Microalgal paste production of the diatom <Emphasis Type="Italic">Chaetoceros calcitrans</Emphasis> using electrolytic flocculation method at optimum culture conditions

The optimum culture conditions of the local strain Chaetoceros calcitrans were determined to improve biomass and reduce cost of production. Under outdoor culture conditions, higher cell density was attained when the cultures were enriched with Tungkang Marine Research Laboratory (TMRL) medium composed of cheap technical grade reagents and cultured at 25 g L^?1 salinity. The cultures were lighted with two 40 W cool-white GE fluorescent tubes (24–35 μmol photon m^?2 s^?1). Using semi-continuous culture system under established optimum culture conditions, C. calcitrans can be re-cultured thrice and concentrated at each culture cycle using electrolytic flocculation method to produce 4.6 kg m^?3 of diatom paste. The viability of concentrated C. calcitrans after 3 months of storage was comparable to live diatom cells. Simple preservation technique by low-temperature storage is convenient for storing algal concentrates for use as starter cultures and for feeding invertebrates. The paste costs USD 8.24 kg^?1 inclusive of the assets and flocculation materials for culturing and harvesting the diatom, respectively. This study established the suitable conditions for mass culture of C. calcitrans and produced concentrated diatoms in paste form that is readily available for aquaculture hatcheries at a lower cost.     

Use of thraustochytrid <Emphasis Type="Italic">Schizochytrium</Emphasis> sp. as source of lipid and fatty acid in a formulated diet for abalone <Emphasis Type="Italic">Haliotis asinina</Emphasis> (Linnaeus) juveniles

The effects of using thraustochytrid Schizochytrium sp. as source of lipid and fatty acids in a formulated diet on growth, survival, body composition, and salinity tolerance of juvenile donkey’s ear abalone, Haliotis asinina, were investigated. Treatments consisted of diets either containing a 1:1 ratio of cod liver oil (CLO) and soybean oil (SBO) (Diet 1) or thraustochytrid (Diet 2) as source of lipid and fatty acids at 2 % level. Natural diet Gracilariopsis heteroclada (Diet 3) served as the control. No significant difference in growth was observed in abalone fed Diet 3 (SGR: 5.3 % BW day^?1; DISL: 265 μm day^?1) and Diet 2 (SGR: 5.2 % BW day^?1; DISL: 255 μm day^?1). Survival ranged from 78 to 85 % for all treatments and was not significantly different from each other. A 96-h salinity stress test showed highest survival of 84 % in abalone fed Diet 2 compared with those fed diets 1 and 3 (42 %). The high growth rate of abalone fed Diet 2 and high tolerance to low salinity could be attributed to its high DHA content (8.9 %), which resulted to its high DHA/EPA ratio of 10.5 %. These fatty acids play a significant role in abalone nutrition. The fatty acid profile of abalone meat is a reflective of the fatty acid profile of the oil sources in the diet. The present study suggests that the use of Schizochytrium oil in lieu of CLO and SBO can support good growth of abalone which is comparable with abalone fed the natural seaweeds diet.     

Foraging of Iberian fattening pigs grazing natural pasture in the dehesa

Two different herds of Iberian pigs have been studied in the montanera fattening period (from November first to end of December) in the dehesa agrosystem (clear forest of evergreen oaks, Quercus rotundifolia) during two different autumns and winters (2003 and 2004) without any supplementary feed. A direct in situ observation method has been used, with continuous observation of ingestive bites taken by continuously monitored pigs (10 uninterrupted hours, from 08:30 to 18:30) to calculate intake. 95 grazing days have been studied corresponding to different randomly chosen pigs. The obtained results show grass and acorns as the main resources with 56.5 and 43.3% of bites respectively. 14 other resources different from grass and acorns were registered, but only 9 resources (berries, bushes, inorganic rubbish, woods, roots, earth and sand, charcoal and ashes, carrion and straw) were consumed at a frequency ≥ 0.01%. The percentage distribution for daily bites showed no significant difference between years. However daily grazing times were significantly affected by year, and were associated with available drinking water from rain. Lack of water in second montanera forced pigs to return to shelters to drink and, in consequence, reduced daily mean grazing time (from 427 ± 14 min in montanera 1 to 368 ± 8 in montanera 2; P < 0.001) and kernel acorn dry matter intake (from 3.6 ± 0.3 kg in montanera 1 to 3.1 ± 0.1 in montanera 2; P < 0.05); however, it did not significantly influence either daily grass dry matter intake (0.38 ± 0.04 kg in montanera 1 versus 0.49 ± 0.04 kg in montanera 2) or total daily dry matter intake calculated from bite number (4.0 ± 0.3 kg in montanera 1 versus 3.6 ± 0.1 in montanera 2).     

The fate of arsenic in soils adjacent to an old mine site (Bustarviejo,Spain): mobility and transfer to native flora

Background, aim, and scope  

The mobility of arsenic in soils and its transfer to other environmental components present significant environmental risks. The management of polluted land is determined by the availability, mobility, and transfer of inorganic pollutants to different ecosystem compartments. In this paper, the fate of arsenic at this mining site has been evaluated to determine future management practises to minimise such risk.     

