Gesellschaft fur Marine Aquakultur

Büsum, Germany

Gesellschaft fur Marine Aquakultur

Büsum, Germany
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Tielmann M.,Gesellschaft fur Marine Aquakultur | Tielmann M.,University of Kiel | Schulz C.,Gesellschaft fur Marine Aquakultur | Schulz C.,University of Kiel | Meyer S.,Landwirtschaftskammer Schleswig Holstein
Aquacultural Engineering | Year: 2017

In this work performance parameters of larval pike-perch (Sander lucioperca) reared under four different light intensities (100, 500, 1000 and 2500 lx) until 21 days post hatch (dph) were investigated. As performance parameters change in length and weight, swim bladder inflation, feed consumption, natural mortality, stress induced mortality and RNA-DNA ratio were measured. Aim was to investigate the influence of light intensity on pike-perch performance during the first three weeks of larval rearing. Significant differences were found in natural and stress induced mortality as well as in weight growth. No single light exposure level combined optimal performance of all tested performance parameters. Highest light intensity of 2500 lx showed good weight growth but an increase in stress induced mortality. Bright light of 500 and 1000 lx intensity was found to improve growth and stress mortality whereas dim light conditions of 100 lx showed significantly lower natural mortality. Thus data suggested that most favorable illumination during larval pike-perch rearing comprise a tradeoff between optimal natural mortality under dim light conditions (100 lx) or optimal larval growth and stress resistance under bright light conditions (500 and 1000 lx). It is shown that high light intensities during larval rearing can be beneficial for pike-perch rearing if offspring supply is not limited. © 2017 Elsevier B.V.


Kroeckel S.,University of Kiel | Harjes A.-G.E.,Gesellschaft fur Marine Aquakultur | Roth I.,Hermetia Futtermittel GbR | Katz H.,Hermetia Futtermittel GbR | And 5 more authors.
Aquaculture | Year: 2012

Larvae of black soldier flies (Hermetia illucens) are commercially produced on agricultural waste streams and convert these into animal body protein and fat. A feeding trial was carried out for 56. days in a recirculating aquaculture system (RAS) by replacing fish meal protein subsequently by Hermetia meal (HM) protein. Six diets were formulated for the replacement and contained 0%, 17%, 33%, 49%, 64%, and 76% of HM (54.1. ±. 1.1% crude protein, 13.4. ±. 0.7% crude lipid, dry matter basis). The diets were fed to triplicate groups of turbot 54.9. ±. 0.9. g once a day by hand until apparent satiation. Feed intake was affected by dietary HM inclusion and decreased with increasing HM incorporation due to low palatability. Growth performance was high, but affected by dietary HM inclusion. SGR was lower in all treatments containing HM whereas FCR was significantly higher at HM inclusion levels. >. 33%. Protein retention was highest at HM inclusion. ≤. 33% and decreased significantly with increasing HM supplementation. Whole-body protein content was not affected by treatment, while body lipid decreased with increasing HM inclusion levels. The apparent digestibility coefficients (ADC) of HM were low for organic matter, crude protein, crude lipid, and gross energy. Chitinase activity or chitinolytic active bacteria were not detected in the mid gut of turbot. The presence of chitin might have influenced the feed intake, availability, and digestibility of the nutrients and therefore growth performance. In general, our study shows that the incorporation of HM protein in fish diets is possible, but limited by its low nutritive value. Considering that HM is produced on local greenhouse waste streams, HM might be a feasible alternative protein source for the partial replacement of fish meal. Further research on HM meal processing to increase nutrient utilization is needed. © 2012 Elsevier B.V.


Winkelbach A.,Leibniz Institute of Freshwater Ecology and Inland Fisheries | Winkelbach A.,University of Kiel | Gunzel D.,Charité - Medical University of Berlin | Schulz C.,Gesellschaft fur Marine Aquakultur | And 2 more authors.
Comparative Biochemistry and Physiology Part - C: Toxicology and Pharmacology | Year: 2015

