Water quality in an aquaponics system interconnected with a biofilter

Objective: To determine the water quality of an aquaponic system interconnected by a biofilter, using loofah (Luffa cylindrica) as an inert support. Design/methodology/approach: The organisms used in the aquaponic system were juvenile tilapia (Oreochromis niloticus) and epazote (Chenopodium ambrosioides). The physical-chemical parameters analyzed in the water were: temperature, pH, dissolved oxygen, electrical conductivity, NH4+, NO2- and NO3-. The data generated in this work were subjected to analysis of variance (ANOVA) and comparison of means (Tukey p<0.05). Results: Recirculation of pond water through the biofilter and plants reduced NH4+ and NO3- by 31.6% and 18.5%, respectively. In the pond, the total ammoniacal nitrogen did not exceed 0.022 mg L-1. The survival of the fish was 100% and 725.8 g of epazotes were harvested, which did not show symptoms of mineral deficiency. Limitations on study/implications: Aquaponic production is still limited to small areas due to the costs involved in its management. Findings/conclusions: The water quality parameters of the tilapia (Oreochromis niloticus)-epazote (Chenopodium ambrosioides) aquaponic system, interconnected through a biofilter with Luffa cylindrica were maintained within the recommendations for said system. Keywords: Biofilter, aquaculture, mineralization, ammoniaObjective: To determine the water quality of an aquaponics system interconnected by a biofilter, using sponge gourd (Luffa cylindrica) as an inert support. Design/Methodology/Approach: The organisms used in the aquaponics system were juvenile tilapia (Oreochromis niloticus) and wormseed (Chenopodium ambrosioides). The following physicochemical parameters of the water were analyzed: temperature, pH, dissolved oxygen, electrical conductivity, NH4+, NO2-, and NO3-. Data generated in this work were subjected to an analysis of variance (ANOVA) and to the comparison of means (Tukey’s test, p<0.05). Results: Recirculating tank water through the biofilter and plants reduced NH4+ and NO3- by 31.6% and 18.5%, respectively. The total ammonia nitrogen in the tank did not exceed 0.022 mg L-1. The fish survival rate was 100% and 725.8 g of wormseed were harvested. The wormseed did not show symptoms of mineral deficiency. Study Limitations/Implications: Aquaponics production is still limited to small surfaces, as a consequence of the costs involved in its handling. Findings/Conclusions: Water quality parameters of the tilapia (Oreochromis niloticus)-wormseed (Chenopodium ambrosioides) aquaponics system —interconnected through a biofilter with Luffa cylindrica— fulfilled the recommendations for such system

Biología y comportamiento sexual del mutante ojos amarillos de anastrepha ludens (diptera: tephritidae)

We compared the biology and sexual behavior between a strain of laboratory with wild phenotype (LFS) and a strain of laboratory with mutant phenotype (LFM) of Anastrepha ludens (Loew), characterized by clear coloration of the body and creamy yellow eyes to determine their potential as genetic marker in the control programmes through the use of the sterile insect technique. The survey results indicated that individuals of the LFM mutant strain not differ significantly from individuals of the LFS strain respect to their fecundity, fertility and survival of immature stages, as well as in the emission of sexual pheromone. This indicates that could be adapted to mass-rearing. However, mating tests indicated that although the LFM insects mated with the insects of field of wild phenotype (CFS), presented some degree of isolation and low percentages of mating of males with both LFS and CFS females, implying that is not recommended the use of the LFM mutant strain as genetic marker in programs that use the sterile insect technique, for the control of the Mexican fruit fly.Se comparó la biología y el comportamiento sexual entre una cepa de laboratorio con fenotipo silvestre (LFS) con una cepa de laboratorio con fenotipo mutante (LFM) de Anastrepha ludens (Loew), que se caracteriza por una coloración del cuerpo clara y ojos amarillo cremoso, para determinar su potencial como marcador genético en los programas de control mediante el uso de la técnica del insecto estéril. Los resultados del estudio indicaron que los individuos de la cepa mutante LFM no difieren significativamente de los individuos de la cepa LFS respecto a su fecundidad, fertilidad y supervivencia de inmaduros, así como en la emisión de feromona sexual. Esto es indicativo de que podría ser adaptada a las condiciones de cría masiva. Sin embargo, las pruebas de apareamiento indicaron que aunque los insectos LFM copularon con los insectos de campo de fenotipo silvestre (CFS), presentaron cierto grado de aislamiento y bajos porcentajes de apareamiento de los machos tanto con hembras CFS y LFS, lo cual implica que no sea recomendable el uso de la cepa mutante LFM como marcador genético en programas que utilizan la técnica del insecto estéril, para el control de la mosca Mexicana de la fruta

