Characterization and finding the origin of off-flavor compounds in Nile tilapia cultured in net cages in hydroelectric reservoirs, São Paulo State, Brazil.

An increasing demand for fish products has led to an intensive aquaculture production in Brazil, and cultivation of fish constituted 860 × 103 tons in 2022, contributing to the 87% of total fish consumption. Nile tilapia constitutes almost half of the aquaculture production, and most tilapia farms use floating net cages. One of the major constraints of intensive fish production is production of off-flavors. Release of nutrients by the fish leads to deterioration of the water quality and stimulates growth of microorganisms, also including off-flavor producing species. The objective of this study was to determine levels of taste and odor compounds (geosmin, 2-MIB and a selection of volatile compounds) and their impact on the flavor quality of Nile tilapia produced in net cages in reservoirs in São Paulo State, Brazil. GC-MS analysis of fish and water from six different farms showed concentrations of geosmin in the water from 1 to 8 ng/L, while geosmin in fish flesh ranged from 40 to 750 ng/kg. The level of 2-MIB in water was 2 to 25 ng/L, and 0 to 800 ng/kg fish. The GC-MS analysis also revealed presence of more than 100 volatile organic compounds in the fish flesh, consisting of aldehydes, alcohols, benzene derivatives, hydrocarbons, ketones and few other compounds. Geosmin and 2-MIB related flavor notes were detected in all fish by a sensory panel, and a high correlation between the chemical and sensory analyses was found. The potential impact of the volatile organic compounds on the fish flavor is discussed. Analysis of the water quality in the reservoirs indicated that levels of geosmin and 2-MIB levels were highly influenced by the nutrient levels in the water.

Influence of Seasonality and Culture Stage of Farmed Nile Tilapia (Oreochromis niloticus) with Monogenean Parasitic Infection.

The aim of this study was to observe how abiotic and biotic factors in a tropical region influence the rate of monogenean parasitism in Nile tilapia (Oreochromis niloticus) that are farmed in net cages. A total of 240 sexually reversed fish were analyzed, and 20 from each culture stage were collected during each sampling month. Overall, 60 fish were sampled in April (autumn), 60 in August (winter), 60 in November (spring), and 60 in February (summer). Fish were collected from a commercial fish farm located in Capivara Reservoir in the lower Paranapanema River region of Paraná, Brazil. In total, 3290 monogenean parasites were collected from fish gills of the following species: Cichlidogyrushalli, C. thurstonae, Scutogyruslongicornis, C. cirratus, C. sclerosus, and C. tilapiae. Higher parasitological indices were observed in colder seasons with lower precipitation. Autumn had the highest parasitic infection values compared to the other seasons. The occurrence of monogenean parasites showed a negative correlation with season, in contrast to the culture stage, in which there was a positive correlation. These results may provide a means for establishing adequate fish farm management to predict periods of high monogenean infestation.

Performance, physical egg quality, and economic index of laying hens under different rearing systems / Desempenho, qualidade do ovo e índice econômico de poedeiras em diferentes sistemas de criação

The objective was to evaluate the performance, physical egg quality (weight and gravity), and economic index of laying hens reared in cage and cage-free systems. A total of 312 40-week-old Hy-line brown laying hens were distributed in a fully randomized design, split into two treatments (cage-free and cage) with 12 replicates in each system. We housed 144 birds in galvanized-wire cages (12 birds each) and 168 birds in a cage-free system in boxes with wood shaving bedding (14 birds each). The experiment lasted 112 days and divided into four 28-day periods. Regarding performance, feed intake (g) and feed conversion (g/g) of birds reared in the cage-free system were higher (p<0.0001) than the cage system, but no differences were observed (p>0.05) for the other performance parameters and also for egg quality. As for economic index, egg production in the cage-free system was higher (p<0.0001) than the cage system. In conclusion, birds reared in the cage-free system have higher feed consumption but worse feed conversion, increasing egg production cost compared to caged birds; however, there are no changes in egg production and physical quality.(AU)

Objetivou-se avaliar o desempenho, qualidade de ovos e índice econômico de poedeiras semipesadas criadas em sistemas cage-free e em gaiolas. Foram utilizadas 312 poedeiras da linhagem Hy Line Brown, com 40 semanas de idade, distribuídas em um delineamento inteiramente casualisado (DIC), em dois tratamentos (cage-free e gaiolas) com 12 repetições em cada sistema, sendo 144 aves alojadas em gaiolas de arame galvanizado com 12 aves em cada gaiola e 168 aves alojadas em sistema cage-free, em boxes sobre cama de maravalha com 14 aves em cada repetição. O experimento teve duração de 112 dias, divididos em quatro períodos de 28 dias. Nos parâmetros de desempenho, o consumo de ração (g/aves/dia) e a conversão alimentar (g/g) foi maior (P<0,0001) nas aves criadas no sistema cage-free comparado ao sistema de gaiolas, não sendo observado diferença (P>0,05) nos demais parâmetros de desempenho e também na qualidade de ovos. No índice econômico, a produção de ovos em sistema cage-free apresentou maior valor (P<0,0001) em relação ao sistema de gaiola. Conclui-se que as aves criadas em sistema cage-free apresentam maior consumo de ração, pior conversão alimentar ocasionando um maior custo nos ovos em relação às aves criadas em gaiolas, no entanto não há alteração na produção e qualidade dos ovos.(AU)

Comparative assessment of metazoans infestation of Nile tilapia (Oreochromis niloticus) (L.) (Perciformes: Cichlidae) in floating cages and ponds from Chiapas, Mexico.

