Effect of cultivated copepods (Acartia tonsa) in first‐feeding of Atlantic cod (Gadus morhua) and ballan wrasse (Labrus bergylta) larvae

The aim of this study was to compare the nutritional composition and effects of short periods with cultivated copepod nauplii versus rotifers in first‐feeding. Atlantic cod (Gadus morhua) and ballan wrasse (Labrus bergylta) larvae were given four different dietary regimes in the earliest start‐feeding period. One group was fed the copepod Acartia tonsa nauplii (Cop), a second fed enriched rotifers (RotMG), a third fed unenriched rotifers (RotChl) and a fourth copepods for the seven first days of feeding and enriched rotifers the rest of the period (Cop7). Cod larvae were fed Artemia sp. between 20 and 40 dph (days posthatching), and ballan wrasse between 36 and 40 dph, with weaning to a formulated diet thereafter. In addition to assessing growth and survival, response to handling stress was measured. This study showed that even short periods of feeding with cultivated copepod nauplii (7 days) had positive long‐term effects on the growth and viability of the fish larvae. At the end of both studies (60 days posthatching), fish larvae fed copepods showed higher survival, better growth and viability than larvae fed rotifers. This underlines the importance of early larval nutrition.     

Effects of light and short-term temperature elevation on the 48-h hatching success of cold-stored Acartia tonsa Dana eggs

The effects of light and short-term temperature elevation on the 48-h egg hatching success (HS) of cold-stored (2 °C) Acartia tonsa Dana (Copepoda: Calanoida) eggs were examined in the present study. The eggs can be stored for up to 7.5 months and maintain their high hatching rate under optimal conditions. Intensively produced eggs from the copepod A. tonsa may be hatched and used as an inoculum for producing copepod nauplii as live feed for fish larvae. The HS for eggs that were directly exposed to LED light declined rapidly after 1 month of storage (from 91 to 25 %), and these eggs did not hatch at all after 3 months of storage. The highest HS found was for eggs stored in complete darkness. The HS for eggs stored in normoxic (≥7 mg DO L^?1) and anoxic (≤0.03 mg DO L^?1) seawater was not affected by short-term temperature transitions from 2 °C up to 9 or 17 °C for a period of 12 or 24 h, when hatched 1 week post-exposure. The global mean HS for eggs stored in normoxic seawater was 85.9 % and significantly lower compared to eggs stored under anoxic conditions after 3 weeks of storage (91.8 %) (P = 0.001; SNK).     

Comparative studies of the standardization of erysipeloid immune sera "Dessau" from swine using the mouse-protection test and ELISA]

Different serological methods were used in determining the valence of red murrain immune sera. By using a grow test it is possible to accomplish an immunological differentiation of the immune sera. The used ELISA was tested in comparison to the conventional mouse protective test (PRIGGE, 1950) with regard to its valuation of immune sera. Both procedures have been tested on a possible correlation. In almost all cases a correlation between high titres in ELISA and a mouse protective value over 100 I.E. could be proven. The statistical processing of the test results proved an assumed correlation of both procedures. But it is necessary to carry out further research in order to be able to recommend this procedure as an alternative for the mouse protection test.     

Über die Mischungsverhältnisse in Mischzellen des Statusalbomaculatus vonAntirrhinum majus L.

Summary 1. In variegated leaves of a statusalbomaculatus ofAntirrhinum majus L. mixed cells are present containing two types of plastids (green and pale). Data are given for the frequency of the different ratios of green and pale plastids (Table 1).2. In young foliage leaves (Fig. 1), bracts, and sepals (Fig. 2) the frequency distribution of the different ratios is very similar to a normal curve.3. From the mean and this frequency distribution it is concluded that in mixed cells green and pale plastids have nearly the same rate of multiplication.4. In old foliage leaves a skew distribution is found (Fig. 1). The reason for this is, that the pale plastids decay with increasing age of the leaves. Therefore in mixed cells the green plastids prevail.5. In order to demonstrate differences in the rate of multiplication between two types of plastids it is necessary to pay attention to changes of the ratios caused by aging. Secondary changes of this kind must be excluded.

