Energy balance of Litopenaeus vannamei postlarvae fed on animal or vegetable protein based compounded feeds

L. vannamei postlarvae are normally raised with a protein dense diet (50% protein) rich in fishmeal. Part of the protein is utilized for energy purpose instead of protein synthesis. Based on a previous energy partitioning study, the effects of two isoenergetic compounded feed treatments – animal protein (AP) and vegetable protein and carbohydrates (VPC) – upon growth efficiency and energy budget of shrimp postlarvae and early juveniles were determined. Recovered energy (RE) or production (P) after 50 days trial was similar (2 J day^− 1) in both treatments, from PL₁₄ to PL₁₉. However, early juveniles discriminated between animal protein (116 J day^− 1) and vegetable protein and carbohydrates (88 J day^− 1). The difference in respiration indicated a higher heat increment with AP compared to VPC. At maintenance level, energy used was lower with AP than VPC treatment. Postlarvae and early juveniles employed protein as a main energy substrate (O:N < 20). Differences in the efficiencies observed in the calculated energy budget were attributed to the presence of carbohydrates in diet and not to the protein source. The advantage of incorporating vegetable protein source in the diet of harvesting shrimp may eventually contribute towards a reduction of fishmeal costs and waste products as well as to achieve sustainable shrimp farming.     

Changing patterns in insect pests on trees in The Netherlands since 1946 in relation to human induced habitat changes and climate factors—An analysis of historical data

In The Netherlands, insect pests on trees and shrubs are being monitored continuously since 1946. During these years, almost all insect pest populations showed marked changes, which may be the result of changes in forest management, shifts in forest composition, climate change and the arrival of new pests from the Mediterranean region or from other continents. In order to generate hypothesis about possible relationships between species ecology and environmental factors, we have analyzed 61 years of population development of the 98 most abundant species in the database while paying attention to life history traits and preferred host plants. The 22 species with infestations lasting a few years only were excluded from the analysis. Of the remaining 76 species, 18 were present over the entire observation period of 61 years. Of the other species, 27 showed a decline and 31 showed an increase. On coniferous trees most species showed decreasing populations. Increasing populations were found most on deciduous trees. Not directly climate-related factors such as changes in forest age, tree composition and forest management were identified as the most important causes for the fluctuations in pest insect populations. Climate change is a possible driver of the population increase in Thaumetopoea processionea, Haematoloma dorsatum and of the population decrease in Euproctis chrysorrhoea. The recently increasing exotic species Eupulvinaria hydrangeae and Pulvinaria regalis were exclusively found on trees in cities, presumably in relation to the higher temperatures of the urban habitat.     

The conservation effects of meadow bird agreements on farmland in Zeeland, The Netherlands, in the period 1989-1995

Meadow bird agreements are the most important Dutch agri-environment schemes, both in terms of uptake and of aim. Meadow bird agreements postpone the first agricultural activities on grassland thus reducing egg and chick mortality due to mowing or grazing. We investigated the conservation effects of meadow bird agreements by analysing settlement densities of meadow birds on 34 fields in 1989, 1992 and 1995 in the province of Zeeland, The Netherlands. We compared territory numbers on fields with meadow bird agreements with paired nearby control fields that were conventionally managed. In 1995, the number of territories of black-tailed godwit (Limosa limosa), lapwing (Vanellus vanellus) and the total number of meadow birds were significantly higher on fields with conservation management. These differences were partly caused by the higher quality (i.e. higher groundwater level) of fields with meadow bird agreements. Population trends were similar on fields with and without meadow bird agreements and the observed difference in settlement density in 1995 was already present in 1989. Furthermore the effectiveness of the scheme did not increase with time. Thus we found no conclusive evidence that the conservation measures themselves did result in higher territory numbers. Currently, we do not have sufficient ecological and behavioural knowledge of meadow birds to explain why the higher reproductive success does not result in higher settlement densities.     

Deposition and depletion of five anticoccidials in eggs

Anticoccidials are compounds that are widely used as feed additives to prevent and treat coccidiosis. They are licensed for use in a prescribed concentration and during a certain time interval for broilers and pullets but not for laying hens. It was shown in the past that carry-over at the feeding mill is found to be the main reason for the presence of residues in eggs. An animal experiment was set up to investigate the effect of carry-over at the feeding mill on the presence of residues of anticoccidials in eggs. For the compounds diclazuril, robenidine, halofuginone and nicarbazin in combination with narasin, two concentration levels were tested: the maximum allowed concentration for broilers (100%) and a concentration corresponding to 5% carry-over during feed preparation. Also dimetridazole was included in the experiment but only at one concentration level. Eggs were sampled during treatment (14 days) and for a period of 30 days after withdrawal of the anticoccidial-containing feed. Residues were determined, and deposition and depletion curves were generated. Analyses were performed by ELISA and LC-MS/MS. For all compounds, substantial residues could be found in the 5% groups, which points out the risk of carry-over at the feeding mill. The distribution of the residues between egg yolk and white was determined by analyzing both fractions.     