Nile tilapia is the most commercially important fish in Chiapas as well as in other parts of the world. An understanding of parasite infection dynamics in tilapia may assist in applying proper prophylactic measures for reducing the loss of fish caused by parasitic diseases. Different environments and culture systems may imply different infection dynamics; therefore, the present study identified and compared the infection parameters (prevalence, mean abundance, and intensity) of parasites of Oreochromis niloticus cultured in floating cages and ponds. A total of 18 metazoan parasite taxa were recovered from gills, skin, fins and intestines of 310 specimens from floating cages and ponds. Fourteen species of parasites were found in floating cages: 8 monogenean species, 1 nematode, 1 digenea, 1 crustacea, 3 protozoans. In ponds, 16 parasite taxa were reported: 11 were monogeneans species, 4 protozoans and 1 crustacean. In both systems, monogeneans (Cichlidogyrus sclerosus, C. tilapiae, Gyrodactylus cichlidarum) and protozoans (Trichodina compacta) were most prevalent. Tilapia in ponds sustained higher parasitic infections than those in floating cages (p < 0.05). The Canonical Correspondence Analysis showed two groups: the first grouped the ponds, associated with high values of nitrite, nitrate, ammonia, conductivity, temperature, and the abundance of the ectoparasites C. halli, C. dossoui, Scutogyrus longicornis, C. sclerosus and T. compacta. The second group grouped the cages, associated with Clinostomum marginatum, Apiosoma piscicola, Lernea sp., and Contracaecum sp. and a high dissolved oxygen concentration. Our findings suggest that monitoring programs are required to improve the sanitary conditions of tilapia cultures in Chiapas.

Advances in the Structural Strategies of the Self-Assembly of Photoresponsive Supramolecular Systems.

Photosensitive supramolecular systems have garnered attention due to their potential to catalyze highly specific tasks through structural changes triggered by a light stimulus. The tunability of their chemical structure and charge transfer properties provides opportunities for designing and developing smart materials for multidisciplinary applications. This review focuses on the approaches reported in the literature for tailoring properties of the photosensitive supramolecular systems, including MOFs, MOPs, and HOFs. We discuss relevant aspects regarding their chemical structure, action mechanisms, design principles, applications, and future perspectives.

Phytase Supplementation under Commercially Intensive Rearing Conditions: Impacts on Nile Tilapia Growth Performance and Nutrient Digestibility.

This study evaluated the effects of phytase supplementation on growth performance and apparent digestibility of Nile tilapia (Oreochromis niloticus) in a commercial fish farm setting. Nile tilapia (6300 male, 57.48 ± 1.04 g) were randomly stocked into 42 floating cages. The experimental design was completely randomized, comprising six treatments and seven replications. Fish were fed five phosphorus deficient plant-based diets with graded levels of phytase supplementation (0, 500, 1000, 1500, 2000 UF kg-1) and an additional diet containing phosphorus supplementation to meet the requirement of this fish species (positive control). After 97 days of feeding, growth performance data were collected and 900 fish (500 ± 10 g) were relocated to 6 floating cages for the digestibility assessment. Quadratic polynomial regression analysis indicated 1537.5 and 1593.2 UF kg-1 as the optimum dietary levels for daily weight gain and feed conversion rate, respectively. Including 2000 UF kg-1 resulted in the higher dry matter, crude protein, energy, and ash apparent digestibility coefficient values. Therefore, phytase supplementation from 1500 to 2000 UF kg-1 is recommended to enhance growth performance and nutrient bioavailability of Nile tilapia reared according to industry practices.

Capture of Fullerenes in Cages and Rings by Forming Metal-π Bond Arene Interactions.

Nowadays, the task of the selectively capture of fullerene molecules from soot is the subject of several studies. The low solubility of fullerenes represents a drawback when the goal is to purify them and to carry out chemical procedures where they participate. There are different molecules that can act as a kind of cocoon, giving shelter to the fullerene cages in such a way that they can be included in a solution or can be extracted from a mix. In this work, a theoretical study of some known and new proposed organic molecules of this kind is presented. In all cases, the interaction occurs with the help of a metallic atom or ion which plays the role of a bridge, providing a place for a metallocene like interaction to occur. The thermodynamic arguments favoring the formation of this adduct species are addressed as well as the nature of the bond by means QTAIM parameters and frontier molecular orbitals analysis.