Oral IgY antibodies offer promising potential for passive immunization strategies. To evaluate barriers for successful IgY plasma recovery after oral application in vivo, gastric rainbow trout and agastric common carp were comparatively assessed. A positive control that received a low dose of unspecific IgY antibodies by intraperitoneal injection (0.0076 mg IgY g BW- 1 d- 1; BW = body mass) was compared with an oral administration of 75 and 150 fold in rainbow trout (corresponding to 0.57 and 1.14 mg g BW- 1) and in carp (0.57 mg g BW- 1). Dietary antibodies were delivered with the antacid sodium bicarbonate and three different putative uptake enhancers (Tween 20, vitamin E TPGS, sodium deoxycholate). IgY concentrations in the plasma were determined 1 d (rainbow trout) or 5 d after last feeding (both species). Irrespective of the enhancer used, ELISA revealed IgY absorption after feeding in carp, whereas IgY concentration in rainbow trout remained below the detection threshold. Intraperitoneal injections revealed IgY in plasma of both species. In vitro Ussing chamber experiments with posterior intestine tissue of carp and trout were carried out to determine whether species-specific differences in IgY translocation were due to acidic stomach passage or species-specific differences in transepithelial IgY passage. Significantly higher IgY translocation was measured in carp at high application dosage compared to all other groups, indicating that species-specific differences in IgY uptake after oral administration are not only related to peptic IgY degradation in the stomach, but also likely a result of differences in IgY transcytosis in the posterior intestine. © 2014 Elsevier Inc.


Wurtz S.,Gesellschaft fur Marine Aquakultur
Chemical Engineer | Year: 2010

Sven Würtz informs that fatty acid barcoding can help in overcoming the threat of extinction of sturgeon due to increasing demand for caviar. The demand for sturgeon eggs continues to increase, as they are the most valuable animal products in the world when close to maturity before ovulation. The Convention on International Trade in Endangered Species (CITES) continues to make efforts to prevent illegal fishing of the main species of sturgeon through specific barcoding techniques. The basis of CITES enforcement is a standardized labeling system, implemented in 2006, that allows law enforcers to track the origins and identify illicit caviar. This label includes a standard species code identifying the species whose origin stated as a 'W' for wild and a 'C' for captive-bred.


Stiller K.T.,University of Kiel | Moran D.,Lund University | Vanselow K.H.,University of Kiel | Marxen K.,University of Kiel | And 3 more authors.
Aquacultural Engineering | Year: 2013

In this study we describe a novel flow-through respirometer with automated and semi-continuous detection of key water variables. The recirculating aquaculture system was designed to house aquatic organisms in culture-like conditions and allow long-term, high-precision measurements. Nine respirometry tanks (250L in volume each) housed animals, and a tenth (without animals) acted as a reference tank. A single measurement unit made sequential measurements of each tank to eliminate the problem of sensor variation associated with multi-probe setups. The accuracy of the analyzers in relation to measurement range was: O2=1%; CO2<1%; NH3=2%; temperature ≤ 0.25%; and pH±0.01. Dissolved CO2 was measured using air-water equilibration coupled with non-dispersive infrared detection of carrier gas, and NH3 was quantified using a reagent-based assay and spectophotometric autoanalyzer. Though expensive and not common in aquaculture or physiology research, these two automated metabolite analyzers could operate in both fresh and seawater, and offered high precision and accuracy. We report on the performance of these instruments for aquaculture research in two trials using a freshwater (rainbow trout, Oncorhynchus mykiss) and seawater fish species (turbot, Scophthalmus maximus). One of the main constraints imposed by the sequential measurement of multiple tanks was the measurement frequency of each tank. In the aforementioned system, NH3 analyzes took the longest (12min), followed by CO2 (7min), O2 (6min), and pH (3min). © 2013 Elsevier B.V.


Tielmann M.,Gesellschaft fur Marine Aquakultur | Tielmann M.,University of Kiel | Schulz C.,Gesellschaft fur Marine Aquakultur | Schulz C.,University of Kiel | And 2 more authors.
Aquacultural Engineering | Year: 2016

The phototactic behavior of pike-perch (Sander lucioperca) larvae from 1 to 50 days post hatch (dph) was evaluated using a channel system with 0 and 700 lx light treatment. The findings of this work show larval pike-perch to be highly positive phototactic during its larval stage with a peak of positive phototactic behavior between 10 and 22 dph. After 22 dph positive phototaxis decreased and pike-perch increasingly preferred the lower light treatment. In a second experiment observed positive phototaxis was used to evaluate the effectiveness of a light triggered self-grading mechanism for pike-perch larvae at 16, 22, 28 and 34 dph. The use of larvae's positive phototaxis for a gentle self-grading was successful at 16 and 22 dph and decreased the length variability between 14 and 18% at 16 dph and between 18 and 28% at 22 dph. Whereas the grading at 28 and 34 dph led to an insufficient reduction in length heterogeneity. As a result the light triggered self-grading has the potential to be implemented in future rearing protocols and to be applied on pike-perch between 16 to 22 dph. Furthermore, it is suggested to consider a light triggered self-grading mechanism within upcoming tank designs for the rearing of larval pike-perch. © 2016 Elsevier B.V.


