ABSTRACT This study evaluated the dietary supplementation of ginger Zingiber officinale essential oil for the Neotropical catfish Pseudoplatystoma reticulatum, its effects on fish hematology, immunology, the response of these variables to induction of stress (exposition to air for 3 min), and a bacterial challenge with Aeromonas hydrophila, and the effects on liver histomorphometry. Three levels of the ginger essential oil were evaluated (0.5, 1.0 and 1.5%) in addition to a control group (0%) in a feeding trial for 65 days in triplicate. Fish hematology and immunology were assessed at five different moments: after the feeding trial (0), after the stress induction (stress), and three points after the bacterial challenge (3, 6 and 24 h post-challenge). Fish fed the ginger essential oil supplemented diets did not exhibit significant differences between the hematocrit at the 0-sample point and the 24 h post-challenge point (P ≥ 0.05), while fish fed the control diet presented significantly lower values for the hematocrit when comparing those same two moments (P < 0.05). The thrombocytes count for fish fed the 0.5% essential oil supplemented diet was significantly higher than all other groups after the feeding trial (P < 0.05), and their total leukocytes count after the stress induction was also significantly higher than the other treatments (P < 0.05). Although the results mentioned above indicate that the ginger essential oil had positive health effects on the fish, no significant differences in survival after the challenge with A. hydrophila were observed (P ≥ 0.05). Lastly, histomorphometry suggests that the essential oil did not negatively impact fish hepatocytes.

Objetivou-se avaliar o rendimento de carcaça de surubins Pseudoplatystoma spp. produzidos em tanque-rede e viveiro. Adotou-se o delineamento inteiramente casualizado, com dois tratamentos (tanque-rede e viveiro) e vinte repetições. Os surubins com peso total médio de 0,839 ± 0,181kg e 0,983 ± 0,108kg para tanque-rede e viveiro, respectivamente, foram sacrificados por choque térmico em gelo para determinação do: rendimento do peixe eviscerado com e sem cabeça (RPECC, RPESC); rendimento de brânquias (RB); rendimento do filé lateral com e sem pele (RFLCP, RFLSP); rendimento do filé abdominal com e sem pele (RFACP, RFASP); rendimento de cabeça (RC); rendimento de pele (RP); rendimento de resíduos (RR). Entre as variáveis estudadas foi verificada diferença estatística apenas para o RB, cujas médias foram de 3,79 ± 0,38% para produção em tanque-rede e 4,44 ± 0,47% para produção em viveiro. O RC do surubim representou 15,46 ± 0,97% e 15,83 ± 1,04% para a produção em tanque-rede e viveiro, respectivamente. Para RPECC os valores foram de 89,98 ± 1,06% para produção em tanque-rede e 89,40 ± 4,90% para produção em viveiro. Os valores de RFLSP e RFASP para produção em tanque-rede foram de 31,15 ± 1,78%; 9,01 ± 0,50% respectivamente, e para produção em viveiro foram de 30,14 ± 1,75%; 8,83 ± 0,51%. Surubins Pseudoplatystoma spp. produzidos em tanque-rede e viveiro apresentam rendimentos de carcaça semelhantes.

This study aimed to evaluate the carcass yield of surubins Pseudoplatystoma spp. produced in cage and fishponds. Adopted was a completely randomized design with two treatments (cages and fishponds) and twenty repetitions. The surubins with a total weight average 0.839 ± 0.181kg and 0.983 ± 0.108kg cages and fishponds respectively, were sacrificed by thermal shock on ice for determining: yields of eviscerated fish with and with no head (YEFWH; YFWNH); yield of gills (YG); yield of the lateral fillet with and with no skin (YLFWS; YLFWNS) yield of the abdominal fillet with and with no skin (YAFWS; YAFWNS), yield of head (YH), yield of skin (YS), yield of viscera (YV) yield of residues (YR). Data were submitted to analysis of variance and means were compared by Tukey test at 5%. Among the variables analyzed, there was a statistical difference only for YG, with averages of 3.79 ± 0.38% for production in cages and 4.44 ± 0.47% for production fishponds. The YH surubim represented 15.46 ± 0.97% and 15.83 ± 1.04% for production in cages and fishpond, respectively. For the eviscerated fish with head yield values were 89.98 ± 1.06% production in cages and 89.40 ± 4.90% for production in fishpond. The values of YLFWNS and YAFWNS production in cages were 31.15 ± 1.78%, 9.01 ± 0.50%, respectively, and for production in fishponds were 30.14 ± 1.75%; 8.83 ± 0.51%. Surubins Pseudoplatystoma spp. produced in cages and fishponds have carcass yield similar.

Realizou-se análise histológica de brânquias de 15 espécimes de Piaractus mesopotamicus e 19 Prochilodus lineatus coletados de abril a novembro de 2004, no Rio Aquidauana, MS, com intuito de contribuir com achados anatomopatológicos em brânquias dessas espécies de peixes de água doce. Amostras de brânquias foram fixadas em formalina 10%, tamponadas e processadas conforme rotina histológica. Em P. mesopotamicus observou-se presença de monogênea e cistos de mixosporídio da espécie Henneguya piaractus, com localização intralamelar em vários estágios de desenvolvimento, localizados em todas as regiões (basal, mediana ou distal) das lamelas. Cistos intraepiteliais causaram dilatação e deformação das lamelas vizinhas. Em brânquias de P. lineatus, observou-se presença de monogênea. Nas duas espécies de hospedeiro foram registradas hiperplasia do epitélio branquial e desorganização estrutural das lamelas em extensas regiões, alterações que causaram a fusão lamelar. Em poucos casos registrou-se presença de células inflamatórias mononucleares e focos hemorrágicos na região distal das lamelas.

A histological analysis was conducted on the gills of 15 Piaractus mesopotamicus and 19 Prochilodus lineatus specimens collected between April and November 2004 from the Aquidauana River, State of Mato Grosso do Sul, Central-West Brazil, to describe the anatomopathological characteristics of the gills of these freshwater fish. Gill samples were fixated in 10% buffered formalin and processed following histological routine procedures. The histological examination of the gills of P. mesopotamicus revealed intralamellar monogenean and mixosporean cysts of Henneguya piaractus at several developmental stages over the entire (basal, median and distal) lamella. Intraepithelial cysts caused lamella dilation and deformity of adjacent lamellae. In P. lineatus gills, monogenean cysts were detected. In both host species, hyperplasia of the gill epithelium and structural disorganization of secondary lamellae was seen diffusely in the gills, leading to fused lamellae in the gills. In few cases, there was found mononuclear inflammatory cells and hemorrhagic focal points distally in the lamellae.