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Detection of Erysipelothrix rhusiopathiae specific antibodies in the serum of experimentally-infected swine by ELISA and immunoblotting

In an attempt to characterize the immuno response of the animal organism to experimental infection, ELISA and immunoblotting were used to test the antibody levels of erysipelas hyperimmune sera (HIS) which had been induced by Erysipelothrix rhusiopathiae. Also, 5 pigs were accidentally chosen to check on individual curves of antibody formation, following periodical inoculation up to HIS collection. All HIS verified and confirmed by the mouse protective test responded by high titres. Yet, the results so far obtained from HIS titration have failed to be conclusive as to valency. The animals selected for these experiments exhibited differentiated antibody levels during the phase of immunisation, although they were at one and the same level, when measured by the final titre, following last boostering. The desired rise in antibody levels was achieved only by the 4th to 9th boostering in almost all cases. Extinction values determined by ELISA were confirmed or supplemented by the results obtained from immunoblotting.     

Comparative behaviour studies in horses infested with flying insects treated with insecticide or repellent substances

The aim of this study was to estimate the effects of flying insects (Order Diptera) on the behaviour of grazing horses in relation to the use of insecticide and repellent substances. The investigations were done between June and August in 2008 in 3 periods of 7 days each. As insecticide and repellent two substances were used: "Well-care emulsion" (Co. Essex Tierarznei, München, GER) containing Permethrin and "Bremsen-Frei-Plus" (Co. Dr. Schaette AG, Bad Waldsee, GER) based on etheric oils. Both groups were compared with a non treated control group in a crossover-design. Each group (n = 3-5) was used alternately as control and treatment group. Several climate parameters were taken during the study. Furthermore, the number of insects per animal was estimated at certain times. Once per observation period insects were caught using Malaise traps and differentiated by species. The proportion of horse relevant species of the genera Diptera, especially Culex pipiens and Musca autumnalis, caught was 9% on an average. There was no correlation between the number of Tabanidae caught in the Malaise traps and the number observed near by the horses. Behaviour parameters like tailswishing, headshaking, stamping, skintwitching, snapping at the body, and moving were observed more frequently with increasing insect infestation. When horses were infested with a high number of flying insects, feeding activity was significant lower, whereas locomotion activity was significant higher. Both substances had positive effects for about 50 hours after application with no apparent difference between the substances. However, a lower frequency of headshaking and tailswishing could be observed in the Permethrin treated horses.     

Exhaustive Screening of Long-Term Pollutants in Riverbank Sediments of the Wurm River,Germany

Fluvial sediments can act as archives for long-term pollution. However, in environmental studies, often only preselected contaminants and, therefore, only a limited part of the pollution are considered. Herein, geochemical investigations of riverbank samples of the Wurm River (catchment <?400 km²) depict the anthropogenic impact of the city Aachen (250,000 inhabitants) to its main outlet resulting in an exhaustive list of present pollutants including their concentrations. The study is based on 14 riverbank sediment samples at eight sampling sites on a 7.6-km-long segment of the Wurm River. The sediment samples were analyzed for grain size composition (laser diffraction particle size analyzer), total organic carbon (TOC), trace element inventory (X-ray fluorescence), and organic compounds (chromatography-mass spectrometry). Here, we report quantitative data for 71 persistent organic substances as well as six trace elements (Cu, Zn, As, Ba, Hg, and Pb) entering the Wurm River due to domestic and industrial emissions. In general, a slight decline of, e.g., PTEs, DDX, and PCB concentrations with decreasing sampling depth points to a steady improvement of conditions. Whereas no clear trends can be seen for organic pollutants along the investigated reach with increasing distance to the main source of pollution (Aachen city). As obtained concentrations for organic pollutants indicate a rather low level of pollution, trace element values exceed geogenic background values by far. Furthermore, we used selected compounds as time markers for a rough estimation of sedimentation rates. Obtained values point to a highly complex morphodynamic regime with changing sedimentation rates (0.6 to 3.0 cm a^?1) within barely 100 m of river course.