SO2 Capture Using Porous Organic Cages.

We report the first experimental investigation of porous organic cages (POCs) for the demanding challenge of SO2 capture. Three structurally related N-containing cage molecular materials were studied. An imine-functionalized POC (CC3) showed modest and reversible SO2 capture, while a secondary-amine POC (RCC3) exhibited high but irreversible SO2 capture. A tertiary amine POC (6FT-RCC3) demonstrated very high SO2 capture (13.78 mmol g-1 ; 16.4 SO2 molecules per cage) combined with excellent reversibility for at least 50 adsorption-desorption cycles. The adsorption behavior was investigated by FTIR spectroscopy, 13 C CP-MAS NMR experiments, and computational calculations.

New Species of Rhabdosynochus Mizelle and Blatz 1941 (Monogenoidea: Diplectanidae) From the Gills of the Cultured Centropomus viridis (Perciformes) in the Mexican Eastern Tropical Pacific.

PURPOSE: There are currently nine monogenoidean species of Rhabdosynochus infecting the gill lamellae of wild and cultured centropomid fishes from tropical and subtropical waters of the western Atlantic and eastern Pacific Oceans. The purpose of the present study was to describe the morphological distinctiveness of two new species of Rhabdosynochus found on the cultured Centropomus viridis collected from floating cages from the Mexican eastern Tropical Pacific in 2018. METHODS: monogenoideans were fixed with 4-5% formalin solution, observed and measured as temporary or permanent mounts stained with Gomori's trichrome, and mounted in Canada balsam. Other specimens were mounted on slides using a mixture of lactic acid (LA) and glycerin-ammonium picrate (GAP) and then remounted in Canada balsam to obtain measurements of the haptoral structures and copulatory complex. Illustrations were prepared with the aid of a drawing tube using a Leica microscope DM 2500 with Nomarski interference contrast. RESULTS: Rhabdosynochus viridisi n. sp. is mainly differentiated from all other congeneric species in the shape and size of their copulatory complexes, i.e., length 75-105 µm vs. 45-55 µm in R. alterinstitus, 26-44 µm in R. volucris, 19-22 µm in R. lituparvus, 21-37 µm in R. siliquaus, 48-75 µm in R. hargisi, 37-44 µm in R. hudsoni and 44-61 µm in R. guanduensis. Rhabdosynochus pacificus n. sp. differs from all other species of the genus in having an accessory piece (one subunit) distally twisted. CONCLUSIONS: Based on the morphometric differences of the two new species described above, the number of valid species of Rhabdosynochus has now increased to 11. These two new species of Rhabdosynochus represent the first described species of the genus on C. viridis.

Attractiveness and Sexual Competitiveness of Anastrepha obliqua Males (Diptera: Tephritidae) Fed on a Diet Enriched With Providencia rettgeri.

The West Indian fruit fly, Anastrepha obliqua (Macquart), is the second most important tephritid fruit fly in Mexico, infesting mango, hog plum and guava fruits. To control this pest, the Mexican government has implemented the use of the sterile insect technique (SIT), which involves the mass production, sterilization and release of flies. However, the A. obliqua laboratory males used in SIT are selected to a lesser extent by the wild females during competitiveness tests. The objective of this study was to compare the effects of males fed on fruit fly food enriched with Providencia rettgeri to those in males fed on food alone, assessing male mating competitiveness, capture of females using traps baited with males fed with the enriched diet and sex pheromone components. The results indicated that males fed with the diet enriched with P. rettgeri had increased mating competitiveness and captured more females in the field cage tests. However, no difference was observed in the proportion of volatile sex pheromone components identified during the calling of A. obliqua males. The results suggest the value of incorporating bacteria into the mass rearing technique of A. obliqua adults in order to improve the sexual competitiveness of males from the laboratory compared to wild males.

Isolation and characterization of pathology in case of massive mortality by Photobacterium damselae subsp. piscicida in Rachycentron canadum / Isolamento e caracterização da patologia em caso de mortalidade maciça por Photobacterium damselae subsp. piscicida em Rachycentron canadum

This study aimed to investigate outbreak with high mortality in cultured juvenile cobiaoccurred in Southeast Brazil in 2011. Fish displayed retarded growth rates, lethargy, fin ulceration, skin depigmentation, corneal opacity, and physical deformities. Internally, livers were increased in volume and pale in different degrees. Firm whitish nodules were disseminated in the liver, kidney and spleen. A moderate number of parasites identified as Neobenedenia melleni were recovered from the body surface. Microscopically, severe hepatic steatosis and extensive granulomatous lesion were identified in all fish sampled. Microbiological analysis of moribund fish revealed the presence in pure culture of a Gram-negative bacterium identified as Photobacterium damselae subsp. piscicida using biochemical and molecular characteristics. Analysis of the partial 16S rRNA sequences confirmed the results demonstrating high identity (98%). The isolates were sensitive to chloramphenicol and enrofloxacin and resistant to ciprofloxacin, florfenicol, doxycycline hydrochloride, norfloxacin, oxytetracycline, and tetracycline. Chronic pasteurellosis was considered as the main problem in the farm, while hepatic steatosis and parasitic infestation may have contributed to the development of the process.

