Centesimal composition and meat yield of Hoplias malabaricus: association with intestinal parasites / Composição centesimal e rendimento da carne de Hoplias malabaricus: associação com parasitos intestinais

Abstract Hoplias malabaricus is a non-migratory fish commonly found in the Mogi Guaçu River basin, mainly feeding on fish, small crustaceans and insects. It forms part of the diet for humans, birds and some mammals. This fish has great nutritional value, with both good quality and good quantities of essential vitamins and amino acids. Regarding parasitic fauna, this fish can host different species of helminths in its gastrointestinal tract. The aim of the present study was to investigate the possible interference of parasitism in the meat yield from H. malabaricus and the centesimal composition. For this purpose, fish specimens were collected from marginal lagoons of the Mogi Guaçu River (Pirassununga, state of São Paulo, Brazil) using hooks and fishing nets. We found that all specimens of H. malabaricus were parasitized by at least one species, including larvae of Contracaecum sp. (Nematoda: Anisakidae). Parasitism did not have any significant influence on centesimal composition, but meat yield was negatively correlated with the abundance of larvae.

Resumo Hoplias malabaricus é um peixe comumente encontrado na bacia do rio Mogi Guaçu. Não realiza migração e alimenta-se de peixes, pequenos crustáceos e insetos. Faz parte da dieta de seres humanos, aves e outros mamíferos piscívoros. Apresenta grande valor nutricional em relação à quantidade e à qualidade de vitaminas e aminoácidos essenciais. Em relação à fauna parasitária, este peixe pode albergar diferentes espécies de helmintos em seu trato gastrointestinal. O presente estudo teve como objetivo verificar a eventual interferência do parasitismo no rendimento e na composição centesimal da carne do pescado de H. malabaricus. Para isso, foram realizadas coletas por um ano, em lagoas marginais do rio Mogi Guaçu, Pirassununga, estado de São Paulo, Brasil, utilizando-se anzol e rede de espera. Como resultado, todos os exemplares de H. malabaricus estavam parasitados por, pelo menos, uma espécie de parasita, prevalecendo larvas de Contracaecum sp. (Nematoda: Anisakidae). O parasitismo não afetou a composição centesimal da carne do peixe, mas foi encontrada uma correlação negativa forte entre o rendimento da carne e o número de larvas de parasitos.

Comparación de consumo de pescado de río en ciudades costeras al río Paraná: Rosario y conglomerado Corrientes-Resistencia / Comparison of river fish consumption in cities overlooking the Parana river: Rosario and Corrientes - Resistencia conglomerate

Resumen El presente estudio tuvo como objetivo principal comparar el consumo de pescado de río entre las ciudades de Rosario y el conglomerado Corrientes y Resistencia (CCR). Se encuestaron un total de 508 adultos, seleccionados por un muestreo no probabilístico por conveniencia. Se indagó acerca del consumo de pescado de río, su frecuencia de consumo, especies más consumidas, lugar de adquisición y formas de preparación más utilizadas, mediante una encuesta dirigida con respuestas semiestructuradas. Los datos se procesaron con Microsoft Excel 2010 y EPI Info7. Los resultados indicaron que más del 78% de los participantes manifestaron consumir pescado, pero el número de quienes expresaron consumir pescado de río fue inferior. Se encontró diferencia significativa entre el porcentaje de participantes que declaró consumir pescado de río entre ambas ciudades estudiadas, con un mayor consumo de pescado de río en el CCR (p<0,05). Sólo el 19% de los habitantes del CCR y el 16% de los rosarinos consumen pescado de río semanalmente. En ambas áreas geográficas, el pescado de río se consume "porque les gusta" o "porque lo consideran saludable"; esta última opinión fue significativamente diferente y más importante en CCR (p<0,0001). Dentro de los motivos de rechazo al consumo, en ambas ciudades se encontró como principales causas la "falta de hábito", porque "no les gusta" o porque "producen olor al cocinar". Se encontraron diferencias significativas (p<0,0001) entre las especies más consumidas: en CCR fueron el surubí (73%), dorado (57%) y pacú (46%). Mientras que, en Rosario, fueron boga (62%), dorado (46%) y sábalo (20%). A pesar de ser el pescado de río un recurso disponible en las ciudades evaluadas, la frecuencia de consumo resultó ser baja. Es importante fomentar el consumo de pescado de río, haciendo más eficiente el aprovechamiento de un recurso local y promoviendo una alimentación variada y saludable en la población.

