Metazoan parasites of Plagioscion squamosissimus, an invasive species in the Tietê River, São Paulo, Brazil / Parasitas metazoários de Plagioscion squamosissimus, uma espécie invasora no Rio Tietê, São Paulo

Abstract This study focused on the characterization and analysis of communities and infra-communities of metazoan parasites of Plagioscion squamosissimus caught in Promissão Reservoir in the Tietê River in Borborema (21°39′58"S, 49°8′49"W), state of São Paulo, Brazil. Fifty adult specimens caught by professional fishermen in March 2015 were necropsied. The fish presented an average standard length of 25.2 ± 2.2 cm and average weight of 328.82 ± 89.03 g. A total of 5,227 specimens of metazoan parasites were collected: 2,880 (55.1%) adult Diplectanum piscinarius (Monogenoidea: Diplectanidae) and 2,347 (44.9%) Austrodiplostomum compactum metacercariae (Digenea, Diplostomidae), both with 100% prevalence and mean abundance of 57.6 and 46.9, respectively. Parasite diversity was low (species richness = 2), with a Simpson index (D) equal to 0.505, and low values of Brillouin (HB = 0.687) and Margalef diversity (I = 0.117) indices. Berger-Parker's index of dominance (p = 0.551) indicated a slight dominance of the monogenean parasite D. piscinarius. There was a positive correlation, assessed by Pearson coefficient between parasite abundance of D. piscinarius and standard length (r = 0.43) and weight (r = 0.51) of hosts.

Resumo O objetivo deste trabalho foi caracterizar e analisar as comunidades e infracomunidades de metazoários parasitos de corvinas capturadas no Reservatório de Promissão, Rio Tietê, município de Borborema (21° 67′S, 49° 14′O), Estado de São Paulo. Foram examinados 50 espécimes, capturados por pescadores profissionais no mês de março de 2015, e os parasitas coletados foram quantificados, preparados e montados para identificação taxonômica e análise das comunidades de parasitos. Os peixes analisados no estudo apresentaram comprimento padrão médio de 25,2 ± 2,2 cm e peso médio de 328,82 ± 89,03 g. Foram coletados 5227 espécimes de parasitas metazoários, sendo 2880 (55,1%) Diplectanum piscinarius (Monogenoidea: Diplectanidae) e 2347 (44,9%) metacercárias de Austrodiplostomum compactum (Digenea, Diplostomidae), ambos com prevalência de 100% e abundância parasitária de 57,6 e 46,9, respectivamente. Foi encontrada baixa diversidade parasitária (riqueza de espécies=2), com índice de Simpson (D) igual a 0,505 e baixos valores dos índices de Shannon (H'=0,688) e de diversidade de Margalef (I=0,177). O índice de dominância de Berger-Parker (d=0,551) indicou uma leve dominância do monogenético D. piscinarius. Houve correlação positiva intermediária, avaliada pelo coeficiente de Pearson, entre a abundância parasitária de D. piscinarius e comprimento padrão (r=0,43) e peso (r=0,51) dos hospedeiros.

Bioaccumulation of heavy metals in some tissues of croaker fish from oil spilled rivers of Niger Delta region, Nigeria

Objective: To investigate the level of heavy metals (Cu, Zn, Fe Mn Ni, Pb and Cd) in muscles, gills and liver tissue of Croaker fish from oil spilled rivers of Bonny and Finima, Niger Delta region, Nigeria. Methods: Twenty four Croacker fishes (Genyonemus lineatus) weighing between 250 and 260 g and 24–26 cm length were collected from each sampling sites (Bonny and finima rivers). The frozen fishes were thawed and dried at 105 ℃ until they reach a constant weight. The dried samples were homogenized and digested with 10 ml tri-acid mixture (HNO3: HClO4:H2SO4), and then the digested samples were diluted to 100 ml with deionized water. Heavy metals (Cu, Ni, Zn, Pb, Mn, Iron Fe, and Cd) concentrations were determined by atomic absorption spectrophotometer. Results: Our results revealed that concentrations and distribution patterns of all heavy metals studied varied significantly (P < 0.05) amongst the fish tissues analyzed and sampling sites. Moreover, liver tissue of fish caught from Finima creek accumulated the highest concentrations of Cu (52.64 ± 3.01μg/g dry wt), Zn (166.50 ± 6.45μg/g dry wt) and Fe (801.50 ± 14.15μg/g dry wt) in comparison to the liver of fish caught from Bonny river in which the levels of Cu, Zn and Fe were (45.00 ± 2.79), (49.90 ± 2.91) and (216 ± 6.11μg/g dry wt), respectively. In addition, Mn, Ni, Pb and Cd exhibited their highest concentrations in gills from both locations. As expected, muscle tissue contained the least concentrations of all metals investigated from both sampling sites. Furthermore, all the metals investigated exhibited highest concentration in fish collected from Finima creek. These abnormal high level heavy metals accumulation observed in this location could be linked to the frequent crude oil spills as well as industrial activity around the area which might get discharged into Finima creek. In general, the mean concentrations of some toxic heavy metals investigated exceed the recommended maximum permissible limits set by the Joint FAO/WHO committee. However, some metals are within the acceptable limits. Conclusions: In conclusion, our data showed the abnormal higher concentration of these metals and this might be toxic to the fish and other aquatic organisms directly or by extension to humans that frequently consumed such contaminated fishes.