Estudio de tiempos para mejorar la productividad de las líneas de producción en una planta de autopartes de Celaya

Garantizar el buen uso de recursos humanos y materiales en las operaciones productivas son metas que las empresas establecen como parte de sus operaciones diarias. Para conseguirlas, es necesario primero identificar los elementos y/o procesos críticos que afectan directamente el nivel de productividad de las células o estaciones de trabajo, identificar oportunidades de mejora de condiciones de trabajo del operador para que sean ergonómicas y seguras.En este sentido el desarrollo de cualquier empresa trae consigo la necesidad de mejora continua en los procesos, la gente y las células de trabajo con el fin de lograr y mantener un alto nivel de productividad de sus unidades de negocio, por tanto, la mecánica adecuada de balanceo de operaciones entre hombre y máquina, nos permitirá identificar y establecer los parámetros adecuados de medición para la productividad de las célulasEn este trabajo se presenta el caso de una planta de autopartes de Celaya donde se aplican las herramientas del estudio de tiempos para establecer la mecánica adecuada de balanceo de operaciones entre hombre y máquina, así como identificar y establecer los parámetros adecuados de medición para la productividad de las células

Isolation and identification of marine strains of Stenotrophomona maltophilia with high chitinolytic activity

Chitin is the second most abundant organic compound in nature and represents a rich carbon and nitrogen source that is primarily transformed by bacterial communities. Bacteria capable of gradually hydrolyzing chitin into N-acetylglucosamine monomers can have applications in the transformation of residues from shrimp and other crustaceans. The objective of the present study was to isolate, characterize and identify microorganisms with high chitinolytic activity. These microorganisms were isolated and characterized based on macro- and microscopic morphological traits. Strains were selected on colloidal chitin agar medium primarily based on a hydrolysis halo larger than 2 mm and a growing phase no longer than 6 days. Secondary selection consisted of semi-quantitative evaluation of chitinolytic activity with a drop dilution assay. From the above, ten strains were selected. Then, strain-specific activity was evaluated. The B4 strain showed the highest specific activity, which was 6,677.07 U/mg protein. Molecular identification indicated that the isolated strains belong to the species Stenotrophomonas maltophilia

Development of Jatropha curcas grown under limited amounts of daily water supply

Jatropha curcas plant is known for its soil tolerance and ability to thrive in low humidity conditions; however, there is a lack of systematic reports documenting the impact of limited water availability on its growth and development. This work aimed to analyze the development of J. curcas cultivated with daily supplementation of limited amounts of water. Five daily irrigation treatments were established to simulate varying annual rainfall levels: 250, 750, 1250, 1750 mm and 2250 mm. In each treatment, we used 16 seedlings of J. curcas MAP-08. The seedlings were sown in pots containing loam soil substrate mixed with vermicompost (19: 1 weight to weight). After 60 weeks of cultivation, plants receiving irrigation of 2250 mm per year exhibited growth rates 1.28, 1.51, 1.95 and 1.95 times higher, with respective increases in stem diameter of 15.6, 22.2, 41.9% and 47.7%, as well as 1.2, 1.4, 1.8, and 1.8 more leaves compared to those receiving 1750, 1250, 750, and 250 mm. There was no statistical difference in the number of branches (3.86 branches per plant) between the plants of the treatment with irrigation of 2250, 1750 mm and 1250 mm per year or between the plants belonging to the 750 and 250 mm per year (2.90 branches per plant) treatments. The plants of treatments 1750 and 2250 were the only ones that produced flowers. Although J. curcas typically functions as a succulent deciduous bush, with its stem serving to regulate leaf water potential and acting as a shock absorber against soil water potentials, its morphological and reproductive characteristics were recorded to be negatively affected when subjected to reductions of 22, 44, 67% and 89% in water availability compared to the maximum annual level recorded in the work area (2250 mm)