Este estudo objetivou investigar um surto com alta mortalidade em cobia juvenis cultivadas na região Sudeste do Brasil em 2011. Os peixes apresentavam baixa taxa de crescimento, letargia, ulceração nas nadadeiras, despigmentação da pele, opacidade da córnea e deformidades físicas. Internamente o fígado apresentava aumentado e pálido em diferentes graus, com nódulos esbranquiçados e firmes disseminados no fígado, rins e baço. Na superfície corporal dos peixes foram observados moderado número de parasitas identificados como Neobenedenia melleni. Microscopicamente verificou-se esteatose hepática grave e extensa lesão granulomatosa em todos os peixes amostrados. A análise microbiológica dos peixes moribundos revelou a presença, em cultura pura de uma bactéria Gram-negativa identificada como Photobacterium damselae subsp. piscicida usando características bioquímicas e moleculares. A análise das sequências parciais de 16S rRNA confirmou os resultados demonstrando alta identidade (98%). Os isolados foram sensíveis a cloranfenicol e enrofloxacina e resistente a ciprofloxacina, florfenicol, cloridrato de doxiciclina, norfloxacina, oxitetraciclina e tetraciclina. A pasteurelose crônica foi considerada como o principal problema na maricultura, enquanto a esteatose hepática e a infestação parasitária podem ter contribuído para o desenvolvimento do processo.

Production performance of cachara and hybrid cachapinta / Desempenho produtivo do cachara e híbrido cachapinta

This study aimed to compare the growth performance of surubins (cachara Pseudoplatystoma reticulatum and hybrid cachapinta P. reticulatum × Pseudoplatystoma corruscans) produced in cages. The experiment had a randomized design with two treatments and three replicates, with one cage comprising an experimental unit, i.e., six cages in total. Fingerlings of the two genetic groups(cachara and hybrid cachapinta) were fed twice a day with extruded feed for carnivorous fishes. After 216 days of production, the growth parameters were evaluated, including total length, final weight, final biomass, biomass gain, survival, and apparent feed conversion values. No differences were found between cachara and cachapinta in the variables analyzed. In conclusion, cachara and cachapinta produced in cages exhibit the same growth performances.

Objetivou-se comparar o desempenho zootécnico do cachara, Pseudoplatystoma reticulatum, e do híbrido cachapinta, P. reticulatum × Pseudoplatystoma corruscans, produzidos em tanques-rede. Utilizou-se o delineamento inteiramente casualizado com dois tratamentos e três repetições, sendo que cada tanque-rede foi considerado uma unidade experimental, totalizando seis tanques-rede. Alevinos dos dois grupos genéticos (cachara e cachapinta) foram alimentados duas vezes ao dia com ração extrusada para peixes carnívoros. Após 216 dias de produção, os parâmetros zootécnicos avaliados foram: comprimento total, peso final, biomassa final, ganho de biomassa, sobrevivência e conversão alimentar aparente. Não foram encontradas diferenças significativas para as variáveis analisadas entre cachara e cachapinta. Pode-se concluir que o cachara e cachapinta produzidos em tanque-rede apresentam o mesmo desempenho zootécnico.

Production performance of cachara and hybrid cachapinta / Desempenho produtivo do cachara e híbrido cachapinta

This study aimed to compare the growth performance of surubins (cachara Pseudoplatystoma reticulatum and hybrid cachapinta P. reticulatum × Pseudoplatystoma corruscans) produced in cages. The experiment had a randomized design with two treatments and three replicates, with one cage comprising an experimental unit, i.e., six cages in total. Fingerlings of the two genetic groups(cachara and hybrid cachapinta) were fed twice a day with extruded feed for carnivorous fishes. After 216 days of production, the growth parameters were evaluated, including total length, final weight, final biomass, biomass gain, survival, and apparent feed conversion values. No differences were found between cachara and cachapinta in the variables analyzed. In conclusion, cachara and cachapinta produced in cages exhibit the same growth performances.(AU)

Objetivou-se comparar o desempenho zootécnico do cachara, Pseudoplatystoma reticulatum, e do híbrido cachapinta, P. reticulatum × Pseudoplatystoma corruscans, produzidos em tanques-rede. Utilizou-se o delineamento inteiramente casualizado com dois tratamentos e três repetições, sendo que cada tanque-rede foi considerado uma unidade experimental, totalizando seis tanques-rede. Alevinos dos dois grupos genéticos (cachara e cachapinta) foram alimentados duas vezes ao dia com ração extrusada para peixes carnívoros. Após 216 dias de produção, os parâmetros zootécnicos avaliados foram: comprimento total, peso final, biomassa final, ganho de biomassa, sobrevivência e conversão alimentar aparente. Não foram encontradas diferenças significativas para as variáveis analisadas entre cachara e cachapinta. Pode-se concluir que o cachara e cachapinta produzidos em tanque-rede apresentam o mesmo desempenho zootécnico.(AU)

