ABSTRACT. Oreochromis niloticus (Nile tilapia) is one of the most produced fish for human consumption globally; however, these fish are susceptible to exposure to toxic chemicals in the water. Pyriproxyfen is a pesticide widely used to control mosquitoes in drinking water supplies and pests in crops. The present study aimed to examine pyriproxyfen's effects on fish O. niloticus fingerlings exposed using an acute 96 h and subchronic tests for 28 days. The lethal concentration LC50−96 h for O. niloticus was 2.77 mg L−1, no observed effect concentration (NOEC), and the lowest observed effect concentration (LOEC) was 1.0 and 2.5 mg L−1, respectively. The hepatic catalase activity was significantly changed after exposure to pyriproxyfen above 0.4 mg L−1. Pyriproxyfen also induced histopathological lesions in the hepatic tissue at 28 days in a dose-dependent pattern at concentrations above 0.4 mg L−1. Pyriproxyfen above 1.2 mg L−1 reduced the locomotor behavior, distance traveled inside the tank, mean speed, and angular variation. This pesticide also decreased weight gain, food conversion, and specific growth rate at concentrations above 1.2 mg L−1. In conclusion, exposure to pyriproxyfen in water from 0.4 mg L−1 may impair O. niloticus development; consequently, pyriproxyfen may affect this fish's production and quality at higher concentrations than commonly used in water (0.01 mg L−1).

Resumo Um levantamento histopatológico foi realizado para pesquisar a presença de microparasitas, no peixe Archosargus probatocephalus, em um rio próximo a Maceió, Brasil. Observações ao microscópio óptico de fragmentos de brânquias mostraram a presença de pequenos cistos contendo numerosos mixósporos, identificados morfologicamente como Henneguya. Ocasionalmente, na microscopia eletrônica de transmissão, foram observados vários corpos citoplasmáticos de inclusão, grupo aparentemente de células procarióticas que vivem dentro de um grande vacúolo citoplasmático de algumas células branquiais. As células hospedeiras infectadas tinham um único vacúolo contendo um número variável de células do tipo Rickettsia, até 11, algumas das quais em forma do haltere, característica da fissão binária. Essas células eram pleomórficas sem núcleo, tendo a cromatina dispersa no citoplasma e possuíam uma parede densa de elétrons finos do tipo Gram-negativo. A morfologia dessas células procarióticas foi semelhante àquelas da ordem Rickettsiales e foram descritas como organismos tipo Rickettsiae. A histopatologia mostra várias membranas de vacúolos circundantes com aspetos lisados, enquanto outras apresentam rupturas que mostram contato direto do organismos tipo Rickettsiae com o citoplasma da célula hospedeira. A ruptura do epitélio branquial pode ter contribuído para a redução da superfície das brânquias, mas não é possível afirmar que foi a causa da morte do hospedeiro.

Abstract A histopathological survey was conducted to investigate the presence of microparasites in fish Archosargus probatocephalus in a river near Maceió, Brazil. Light microscope observations of fragments of gill showed the presence of small cysts containing numerous myxospores that were morphologically identified as Henneguya. Transmission electron microscopy observations further revealed several gill cells containing groups of prokaryotic cells within large cytoplasmic vacuoles. Each infected host cell displayed a single vacuole containing a variable number of Rickettsia-like cells (up to 11), some of which presented the dumbbell shape characteristic of binary fission. The Rickettsia-like cells were pleomorphic, without a nucleus and with chromatin dispersed in the cytoplasm. They had a thin electron-dense wall of Gram-negative type. The morphology of these prokaryotic was similar to those of the order Rickettsiales and was described as a Rickettsia-like organism. Histopathological evaluation showed that several vacuole membranes had a lysed appearance. Some had ruptured, thus allowing direct contact between the Rickettsia-like organism and the cytoplasm of the host cell. The rupturing of the branchial epithelium may have contributed towards reduction of the surface area of the gills, but it is not possible to say that this was the cause of the host’s death.

Resumo Este trabalho descreve a morfologia ultraestrutural detalhada do fagócito encarcerando um oocisto de Nematopsis (Apicomplexa) encontrado em Crassostrea rhizophorae, na cidade de Maceió (AL), Brasil. Os hospedeiros muito infectados apresentavam valvas entreabertas com retração fraca e lenta dos músculos abdutores. Número variável de oócitos de forma elipsoide, isolados e ou agrupados foi encontrado entre as miofibrilas do músculo abdutor. Cada oocisto estava encarcerado num vacúolo parasitóforo do fagócito uninucleado do hospedeiro. Os oocistos eram compostos por uma parede densa contendo um esporozoíto vermiforme uninucleado. A parede dos oocistos finos era composta de material electron-lucente homogêneo formado por três camadas de espessura igual, possuindo um orifício circular - micrópila, obstruída pelo opérculo. Os oocistos apresentavam morfologia elipsoide, sua parede era circundada por uma complexa rede de numerosas microfibrilas. Detalhes de valor taxonômico importantes foram visualizados tais como: a organização ultraestrutural da parede do oocisto e a organização da micrópila e do opérculo, além das microfibrilas que se projetam da parede do oocisto, estrutura apenas observada em microscopia eletrônica de transmissão (MET) e que pode auxiliar na identificação da espécie. Contudo, para esclarecer a posição sistemática da maioria das espécies relatadas do gênero Nematopsis é importante prosseguir com as análises genéticas.

