Aquaponics is the combined production of aquaculture and hydroponics, connected by a water recirculation system. In this productive system, the microbial community is responsible for carrying out the nutrient dynamics between the components. The nutrimental transformations mainly consist in the transformation of chemical species from toxic compounds into available nutrients. In this particular field, the microbial research, the “Omic” technologies will allow a broader scope of studies about a current microbial profile inside aquaponics community, even in those species that currently are unculturable. This approach can also be useful to understand complex interactions of living components in the system. Until now, the analog studies were made to set up the microbial characterization on recirculation aquaculture systems (RAS). However, microbial community composition of aquaponics is still unknown. “Omic” technologies like metagenomic can help to reveal taxonomic diversity. The perspectives are also to begin the first attempts to sketch the functional diversity inside aquaponic systems and its ecological relationships. The knowledge of the emergent properties inside the microbial community, as well as the understanding of the biosynthesis pathways, can derive in future biotechnological applications. Thus, the aim of this review is to show potential applications of current “Omic” tools to characterize the microbial community in aquaponic systems.

The density-dependents and physiological effects in bullfrog tadpoles (Rana catesbeiana Shaw, 1802) was evaluated to asses optimum stocking density. During 70 days, five treatments (1/4, 1/3, 1/2, 1 and 2 tadpole L -1 ) were evaluated under greenhouse conditions. Environmental variables, water quality parameters, biometric data, oxygen consumption and nitrogen excretion were measure every 3 weeks. At the end of experiment, the treatment of 1/4 tadpole L -1 obtained the highest weight, length and biomass. However, maximum survival (92.59%) and estimated final biomass (0.3051 g L . We suggest a stocking density of 1 tadpole per 3 L in order to minimize stress and optimize water.

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ABSTRACT. The effects of stocking density on oxygen consumption and growth in Nile tilapia (Oreochromis niloticus) under greenhouse conditions were investigated in this experiment. Fingerlings with 1.57 ± 0.14 g mean body weight were stocked in 972 L, rectangular plastic tanks placed inside a polyethylene greenhouse 504 m 2 , at three densities 90 (T1), 180 (T2), and 270 (T3) ind m -3 (biomass of 0.14, 0.28, and 0.42 kg m -3). Fish were feeding with a commercial diet for Nile tilapia (Api-Tilapia 1, MaltaCleyton® with 50%, protein and 12% lipid) to apparent satiation, three times a day, for 60 days. Fish in each treatment were selected randomly in order to measure aerobic metabolism using closed respirometric chamber technique with constant temperature and volume (1 L). It was found that growth rate of T1 (0.38 g day ; 3.68% day -1 ) was significantly higher than T3 (0.11 g day ). Thus, according to the results the culture of tilapia at a density of 90 ind m -3 can be used for increase production of O. niloticus under greenhouse conditions. Keywords: Oreochromis niloticus, density, growth, oxygen consumption, aquaculture.Efecto de la densidad de siembra sobre el crecimiento y el consumo de oxígeno de la tilapia del Nilo (Oreochromis niloticus) bajo condiciones de invernadero RESUMEN. El efecto de la densidad y el consumo de oxígeno sobre el crecimiento de la tilapia (Oreochromis niloticus) fueron analizados. Alevines con un peso húmedo promedio de 1,57 ± 0,14 g se colocaron en estanques rectangulares de plástico de 972 L, dentro de un invernadero de polietileno con un área de 504 m 2 , las densidades utilizadas fueron 90 (T1), 180 (T2), and 270 (T3 ind m -3 (con una biomasa promedio total por tanque de 0,14, 0,28 y 0,42 kg m -3 ). Para la alimentación se utilizó alimento comercial (Api-Tilapia 1, MaltaCleyton® con 50% proteína y 12% de lípidos), que se suministró hasta la aparente saciedad tres veces al día durante un periodo de 60 días. Al finalizar este periodo se seleccionaron aleatoriamente individuos de cada tratamiento para determinar el metabolismo aerobio, que se determinó por el método de cámaras semicerradas mantenidas a temperatura constante y volumen conocido (1 L). Se determinó que la tasa de crecimiento de T1 (0,38 g día ). De acuerdo con los resultados obtenidos, el cultivo de tilapia bajo condiciones de invernadero a una densidad de 90 ind m -3 puede ser utilizado para incrementar la productividad de O. niloticus.

