ABSTRACT
The aim of this study was to determine the acute toxicity of the essential oils (EOs) of Aloysia triphylla, Lippia gracilis and Piper aduncum in juvenile tambaqui (Colossoma macropomum), and evaluate the possible histopathological alterations in their gills. For the acute toxicity tests, juvenile tambaqui (n=24/treatment) were distributed in six treatments with three replicates, which comprised the control and five EO concentrations of A. triphylla (60, 80, 100, 120 and 140 mg L-1), L. gracilis (35, 40, 45, 50 and 55 mg L-1) and P. aduncum (42.5, 45, 47.5, 50 and 52.5 mg L-1), with an exposure period of 4 h. The mortality rate and severity of damage to the tambaqui gills were proportional to the increase in the concentration of the EO, with LC50-4 h values estimated at 109.57 mg L -1 for A. triphylla, 41.63 mg L -1 for L. gracilis and 48.17 mg L -1 for P. aduncum. The main morphological damages observed in the gills of the tambaqui exposed to the three EOs, were Grade I: hypertrophy and hyperplasia of lamellar epithelial cells, lamellar fusion, epithelial detachment, capillary dilation and constriction, proliferation of chloride cells and mucosal cells and edema; in low frequency Grade II damage as epithelial rupture and lamellar aneurysm. Necrosis (Grade III damage) was observed only in gill lamellae exposed to P. aduncum EO (47.5, 50.0 and 52.5 mg L-1). Concentrations of EOs below LC50-4 h can be used sparingly, for short periods of exposure for the treatment of diseases in tambaqui breeding.
Subject(s)
Characiformes , Lippia , Oils, Volatile , Verbenaceae , Animals , Oils, Volatile/toxicity , Plant BreedingABSTRACT
Third-stage larvae (L3) of Hysterothylacium sp. were collected by the first time in juveniles of pirarucu Arapaima gigas farmed in the Rio Preto da Eva, Amazonas state. Ninety-eight (98) out of 100 examined fish showed to be parasitized. Five hundred and ninety larvae of Hysterothylacium sp. were collected from the intestines, stomach and pyloric caeca. The mean intensity of parasite indexes was 6.02 (±5.75) ranging from 1 to 40 larvae per host and the mean abundance was 5.9 (±5.76). The A. gigas is the new host record for larvae of Hysterothylacium sp. in Brazil, and this is the first record of larvae of Hysterothylacium (Nematoda: Anisakidae) with zoonotic potential in the pirarucu from South America.
Subject(s)
Ascaridoidea/physiology , Fishes/parasitology , Animals , Ascaridoidea/anatomy & histology , Ascaridoidea/growth & development , Brazil , Larva/anatomy & histology , Larva/growth & development , Larva/physiologyABSTRACT
Abstract Third-stage larvae (L3) of Hysterothylacium sp. were collected by the first time in juveniles of pirarucu Arapaima gigas farmed in the Rio Preto da Eva, Amazonas state. Ninety-eight (98) out of 100 examined fish showed to be parasitized. Five hundred and ninety larvae of Hysterothylacium sp. were collected from the intestines, stomach and pyloric caeca. The mean intensity of parasite indexes was 6.02 (±5.75) ranging from 1 to 40 larvae per host and the mean abundance was 5.9 (±5.76). The A. gigas is the new host record for larvae of Hysterothylacium sp. in Brazil, and this is the first record of larvae of Hysterothylacium (Nematoda: Anisakidae) with zoonotic potential in the pirarucu from South America.
Resumo Larvas de terceiro estágio (L3) de Hysterothylacium sp. foram coletadas pela primeira vez em juvenis de pirarucu Arapaima gigas cultivados no Rio Preto da Eva, Estado do Amazonas. Noventa e oito (98) dos 100 peixes examinados estavam parasitados. Quinhentos e noventa larvas de Hysterothylaciumsp.foram coletados no intestino, estômago e cecos pilóricos. O índice parasitário de intensidade média foi de 6,02 (±5,75) variando de 1 a 40 larvas por hospedeiro e o de abundância média foi de 5,9 (±5,76). A. Gigas é um novo registro de hospedeiro para larvas de Hysterothylacium sp. no Brasil, também sendo, o primeiro registro de larvas de Hysterothylacium sp. com potencial zoonótico em pirarucu da América do Sul.
