Environmental impact of razor clam harvesting using salt in Ria Formosa lagoon (Southern Portugal) and subsequent recovery of associated benthic communities

• 1. Razor clams are found in different habitats ranging from sheltered systems (e.g. lagoons and estuaries) to open coasts. They are distributed worldwide and comprise a small number of species of high economic value. Depending on the specific habitat and species exploited, different mechanical and hand‐harvesting techniques are employed. While the environmental effects resulting from mechanized methods have been described by several authors, the impacts caused by traditional hand‐harvesting methods remain unknown. Therefore, a study was undertaken in Ria Formosa lagoon (South of Portugal) addressing the environmental effects resulting from harvesting Solen marginatus with salt.
• 2. No significant impact on the sediment was found; the main effect was an increase in salinity after covering the area with salt, which decreased rapidly with the flood tide and after a few hours had returned to pre‐harvesting levels.
• 3. No effects on benthic communities were observed, with similar fluctuation patterns recorded in control and experimental areas, the observed differences being attributed to the natural variability of benthic populations.
• 4. Based on the results obtained in the present study, a razor clam fishery using salt in intertidal areas can be considered environmentally ‘friendly’.

Copyright © 2008 John Wiley & Sons, Ltd.     

Functional Feeds to Tackle Meagre (Argyrosomus regius) Stress: Physiological Responses under Acute Stressful Handling Conditions

Marine algae are recognised sources of bioactive compounds that have attracted great interest as nutritional supplements for aquaculture fish. Intensive rearing conditions often expose fish to husbandry-related stressors, rendering fish more susceptible to disease and reducing production yields. The present work evaluated the potential of two marine algae extracts (Fucus vesiculosus and Nannochloropsis gaditana) as nutritional supplements to mitigate stress effects in meagre (Argyrosomus regius) exposed to an acute handling stress (AS). A plant-based diet was used as a control, and three other diets were prepared, which were similar to the control diet but supplemented with 1% of each algal extract or a combination of the two extracts (0.5% each). The effects of supplemented diets on stress biomarkers, antioxidant enzyme activities, and immune response were analysed in fish exposed to AS after 4 weeks of feeding. Supplemented diets did not affect growth performance but the inclusion of F. vesiculosus promoted higher feed efficiency, as compared to the control group. Dietary algal extracts supplementation reduced plasma glucose levels, increased white blood cell counts, and reduced the expression of pro-inflammatory genes when compared with the control. N. gaditana supplementation led to a reduction in hepatic antioxidant enzyme activity and glutathione levels, while F. vesiculosus supplementation increased muscle glutathione reductase activity and reduced lipid peroxidation. These findings support the potential of algal extracts as nutraceuticals in aquafeeds to enhance the ability of fish to cope with husbandry-related stressful conditions and ultimately improve fish health and welfare.     

Effects of an Enterococcus faecium‐based probiotic on growth performance and health of Pirarucu,Arapaima gigas

Intensive fish farming has resulted in an increased concern for disease outbreaks. Probiotic use is one of the strategies being developed to improve fish health and productivity. Measures of probiotic colonization, growth performance, haematological characteristics and parasite load were used to evaluate the effect of diets supplemented with Enterococcus faecium on growth and health of Arapaima gigas juveniles. A completely randomized design with four treatments (diet with E. faecium at 1 × 10⁶ CFU/g and 1 × 10⁸ CFU/g, control diet and diet with the culture medium MRS) and three replicates was used. Ninety‐six Arapaima juveniles were distributed in 12 cages fed with the specified diet for 68 days. Colonization of the intestinal tract by lactic acid bacteria reduced the total number of heterotrophic bacteria in fish fed with probiotics compared to controls. Fish fed a supplemented diet containing 1 × 10⁸ CFU/g presented higher values of weight gain, survival and fish growth uniformity, and lower values of feed conversion ratio. The prevalence of Trichodina sp. could have affected the survival of fish in the control group. Reduction in parasite load and an increase in haematocrit, the number of erythrocytes, thrombocytes, neutrophils and monocytes were also observed in fish fed the diet containing 1 × 10⁸ CFU/g. Enterococcus faecium presented a probiotic effect in A. gigas juveniles and can be recommended for use at a concentration of 1 × 10⁸ CFU/g to modify the gut microbiota, improve growth performance and haematology and reduce parasitic load.     

New organic substrates and boron fertilizing for production of yellow passion fruit seedlings

The identification of alternative substrates suitable for seedling production is very important, while boron nutrition is also relevant due to plant requirement and its difficult management. Thus, four experiments were carried out from October 2012 to April 2013 to evaluate the effect of substrates using decomposed buriti (Mauritia vinifera Mart.) stem (DBS) and boron fertilizing for seedling production of yellow passion fruit (Passiflora edulis Sims). The experimental design was completely randomized in factorial scheme 6 × 2 + 1, referring to the substrates [S1: DBS, S2: soil and sand 1:1 (20%) + DBS (80%), S3: soil and sand 1:1 (40%) + DBS (60%), S4: soil and sand 1:1 (60%) + DBS (40%), S5: soil and sand 1:1 (80%) + DBS (20%), S6: commercial substrate (additional treatment) and S7: soil, sand and manure 1:1:2] with and without boron. The seedling emergence, emergence rate, plant height, stem diameter, root length, root volume and dry mass of roots and shoots were recorded. The substrates S2 (without B fertilizing) and S4 (B fertilized with 0.5 mg dm^?3) produced seedlings with more than 3.0 g of shoot dry mass and at least 30 cm in height, and can be used for production of high-quality yellow passion fruit seedlings.     

