Profile of fatty acid lipid fractions of omega-3 fatty acid-enriched table eggs

The omega-3 fatty acid (FA) enrichment of yolk is a key means one of the main objectives to improve the nutraceutical properties of eggs. We evaluated the effect of the dietary inclusion of extruded linseed fed to laying hens on the fatty acid composition of the polar and non-polar lipid classes of the eggs. Two groups of 36 Lohmann White Leghorn layers (65 weeks old) were each fed one of two different diets for a period of 12 weeks. The two diets consisted of a conventional cereal-based diet concentrate (C) and a diet concentrate containing 5% linseed (L). The inclusion of linseed in the diet increased the content of α-linolenic (C18:3n-3), eicosapentaenoic (C20:5n-3) and docosahexaenoic (C22:6n-3) acids in neutral lipids, while a concomitant decrease in arachidonic acid (C20:4n-6) was observed. As regards the polar fraction, the fatty acid composition was slightly affected by the dietary treatments except for C18:0 (+1.14 fold), C18:2n-6 (+1.23 fold), C18:3n-3 (+2.8 fold) and C22:6n-3 (+1.41 fold). Principal component analysis demonstrated that very long-chain FAs were more representative of polar lipids, except for C20:5n-3, while neutral lipids were characterized by dietary n-3 FA (C18:3n-3).     

Detection and quantitation of genetically modified maize (Bt-176 transgenic maize) by applying ligation detection reaction and universal array technology

We have applied the ligation detection reaction (LDR) combined with a universal array approach to the detection and quantitation of the polymerase chain reaction (PCR) amplified cry1A(b) gene from Bt-176 transgenic maize. We demonstrated excellent specificity and high sensitivity. Down to 0.5 fmol (nearly 60 pg) of PCR amplified transgenic material was unequivocally detected with excellent linearity within the 0.1-2.0% range with respect to wild-type maize. We suggest the feasibility of extending the LDR/universal array format to detect in parallel several transgenic sequences that are being developed for food applications.     

Influence of tillage systems on biological properties of a Typic Argiudoll soil under continuous maize in central Argentina

Farmers are increasingly using zero tillage in Central Argentina to replace other tillage systems. Intensive tillage decreases soil organic matter content and causes physical degradation. The objective of this work was to evaluate changes in some soil biological properties induced by different tillage systems. A 6 year experiment in which continuous maize (Zea mays L.) was grown using three tillage systems (conventional tillage, reduced tillage and zero tillage) was carried out at Córdoba Province, Argentina, on a Typic Argiudoll. Variations in total organic C content, microbial biomass C, metabolic quotient (qCO₂) and the proportion of the organic C present in the microbial biomass were evaluated at two sampling depths (0–5 and 5–15 cm). Additional samples from a nearby site (undisturbed grassland) were also taken and considered as a control. Concentrations of soil organic C and microbial biomass C were higher under zero tillage as compared with conventional tillage, at the 0–5 cm soil depth. Differences were not evident among tillage systems at the 5–15 cm soil depth. An analysis of the microbial biomass C content, in relation to the organic C, revealed higher values at the 0–5 cm soil depth only for those systems which provoke less disturbance of the soil (i.e. reduced tillage and zero tillage). Significantly greater amounts of CO₂---C were released from zero tillage and reduced tillage soils than from conventionally tilled soils. This release was positively correlated with microbial biomass C. qCO₂ values were not significantly different between tillage systems. Zero tillage proved to be more efficient in the conservation of organic C and microbial biomass C. The tillage system's impact on respiration was due to its effect on the microbial biomass.     

Community dynamics of soil Collembola in floodplains of the Upper Rhine Valley

In floodplain habitats inundation is a seasonally reoccurring phenomena. It represents a natural disturbance for the biocoenoses, causing their successional development to be reset. Collembola generally have developmental cycles that coincide with the yearly inundation incidences. They show perpetual regeneration, which is dependent on flooding intensity. Collembolan communities have been studied in floodplains of the Upper Rhine Valley since the mid-1990s. The development of collembolan communities was followed spatially in different floodplain levels in close vicinity to one another (with different inundation durations within the same year) as well as temporally within the same floodplain levels in different sites. Community development and structure depended mostly on inundation duration and differed from year to year in the same site. Through the differences in the population densities of the various species between sites as well as in different years, species groups, differing in their inundation tolerance, were distinguished. The species occurred either sympatrically or belonged to a common regional species pool (metacommunity). Which species dominated at individual sites depended on the inundation intensity of the individual site and year. The mixture of different inundation tolerances as well as regeneration strategies in the metacommunity, coupled with probable species exchange between patches, determines the composition and structure of local collembolan communities in floodplain forests. These communities are very heterogeneous at small spatial scales. They can thus differentially respond to different flooding intensities and maintain stabile metacommunities despite frequent, but irregular natural disturbances.     

