11 research outputs found
Development of efficient recirculation system for Tilapia (Oreochromis niloticus) culture using low cost materials
In the current experiment, a recirculation system was built using low cost materials that are available locally and its performance was tested. The performance evaluation procedure was carried out in an aquaculture system in greenhouse with sex-reversed male Nile tilapia (Oreochromis niloticus) production in Querétaro State, Mexico. The recirculation system had four sections (sediment collector, gravel and sand filters, biofilter and clarification) in order to eliminate the organic matter produced by the fish excretion material and uneaten food, as well as, the nitrogenous compounds undesirable in the water tanks, such as, total ammonia nitrogen (TAN). The monitored variables include: temperature, dissolved oxygen, pH, visibility, TAN, nitrites and nitrates. The obtained data were compared with previous studies to evaluate the achieved state of the system. This research clearly demonstrated that it is feasible to use the proposed configuration in aquaculture systems in areas where water source is limited. Consequently, the obtained results represent an environmental standpoint for the conservation of water use in the aquaculture industry and also constitute an important contribution to the aquaculture and farmers who receive minimal economic support.Key words: Water recirculation, aquaculture, sustainability, low cost, water use efficiency
Prebiotic Potential of Agave angustifolia Haw Fructans with Different Degrees of Polymerization
Inulin-type fructans are the most studied prebiotic compounds because of their broad range of health benefits. In particular, plants of the Agave genus are rich in fructans. Agave-derived fructans have a branched structure with both β-(2→1) and β-(2→6) linked fructosyl chains attached to the sucrose start unit with a degree of polymerization (DP) of up to 80 fructose units. The objective of this work was to assess the prebiotic potential of three Agave angustifolia Haw fructan fractions (AFF) with different degrees of polymerization. The three fructan fractions were extracted from the agave stem by lixiviation and then purified by ultrafiltration and ion exchange chromatography: AFF1, AFF2 and AFF3 with high (3–60 fructose units), medium (2–40) and low (2–22) DP, respectively. The fructan profile was determined with high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), which confirmed a branched fructan structure. Structural elucidation was performed by Fourier Transform Infra-Red Spectroscopy. The AFF spectrum shows characteristic fructan bands. The prebiotic effect of these fractions was assessed in vitro through fermentation by Bifidobacterium and Lactobacillus strains. Four growth patterns were observed. Some bacteria did not grow with any of the AFF, while other strains grew with only AFF3. Some bacteria grew according to the molecular weight of the AFF and some grew indistinctly with the three fructan fractions
In vitro clonal propagation and regeneration of the commercially important plant Mexican oregano (Lippia graveolens)
Biomass, chlorophyll fluorescence, and osmoregulation traits let differentiation of wild and cultivated Amaranthus under water stress
Dipole-wind interactions under gap wind jet conditions in the Gulf of Tehuantepec, Mexico: A surface drifter and satellite database analysis
The Flora of the Tenancingo-Malinalco-Zumpahuacán Protected Natural Area, State of Mexico, Mexico
Anuario del Centro de Estudios Martianos (Vol. 39 2016)
El Anuario del Centro de Estudios Martianos es la publicaciĂłn insignia de esta instituciĂłn y heredera directa del Anuario Martiano de la Biblioteca Nacional JosĂ© MartĂ, que se publicĂł entre 1969 y 1977, bajo la direcciĂłn del poeta y ensayista Cintio Vitier.<br>
Desde que saliĂł a la luz su primera entrega, en 1978, se han publicado treinta y cinco nĂşmeros, en los que aparecen artĂculos y ensayos de importantes estudiosos de la vida y obra del ApĂłstol, en Cuba y el resto del mundo.<br>
En sus secciones fijas (Otros textos de JosĂ© MartĂ, Documentos, Estudios y aproximaciones, Vigencias, Publicaciones, BibliografĂa, Constante) y los apartados especiales, los lectores pueden conocer disĂmiles temas del quehacer martiano internacional, en el año que termina además de mantenerse al tanto de las Ăşltimas contribuciones de los promotores e investigadores de la obra martiana en el orbe