ABSTRACT. Native species, in comparison to exotic species in aquaculture, such as tilapias, are an alternative with a lower risk to regional biodiversity, due to competition for resources caused by introduced species. Productivity, length-weight relationship and relative condition factor of a native cichlid Herichthys cyanoguttatus were investigated in comparison to tilapia Oreochromis niloticus. Fish with a wet weight of 0.54 ± 0.07 g were placed in 100 L tanks inside a polyethylene greenhouse during 84 days. Wet weight (g) was obtained each week and standard length once per month. Both species had a high survival rate with a relative condition factor close to 1, showing a length-weight relationship with an isometric growth, meaning that they were in good condition. A significant difference was found in growth (P < 0.05) from the second week, with a specific growth rate of 2.28 ± 0.07% day -1 for tilapia and 1.35 ± 0.02% day -1 for the native cichlid, tilapia reached twice the total weight gain than the native cichlid (31.26 ± 0.95 g; 83.70 ± 4.54 g). Food conversion rate was higher in tilapia than in H. cyanoguttatus. The survival rate of H. cyanoguttatus, as well as the relationship of isometric growth and condition factor of both species, suggests that H. cyanoguttatus has the ability to grow in aquaculture systems. Keywords: Herichthys cyanoguttatus, Oreochromis niloticus, tilapia, condition factor, length-weight, growth, Mexico.Primer prueba productiva de la mojarra nativa Herichthys cyanoguttatus en comparación con la tilapia Oreochromis niloticus RESUMEN. Las especies nativas, en comparación con las especies exóticas usadas en acuicultura, como las tilapias, son una alternativa con menor riesgo para la biodiversidad regional, debido a la competencia por recursos causada por las especies introducidas. Se investigaron los parámetros de crecimiento, relación longitudpeso y factor de condición de la mojarra nativa Herichthys cyanoguttatus comparándola con la tilapia Oreochromis niloticus. Individuos con un peso de 0,54 ± 0,07 g se colocaron en estanques de 100 L en un invernadero de polietileno durante 84 días. El peso (g) se obtuvo cada semana y mensualmente la longitud parcial. Ambas especies presentaron alta supervivencia con un factor de condición relativo cercano a 1 y una relación longitud-peso con crecimiento isométrico, significando que se encontraban en buena condición. Se determinó una diferencia significativa (P < 0,05) en el crecimiento desde la segunda semana, con tasa específica de crecimiento de 2,28 ± 0,07% día -1 en la tilapia y 1,35 ± 0,02% día -1 en la mojarra nativa; la tilapia alcanzó dos veces el peso de la mojarra (31,26 ± 0,95 g; 83,70 ± 4,54 g). La eficiencia de conversión de alimento fue mayor en la tilapia que en H. cyanoguttatus. La supervivencia de H. cyanoguttatus, así como la similitud del crecimiento isométrico y factor de condición con la tilapia, sugieren que tiene la capacidad de ser cultivada en sistemas de acuicultura.

