Seasonal variation on the ectoparasitic communities of Nile tilapia cultured in three regions in southern Brazil

A total of 240 Nile tilapia were examined between April 2007 and March 2008, gathered from three different fish farms, 20 fish in each fish farm, in the four seasons of the year. Fish ponds were located in Joinville, Blumenau and Ituporanga, Santa Catarina state, Brazil and each pond had a different culture system. Prevalence, mean intensity, mean abundance and mean relative dominance were compared among fish ponds and seasons. During this period, the water quality was kept in normal values. Piscinoodinium pillulare (Dinoflagellida) was the most dominant parasite followed by Trichodina magna e T. compacta (Ciliophora), Cichlydogyrus sclerosus, C halli, C. thurstonae, Scutogyrus longicornis (Monogenoidea), copepodids Lernaeidae gen. sp. The highest prevalence, mean intensity and mean abundance of ectoparasites were found on the body surface in fish from Joinville followed by Blumenau and Ituporanga. In the gills, the highest mean intensity and mean abundance were found in fish from Blumenau and Ituporanga in the winter. Piscinoodinium pillulare showed prevalence 100% during autumn in Blumenau and Ituporanga. In winter P. pillulare occurred in all study facilities. Fish from Joinville showed 100% prevalence of Monogenoidea during all seasons, as well as the highest mean intensity and abundance. The results showed that the majority of examined fish had higher infestations by protozoan during autumn and winter and higher infestations by metazoan have occurred in spring and summer

Seasonal variation on the ectoparasitic communities of Nile tilapia cultured in three regions in Southern Brazil

Abstract A total of 240 Nile tilapia were examined between April 2007 and March 2008, gathered from three different fish farms, 20 fish in each fish farm, in the four seasons of the year. Fish ponds were located in Joinville, Blumenau and Ituporanga, Santa Catarina state, Brazil and each pond had a different culture system. Prevalence, mean intensity, mean abundance and mean relative dominance were compared among fish ponds and seasons. During this period, the water quality was kept in normal values. Piscinoodinium pillulare (Dinoflagellida) was the most dominant parasite followed by Trichodina magna e T. compacta (Ciliophora), Cichlydogyrus sclerosus, C halli, C. thurstonae, Scutogyrus longicornis (Monogenoidea), copepodids Lernaeidae gen. sp. The highest prevalence, mean intensity and mean abundance of ectoparasites were found on the body surface in fish from Joinville followed by Blumenau and Ituporanga. In the gills, the highest mean intensity and mean abundance were found in fish from Blumenau and Ituporanga in the winter. Piscinoodinium pillulare showed prevalence 100% during autumn in Blumenau and Ituporanga. In winter P. pillulare occurred in all study facilities. Fish from Joinville showed 100% prevalence of Monogenoidea during all seasons, as well as the highest mean intensity and abundance. The results showed that the majority of examined fish had higher infestations by protozoan during autumn and winter and higher infestations by metazoan have occurred in spring and summer. Keywords: Oreochromis niloticus, ectoparasites, seasonality, Brazil. Variação sazonal na comunidade de ectoparasitos de tilápia do Nilo cultivada em três regiões no sul do Brasil Resumo Um total de 240 tilápias-do-nilo foi examinado entre abril de 2007 e março de 2008, a partir de três diferentes localidades em quatro estações, 20 de cada piscicultura. As pisciculturas estavam localizadas em Joinville, Blumenau e Ituporanga, Estado de Santa Catarina, Brasil. Taxa de prevalência, intensidade média, abundância média e dominância média relativa foram comparadas entre as pisciculturas e entre as estações. Durante esse período, a qualidade da água se manteve em valores normais para tilápia. Piscinoodinium pillulare (Dinoflagellida) foi o mais dominante seguido por Trichodina magna e Trichodina compacta (Ciliophora), Cichlydogyrus sclerosus, Cichlydogyrus halli, Cichlydogyrus thurstonae, Scutogyrus longicornis (Monogenoidea), copepoditos Lernaeidae gen. sp. Os maiores valores de taxa de prevalência, intensidade média e abundância média de ectoparasitos foram encontrados na superfície do corpo de peixes de Joinville, seguidos pelos de Blumenau e Ituporanga. Nas brânquias, as maiores intensidades e abundâncias médias foram encontradas em peixes de Blumenau e Ituporanga examinados no inverno. Piscinoodinium pillulare apresentou prevalência de 100% no outono em Blumenau e Ituporanga. No inverno, a prevalência de P. pillulare ocorreu também em todas as pisciculturas. Peixes de Joinville apresentaram prevalência de 100% de Monogenoidea em todas as estações, assim como as maiores intensidades e abundâncias médias. Os resultados mostraram que a maioria dos peixes examinados apresentaram maiores infestações por protozoários no outono e inverno, e metazoários na primavera e no verão. Palavras-chave: Oreochromis niloticus, ectoparasitos, sazonalidade, Brasil

