Haematological and parasitological assessment of silver catfish Rhamdia quelen farmed in Southern Brazil

Abstract

This study evaluated for two years the haematological parameters and the occurrence of gill parasites in silver catfish Rhamdia quelen, farmed in the state of Santa Catarina, southern Brazil. Between March 2010 and January 2012, a total of 137 fish were caught in a fish farm to compare the haematological and parasitological analysis, during hot and cold seasons. Simultaneously, water quality parameters were measured in the pond to analyze the relationship between environmental conditions and haematology and parasitism. During the hot season, there was an increase in water temperature, electrical conductivity and ammonia followed by a decrease in dissolved oxygen, pH, transparency and alkalinity. Two species of Monogenea were observed in the gills, Aphanoblastella mastigatus (Dactylogyridae) and Scleroductus sp. (Gyrodactylidae). Additionally, during this season, there was a significant increase (p<0.05) in the mean intensity of infection by Monogenea, as well as total leukocytes number, thrombocytes and lymphocytes, and a reduction in monocytes. The changes might be caused by parasitism and/or environmental variations between seasons.Keywords: Siluriformes, parasitology, gills, haematology, blood, seasons. ResumoO presente estudo avaliou, durante dois anos, os parâmetros hematológicos e a ocorrência de parasitos branquiais em jundiá Rhamdia quelen, cultivado no Estado de Santa Catarina, Sul do Brasil. Entre março de 2010 e janeiro de 2012, um total de 137 jundiás foi coletado de uma piscicultura para comparar os parâmetros hematológicos e parasitológicos durante as estações quente e fria. Simultaneamente, foram medidos os parâmetros de qualidade da água do viveiro, para relacionar as condições ambientais com a hematologia e o parasitismo. Na estação quente, houve aumento da temperatura, condutividade elétrica e amônia, e redução do oxigênio dissolvido, pH, transparência e alcalinidade. Duas espécies de Monogenea foram observadas nas brânquias, Aphanoblastella mastigatus (Dactylogyridae) e Scleroductus sp. (Gyrodactylidae). Na estação quente, houve aumento significativo (p<0,05) da intensidade média de infecção por Monogenea, bem como dos valores de leucócitos totais, trombócitos e linfócitos, e redução significativa dos monócitos. As diferenças observadas podem ter sido causadas pelas variações ambientais entre as estações.

Fator de condição e hematologia de tilápias-do-nilo de policultivo com camarão em água salobra

“…The values of total leukocytes were also similar to those of Nile tilapia also farmed in Santa Catarina state, during growth phase (Jerônimo et al, 2011a). The amount of leukocytes in the blood is indicative of immunological capacity and can be influenced by environmental factors (Figueredo et al, 2014), which explains the similarity of results for fish cultured in the same region.…”

Antibacterial potential of phytochemicals alone or in combination with antimicrobials against fish pathogenic bacteria

“…Silver catfish is the most farmed native species of fish in South Brazil, presenting a good adaptation to different environments and artificial diets, resistance to handling and good commercial acceptance (Baldisserotto 2009;Figueredo et al 2014). The majority of the diseases reported in silver catfish farms are related to bacterial pathogens; among these, bacteria of the genus Aeromonas are the most frequently reported micro-organisms (Baldisserotto and Rad€ unz Neto 2004; Barcellos et al 2008).…”

Hematological and biometric traits of tuvira Gymnotus inaequilabiatus (Valenciennes, 1839) (Gymnotiformes: Gymnotidae) from the Brazilian Pantanal

“…In brazilian teleosts, this cell is commonly described in the peripheral blood , Tavares-Dias 2006, Ranzani-Paiva et al 2013, mainly in fish affected by parasites (TavaresDias and Moraes 2004, Ranzani-Paiva et al 2013, Campos et al 2014. However, the percentages of some leukocytic forms were more variable than in others studies (Tavares-Dias et al 2002, RanzaniPaiva et al 1999, Pádua et al 2012, Figueiredo et al 2014. These differences are difficult to explain due to the variability of biotic and abiotic factors associated with these fish communities.…”