Postharvest characteristics of Ataulfo mango grown in Soconusco, Chiapas

Objective: To determine the main indices of evolution of postharvest maturity of the Ataulfo mango from Soconusco, Chiapas, Mexico. Design/methodology/approach: The analyzed variables were color of skin L*, a* and b*, starch, total soluble solids (°Brix), pH, skin instrumental firmness, and color/skin firmness correlation. Results: It was found that, as fruit maturity progresses, from stage 1 to stage 5, the values of the variables skin color L, a* and b*, TSS and pH also increase, but starch concentration and instrumental firmness of the fruit decrease. The negative correlation between color L, a* and b* with the firmness of the fruit, suggest the use of the color variable, as a measure of the maturity of the Ataulfo mango. Limitations on study/implications: The evolution of mango ripening has been studied in varieties such as Tommy Atkins, Keitt, Alphonso, among others, and in Ataulfo grown in other regions of Mexico. Knowing the physicochemical evolution process of the Ataulfo mango grown in Soconusco, Chiapas, is essential for producers. Findings/conclusions: The results obtained could be useful to determine the maturity stage of the Ataulfo mango fruit under the environmental conditions of Soconusco, Chiapas.Objective: To determine the main indices of evolution of postharvest maturity of theAtaulfo mango from Soconusco, Chiapas, Mexico.Design/methodology/approach: The analyzed variables were color of skin L*, a* and b*, starch, total soluble solids (°Brix), pH, skin instrumental firmness, and color/skin firmness correlation.Results: It was found that, as fruit maturity progresses, from stage 1 to stage 5, the values of the variables skin color L, a* and b*, TSS and pH also increase, but starch concentration and instrumental firmness of the fruit decrease. The negative correlation between color L, a* and b* with the firmness of the fruit, suggest the use of the color variable, as a measure of the maturity of the Ataulfo mango.Limitations on study/implications: The evolution of mango ripening has been studied in varieties such as Tommy Atkins, Keitt, Alphonso, among others, and in Ataulfo grown in other regions of Mexico. Knowing the physicochemical evolution process of the Ataulfo mango grown in Soconusco, Chiapas, is essential for producers.Findings/conclusions: The results obtained could be useful to determine the maturity stage of the Ataulfo mango fruit under the environmental conditions of Soconusco, Chiapas

Dietary Use of the Microalga Chlorella fusca Improves Growth, Metabolism, and Digestive Functionality in Thick-Lipped Grey Mullet (Chelon labrosus, Risso 1827) Juveniles

In recent years, a clear emphasis has been placed on replacing fishmeal and fish oil in aquafeeds with other alternative ingredients, including algae, particularly in low trophic omnivorous fish species. This work aimed at evaluating the effects of moderate dietary supplementation with the green microalga Chlorella fusca on growth, metabolism, and digestive functionality in juvenile thick-lipped grey mullet (Chelon labrosus). Fish were fed a control diet (CT) or a diet containing 15% C. fusca (C-15) biomass during 90 days. C. labrosus fed with the C-15 diet showed higher growth performance (in terms of final weight and length, weight gain, and specific growth rate) than the control group. Somatic indices and muscle proximate composition were similar at the end of the feeding trial. Regarding fatty acids profile, C. fusca-fed fish showed a selective retention of docosahexaenoic acid (DHA) in the liver, and arachidonic acid (ARA), eicosapentaenoic acid (EPA), and DHA in the muscle. Dietary inclusion of this microalga significantly increased intestinal total alkaline protease, leucine aminopeptidase, and alkaline phosphatase activities in specimens fed with C-15 diet. Furthermore, intestine histological analysis revealed the absence of damage signs on gut morphology in fish fed the microalgae supplemented diet. Thick-lipped grey mullets fed the C-15 diet increased plasma glucose and decreased plasma lactate. Overall, the effects observed on liver (lipid metabolism, glycolysis and glycogenolysis) enzyme activities, together with adequate fatty acid profile, metabolic response, and gut morphology, and a significant increase in the intestinal mucosa's digestive and absorptive capacity, could explain the positive effects on growth performance obtained in fish fed the microalgae-supplemented diet. In conclusion, the results obtained showed that C. fusca is suitable as dietary ingredient for feeding thick-lipped grey mullet juveniles

