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Perez-Fuentes J.A.,Technological Institute of Boca del Rio | Hernandez-Vergara M.P.,Technological Institute of Boca del Rio | Perez-Rostro C.I.,Technological Institute of Boca del Rio
Aquaculture | Year: 2016

Over a six-month trial, growth performance of juvenile tilapia Oreochromis niloticus, raised under biofloc cultivation, was recorded. Five treatments with three replicates and 237 juveniles per replicate at different C:N ratios were tested (10:1, 12.5:1, 15:1, 17.5:1, 20:1). Molasses was added every fourth day as the carbon source. Trials were performed in eighteen 3.14m3 circular tanks with constant aeration. Survival in all treatments with biofloc was similar and significantly higher (94.60±2.03%) than in the control treatment (84.96±1.53%). Best weight gain (g/day) occurred in the control treatment, but was influenced by low density. The 10:1 and 15:1 C:N treatments had similar weight gains, but not the 12.5:1 and 17.5:1 C:N treatments. Total production in the 10:1 ratio treatment was the highest (18.03±0.25kgm-3), with slightly declining production, in this order: control (17.86±0.16), 15:1 (17.73±0.18), 12.5:1 (17.20±0.28), 17.5:1 (16.44±0.04), and 20:1 (16.28±0.02). Water quality remained similar in all biofloc treatments, but lower concentrations of nitrogen compounds occurred in the 10:1 C:N ratio tanks. These results suggest a 10:1 C:N ratio provides good survival and growth of tilapia with no water exchange. Biofloc technology is a good strategy in areas where alkaline pH is a limiting factor for aquaculture activities because the pH decreases gradually as molasses is added. Statement of Relevance: The success and permanence of aquaculture sector relies on the implementation of sustainable and environment-friendly technology, the BFT optimizes energy and resources during production, so our results contribute significantly to the sector. © 2015 Elsevier B.V.


Hernandez-Vergara M.P.,Technological Institute of Boca del Rio | Olvera-Novoa M.A.,CINVESTAV | Perez Rostro C.I.,Technological Institute of Boca del Rio
Aquaculture Research | Year: 2010

Effect of isolipidic (62.7 ± 5.0 g kg-1) diets with protein levels of 204.6 (T20), 302.3 (T30), 424.6 (T40) or 511.0 g kg-1 (T50) on growth and survival in Nile tilapia (Oreochromis niloticus Linnaeus 1758) fry cultured for 70 days at one of four salinities (0, 15, 20 and 25 g L-1) was evaluated. A bifactorial (4 × 4) design was used with 16 treatments run in triplicate and 20 fry (0.25 ± 0.04 g) per replicate under semi-controlled conditions. Four independent, recirculating systems (one per salinity level) were used, each one with 12 circular tanks (70 L capacity), filters and constant aeration. The different salinities had no significant effect on growth. Weight gain improved significantly as dietary protein content increased, although organisms fed the T50 diet had a lower growth rate. Survival was highest (98.33%) in the T50/15 (protein/salinity levels) treatment and lowest (71.0%) in the T20/20 treatment, with no pattern caused by the variables. The T40/25, T40/20 and T50/0 treatments produced the most efficient growth and feed utilization values while the T20 treatments at all the salinities resulted with the lowest performance. With the exception of the T50 treatments, a non-significant tendency to increased weight gain was observed as water salinity increased, suggesting that the salinity of the culture environment does not influence dietary protein requirements in Nile tilapia O. niloticus fry. © 2010 The Authors. Journal Compilation © 2010 Blackwell Publishing Ltd.