Studies on the biological aspects of fish typically focus on species that currently have commercial value, causing species that lack such market value to be ignored. This is the case of several freshwater fish, specifically of several members of the Goodeidae family. In the State of Querétaro there are several species of this family characterized for being viviparous and having distinctive sexual dimorphism that may have commercial potential. The subject of this study is Girardinichthys multiradiatus, a viviparous fish endemic to the upper-half of the Lerma River basin. The lack of knowledge regarding its biology and ecology has prevented the development of guidelines to manage its habitat and to preserve its population. The objective was to determine the ecophysiological responses of G. multiradiatus to its environmental management. From the sampling (24 hours every two months) population structure and dynamics were analyzed throughout a hydrological cycle using meristic data (standard length). Trophic and ecophysiological responses to fluctuations in environmental factors were also identified. Although the mexcalpique is a polytrophic species, results show that it prefers feeding on Diptera or Cladocera, while detritus is the third substance frequently found in their stomachs. Environmentally, the water regime is responsible for fluctuations in the population dynamics of the species, while temperature changes are the most influence its energy balance. These results can guide efforts to conserve this species and its habitat.Los estudios sobre aspectos biológicos de los peces se centran, generalmente, en especies que actualmente tienen interés comercial, lo que ocasiona que las especies que carecen de tal valor en el mercado estén prácticamente olvidadas; tal es el caso de varios peces de agua dulce y más específicamente de algunos integrantes de la familia Godeidae. En el estado de Querétaro se encuentran varias especies pertenecientes a esta familia que se caracterizan por ser vivíparas y presentar un marcado dimorfismo sexual, aspectos que pudieran definir un potencial comercial. El pez objeto de este estudio es Girardinichthys multiradiatus, especie endémica de la parte alta-media de la cuenca del río Lerma; los lugares donde habita presentan procesos de degradación, fragmentación del hábitat y extracción de agua, que ponen en riesgo su existencia. Además, la falta de conocimiento sobre su biología y ecología, no permiten que se elaboren pautas de gestión de sus poblaciones o hábitats con fines de conservación y preservación de la especie o de los procesos ecológicos que mantienen la estabilidad del ecosistema que ocupa. En el presente trabajo se estudió la población de G. multiradiatus localizada en el bordo de San Martín, Amealco. El objetivo del presente trabajo fue determinar las respuestas ecofisológicas de G. multiradiatus debido al manejo de su ambiente. Se hicieron ciclos de 24 horas en muestreos bimensuales a lo largo de un ciclo hidrológico en el que se analizaron la estructura y dinámica de la pob...

T he demand for nixtamalized products has broadened the industrialization of maize. The nejayote is a product of the alkaline cooking of grain, and unfortunately contributes to environmental deterioration after being dumped into the public sewer system. There is evidence that adequate treatment of this byproduct not only reduces pollution, but it is also a source of compounds with high added value with potential for technological applications. The objective of this review was to provide an overview of the main methodologies and technological developments which have been implemented to explore the physicochemical properties of nejayote and to assign a treatment or an application to it. With the work performed it was possible to detect that the recovery of materials with high added value (polyphenols, carbohydrates, sugars, gums and calcium components) can be used in various areas such as the food, pharmaceutical and biotechnological sectors. In addition, it was identified that the obtaining of these components can be carried out through the coupling of various bioprocesses (fermentation, filtration, centrifugation and decantation).Resumen L a demanda de productos nixtamalizados ha incrementado la industrialización del maíz. El nejayote surge de la cocción alcalina del grano, y desafortunadamente contribuye en el deterioro ambiental tras ser vertido al alcantarillado público. Existe evidencia de que el tratamiento adecuado de este subproducto no sólo disminuye la contaminación, también es fuente de compuestos de valor agregado alto con potencial para aplicaciones tecnológicas. El objetivo de esta revisión fue proveer un panorama sobre las principales metodologías y desarrollos tecnológicos que se han implementado para explorar las propiedades físico-químicas del nejayote y proveerle un tratamiento o aplicación. Con el trabajo realizado se pudo detectar que la recuperación de materiales con valor agregado alto (polifenoles, carbohidratos, azúcares, gomas y componentes de calcio) puede ser utilizada en diversas áreas como la alimenticia, farmacéutica y biotecnológica. Además, se identificó que la obtención de dichos componentes se puede llevar a cabo mediante el acoplamiento de diversos bioprocesos (fermentación, filtración, centrifugación y decantación).

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