Bioaccumulation of heavy metals in some tissues of croaker fish from oil spilled rivers of Niger Delta region, Nigeria

Objective To investigate the level of heavy metals (Cu, Zn, Fe Mn Ni, Pb and Cd) in muscles, gills and liver tissue of Croaker fish from oil spilled rivers of Bonny and Finima, Niger Delta region, Nigeria. Methods Twenty four Croacker fishes (Genyonemus lineatus) weighing between 250 and 260 g and 24–26 cm length were collected from each sampling sites (Bonny and finima rivers). The frozen fishes were thawed and dried at 105 °C until they reach a constant weight. The dried samples were homogenized and digested with 10 ml tri-acid mixture (HNO

17,20 beta-P and cortisol are the main in vitro metabolites of 17-hydroxy-progesterone produced by spermiating testes of Micropogonias furnieri (Desmarest, 1823) (Perciformes Sciaenidae)

The aim was to investigate the major C21 steroids produced by spermiating white croaker Micropogonias furnieri (Sciaenidae) in order to establish the potential mediator of gamete maturation in males of this species. The testes steroid production at the spawning season was identified incubating the 3H-17-hydroxy-4-pregnene-3,20-dione precursor through thin layer chromatography, high pressure liquid chromatography, enzymatic oxydation, acetylation and immunochemistry analyses. 17,20β-Dihydroxy-4-pregnen-3-one (17,20β-P) and 11β,17,21-Trihydroxy-4-pregnene-3,20-dione (cortisol) were the main metabolites produced. Contrary to what we expected, 17,20β,21-Trihydroxy-4-pregnen-3-one was not detected. Circulating levels of 17,20β-P were undetectable in immature testes and in those at the first spermatogenesis stages, while a clear increase was observed during the whole spermatogenesis and spermiation phases (from undetectable to 1047 pg mL-1). In vitro studies together with plasma detection suggest that 17,20β-P is a good steroid candidate involved in M. furnieri testes maturation. The role of cortisol during late phases of testes development needs further studies.

El objetivo fue investigar cuales eran los esteroides C21 más importantes producidos por los testículos en espermiación de la corvina blanca Micropogonias furnieri (Sciaenidae) para poder identificar los potenciales mediadores de la maduración gamética de los machos de esta especie. Los esteroides producidos por los testículos en espermiación fueron identificados después de su incubación con el precursor 3H-17-hidroxi-4-pregnene-3,20-diona a través de cromatografía de capa fina y cromatografía líquida de alta presión y posteriormente por oxidación enzimática, acetilación e inmunoquímica. Los principales metabolitos producidos por los testículos en espermiación fueron la 17,20β-Dihidroxi-4-pregnen-3-ona (17,20β-P) y la 11β,17,21-Trihidroxi-4-pregnene-3,20-diona (cortisol). Contrariamente a lo esperado, no se encontró el derivado tri-hidroxilado de la progesterona llamado 17,20β,21-Trihidroxi-4-pregnen-3-ona. Los niveles circulantes de 17,20β-P fueron no detectable en los testículos inmaduros y en aquellos en inicios de espermatogénesis, mientras que un aumento claro en las concentraciones circulantes fue detectada en corvinas en plena espermatogénesis y en espermiación (desde no detectable a 1047 pg mL-1). Los resultados obtenidos in vitrojunto a los cambios a nivel plasmático sugieren que la 17,20β-P es un buen candidato a proponer como esteroide involucrado en la regulación del proceso de maduración testicular de la corvina. La función del cortisol a nivel testicular debería ser mejor estudiada en las etapas finales del desarrollo testicular de esta especie.

Hydrolysis of insoluble fish protein residue from whitemouth croaker (Micropogonias furnieri) by fungi

A significant amount of insoluble fibrous protein, in the form of feather, hair, scales, skin and others are available as co-products of agro industrial processing. These wastes are rich in keratin and collagen. This study evaluated different fungi for the hydrolysis of insoluble fish protein residues. Proteins resulting from Micropogonias furnieri wastes through pH-shifting process were dried and milled for fermentation for 96 h. This resulted the production of keratinolytic enzymes in the medium. Trichoderma sp. on alkaline substrate (28.99 U mL-1) and Penicillium sp. on acidic substrate (31.20 U mL-1) showed the highest proteolytic activities. Penicillium sp. showed the largest free amino acid solubilization (0.146 mg mL-1) and Fusarium sp. the highest protein solubilization (6.17 mg mL-1).

Método de índice de qualidade (QIM): desenvolvimento de um protocolo sensorial para corvina ( Micropogonias furnieri) / Quality Index Method (QIM): development of a sensorial scheme for whitemouth croaker ( Micropogonias furnieri)

Os métodos sensoriais são acurados e amplamente utilizados na avaliação do frescor de peixe. Esta pesquisa descreve o desenvolvimento de um protocolo sensorial para corvina (Micropogonias furnieri) baseado no Método de Índice de Qualidade (MIQ). O protocolo de Índice de Qualidade (IQ) pontuou atributos de aspecto geral, de olhos e de brânquias, além da cor do rim e da musculatura, cujo somatório variou de zero (máximo frescor) a 22 (limite de aceitabilidade). As contagens de bactérias atingiram o limite aceitável no 14o dia de estocagem a 0oC. O protocolo criado especificamente para a corvina eviscerada poderá ser empregado nos diversos segmentos como na comercialização, estocagem e processamento, reduzindo perdas econômicas e auxiliando na proteção da saúde do consumidor.

Sensory methods are the accurate and widely used methods to evaluate fish freshness. This paper describes the development of a sensorial scheme for whitemouth croaker (Micropogonias furnieri) based on Quality Index Method (QIM). The Quality Index protocol (QI) it punctuated attributes of general aspect, of eyes, of gills, besides the kidneys' and musculature's color, which sum varied from zero (maximum freshness) to 22 (acceptability limit). The counting of bacterial reached the accepted limit on the 14th day of storage at 0oC. The protocol specifically created for the gutted whitemouth croaker stored in ice can be used in several segments as commercialization, storage and processing, reducing economical losses and aiding in the protection of the consumer's health.