Lopez-Naranjo E.J.,Research Center Cientifica Of Yucatan | Alzate-Gaviria L.M.,Research Center Cientifica Of Yucatan | Hernandez-Zarate G.,Technological Institute of Boca del Rio | Reyes-Trujeque J.,Autonomous University of Campeche | And 2 more authors.
Journal of Applied Polymer Science | Year: 2013

Wood-plastic composites (WPCs) are considered to be highly durable materials and immune to any type of biological attack. However, when one of these composites is exposed to accelerated weathering, its surface is affected by the appearance of cracks, which constitute an ideal access route for biotic agents. Although the destruction of wood caused by termites is recognized worldwide, information on their effects on WPC-based products is scarce. Thus, in this study, we aimed to examine the effects of termite attacks on weathered and nonweathered pinewood residue/recycled high-density polyethylene composites. In this study, WPCs with 40 wt % wood were prepared. Test samples obtained by compression molding and profile extrusion were subjected to weathering cycles for 1000 and 2000 h with a UV-type accelerated tester equipped with UVA-340 fluorescent lamps. Afterward, specimens were exposed to the attack of higher termites (Nasutitermes nigriceps) native to the Yucatan Peninsula. Subsequently, flexural mechanical essays, Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) analyses were performed. FTIR spectroscopy and DSC showed that the surfaces of the compression-molded specimens were degraded to a higher extent because of the accelerated weathering. The microscopy results revealed that severe damage was caused by the termites on the surface of the compression-molded samples. Statistical analysis of the mechanical test results showed that biotic attack produced significant changes in the samples previously exposed to accelerated weathering. The results show that the processing method directly affected the sample performance because of differences in the surface composition. The profile-extruded composites seemed to better resist termite attack. © 2012 Wiley Periodicals, Inc.


Espana-Gamboa E.,Research Center Cientifica Of Yucatan cy | Barahona-Perez L.,Research Center Cientifica Of Yucatan cy | Dominguez-Maldonado J.,Research Center Cientifica Of Yucatan cy | Hernandez-Zarate G.,Technological Institute of Boca del Rio | Alzate-Gaviria L.,Research Center Cientifica Of Yucatan cy
Waste Management and Research | Year: 2011

The final products of the ethanol industry are alcoholic beverages, industrial ethanol and biofuels. They are produced by the same production process, which includes fermentation and distillation of raw materials which come from plant biomass. At the end of the distillation process a waste effluent is obtained called vinasse or stillage. The direct disposal of stillages on land or in groundwater (rivers, streams or lakes), or even for the direct irrigation of crops, pollutes the environment due to their high organic contents, dissolved solids and many other compounds which are toxic or could be contaminants under certain environmental conditions. This work reviews the characterization of vinasses from different feedstock sources and the main treatments for conditioning the soluble solids of vinasses before their disposal. © 2011 International Solid Waste Association.


Espana-Gamboa E.I.,Research Center Cientifica Of Yucatan Ac Cicy | Hernandez-Zarate G.,Technological Institute of Boca del Rio | Maldonado J.A.D.,Research Center Cientifica Of Yucatan Ac Cicy | Alzate-Gaviria L.M.,Research Center Cientifica Of Yucatan Ac Cicy
Biotechnology for Biofuels | Year: 2012

Background: A modified laboratory-scale upflow anaerobic sludge blanket (UASB) reactor was used to obtain methane by treating hydrous ethanol vinasse. Vinasses or stillage are waste materials with high organic loads, and a complex composition resulting from the process of alcohol distillation. They must initially be treated with anaerobic processes due to their high organic loads. Vinasses can be considered multipurpose waste for energy recovery and once treated they can be used in agriculture without the risk of polluting soil, underground water or crops. In this sense, treatment of vinasse combines the elimination of organic waste with the formation of methane. Biogas is considered as a promising renewable energy source. The aim of this study was to determine the optimum organic loading rate for operating a modified UASB reactor to treat vinasse generated in the production of hydrous ethanol from sugar cane molasses. Results: The study showed that chemical oxygen demand (COD) removal efficiency was 69% at an optimum organic loading rate (OLR) of 17.05 kg COD/m 3-day, achieving a methane yield of 0.263 m3/kg COD added and a biogas methane content of 84%. During this stage, effluent characterization presented lower values than the vinasse, except for potassium, sulfide and ammonia nitrogen. On the other hand, primers used to amplify the 16S-rDNA genes for the domains Archaea and Bacteria showed the presence of microorganisms which favor methane production at the optimum organic loading rate. Conclusions: The modified UASB reactor proposed in this study provided a successful treatment of the vinasse obtained from hydrous ethanol production. Methanogen groups (Methanobacteriales and Methanosarcinales) detected by PCR during operational optimum OLR of the modified UASB reactor, favored methane production. © 2012 España-Gamboa et al.; licensee BioMed Central Ltd.


