Prevalence of ectoparasites and bacteriological diagnosis in Nile tilapia bred in net-tanks in the Corvo’s river, Paraná, Brazil

Autor: Ricardo Hideo Mori, Renata Alari Chedid, Graciela Lucca Braccini, Carlos Antonio Lopes de Oliveira, Lucienne Garcia Pretto-Giordano, Lauro Vargas
Jazyk: English<br />Portuguese
Rok vydání: 2015
Předmět:
Zdroj: Semina: Ciências Agrárias, Vol 36, Iss 2, Pp 1145-1154 (2015)
Druh dokumentu: article
ISSN: 1679-0359
1676-546X
DOI: 10.5433/1679-0359.2015v36n2p1145
Popis: Predominance of ectoparasites and bacteria diagnosis were identified in Nile tilapia (Oreochromis niloticus), GIFT strain, bred in net-tanks at different densities. Current experiment was performed in the Corvo’s river, State of Paraná, Brazil, in two cycles: cycle A installed in August 2010 with 155 days, and cycle B, installed in February 2011 with 128 days. Twenty 6.8 m-3 (2.0 x 2.0 x 1.7 m) net-tanks were employed, using 6.0 m-3 and five densities (150, 175, 200, 225 and 250 fish/m-3), with four replications each. No significant difference was registered with regard to the prevalence of ectoparasites due to densities in the two experimental cycles. In the months of September to November cycle A displayed increase in the predominance of Trichodina and a decrease in the prevalence of Monogenoidea and mixed parasites. Further, an inverse relationship with a decrease in the prevalence of Trichodina and an increase in the prevalence of Monogenoidea and mixed parasites occurred during October and November. Trochodina prevalence occurred in October and November. Cycle B showed a significant difference in total prevalence of ectoparasites due to months. There was an increase in tricodinid infestation between March and June in proportion to increase of density and throughout the experiment. More care should be taken with regard to densities during the period. No positive result was registered in the diagnosis of bacteria in Nile tilapias in the two cycles. The above was perhaps due to the water quality standards for the species and the cleanliness of the net-tanks for the experiments. Density increase did not affect the prevalence of ectoparasites and influenced tricodinid infestation between March and June.
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