Abstract This work describes the detailed ultrastructural morphology of the phagocyte imprisoning an oyster of Nematopsis (Apicomplexa) found in Crassostrea rhizophorae, in the city of Maceió (AL), Brazil. The highly infected hosts had half-open leaflets with weak, slow retraction of the adductor muscles. Variable number of ellipsoid oocytes, either isolated and or clustered, was found between myofibrils of the adductor muscle. Each oocyst was incarcerated in a parasitophorous vacuole of host uninucleated phagocyte. The oocysts were composed of a dense wall containing a uninucleate vermiform sporozoite. The wall of the fine oocysts was composed of homogeneous electron-lucent material formed by three layers of equal thickness, having a circular orifice-micropyle obstructed by the operculum. The oocysts presented ellipsoid morphology with their wall was surrounded by a complex network of numerous microfibrils. Important details of the taxonomic value were visualized such as the ultrastructural organization of the oocyst wall and the organization of the micropyle and operculum, beyond the microfibrils that protrude from the oocyst wall only observed by transmission electron microscopy (TEM) and that may aid in the identification of the species. However, in order to clarify the systematic position of the species reported of the genus Nematopsis, it is important to proceed with genetic analyses.

ABSTRACT Polyculture systems are integrated cultivation systems where two or more aquatic species are maintained at the same place using locally available ecological resources. The purpose of this study was to analyze the zootechnical performance of curimatã-pacu (Prochilodus argenteus) when polyculture with canela shrimps (Macrobrachium acanthurus) and with dehydrated cassava leaf bran comparatively with monoculture. 96 curimatã-pacu fishes (P. argenteus) and 72 canela shrimps (M. acanthurus) were cultivated. At the beginning of the experiment, their average body masses were 10.77 ± 1.29 and 3.68 ± 0.74 g, respectively, randomly distributed in a factorial scheme with a full random experimental design in 24 polyethylene water tanks (70 L) in water recirculation system, comprising two simultaneous factors: curimatã pacu monoculture (4 fishes: 0 shrimps per tank) and curimatã pacu and canela shrimp polyculture (4 fishes: 6 shrimps per tank), was added dehydrated cassava leaf meal (DCLM) to the monocultures and polycultures in different percentages: 0% (treatment 1, T1), 10% (T2) and 20% (T3), with four replicas each. The results indicated that presence of shrimps and the higher concentration of DCLM (20%) had a negative impact on the fish development regarding final total biomass (BF), absolute growth rate (AGR), and feed conversion rate (FCR). However, the diet with the addition of up to 10% DCLM in P. argenteus in monoculture systems, obtained a zootechnical performance similar to control, thereby reducing the feed costs for this species.

Foram realizados dois experimentos, sendo o primeiro de digestibilidade das rações e o segundo de desempenho na tentativa de avaliar o farelo do resíduo de abacaxi nas dietas para tilápia do Nilo. Foram utilizados para o ensaio de digestibilidade 80 animais com peso de 63,9 ± 0,79g, em um delineamento experimental inteiramente casualizado, com o objetivo de avaliar o coeficiente de digestibilidade aparente da matéria seca, proteína bruta, energia bruta, energia digestível e proteína digestível. No experimento de desempenho foram utilizados 240 juvenis, distribuídos em três faixas de pesos: 34,9 ± 0,06; 44,4 ± 0,27 e 55,5 ± 0,10 g, com o objetivo de avaliar desempenho produtivo, rendimento de carcaça e índices somáticos da tilápia do Nilo. O delineamento utilizado foi em blocos casualizados com três blocos, com quatro tratamentos e cinco repetições, As rações em ambos os experimentos continham quatro níveis de inclusão do farelo de resíduo de abacaxi (0, 5, 10 e 15%). Os coeficientes de digestibilidade das rações foram: matéria seca (76,17; 75,42; 75,31 e 75,77%), proteína bruta (87,90; 90,24; 89,51 e 89,03%), energia bruta (79,12; 79,33; 79,07 e 77,48%), energia digestível (3649, 3559, 3560 e 3190 kcal kg-1) e proteína digestível (29,28; 30,35; 29,82 e 29,79%), respectivamente. Foi observado o efeito significativo sobre o rendimento de carcaça sem cabeça, recomenda-se, então, a inclusão de até 10,39% de inclusão do farelo de resíduo de abacaxi nas rações de tilápia do Nilo.

Two experiments were conducted, the first being the digestibility of feed and the second performance in an attempt to evaluate the residue of pineapple bran in diets for Nile tilapia. Eighty animals weighing 63.9 ± 0.79 g in a completely randomized design were used to test the digestibility in order to evaluate the apparent digestibility of dry matter, crude protein, gross energy, digestible energy and digestible protein. In the performance of 240 juveniles were distributed in three ranges of weights: 34.9 ± 0.06, 44.4 ± 0.27 and 55.5 ± 0.10 g, in order to evaluate performance, yield Housing and somatic indices of Nile tilapia. The design was a randomized block with three blocks, with four treatments and five repetitions, rations in both experiments contained four levels of inclusion of pineapple bran residue (0, 5, 10 and 15%). The digestibility of the diets were: dry matter (76.17, 75.42, 75.31 and 75.77%), crude protein (87.90, 90.24, 89.51 and 89.03%) gross energy (79.12, 79.33, 79.07 and 77.48%), digestible energy (3649, 3559, 3560 and 3190 kcal kg-1) and digestible protein (29.28, 30.35, 29.82 and 29.79%), respectively. It was observed the significant effect on the carcass without head, so we recommend the inclusion of up to 10.39% for the inclusion of pineapple bran residue in diets of Nile tilapia.