Galicia-Garcia C.,Technological Institute of Boca del Rio | Robinson N.M.,Technological Institute of Boca del Rio | Okolodkov Y.B.,University of Veracruz
Acta Botanica Mexicana | Year: 2013

Descriptions of 21 red algal species collected in March and November 2008 and June 2010 are given. They are considered new records for Cabezo reef in the southeastern part of the National Park Sistema Arrecifal Veracruzano (NPSAV), southwestern Gulf of Mexico. The new records belong to the genera Amphiroa, Bryothamnion, Ceramium, Ceratodictyon, Colaconema, Galaxaura, Hypnea, Jania, Laurencia, Liagora, Neosiphonia, Pneophyllum, Polysiphonia, Porolithon, Stylonema, Titanophycus and Yuzurua. The families Rhodomelaceae and Corallinaceae contain the largest number of species (6 and 5, respectively). Descriptions include morphometric and biological data and are accompanied by photographs and line drawings for each species. Geographic distribution of these algae in the State of Veracruz, park and the Gulf of Mexico are also provided. Polysiphonia pseudovillum is a new record for the Gulf of Mexico, while Colaconema hallandicum and Ceratodictyon planicaule are new records for the park. Nine species have been found as epiphytes mainly on green and red algae. Tetrasporangia were the dominant reproductive structures found in the studied species during both rainy and dry seasons. Vegetative and reproductive thalli of 10 species from the NPSAV were usually smaller compared to those of the same species found in the Caribbean.


Ek-Huchim J.P.,National Polytechnic Institute of Mexico | Jimenez-Garcia I.,Technological Institute of Boca del Rio | Perez-Vega J.A.,National Polytechnic Institute of Mexico | Rodriguez-Canul R.,National Polytechnic Institute of Mexico
Diseases of Aquatic Organisms | Year: 2012

Infection of Nile tilapia Oreochromis niloticus by monogeneans of the genus Cichlidogyrus is harmful. Currently, diagnosis of this infection is based on invasive techniques and the identification of isolated parasites by their morphology. To facilitate diagnosis, we have developed a non-lethal polymerase chain reaction (PCR) test for detection of Cichlidogyrus spp. DNA in the gill mucus of O. niloticus, using 5 pairs of specific primers based on Cichlidogyrus sclerosus 28S rRNA (Cicly 1 to Cicly 5) which generate fragments of approximately 188, 180, 150, 159 and 189 bp, respectively. PCR specificity was tested using genomic DNA extracted individually from 175 isolated Cichlidogyrus spp., 75 Gyrodactylus cichlidarum and 75 endopararasitic Entero-gyrus spp., as well as from 75 protozoans Trichodina spp. The Cicly primers were used to detect Cichlidogyrus spp. DNA in mucus from the gills of 23 Nile tilapia confirmed to be infected with the parasite. Negative controls consisted of 45 uninfected Nile tilapia. The limit of sensitivity of the assay was 1.2 ng of purified parasite DNA. The Cicly primers did not amplify DNA from the mucus of non-infected Nile tilapia, G. cichlidarum, Trichodina spp. or Enterogyrus spp. In all cases, the sensitivity and specificity of the test were 100%. The sequences of all the amplified fragments showed a high similarity to that of the 28S rRNA region of C. sclerosus (93 to 100% identical to GenBank Accession No. DQ157660.1). We provide evidence for a safe and noninvasive DNA-based diagnostic method for the presence of Cichlidogyrus in the gill mucus of O. niloticus. © Inter-Research 2012.