Acute inflammation and hematological response in Nile tilapia fed supplemented diet with natural extracts of propolis and Aloe barbadensis

This study evaluated the acute inflammatory response induced by carrageenin in the swim bladder of Nile tilapia supplemented with the mixture of natural extracts of propolis and Aloe barbadensis (1:1) at a concentration of 0.5%, 1% and 2% in diet during 15 days. Thirty-six fish were distributed into four treatments with three replicates: fish supplemented with 0.5% of admix of extracts of propolis and Aloe (1:1) injected with 500 µg carrageenin; fish supplemented with 1% of admix of extracts of propolis and Aloe (1:1) injected with 500 µg carrageenin; fish supplemented with 2% of admix of extracts of propolis and Aloe (1:1), injected with 500 µg carrageenin and unsupplemented fish injected with 500 µg carrageenin. Six hours after injection, samples of blood and exudate from the swim bladder of fish were collected. It was observed an increase in the leukocyte count in the swim bladder exudate of fish supplemented with extracts of propolis and Aloe injected with carrageenin. The most frequent cells were macrophages followed by granular leukocytes, thrombocytes and lymphocytes. Supplementation with propolis and Aloe to 0.5% caused a significant increase in the number of cells on the inflammatory focus mainly macrophages, cells responsible for the phagocytic activity in tissues, agent of innate fish immune response

Haematological and histopathological analysis in South American fish Piaractus mesopotamicus parasitized by monogenean (Dactylogyridae)

Monogeneans are the parasites mostly found on the body surface and gills of fish and can cause large losses in farmed fish. Some studies demonstrate elevated parasitic levels causing hematological alterations. But few of them relate the effects of parasitism on the hematology and histopathology of native freshwater farmed fish. This study evaluated the host-parasite relationship in pacu (Piaractus mesopotamicus) parasitized by the monogenean Anacanthorus penilabiatus. Hematological and parasitological assessments were obtained in 60 fish captured in a fish farm located in Dourados, State of Mato Grosso do Sul, Central Brazil. Fish were analyzed in different categories of parasite number: class I (n=13; 0-200 parasites), class II (n=17; 201-1200 parasites); class III (n=7; 1201-2200 parasites); and class IV (n=23; more than 2200 parasites per host). The highest levels of parasitism caused significant decrease (p<0.05) in the hematocrit, red blood cells (RBC), mean hemoglobin concentration (MCHC) and basophils number. Thrombocytes, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), monocytes, eosinophils, neutrophils and LG-PAS did not present significant difference among the parasitic levels. In contrast, increased number of total leukocytes and lymphocytes were found in highly-parasitized fish. A positive linear correlation (p<0.01) was found between the amount of parasites and fish weight. Histopathology revealed severe hyperplasia, sub-epithelial edema, fusion of the secondary lamellae, focal and multifocal necrosis in highly parasitized fish

Parasite fauna of wild and cultured dusky-grouper Epinephelus marginatus (Lowe, 1834) from Ubatuba, Southeastern Brazil

This study aimed at identifying and quantifying the parasites of wild and cultured dusky grouper Epinephelus marginatus. During a year and thereby all four seasons, 20 wild and 20 cultured groupers were examined for the presence of parasites, except in the last season, in which 19 wild and 20 cultured fish were examined, totalling 159 groupers analysed from Ubatuba, southeastern Brazil. Prevalence, mean intensity of infection, mean abundance and mean relative dominance were calculated. Five species of parasites were identified in fish from both origins: Pseudorhabdosynochus beverleyburtonae (Monogenea), Neobenedenia melleni (Monogenea), Pseudempleurosoma sp. (Monogenea), Helicometrina nimia (Digenea) and larvae of Contracaecum sp. (Nematoda). The prevalence of ectoparasites, in most cases, was higher than endoparasites. The most abundant parasite was the monogenea Pseudorhabdosynochus beverleyburtonae in both wild and cultured fish, along all seasons. Neobenedenia melleni was observed in wild and cultured fish in all seasons, with a gradual increase in the number of parasites from the coldest to the hottest seasons, with the highest prevalence and mean intensity in the summer. Helicometrina nimia was found in all seasons in both wild and cultured fish, except for summer, where its presence was detected only in wild fish. Pseudempleurosoma sp. and larvae of Contracaecum sp. showed low prevalence occurring in wild and cultured fish in the autumn and spring, respectively. This study revealed high intensities of potentially pathogenic parasites that could favour disease outbreaks in culture conditions