Evolución de las cajas de polyetheretherketone (PEEK). Estudio clínico y radiológico / Évolution des cages en polyétheréthercétone (PEEK). Étude clinique et radiologique / Evolution of polyetheretherketone (PEEK) boxes. Clinical and radiological study

Introducción: las cajas cervicales son implantes desarrollados como una alternativa a la utilización del injerto óseo estructural para la fusión cervical anterior. El objetivo de este estudio fue analizar la clínica y los resultados radiológicos en una serie de pacientes sometidos a disectomía y descompresión cervical anterior, a los que se les implantó una caja PEEK. Método: estudio retrospectivo, descriptivo, longitudinal de una serie de 78 pacientes incluidos en el estudio desde el año 2007 al 2013. El control radiológico incluyó radiografía anteroposterior y lateral. El seguimiento clínico y radiológico de los pacientes se llevó a cabo desde los 3 meses hasta los 12 meses. Resultados: 65 pacientes tuvieron una evolución clínica favorable (83,3 por ciento) y la evolución radiológica confirmó que 66 pacientes (84,6 por ciento) tenían una buena colocación del injerto, sin lesiones en espacios adyacentes con una fusión correcta. Conclusiones: hasta la fecha hay pocos estudios descriptivos sobre el implante de las cajas PEEK, los resultados mostrados en este trabajo están acordes a los publicados con anterioridad en este mismo campo, lo que da validez al trabajo presentado. Este estudio confirma los buenos resultados clínicos y radiológicos de pacientes a los que se les implantó una caja PEEK; se muestra su eficacia en la discectomía cervical anterior y artrodesis(AU)

Introduction: Cervical cases are implants developed as an alternative to the use of structural bone graft for anterior cervical fusion. The objective of this study was to analyze the clinical and radiological results in a series of patients submitted to anterior cervical dissectomy and decompression, to whom a PEEK box was implanted. Method: A retrospective, descriptive, longitudinal study was conducted in a series of 78 patients included in the study from 2007 to 2013. Radiological control included anteroposterior and lateral radiographies. Clinical and radiological follow-up of these patients was carried out from 3 months to 12 months. Results: 65 patients had a favorable clinical course (83.3 percent) and the radiological evolution confirmed that 66 patients (84.6 percent) had a good placement of the graft without lesions in adjacent spaces with a correct fusion. Conclusions: To date there are few descriptive studies on the implantation of PEEK boxes. This paper results are in line with those published previously in this same field, which legitimate the presented work. This study confirms the good clinical and radiological results in patients who were implanted with a PEEK box; its effectiveness in anterior cervical discectomy and arthrodesis is shown(AU)

Introduction: Les cages cervicales sont des implants développés comme alternative de la greffe osseuse structurelle pour la fusion cervicale antérieure. Le but de cette étude est d'analyser la technique et les résultats radiologiques dans une série de patients traités par discectomie et décompression cervicale antérieure, et implantation d'une cage PEEK. Méthodes: Étude rétrospective, descriptive et longitudinale d'une série de 78 patients inclus dans une étude depuis l'année 2007 jusqu'à l'année 2013. L'étude radiologique a compris des clichés en position antéro-postérieure et latérale. Le suivi clinique et radiologique des patients a pris de 3 à 12 mois. Résultats: L'évolution clinique a été satisfaisante chez 65 patients (83,3 pourcent), tandis que l'étude radiologique a confirmé que le greffon était bien placé, il n'y avait pas de lésions dans les espaces adjacentes, et la fusion était correcte chez 66 patients (84,6 pourcent). Conclusions: Jusqu'à maintenant, il y a peu d'études descriptives abordant l'implantation des cages PEEK. Le présent travail est validé, car ses résultats sont en concordance avec les travaux publiés auparavant dans ce domaine. Cette étude confirme les bons résultats obtenus chez les patients ayant subi l'implantation d'une cage PEEK ; son efficacité est démontrée dans la discectomie cervicale antérieure et l'arthrodèse(AU)

Economic analysis of Deuterodon iguape cultured in Nile tilapia ponds / Análise econômica de Deuterodon iguape cultivado em viveiros de tilápia-do-nilo

Polyculture systems can promote greater economic efficiency with decreased use of inputs, making the activity more sustainable. The aim of this study was to evaluate the economic feasibility to grow-out lambari (Deuterodon iguape) in cages installed in Nile tilapia (Oreochromis niloticus) ponds. We calculated operational costs and determined the Internal Rate of Return (IRR), Net Present Value (NPV) and the Pay Back Period (PBP) to assess the economic viability of the investment. In a ten-year horizon, the largest positive NPV obtained was $ 83,082.55 for the sale price of $ 0.09 unit-1 of lambari and $ 2.11 kg-1 of Nile tilapia. Under these conditions, the IRR was 61% and PBP was 1.58 years, considered a low risk result due to the speed of the return on invested capital. A simulation of increase the prices of commercial diets shows that the polyculture system can be economic unfeasible if the farmer cannot access the market of live baits for lambari. The polyculture system is economic feasible, even assuming an annual loss of production, considering selling lambari as live baits.