Linking models for assessing agricultural land use change

The ex-ante assessment of the likely impacts of policy changes and technological innovations on agriculture can provide insight into policy effects on land use and other resources and inform discussion on the desirability of such changes. Integrated assessment and modeling (IAM) is an approach that can be used for ex-ante assessment. It may combine several quantitative models representing different processes and scales into a framework for integrated assessment to allow for multi scale analysis of environmental, economic and social issues. IAM is a challenging task as models from different disciplines have a different representation of data, space and time. The aim of this paper is to describe our strategy to conceptually, semantically and technically integrate a chain of models from different domains to assess land use changes. The models that were linked are based on different modeling techniques (e.g. optimization, simulation, estimation) and operate on different time and spatial scales. The conceptual integration to ensure consistent linkage of simulated processes and scales required modelers representing the different models to clarify the data exchanged and interlinking of modeling methodologies across scales. For semantic integration, ontologies provided a way to rigorously define conceptualizations that can be easily shared between various disciplines. Finally, for technical integration, OpenMI was used and supplemented with the information from ontologies. In our case, explicitly tackling the challenge of semantic, conceptual and technical integration of models forced researchers to clarify the assumptions of their model interfaces, which helped to document the model linkage and to efficiently run models together. The linked models can now easily be used for integrated assessments of policy changes, technological innovations and societal and biophysical changes.     

Structural development of Pacific red snapper Lutjanus peru from hatching to the onset of first feeding

Successful rearing of larval fish requires culture conditions and feeding strategies matching the ontogenetic status of larvae. This study describes the external morphology and development of organs and structures involved in the feeding process (i.e. sensorial organs, mouthparts and digestive system) from hatching until first feeding in Pacific red snapper. Hatching occurred 26 h after fertilization at 26°C and total length (TL) was 2.45 ± 0.08 mm. The larvae showed an undifferentiated eye and digestive tract. At 48 hah, TL was 3.31 ± 0.12 mm. Yolk and oil globule were still present. The mouth was still closed, but the Meckel's, quadrate, hyoid and hyomandibular cartilages were present. The retina was formed by 5 layers, and a thin layer of pigment epithelium was observed in the outer nuclear layer (ONL). At 70 hah, TL was 3.44 ± 0.22 mm. A remnant of oil globule was still present. The mouth and anus were open. At 93 hah, the number of cones in the ONL of the retina have increased and there was more pigment in the pigment epithelial layer. A joint between Meckel's and the quadrate cartilage and also a joint between the hyomandibular cartilage and the skull were present. The presence of live feed was detected in the digestive tract of these larvae. Based on these observations, the Pacific red snapper larvae is functional to start ingesting live feed between the 3rd and 4th day after hatching.     

Benzophenone-3 Removal Using Heterogeneous Photocatalysis at Pilot Scale

This paper presents the main results obtained using the heterogeneous photocatalysis with TiO₂ technology in the removal of the emerging contaminant benzophenone-3 at pilot plant scale in a cylinder parabolic solar collector. In this sense, the effects of the operational parameters, pH and catalyst concentration, were analyzed, and after the use of the response surface methodology, the conditions that, under the experimental range, conduct to a higher removal of the analyte were selected. Additionally, analysis of the total organic carbon content and the biodegradability index (relationship between BDO₅ and COD) of the treated samples were carried out. In general, results allowed us to infer that this kind of treatment is effective in removing a considerable percentage of the substrate, and that it could become an effective alternative to water treatment and decontamination.     

Relevance of age at slaughter on meat quality of turkeys stunned with CO2

1. The objective of this work was to determine the effect of slaughter age and stunning method on the quality of turkey meat from poultry processing plants.

2. One hundred B.U.T. Premium turkeys were divided into 4 groups of 25 animals according to slaughter age (15 or 17 weeks) and CO₂ stunning procedure (G1 stepwise: step1: 30% CO₂, 15 s; step 2: 55% CO₂, 40 s; step 3: 70% CO₂, 45 s; G2: progressive increase of the CO₂ concentration at a rate of 0.8% per s for 100 s). The quality of the breast meat was determined in fillets taken at different post-mortem times.

3. There were differences between the stunning groups for several variables (pH: 6.01 ± 0.01 and 5.95 ± 0.02; a*: ?1.84 ± 0.05 and ?2.21 ± 0.04; b*: 4.99 ± 0.15 and 4.68 ± 0.16; drip loss: 0.85 ± 0.02 and 0.71 ± 0.02 for G1 and G2, respectively), while no significant differences were found for L*, cooking loss and texture analysed with a Warner Bratzler Shear Force cell (WBSF).

4. Slaughter age had a significant effect on all the parameters studied (pH: 6.01 ± 0.01 and 5.95 ± 0.01; a*: ?2.21 ± 0.05 and ?1.88 ± 0.05, b*: 5.50 ± 0.17 and 4.42 ± 0.15; drip loss: 0.71 ± 0.02 and 0.86 ± 0.02, cooking loss: 12.56 ± 0.22 and 14.69 ± 0.16 for turkeys slaughtered at 15 and 17 w, respectively) except on L* and WBSF.

5. The ageing of the meat affected pH, colour values, drip loss and WBSF, with differing degrees of evolution: mean values of L* (39.36 ± 0.35. 45.77 ± 0.20 and 46.30 ± 0.24, for 20 min, 24 h and 7 d post mortem, respectively) and drip loss (0.75 ± 0.03 and 0.84 ± 0.02 for 24 h and 7 d post mortem, respectively) increased, those of a* (?1.77 ± 0.08, ?1.94 ± 0.07 and ?2.22 ± 0.05 for 20 min, 24 h and 7 d post mortem, respectively) and WBSF decreased (3.73 ± 0.06 and 2.63 ± 0.04 for 24 h and 7 d post mortem, respectively), those of pH decreased in the first 24 h and remained stable for the next 6 d (6.19 ± 0.02, 5.87 ± 0.01 and 5.88 ± 0.01), and those of b* increased in the first 24 h post-mortem and remained stable for the next 6 d (3.26 ± 0.31, 5.86 ± 0.16 and 5.47 ± 0.08).

6. The results revealed no critical differences between stunning methods, and suggest that animals slaughtered at 15 weeks present higher quality meat than those slaughtered at 17 weeks.