Salgado-Maldonado G.,National Autonomous University of Mexico | Caspeta-Mandujano J.M.,Autonomous University of the State of Morelos | Moravec F.,Academy of Sciences of the Czech Republic | Soto-Galera E.,National Polytechnic Institute of Mexico | And 3 more authors.
Parasitology Research | Year: 2011

An inventory based on previously published records and original data is presented for the helminth parasites reported in 54 fish species from 17 families from the state of Chiapas, southeast Mexico. This survey reports the presence of 43 helminth species in Chiapas for the first time. The actualized inventory of helminth parasites of freshwater fish from Chiapas contains 88 species from 67 genera and 40 helminth families. Trematodes and nematodes were the most abundant taxonomic groups. The helminth fauna in freshwater fishes from Chiapas consists of Central American species. All the helminth species recorded in Chiapas have also been collected from bodies of freshwater between the Isthmus of Tehuantepec and the Isthmus of Panama. This inventory shows that this fauna is quite similar to that from the neighboring basins of the lower Grijalva-Usumacinta system and the Yucatan Peninsula. The taxonomic composition and distribution data reported here for the helminth fauna of Chiapas' freshwater fish, contribute to a better understanding of this faunal component in Central America. © 2010 Springer-Verlag.


Lango-Reynoso F.,Technological Institute of Boca del Rio | Landeros-Sanchez C.,Colegio de Mexico | Castaneda-Chavez M.R.,Technological Institute of Boca del Rio
Revista Internacional de Contaminacion Ambiental | Year: 2010

The accumulation of heavy metals in oysters, C. virginica, from Tamiahua Lagoon System along the gulf coast in the state of Veracruz, México, results from inputs provided by anthropogenic activities and the physicochemical and ecophysiological processes occurring in these systems. The objective of this study was to determine concentrations of Cd, Pb and As in gonad-digestive gland (GDG) and muscle-mantle-gill (MMG) tissues in females and males of C. virginica from Tamiahua Lagoon. Two sampling sites were selected, and each sample consisted of 500 oysters of commercial size. Concentrations of Cd, Pb and As were determined using atomic absorption spectrophotometry and a graphite furnace. The highest concentrations were found in MMG tissues, whose mean values for these metals are 11.77 ± 1.32, 0.484 ± 0.08, 4.02 ± 0.56 mg kg-1. Cadmium concentrations exceeded the limits for the consumption of bivalve mollusks established by the sanitary regulations, indicating a risk to human health.


PubMed | Technological Institute of Boca del Rio and Colegio de Mexico
Type: Journal Article | Journal: Systematic parasitology | Year: 2017

During a parasitological survey of the ichthyofauna of Lake Catemaco, a freshwater system in the Mexican State of Veracruz, the widespread copepod Ergasilus arthrosis Roberts, 1969 was recovered from two cichlid teleosts, Mayaheros urophthalmus (Gnther) and Oreochromis sp. This is the first confirmed record of this copepod species outside of the United States and from Mexico; its finding as a parasite of cichlids represents an expansion of the known host range for this copepod. The local prevalence and intensity of infection of E. arthrosis was highest in M. urophthalmus. The infection prevalence of E. arthrosis on M. urophthalmus (60%) was higher than that known for other ergasilids on cichlids. Ergasilus arthrosis can be distinguished from its closest congener E. lizae Kryer, 1863 by the morphometry of the antennary segments, the ventral ornamentation of the thoracic sclerites and by details of the antennulary setation, but also by its habitat and host preferences. Taxonomic illustrations and morphological details of the specimens examined are also provided together with comments on the variability of this species.

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