Sistemas de policultivo podem promover maior eficiência econômica com redução do uso de insumos, tornando a atividade mais sustentável. O objetivo deste estudo foi avaliar a viabilidade econômica para criação de lambari (Deuterodon iguape) em tanques-rede instalados em viveiros de tilápia-do-nilo (Oreochromis niloticus). Foi calculado o custo operacional e determinada a Taxa Interna de Retorno (TIR), o Valor Presente Líquido (VPL) e o Período de Retorno do Capital Investido (PRC) para avaliar a viabilidade econômica do investimento. Em um horizonte de dez anos, o maior VPL positivo obtido foi de US$ 83.082,55 para o preço de venda de US$ 0,09 unidade-1 de lambari e US$ 2,11 kg-1 de tilápia-do-nilo. Sob essas condições, a TIR foi de 61% e o PRC foi de 1,58 anos, considerado um resultado de baixo risco devido à velocidade do retorno sobre o capital investido. O sistema de policultivo é economicamente viável, mesmo assumindo uma perda anual de produção, considerando a comercialização de lambaris como iscas vivas.

Economic analysis of Deuterodon iguape cultured in Nile tilapia ponds / Análise econômica de Deuterodon iguape cultivado em viveiros de tilápia-do-nilo

Polyculture systems can promote greater economic efficiency with decreased use of inputs, making the activity more sustainable. The aim of this study was to evaluate the economic feasibility to grow-out lambari (Deuterodon iguape) in cages installed in Nile tilapia (Oreochromis niloticus) ponds. We calculated operational costs and determined the Internal Rate of Return (IRR), Net Present Value (NPV) and the Pay Back Period (PBP) to assess the economic viability of the investment. In a ten-year horizon, the largest positive NPV obtained was $ 83,082.55 for the sale price of $ 0.09 unit-1 of lambari and $ 2.11 kg-1 of Nile tilapia. Under these conditions, the IRR was 61% and PBP was 1.58 years, considered a low risk result due to the speed of the return on invested capital. A simulation of increase the prices of commercial diets shows that the polyculture system can be economic unfeasible if the farmer cannot access the market of live baits for lambari. The polyculture system is economic feasible, even assuming an annual loss of production, considering selling lambari as live baits.(AU)

Sistemas de policultivo podem promover maior eficiência econômica com redução do uso de insumos, tornando a atividade mais sustentável. O objetivo deste estudo foi avaliar a viabilidade econômica para criação de lambari (Deuterodon iguape) em tanques-rede instalados em viveiros de tilápia-do-nilo (Oreochromis niloticus). Foi calculado o custo operacional e determinada a Taxa Interna de Retorno (TIR), o Valor Presente Líquido (VPL) e o Período de Retorno do Capital Investido (PRC) para avaliar a viabilidade econômica do investimento. Em um horizonte de dez anos, o maior VPL positivo obtido foi de US$ 83.082,55 para o preço de venda de US$ 0,09 unidade-1 de lambari e US$ 2,11 kg-1 de tilápia-do-nilo. Sob essas condições, a TIR foi de 61% e o PRC foi de 1,58 anos, considerado um resultado de baixo risco devido à velocidade do retorno sobre o capital investido. O sistema de policultivo é economicamente viável, mesmo assumindo uma perda anual de produção, considerando a comercialização de lambaris como iscas vivas.(AU)

New approaches for growth improvement in pejerrey Odontesthes bonariensis (Valenciennes, 1835) culture (Atherinomorpha: Atherinopsidae)

The pejerrey is the most important recreational species in shallow temperate lakes and reservoirs of Argentina and the attempts to develop its culture have started a century ago. A common constraint of pejerrey aquaculture is its poor growth under traditional intensive rearing techniques. The aim of this study was to evaluate the possibility to achieve and maintain high growth rates of pejerrey throughout the rearing process by semi-intensive culture method . Four floating cages were installed in La Salada de Monasterio Lake and each one was stocked with 300 juveniles (10.22 ±0.38cm; 6.52 ±0.82g). From January through March all fish were exposed to natural zooplankton as food source, whereas from April to September two cages were supplied daily with artificial food. The fish exposed to artificial supplementary diets exhibited significantly higher growth (17.5 ±0.98cm; 41.05 ±8.55g) than those in the control cages (15.02 ±0cm ; 23.5 ±0.84g), and exceeded the known values in pejerrey culture. The results suggest that the species potential growth is not fully achieved by common intensive methods and it can be improved by semi-intensive techniques. Accordingly a better understanding of the species nutritional requirements is needed to improve growth rates and enhance pejerrey culture.