Effect of Groundwater Inorganics on the Reductive Dechlorination of TCE by Zero-Valent Iron

Although permeable reactive barriers (PRB) technology appears to be a very suitable and cost effective option, the extent to which remediation results will be realized, greatly depends on the long-term integrity of the system. The formation of mineral precipitates is possibly a major factor in the long-term performance of PRB. Precipitates may passivate reactive surfaces by blocking electron-transfer sites, and thereby reduce the long-term reactivity of the granular iron to degrade groundwater contaminants. To evaluate the potential passivation impacts of inorganic groundwater chemistry, column experiments containing zero-valent iron (Fe⁰) were performed under anoxic conditions to treat two contrasting Danish groundwater types spiked with trichloroethylene (TCE). For most of the experiments using Danish groundwater types, a soft low alkalinity groundwater produced slightly higher TCE dechlorination rate than did a hard high alkalinity groundwater. Compared to a soft low alkalinity baseline groundwater, it was also found the dechlorination of TCE in the column was enhanced in the presence of 1 mM CaCO₃ and 1 mM NaHCO₃. The dechlorination of TCE in the presence of 1 mM KNO₃ and 1 mM Na₂SiO₃ was found to decrease considerably compared with the baseline solution. The results suggest that the composition of field groundwater is likely to strongly affect the ability of Fe⁰ barriers to degrade TCE.     

Development of a seven-target multiplex PCR for the simultaneous detection of transgenic soybean and maize in feeds and foods

The detection of genetically modified organisms (GMOs) in food and feed is an important issue for all the subjects involved in raw material control, food industry, and distribution. Because the number of GMOs authorized in the EU increased during the past few years, there is a need for methods that allow a rapid screening of products. In this paper, we propose a method for the simultaneous detection of four transgenic maize (MON810, Bt11, Bt 176, and GA21) and one transgenic soybean (Roundup Ready), which allows routine control analyses to be sped up. DNA was extracted either from maize and soybean seeds and leaves or reference materials, and the recombinant DNA target sequences were detected with 7 primer pairs, accurately designed to be highly specific for each investigated transgene. Cross and negative controls were performed to ensure the specificity of each primer pair. The method was validated on an interlaboratory ring test and good analytical parameters were obtained (LOD = 0.25%, Repeatability, (r) = 1; Reproducibility, (R) = 0.9). The method was then applied to a model biscuit made of transgenic materials baked for the purpose and to real samples such as feed and foodstuffs. On account of the high recognition specificity and the good detection limits, this multiplex PCR represents a fast and reliable screening method directly applicable in all the laboratories involved in raw material and food control.     

Residues and half-life times of pyrethrins on peaches after field treatments

The behavior of pyrethrins and piperonyl butoxide (PB) on peaches has been studied after field treatment. Three experiments were carried out at 1, 5, and 10x the concentration recommended by the manufacturer. In all experiments, the initial deposition was below the maximum residue level (MRL), and the half-life time calculated in the 10x experiment for total pyrethrins within 2.3 days was in agreement with the preharvest interval (PHI) recommended. In a model system, the photodegradation rates of the pyrethrins in three commercial products were compared with pyrethrum pale (PP), with and without the presence of peach waxes. The pyrethrins in formulations containing PB showed higher half-life times but were not influenced by the presence of waxes, whereas in the case of PP that does not contain any PB, photodegradation was significantly affected by the presence of waxes.     

Nitrogen Deposition and Nitrate Leaching at Forest Edges Exposed to High Ammonia Emissions in Southern Bavaria

The atmospheric deposition of air pollutants was studied by means of monitoring canopy throughfall at six forest stands. The investigation was carried out in Norway spruce (Picea abies L. Karst.) forests in Southern Bavaria with high ambient ammonia concentrations due to either adjacent intensive agriculture or poultry housing. Five monitoring plots transected the forest edges and forest interior from the edge, at 50, 150, about 400 m and about 800m to the interior. Additionally, nutrient concentration in soil solution was sampled with suction cups at each plot, and C/N ratio of the humus layer was also determined. The variation of ambient ammonia concentration between three of the six investigated sites was estimated using diffusive samplers. In order to compare the effects of atmospheric deposition on European beech (Fagus sylvatica L.) and Norway spruce additional monitoring plotswere installed under each of these species in a mixed beech and spruce stand. Bulk deposition and soil water samples were analysed for major ions (NO₃ ^-, NH₄ ⁺, SO₄ ^2-, Cl^-, Na⁺, K⁺, Mg²⁺, Ca^2+M).The results show a substantial increase of deposition towards the forest edges for all ions. This so called 'edge effect' continued in most cases until a distance from 50 to 150 m from edge. For both ambient ammonia concentrations and nitrogen deposition, it can be concluded that increased dry deposition is the main reason for the edge effect. Over 76% of the nitrogen ratios in throughfall deposition between the edge and 50 m distance into the spruce forest exceed 1.0. Except for potassium, beech generally showed lower ratios than spruce.Due to high nitrogen deposition the forest floor, C/N ratios were lower at stand edges when compared to their interior. In contrast to the increase of nitrogen deposition at the edge, nitrate export below the main rooting zone was lower at the edge. Nitrate export was generally lower under beech than spruce. Nitrogen budgets of some plots were negative, indicating a reduction of total ecosystem nitrogen stock.The results show that forest edges, especially in areas with high air pollution, receive much more atmospheric deposition than the interior parts of closed forest stands. As many deposition studies in forests were conducted at field stations in the central parts of forests the estimated deposition for the whole forest may be underestimated. This may be important to consider in geo-statistical studies and models aiming to estimate spatial critical deposition values, especially with an increasing fragmentation of the forest cover.