Monitoring Metal Speciation in The rivers Meuse and Rhine Using DGT

Although a number of metal speciation methods are nowadays available, most water quality regulations are based on total metal concentrations. One of the main reasons for the ignorance of speciation is the lack of methods with potentiality for monitoring. Conditions that have to be met by such speciation methods are: simple performance, robust and sufficiently accurate. In this study the potential for monitoring purposes of Diffusive Gradients in Thin films (DGT) is investigated as part of a European project for sensor development for routine prediction of metal biouptake in natural waters. Performance characteristics of DGT have been assessed in experiments under controlled laboratory conditions and during in situ application over 4–9 months under different hydrological conditions in the rivers Meuse and Rhine. Results have been worked out for Cu, Ni and Pb. The study shows that DGT has sufficient potential as a robust tool in routine monitoring to observe trends in water quality. However, it appears that during in situ application of DGT the measurement uncertainty of the results is much larger than under laboratory conditions. The increase in measurement uncertainties will partially be due to uncertainties in some as constant considered factors in the calculation of the DGT concentration. For Cu and Ni, the average values for the reproducibility in the rivers Meuse and Rhine appeared to be 28% and 17%, respectively, whereas under laboratory conditions the reproducibilities for both metals were better than 10%. In the speciation of Cu, Ni and Pb in the rivers Meuse and Rhine, the labile fraction, determined using DGT, decreased in the series Ni, Cu, Pb. The ratio of the non-labile and labile fractions of the metals appeared to decrease with increasing content of Dissolved Organic Carbon (DOC).     

Phenolic diterpenes,flavones, and rosmarinic acid distribution during the development of leaves,flowers, stems,and roots of Rosmarinus officinalis. Antioxidant activity

The distribution of six compounds with three different polyphenol skeletons have been studied in Rosmarinus officinalis: phenolic diterpenes (carnosic acid, carnosol, and 12-O-methylcarnosic acid), caffeoyl derivatives (rosmarinic acid), and flavones (isoscutellarein 7-O-glucoside and genkwanin), each showing a characteristic behavior and distribution during the vegetative cycle. Only in leaves were all six compounds present, and the highest accumulation rate was related with the young stages of development. Rosmarinic acid showed the highest concentrations of all the polyphenols in all organs. The distribution of this acid in leaves, flowers, and stems suggests that in the first stages of flower growth, levels were due to in situ biosynthesis, and in the last stages, the contribution of transport phenomena was increased. The antioxidant activity of six extracts with different polyphenolic composition was evaluated in aqueous and lipid systems. The results clearly suggest that rosemary extracts are excellent antioxidants in both aqueous and lipid systems.     

Eliminating amino acid interference during spectrophotometric NH4 analysis

Amino acids can interfere with NH₄⁺ in spectrophotometric NH₄⁺ determination hampering accurate quantification of the fate of NH₄⁺ and dissolved organic N in soils. Serious interference has been reported for soils rich in organic matter, and for soils that have been fumigated, oven-dried or fertilized where between 5 and 60% of the NH₄⁺ detected could be attributed to amino acid interference. We investigated whether a combination of gas diffusion and the classical Berthelot method can eliminate this interference, increasing the selectivity of the NH₄⁺ analysis. We tested this approach using synthetic amino acid solutions and a large set of terrestrial samples (n = 353), including pore water samples, (fumigated or dried) soil extracts, and extracts of manures, composts and crop residues. The evaluated method produced accurate (recovery > 99.7%) and reproducible (standard error = 2.2%) NH₄⁺ concentrations, eliminating any interference between amino acids and NH₄⁺ (interference < 0.3%). Interference from K₂SO₄ was also eliminated. The method is robust, broadly applicable and will improve our understanding of nitrogen cycling in various ecosystems, in particular those where high levels of amino acids occur.     

Influence of grape-harvesting steps on varietal thiol aromas in Sauvignon blanc wines

The intense tropical fruit aroma of Sauvignon blanc wines has been associated with the varietal thiols 3-mercaptohexanol (3MH), derived from odorless precursors in the grape, and 3-mercaptohexyl acetate (3MHA), arising from 3MH during fermentation. Grapes and juice were sourced from five locations in Marlborough, New Zealand, taking hand-picked grapes and samples at four stages during the mechanical harvesting process and pressing, which were then fermented in replicated 750 mL bottles. With each set of juices, the highest concentrations of Cys-3MH and Glut-3MH were found in the juices pressed to 1 bar, but these juices produced wines with lower 3MH and 3MHA concentrations. With three of the juices, there was an increase in varietal thiol content for wines made from juices that had been machine harvested compared to the hand-picked samples, which matched earlier findings of lower 3MH and 3MHA levels in wines made from hand-picked grapes. Juices that were more oxidized, and which showed a higher absorbance at 420 nm, were found to produce wines with lower 3MH and 3MHA concentrations.     

Temporal trends in dioxin, furan and polychlorinated biphenyl concentrations in bovine milk from farms adjacent to industrial and chemical installations over a 15 year period

The concentrations of polychlorinated dibenzo-p-dioxins, furans and polychlorinated biphenyls (PCBs) were measured in pooled bovine milk samples collected between 1991 and 2005 in County Cork, Ireland. The pooled samples were of bulk-tank milk collected from farms adjacent to industrial, chemical and pharmaceutical installations (target milk) or from rural farms distant from industrial activity (control milk). Comparing data between the first and last 3-year periods of the study revealed a 62% decrease in the mean total dioxin concentration in target milk from 1.58 to 0.60pg toxic equivalents (TEQ)/g fat. On the same basis the dioxin-like PCB concentration in target milk decreased by 80% over the study period (from 0.95pg to 0.19pg TEQ/g fat). The mean 'marker' PCB concentration in target milk from 1991 to 1993 inclusive was 3359pg/g fat. This value decreased by 75% to a mean of 849pg/g fat for the years 2003-2005 inclusive. The results of this study are consistent with low background dietary/environmental PCB contamination in both target and control herds. The total dioxin concentrations in all samples were well below the maximum tolerable limits permitted for marketable milk. The decrease in the total dioxin concentration in target and control milk samples over the study period was chiefly due to decreases in the concentration of dioxin-like PCBs, consistent with significant reductions in the concentration of PCBs in the dairy cow diet over the 15 year study period.