Impacto de la actividad antropogénica en el suelo de la reserva de la biosfera “el triunfoâ€, Chiapas (México)

The impact of human activity on the soil of “El Triunfo†Biosphere Reserve, Chiapas, was studied. For this purpose, the values of 14 parameters were determined throughout a year: six physical-chemical and eight biochemical, in forest, coffee plantation, pasture and milpa soils. The values of the parameters in the forest soil were significantly different from those in the coffee plantation, pasture and milpa soils. On the basis of the forest soil, it was considered that human activity altered the soil quality negatively. To have clarity about the level of impact, a scale of 0.0 to 5.0 was suggested, identified as the Soil Deterioration Index (SDI), and the procedure was developed to determine it in the soils with human alteration. The milpa soil had the highest SDI value, placing it in the range of high degradation. The coffee plantation and pasture soils were found in the range of medium degradation. The procedure and scale of SDI was reinforced by discriminant analysis.Se estudió el impacto de la actividad humana en el suelo de la Reserva de la Biosfera “El Triunfoâ€, Chiapas. Para ello se determinaron, a lo largo de un año, los valores de 14 parámetros, seis físico-químicos y ocho bioquímicos, en suelos de bosque, cafetal, pastizal y milpa. Los valores de los parámetros en el suelo del bosque fueron diferentes significativamente a los de cafetal, pastizal y milpa. Tomando como base el suelo de bosque se consideró que la actividad humana alteró negativamente la calidad del suelo. Para tener claridad del nivel de impacto se propuso una escala, de 0.0 a 5.0, identificada como Ãndice de Deterioro del Suelo (IDS), y se desarrolló el procedimiento para determinarlo en los suelos con alteración humana. El suelo de milpa tuvo el mayor valor de IDS, ubicándose en el rango de alta degradación. Los suelos de cafetal y de pastizal se ubicaron en el rango de mediana degradación. El procedimiento y escala de IDS se reforzó a través del análisis discriminante

Dietary use of the microalga Chlorella fusca improves growth, metabolism, and digestive functionality in thick- lipped grey mullet (Chelon labrosus, Risso 1827) Juveniles

In recent years, a clear emphasis has been placed on replacing fishmeal and fish oil in aquafeeds with other alternative ingredients, including algae, particularly in low trophic omnivorous fish species. This work aimed at evaluating the effects of moderate dietary supplementation with the green microalga Chlorella fusca on growth, metabolism, and digestive functionality in juvenile thick-lipped grey mullet (Chelon labrosus). Fish were fed a control diet (CT) or a diet containing 15% C. fusca (C-15) biomass during 90 days. C. labrosus fed with the C-15 diet showed higher growth performance (in terms of final weight and length, weight gain, and specific growth rate) than the control group. Somatic indices and muscle proximate composition were similar at the end of the feeding trial. Regarding fatty acids profile, C. fusca-fed fish showed a selective retention of docosahexaenoic acid (DHA) in the liver, and arachidonic acid (ARA), eicosapentaenoic acid (EPA), and DHA in the muscle. Dietary inclusion of this microalga significantly increased intestinal total alkaline protease, leucine aminopeptidase, and alkaline phosphatase activities in specimens fed with C-15 diet. Furthermore, intestine histological analysis revealed the absence of damage signs on gut morphology in fish fed the microalgae supplemented diet. Thick-lipped grey mullets fed the C-15 diet increased plasma glucose and decreased plasma lactate. Overall, the effects observed on liver (lipid metabolism, glycolysis and glycogenolysis) enzyme activities, together with adequate fatty acid profile, metabolic response, and gut morphology, and a significant increase in the intestinal mucosa’s digestive and absorptive capacity, could explain the positive effects on growth performance obtained in fish fed the microalgae-supplemented diet. In conclusion, the results obtained showed that C. fusca is suitable as dietary ingredient for feeding thick-lipped grey mullet juveniles