El pejerrey es la especie de mayor importancia deportiva en lagos someros templados y embalses de Argentina y el desarrollo de su acuicultura data de cien años atrás. Un impedimento común para el desarrollo de la acuicultura del pejerrey es el pobre crecimiento que manifiesta bajo cultivo intensivo. El objetivo de este estudio fue evaluar la posibilidad de alcanzar y mantener altas tasas de crecimiento en el pejerrrey mediante cultivo semi-intensivo. Se instalaron cuatro jaulas flotantes en la laguna La Salada de Monasterio, sembrándose cada una con 300 juveniles (10.22 ±0.38cm; 6.52 ±0.82g). Desde enero hasta marzo los peces se alimentaron con el zooplancton natural de la laguna, mientras que desde abril hasta septiembre dos jaulas fueron suplementadas diariamente con alimento balanceado, dejándose las otras dos como controles. Los peces bajo dietas suplementadas mostraron crecimientos significativamente superiores (17.5 ±0.98cm; 41.05 ±8.55g) a los de las jaulas control (15.02 ±0cm ; 23.5 ±0.84g), excediendo incluso los conocidos en el cultivo de pejerrey en períodos similares. Los resultados obtenidos sugieren que el potencial de crecimiento del pejerrey no está siendo explotado en su totalidad bajo las técnicas de cultivo tradicionales y puede mejorarse mediante el cultivo semi-intensivo. En consecuencia es necesaria una mejor comprensión de los requerimientos nutricionales del pejerrey para incrementar sus tasas de crecimiento y así mejorar su cultivo.

New approaches for growth improvement in pejerrey Odontesthes bonariensis (Valenciennes, 1835) culture (Atherinomorpha: Atherinopsidae)

The pejerrey is the most important recreational species in shallow temperate lakes and reservoirs of Argentina and the attempts to develop its culture have started a century ago. A common constraint of pejerrey aquaculture is its poor growth under traditional intensive rearing techniques. The aim of this study was to evaluate the possibility to achieve and maintain high growth rates of pejerrey throughout the rearing process by semi-intensive culture method . Four floating cages were installed in La Salada de Monasterio Lake and each one was stocked with 300 juveniles (10.22 ±0.38cm; 6.52 ±0.82g). From January through March all fish were exposed to natural zooplankton as food source, whereas from April to September two cages were supplied daily with artificial food. The fish exposed to artificial supplementary diets exhibited significantly higher growth (17.5 ±0.98cm; 41.05 ±8.55g) than those in the control cages (15.02 ±0cm ; 23.5 ±0.84g), and exceeded the known values in pejerrey culture. The results suggest that the species potential growth is not fully achieved by common intensive methods and it can be improved by semi-intensive techniques. Accordingly a better understanding of the species nutritional requirements is needed to improve growth rates and enhance pejerrey culture.(AU)

El pejerrey es la especie de mayor importancia deportiva en lagos someros templados y embalses de Argentina y el desarrollo de su acuicultura data de cien años atrás. Un impedimento común para el desarrollo de la acuicultura del pejerrey es el pobre crecimiento que manifiesta bajo cultivo intensivo. El objetivo de este estudio fue evaluar la posibilidad de alcanzar y mantener altas tasas de crecimiento en el pejerrrey mediante cultivo semi-intensivo. Se instalaron cuatro jaulas flotantes en la laguna La Salada de Monasterio, sembrándose cada una con 300 juveniles (10.22 ±0.38cm; 6.52 ±0.82g). Desde enero hasta marzo los peces se alimentaron con el zooplancton natural de la laguna, mientras que desde abril hasta septiembre dos jaulas fueron suplementadas diariamente con alimento balanceado, dejándose las otras dos como controles. Los peces bajo dietas suplementadas mostraron crecimientos significativamente superiores (17.5 ±0.98cm; 41.05 ±8.55g) a los de las jaulas control (15.02 ±0cm ; 23.5 ±0.84g), excediendo incluso los conocidos en el cultivo de pejerrey en períodos similares. Los resultados obtenidos sugieren que el potencial de crecimiento del pejerrey no está siendo explotado en su totalidad bajo las técnicas de cultivo tradicionales y puede mejorarse mediante el cultivo semi-intensivo. En consecuencia es necesaria una mejor comprensión de los requerimientos nutricionales del pejerrey para incrementar sus tasas de crecimiento y así mejorar su cultivo.(AU)

Evaluating mating compatibility within fruit fly cryptic species complexes and the potential role of sex pheromones in pre-mating isolation.