Abstract The main objective of this study was to compare the consumption of river fish between the cities of Rosario and Corrientes and Resistencia conglomerate (CRC). A total of 508 adults were surveyed, selected by non-probability convenience sampling. The consumption of river fish, its frequency of consumption, the most consumed species, the place of acquisition and the most used forms of preparation were investigated through a directed survey with semi-structured responses. The data was processed via Microsoft Excel 2010 and EPI Info7. Results indicated that more than 78% of the participants stated that they consumed fish; but the number of those who consumed river fish was lower. A significant difference was found between the percentage of participants who declared consuming river fish between both cities studied, with a higher consumption in the CRC (p <0.05). Only 19% of the inhabitants of the CRC and 16% of Rosario's residents consume river fish weekly. In both geographic areas, river fish is consumed because "they like it" or because "they consider it healthy"; this last opinion was significantly different and more important in CRC (p <0.0001). Among the reasons for rejection of consumption, in both cities the main causes were "lack of habit", because "they don't like it" or because "they produce smell when cooking". Significant differences (p <0.0001) were found among the most consumed species: in CRC they were surubí (73%), gold (57%) and pacu (46%), while in Rosario they were boga (62%), gold (46%) and shad (20%). Even though river fish is an available resource in the cities evaluated, the frequency of consumption turned out to be low. It is important to encourage the consumption of river fish, to make a local resource more efficient and promote a varied and healthy diet in the population.

Crecimiento del pez Plagioscion squamosissimus (Perciformes: Sciaenidae) según la inferencia de modelos múltiples en la cuenca del Orinoco medio, Venezuela / Growth of the fish Plagioscion squamosissimus (Perciformes: Sciaenidae) according to multiple models inference in the middle Orinoco basin, Venezuela

Introducción: El uso a priori del modelo de von Bertalanffy ha sido generalmente utilizado en el estudio del crecimiento en peces, sin considerar la existencia de otros modelos de crecimiento que pueden producir un mejor ajuste de los datos que se utilizan; considerándose como una mejor alternativa el uso de modelos múltiples de crecimiento, para seleccionar el que produzca un mejor ajuste. Objetivo: Ante la incertidumbre de los resultados obtenidos en un trabajo anterior sobre el crecimiento de Plagioscion squamosissimus (Heckel 1840) en la región del Orinoco medio en Venezuela, aplicando a priori el modelo de von Bertalanffy, los mismos datos fueron ajustados a otros modelos de crecimiento para entre ellos seleccionar el de mejor ajuste. Métodos: Los modelos evaluados fueron el U-von Bertalanffy, el U-Logístico y el U-Gompertz, derivados del modelo global U-Richards, entre los cuales se seleccionó el de mejor ajuste utilizando el Criterio de la Información de Akaike (AIC). Resultados: Contradiciendo el uso a priori del modelo de von Bertalanffy en el estudio anterior, el modelo que realmente produce un mejor ajuste de los datos usados fue el U-Gompertz. Conclusiones: Es necesario evaluar nuevamente el stock de P. squamosissimus en la región del Orinoco medio usando parámetros de crecimiento estimados a partir de una inferencia de modelos múltiples, para validar la información que se tiene en cuanto a la existencia de un recurso moderadamente explotado.

Introduction: The prior use of von Bertalanffy's model has been generally used in the study of fish growth, without considering the existence of other growth models that can produce a better adjustment of the data used; considering the use of multiple growth models as a better alternative, to select the one that produces a better adjustment. Objective: Due to uncertainty of the results obtained in a previous work on the growth of Plagioscion squamosissimus (Heckel 1840) in the middle Orinoco region in Venezuela, applying a priori the model of von Bertalanffy, the same data were adjusted to other models of growth to select the best adjustment. Methods: The models evaluated were the U-von Bertalanffy, the U-Logistics and the U-Gompertz, derived from the global U-Richards model, then the best adjustment was selected using the Akaike Information Criteria (AIC). Results: Contradicting the prior use of von Bertalanffy's model in the previous study, the model that actually produces a better adjustment of the data used was the U-Gompertz. Conclusions: It is necessary to evaluate the stock of P.squamosissimus in the middle Orinoco region using growth parameters estimated from an inference of multiple models, in order to validate the existing information of a moderately exploited resource.

Organophosphorous residue in Liza aurata and Cyprinus carpio

Objective:To determine the amount of azinphos methyl and diazinon residues in two river fishes, Liza aurata and Cyprinus carpio, in the north of Iran. Methods: This study was done during 2006-2007. In this survey, 152 water and fish samples from Gorgan and Qarasu rivers, north of Iran, were investigated. Sampling was done in three predetermined stations along each river. Organophosphorus compounds (OPs) were extracted from the fishes and the water of rivers. After extraction, purification and concentration processes, the amount and type of insecticides in water and fish samples were determined by high performance thin layer chromatography (HPTLC). Results:There was a significant difference in the residue of the insecticides in the water and fish samples between summer and other seasons in the two rivers. The highest amount of insecticides residue was seen during summer. In both rivers, the amount of diazinon and azinphos methyl residues in the two fishes was more than 2 000 mg/L in summer. There was no significant difference in insecticides residue between the fishes in two rivers. The diazinon residue was higher than the standard limits in both rivers during the spring and the summer, but the residual amount of azinphos methyl was higher than the standard limits only during the summer and only in Qarasu River. Conclusions:It can be concluded that the amount of OPs in the water and the two fishes, Liza aurata and Cyprinus carpio, is higher than the permitted levels.