg L−1 were then tested to determine the median lethal concentration of 50% of the fish per immersion bath. Fish behavior was also observed during the first 6 h of exposure. The 200 mg L−1 concentration was the most rapid efficacy for D. minutus, killing all parasites in 16 min. All parasites were killed in 47 min at concentration 100 mg L−1. Concentration 200 mg L−1 was the most lethal for fish in less than 24 h exposure, with 24 h LC50 at 135.44 (119.78–153.14) mg L−1. The therapeutic index was 2.05–30 min and 1.15–16 min. A short bath (1 h) is recommended in koi carp with a minimum concentration of 75 mg L−1 of formalin, not exceeding 100 mg L−1 for treatment against D. minutus.

This study evaluated the use in vitro and in vivo of Bixa orellana seed extracts on the hematological and biochemical parameters of Colossoma macropomum co-infected with bacterium and monogenean, Anacanthorus spathulatus. The extract presented antimicrobial and antiparasitic activity in vitro against the pathogens. Fish supported the toxicity test and in vivo assay used 180 fish distributed in six treatments in triplicate: non-parasitized fish non-injected with A. hydrophila; non-parasitized fish non-injected exposed to acetone 0.2%; parasitized fish injected non-treated with the extract; parasitized fish injected treated with 125 μg mL−1 of extract in 2 h bath for two consecutive days; parasitized fish injected treated with 250 μg mL−1 of extract in 2 h bath for two consecutive days; parasitized fish injected treated with 125 μg mL−1 of extract for 12 h. After last bath, the fish were examined. Acetonic extract showed minimal inhibitory concentration of 125 μg mL−1 against A. hydrophila in the in vitro test and 100% efficacy against monogenean with therapeutic baths in relation to control non-treated in the in vivo test. Aeromonas hydrophila infection did not cause mortality. The gross pathology analysis showed ascites and hemorrhagic liver, kidney and spleen. Increased hemoglobin concentration, mean corpuscular hemoglobin concentration and total number of erythrocytes was followed by a decrease in hematocrit percentage in non-treated fish compared to basal group. Lymphocytes from fish in the control group were higher than in the other groups. Glucose was higher in treated fish than that found in those of basal and control. The results demonstrated that B. orellana bath was an effective alternative to treat fish diseases.

The aim of this study was to evaluate the use of synthetic fibre as a biological support for the adhesion of nitrifying bacteria in an aquaculture recirculation system (RAS). It was developed from three assays over 120 days. In the first assay, the synthetic fibres used as biological support were introduced in tanks of biological filtration of the system for posterior respirometry analysis and scanning electron microscopy (SEM). Respirometry and SEM were performed 10 days after inoculation with nitrifying microorganisms. Water quality parameters were monitored daily, and the respirometry showed that the bacteria in this assay were consuming the following amounts of ammonium: concentrations [C1]35.369 mg NH3/L, R2 = 0.9912; [C2]51.628 mg NH3/L, R2 = 0.9883; [C3]79.494 mg NH3/L, R2 = 0.986; and [C4]215.225 mg NH3L, R2 = 0.9934. In the second assay, a 1920-L tank was stocked with 120 Nile tilapia, Oreochromis niloticus, with an initial weight 32.11 ± 7.6 g and a biomass of 3.8 kg. After 60 days, the tank and its contents were assessed to evaluate zootechnical parameters and physical–chemical parameters of water quality. From these results, a third assay was developed in which the biomass of fish was increased to challenge the recirculation system. The tank was stocked with 480 jundia Rhamdia quelen (initial weight 11.34 ± 2.4 g and biomass 5.4 kg) for 60 days. In both the tilapia and jundia assays, the fish were fed four times per day with a commercial diet of 35% crude protein and 42% crude protein, respectively, at 5% of each individual fish’s body weight. At the end of the zootechnical assays, the synthetic fibres used showed efficient biological support for bacterial growth, as confirmed by scanning electron microscopy. The fibres also demonstrated maintenance of the water quality, which allowed good fish growth in the recirculating aquaculture system, and the maintenance of up to 11.19 kg/m³ of biomass of fish.

Isopods from the family Cymothoidae are fish ectoparasites displaying low host specificity found commonly attached to the gills, mouth, opercular cavity, nostrils and body surface of several host species. Damage can vary according to the degree of parasitism and the infestation site and may provoke respiratory discomfort in hosts. The aim of this study was to report the occurrence of a Nerocila sp. Leach, 1818 isopod parasitizing Mugil liza Valenciennes, 1836 captured in the Babitonga Bay, Santa Catarina State, Brazil. The female parasite specimen was recovered from the pectoral fin of M. liza and was 24 mm in length and 11 mm in width, and the mean egg size was 1.18 ± 0.08 x 1.03 ± 0.06 mm. Isópodes da família Cymothoidae são ectoparasitos de peixes, com baixa especificidade de hospedeiros, comumente encontrados fixados nas brânquias, boca, cavidade opercular, narinas e tegumento de ampla variedade de hospedeiros. Os danos causados são variáveis em função do grau de parasitismo e do sítio de infestação e podem provocar desconforto respiratório nos hospedeiros. O objetivo deste estudo foi relatar a ocorrência do isópode Nerocila sp. Leach, 1818 parasitando Mugil liza Valenciennes, 1836, capturada na Baía da Babitonga, estado de Santa Catarina, Brasil. Uma fêmea de 24 mm de comprimento e 11 mm de largura, contendo ovos de 1.18 ± 0.08 x 1.03 ± 0.06 mm, foi encontrada na nadadeira peitoral de M. liza.

Nile tilapia (Oreochromis niloticus) is the most farmed freshwater fish in the world, however, disease outbreaks are the main cause of losses in production. Due to this, there is an increasing interest in natural products for enhancing disease resistance, without causing physiological impairment. The aim of this study was to verify the effect of the essential oils of clove basil (Ocimum gratissimum) and ginger (Zingiber officinale) on physiological and immunological parameters of nile tilapia. After 35 and 55 days of supplementation (0.5%, 1.0% and 1.5%), blood collection was performed for determination of metabolites (glucose, cholesterol, triglycerides, serum total protein and immunoglobulins) and lysozyme activity. Spleen tissue was also collected at 55 days for analyzing melanomacrophages centers. At 35 days, cholesterol showed significant reduction in the treatments 0.5% and 1.5 ginger and 1.5% clove basil. The serum triglycerides showed significant reduction in these same treatments, in addition to 1.0% clove basil. At 55 days all the supplemented groups showed significant reduction for both parameters. The lysozyme activity at 35 days was significantly higher in fish supplemented with 1.0% ginger and showed no difference among the treatments at 55 days. Regarding the melanomacrophage centers, at 35 days increased number in fish supplemented with 0.5% clove basil was observed but with no significant difference in the total percent area of spleen occupied by centers. The levels of glucose, total serum protein and immunoglobulins did not show significant differences in both sampling times. The addition of essential oils showed to be useful for improving physiological status of the fish, without excessive activation of defense mechanisms.