The study of sexual behavior and the identification of the signals involved in mate recognition between con-specifics are key components that can shed some light, as part of an integrative taxonomic approach, in delimitating species within species complexes. In the Tephritidae family several species complexes have received particular attention as they include important agricultural pests such as the Ceratitis fasciventris (Bezzi), Ceratitis anonae (Graham) and Ceratitis rosa Karsch (FAR) complex, the Bactrocera dorsalis (Hendel) complex and the Anastrepha fraterculus (Wiedemann) complex. Here the value and usefulness of a methodology that uses walk-in field cages with host trees to assess, under semi-natural conditions, mating compatibility within these complexes is reviewed, and the same methodology to study the role of chemical communication in pre-mating isolation among Anastrepha fraterculus populations is used. Results showed that under the same experimental conditions it was possible to distinguish an entire range of different outcomes: from full mating compatibility among some populations to complete assortative mating among others. The effectiveness of the methodology in contributing to defining species limits was shown in two species complexes: Anastrepha fraterculus and Bactrocera dorsalis, and in the case of the latter the synonymization of several established species was published. We conclude that walk-in field cages constitute a powerful tool to measure mating compatibility, which is also useful to determine the role of chemical signals in species recognition. Overall, this experimental approach provides a good source of information about reproductive boundaries to delimit species. However, it needs to be applied as part of an integrative taxonomic approach that simultaneously assesses cytogenetic, molecular, physiological and morphological traits in order to reach more robust species delimitations.

Bioacumulação de metais pesados em tilápia do nilo e retenção no solo e sedimento dos viveiros com adição de probióticos na dieta / Ioaccumulation of heavy metals in nile tilapia and concentrations in soil and sediment of the ponds with addition of the probiotics in the diet

O trabalho objetivou monitorar a bioacumulação de Cd, Pb e Cr na tilápia do Nilo e retenção no sedimento da caixa de coleta e no solo de viveiros com administração de probióticos na ração. A dieta foi composta de ração comercial peletizada, para alevinos e probióticos liofilizados incluídos na dieta utilizando 2% de óleo vegetal, constituindo de: ração isenta de probióticos (Isento); ração + 0,5% de B. cereus var. Toyoi (ração + B. cereus); ração + 0,5% de B. subtilis C-3102 (ração + B. subtilis); ração + 0,25% de B. cereus var. Toyoi + 0,25% de B. subtilis C-3102 (ração + B. cereus + B. subtilis). Amostragens de ração, filé, pele, brânquias, fígado, carcaça, solo e sedimento da caixa de coleta dos viveiros foram realizadas para a determinação de metais pesados tóxicos por digestão nitro perclórica, e, espectrometria de absorção atômica. Não houve diferença significativa (p>0,05) nos teores dos metais observados nos tecidos analisados dos juvenis alimentados com diferentes combinações de probiótico e ração. Teores de Pb no filé foram superiores ao preconizado pela legislação. Teores de Cr foram detectados somente na pele dos juvenis. O teor de Pb do solo no final do cultivo (71,15 mg kg-1) foi maior (p<0,05) que o encontrado inicialmente (49,10 mg kg-1) e o Cr no sedimento da caixa de coleta (29,95 mg kg-1) foi maior (p<0,05) que o encontrado no solo (18,4 mg kg-1). A adição de probióticos não tem efeito sobre a bioacumulação de metais em juvenis, e sobre a retenção no solo e sedimento.

The study aimed to monitor the bioaccumulation of Cd, Pb and Cr in the Nile tilapia and sediment retention in the collection box in the ground and nursery with administration of probiotics in the ration. The diet consisted of commercial pelleted ration to fingerlings and probiotics included in the diet using 2% vegetable oil, constituting of: diet free of probiotics (Exempt); ration + 0.5% B. cereus var. Toyoi (ration + B. cereus); ration + 0.5% B. subtilis C-3102 (ration + B. subtilis); ration + 0.25% B. cereus var. Toyoi + 0.25% B. subtilis C-3102 (ration + B. cereus + B. subtilis). Samples of ration, filet, skin, gills, liver, carcass, soil and sediment of the collection box of the ponds were performed for the determination of toxic heavy metals by nitro perchloric digestion, and atomic absorption spectrometry. There was no significant difference (p>0.05) observed in the levels of metals in the tissues analyzed for juveniles fed different combinations of probiotic and ration. Lead levels in the filet were greater than recommended by law. Levels of Cr were detected only in the skin of the juveniles. The level of the Pb content of soil at the end of cultivation (71.15 mg kg-1) was higher (p<0.05) than that found initially (49.10 mg kg-1) and the Cr in the sediment of the collection box (29.95 mg kg-1) were greater (p<0.05) than that found in the soil (18.4 mg kg-1). The addition of probiotics has no effect on the bioaccumulation of metals in juveniles, and on the retention in the soil and sediment.