Bahiagrass response and N loss from selected N fertilizer sources

The increasing cost of commercial fertilizers and environmental problems associated with improper fertilization management have prompted the need to re‐examine commercial N sources that can effectively supply N to pastures while minimizing N losses. This 3‐year study evaluated the effects of selected N sources on bahiagrass (Paspalum notatum Flügge) responses, soil properties and N losses. Treatments consisted of a factorial combination of 6 N sources [(i) ammonium nitrate (AN), (ii) ammonium sulphate (AS), (iii) urea (U), (iv) urea treated with Agrotain (U + Agrotain), (v) SuperU and (vi) ammonium sulphate nitrate] and 3 N levels (0, 60 or 120 kg ha^?1 year^?1), replicated three times. Bahiagrass dry‐matter yield (DMY), crude protein (CP) concentration, N uptake and recovery were not affected by N source, with the exception of AN that resulted in reduced DMY in 2010 compared with the other sources. Bahiagrass DMY, CP concentration, N uptake and recovery increased linearly as N levels increased. Nitrogen fertilization showed no effect on soil pH or soil N accumulation. Soil pore‐water N concentrations from treatments fertilized with N were similar to the control plots indicating no threat to the environment. At the N levels evaluated in this study, selection of N source should be based on the fertilizer cost.     

Modelling interception loss from evergreen oak Mediterranean savannas: Application of a tree-based modelling approach

In a previous study, it was shown that an isolated, fully saturated tree-crown behaves like a wet bulb, allowing evaporation of intercepted rainfall to be estimated by a simple diffusion equation for water vapour. This observation was taken as the basis for a new approach in modelling interception loss from savanna-type woodland, whereby the ecosystem evaporation is derived by scaling up the evaporation from individual trees, rather than by considering a homogeneous forest cover. Interception loss from isolated trees was estimated by combining the aforementioned equation for water vapour flux with Gash's analytical model. A new methodology, which avoids the subjectivity inherent in the Leyton method, was used for estimating the crown storage capacity. Modelling performance was evaluated against data from two Mediterranean savanna-type oak woodlands (montados) in southern Portugal. Interception loss estimates were in good agreement with observations in both sites. The proposed modelling approach is physically based, requires only a limited amount of data and should be suitable for the modelling of interception loss in isolated trees and savanna-type ecosystems.     

Intestinal antiinflammatory activity of a lyophilized infusion of Turnera ulmifolia in TNBS rat colitis

Turnera ulmifolia is a plant popularly known in Brazil and South America as chanana. Some species of Turnera are widely used in folk medicine for different types of inflammatory diseases. In this study, the preventive intestinal antiinflammatory activity of a lyophilized infusion obtained from the aerial parts of T. ulmifolia was tested in the trinitrobenzenesulphonic acid (TNBS) model of rat colitis. The results obtained revealed that pretreatment to colitic rats with the extract, at 250 and 500 mg/kg, significantly attenuated the colonic damage induced by TNBS. This beneficial effect was associated with an improvement in the colonic oxidative status, since the infusion prevented the glutathione depletion that occurred as a consequence of the colonic inflammation. On the other hand, this antioxidant activity was confirmed in in vitro studies. In conclusion, the preventive effect exerted by the lyophilized infusion of T. ulmifolia in the TNBS model of rat colitis is probably related to its antioxidant properties, due to its flavonoids content.     

Medium Light and Medium Roast Paper-Filtered Coffee Increased Antioxidant Capacity in Healthy Volunteers: Results of a Randomized Trial

We compared the effects of medium light roast (MLR) and medium roast (MR) paper-filtered coffee on antioxidant capacity and lipid peroxidation in healthy volunteers. In a randomized crossover study, 20 volunteers consumed 482?±?61?ml/day of MLR or MR for four weeks. Plasma total antioxidant status (TAS), oxygen radical absorbance capacity (ORAC), oxidized LDL and 8-epi-prostaglandin F2α, erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activity were measured at baseline and after the interventions. MLR had higher chlorogenic acids-(CGA; 334?mg/150?mL) and less caffeine (231?mg/150?ml) than MR had (210 and 244?mg/150?ml, respectively). MLR also had fewer Maillard reaction products (MRP) than MR had. Compared with baseline, subjects had an increase of 21 and 26?% in TAS, 13 and 13?% in CAT, 52 and 75?% in SOD, and 62 and 49?% in GPx after MLR and MR consumption (P?相似文献   

Validation of a thermal threshold nociceptive model in bearded dragons (Pogona vitticeps)

Objectives

To validate a thermal threshold (TT) nociceptive model in bearded dragons (Pogona vitticeps) and to document TT changes after administration of morphine.