LD5o of the bacteria Aeromonas hydrophila to matrinxã, Brycon amazonicus

Acta Amazonica

Sarah Ragonha De Oliveira²  Rondon Tatsuta Yamane Baptista De Souza¹  Elenice Martins Brasil¹  Jaqueline Inês Alves De Andrade¹  Érica Da Silva Santiago Nunes¹  Eduardo Akifumi Ono¹  Elizabeth Gusmão Affonso¹ 

[1] ,Instituto Federal de Educação, Ciência e Tecnologia do Amazonas - IFAM

关键词: Aeromonas hydrophila;    96-h LD50;    matrinxã;    tropical fishes;    Aeromonas hydrophila;    DL50 96-h;    matrinxã;    peixes tropicais;   

DOI  :  10.1590/S0044-59672011000200019

来源: SciELO

【 摘 要 】

In order to determine the lethal dose (96-h LD50) of the bacteria Aeromonas hydrophila to matrinxã, Brycon amazonicus, to be applied in challenge tests, 90 fish (63.23 ± 6.39 g) were divided into five treatments, with different bacterial solutions: T1 - Control (0.9% NaCl saline solution); T2 (4 x 10(11) cells/ mL); T3 (5 x 10(11) cells/ mL); T4 (1.36 x 10(12) cells/ mL) and T5 (3.06 x 10(12) cells/ mL). Fish were previously anesthetized with benzocaine (60 mg L-1), inoculated in the peritoneal cavity with the bacterial suspensions and then distributed into fifteen 80-L test chambers, where the water variables were monitored and fish mortality was observed. The experiment was randomly designed in three replicates and the 96-h LD50 was estimated according to the trimmed Spearman-Karber method. Water quality variables remained within adequate ranges for fish health and performance. Fish mortality rate increased with the bacterial concentrations of A. hydrophila (T1 = 0%; T2 = 16.66%; T3 = 44.44%; T4 = 72.22% and T5 = 100%), and the first mortalities were observed after 57 h, although the signs of the bacterial infection were already observed 24 h after the inoculation. The results indicate that the 96-h LD50 value of A. hydrophila to matrinxã is 6.66 x 10(11) cells/ mL.

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