Carsten Schulz

Treatment of rainbow trout farm effluents in constructed wetland with emergent plants and subsurface horizontal water flow

The objective of this research was to investigate treatment of aquaculture effluents of flow-through systems in created wetlands. The constructed wetlands types used in this study were subsurface root zone systems with emergent plants and horizontal effluent soil percolation. Three 1.40×1.00×0.70 m (L×W×H) root zone systems were filled with sands of 1–2 mm particle size and planted with 20 rooted shoots of reed per square meter (Phragmites australis). Nutrient removal of rainbow trout (Oncorhynchus mykiss) effluents flowing through the wetland was determined for hydraulic loading rates of 1, 3 and 5 l/min corresponding to very short hydraulic residence times (HRTs) of 7.5, 2.5 and 1.5 h, respectively. Inflowing nutrients were removed within every continuously flooded wetland. Total suspended solids (TSS) and chemical oxygen demand (COD) were reduced by 95.8–97.3% and 64.1–73.8%, respectively, and demonstrated no influence of HRT. Total phosphorus (TP) and total nitrogen (TN) removal rates varied from 49.0% to 68.5% and 20.6% to 41.8%, respectively, and were negatively correlated with HRTs. Effluent purification was best at HRT of 7.5 h, but sufficient removal rates were achieved for shorter HRTs.

Growth performance and body composition of pike perch (Sander lucioperca) fed varying formulated and natural diets

To assess the effect of dietary composition on growth performance and body composition of pike perch (Sander lucioperca), fingerlings with an initial body weight of 1.36xa0g (just trained to accept formulated feed) were fed three experimental diets in triplicate for 90xa0days. Two feeding groups were fed with formulated diets (CD, CD+7) containing varying levels of crude lipid (CL) of 14.65% and 21.94% dry matter (d.m.) with crude protein (CP) levels of 59.73% and 56.56%, and one feeding group was fed a natural diet (chironomids, CP xa0=xa065.93% d.m.; CL xa0=xa07.20% d.m.). Furthermore, pike perch of the same age caught in different natural habitats were analysed to determine their naturally fluctuations in body composition. Specific growth rate (SGR; CDxa0=xa03.36, CD+7xa0=xa03.47) and feed conversion ratio (FCR; CDxa0=xa01.02, CD+7xa0=xa00.93) of fish fed formulated diets did not differ significantly with rising dietary lipid content, due to high variability within the individuals of each feeding groups. In contrast, pike perch fed with chironomids showed a significantly lower SGR of 2.49 and higher FCR of 2.37 (on a dry matter basis). Body composition of pike perch fed formulated diets was affected by dietary composition and showed increased lipid contents [CD=6.25% original matter (o.m.), CD+7xa0=xa09.00% o.m.] with rising dietary lipid levels. Pike perch of CD and CD+7 feeding groups showed significant increased hepatosomatic indices (HSIs) of 1.99 and 2.05 in contrast to fish fed chironomids with HSI of 1.11. Fish caught in the different natural habitats were characterised by low body lipid and dry matter contents of 0.64–1.88% o.m. and 21.08–23.75% o.m. Higher lipid incorporation of fish fed with formulated diets accompanied with poor benefit on growth performance at higher dietary lipid content indicated that pike perch ability to utilise lipids is low when dietary crude protein content is higher than 56.56%.

Current Status and Future Trends of Nanoscale Technology and Its Impact on Modern Computing, Biology, Medicine and Agricultural Biotechnology

Nanoscale technologies have gone from being just an ambitious concept to being a rapidly advancing area of interdisciplinary science with immense practical importance. Feynmans vision on nanoscience provided great impetus to the development of nanophysics, nanochemistry, nanoelectronics and nanotechnology in general. High resolution microscopic devices such as scanning tunneling microscope, transmission electron microscope and atomic force microscope etc. in mid 1980s allowed researchers to see individual atoms on surfaces and arrange them. The authors (nanobiologists, computer scientists, biotechnologists and material scientists) attempt to provide a review of the state of the art in the field of nanoscale technologies and its impact on various fields of research like computation, basic biology, medicine and agricultural biotechnology. Imprints of memory mechanisms in living systems operating at different levels (e.g. biochemical, immunological and neuronal) have provided inputs to design and fabricate bio-inspired nanoelectronic devices suitable for various applications. Several examples of such nanoscale technology based frameworks and devices are presented in the scenario of their potential role in the development of future nanoscale technologies. Nanoscale technologies might finally revolutionize computational intelligence and thinking. The power and limits of computing processes govern the intelligence, knowledge acquisition and thinking process of human and machine. Present computational methods and models provide us courage to study the problem, but these tools are not yet sufficient to answer the following riddles of machine intelligence - what can computers do better than humans? What can humans do better than computers? And the most important one - what is computable? The authors try to present evidences that show bio-inspired nanoscale technologies might gain the power in helping us to go deeper into these challenges of research in future

Comparison of oral, rectal and intraperitoneal administration of IgY antibodies in passive immunization of rainbow trout (Oncorhynchus mykiss)

IgY antibodies serve an interesting opportunity for drug administration and passive immunization. For routine application in aquaculture, oral delivery needs to be established. Two feeding trials with non-specific IgY antibodies were conducted in juvenile trout to assess IgY uptake through the intestinal wall and to identify target tissue of IgY. In experiment 1, a positive control that received the lowest effective dose by intraperitoneal injection (0.0076xa0mg IgY gxa0BW−1xa0day−1) was compared with three groups fed a 10-, 50- and 75-fold dosage and a negative control. After 12, 24 and 36xa0h, plasma IgY concentrations of all treatments were below the detection threshold. In experiment 2, an excessive oral administration (200-fold) was compared with two groups that received IgY rectally at 75- and 150-fold dosage of the injected control. Blood samples taken 2, 4, 6, 12 and 24xa0h did not result in detectable IgY concentrations, suggesting that neither the increased oral dosage nor the bypassing of the stomach improved IgY uptake. In both experiments, only intraperitoneal injection resulted in IgY uptake, revealing a decrease from 40.33xa0±xa021.72xa0µgxa0ml−1 after 12xa0h to 19.48xa0±xa012.67xa0µgxa0ml−1 at 36xa0h in experiment 1 and a peak at 75.58xa0±xa023.75xa0µgxa0ml−1 after 2xa0h in experiment 2. Immunohistochemistry was carried out to localize IgY in selected target tissues of IgY action. Staining revealed IgY in the liver but not in white muscle, pituitary and brain, irrespective from the time point measured.