Kroeckel S.,University of Kiel | Dietz C.,University of Kiel | Schulz C.,Gesellschaft fur Marine Aquakultur | Schulz C.,University of Kiel | Susenbeth A.,University of Kiel
British Journal of Nutrition | Year: 2015

In the present study, a linear regression analysis between lysine intake and lysine retention was conducted to investigate the efficiency of lysine utilisation (kLys) at marginal lysine intake of either protein-bound or free lysine sources in juvenile turbot (Psetta maxima). For this purpose, nine isonitrogenous and isoenergetic diets were formulated to contain 2·25-4·12 g lysine/100 g crude protein (CP) to ensure that lysine was the first-limiting amino acid in all diets. The basal diet contained 2·25 g lysine/100 g CP. Graded levels of casein (Cas), fishmeal (FM) and l-lysine HCl (Lys) were added to the experimental diets to achieve stepwise lysine increments. A total of 240 fish (initial weight 50·1 g) were hand-fed all the experimental diets once daily until apparent satiation over a period of 56 d. Feed intake was significantly affected by dietary lysine concentration rather than by dietary lysine source. Specific growth rate increased significantly at higher lysine concentrations (P<0·001). CP, crude lipid and crude ash contents in the whole body were affected by the dietary treatments. The linear regression slope between lysine retention and lysine intake (kLys) was similar between all the dietary lysine sources. The kLys values for the diets supplemented with Cas, Lys or FM were 0·833, 0·857 and 0·684, respectively. The bioavailability of lysine from the respective lysine sources was determined by a slope-ratio approach. The bioavailability of lysine (relative to the reference lysine source Cas) from FM and Lys was 82·1 and 103%, respectively. Nutrient requirement for maintenance was in the range of 16·7-23·4 mg/kg0·8 per d, and did not differ between the treatments. There were no significant differences in lysine utilisation efficiency or bioavailability of protein-bound or crystalline lysine from the respective sources observed when lysine was confirmed to be the first-limiting nutrient. © The Authors 2015.


Stiller K.T.,University of Kiel | Vanselow K.H.,University of Kiel | Moran D.,Seafood Technologies Group | Bojens G.,University of Kiel | And 4 more authors.
Aquaculture | Year: 2015

Land-based aquaculture is an increasingly important method of fish production, and fish grown in such systems may be exposed to substantially higher carbon dioxide concentrations than fish in the wild. Chronic exposure to elevated CO2 levels in recirculated aquaculture systems can correlate with lower growth and condition indices for many fish species, however, the physiological basis behind this loss of performance is largely unknown. The aim of this study was to investigate the growth, condition and protein catabolism rates of juvenile turbot (55-176g) reared for 8weeks at three different dissolved carbon dioxide concentrations: 5, 26, and 42mgl-1 (~3000, 15000, 25000μatm; pH7.37, 6.66, 6.44). A commercial diet was administered once per day until satiation, and uneaten food was collected from a solids collector. Oxygen consumption and ammonia excretion were measured weekly using high precision automated methods in a recirculating aquaculture respirometer system. Increased CO2 levels were associated with reduced condition factor, feed intake and weight gain. Compared to the low CO2 treatment, the specific growth rates under the medium and high treatments were reduced by 21% and 58%, respectively. Feed conversion ratios were similar between treatments. The oxygen consumption rates broadly followed a dose-response pattern, where fish in the low CO2 treatment exhibited the highest respiration rates. Comparison of ammonia quotients over time and at comparable feed intake showed the rates of protein catabolism correlated with CO2 exposure levels. By the end of the 8week trial fish from the high CO2 treatment exhibited up to 3 times the protein catabolism rates observed in the low treatment, and the medium treatment was approximately intermediate between the two. The conclusion from the study was that the loss of growth and condition of turbot reared at elevated CO2 concentrations (relevant to land-based aquaculture systems) can be traced to decreased feed intake and an increased reliance on protein as a fuel source. © 2015 Elsevier B.V.


Kroeckel S.,University of Kiel | Dietz C.,University of Kiel | Schulz C.,Gesellschaft fur Marine Aquakultur | Schulz C.,University of Kiel | Susenbeth A.,University of Kiel
Archives of Animal Nutrition | Year: 2013

A 10-week feeding trial was conducted to study the effect of feeding level and dietary lysine concentration on growth, protein and lysine retention, and body composition in juvenile turbot. Maintenance requirement for lysine and the efficiency of lysine utilisation were determined as well. Two experimental diets were formulated based on fishmeal or wheat gluten as main protein sources, containing 6.4 g (Diet A, control) and 4.5 g lysine per 100 g CP (Diet B), respectively. Diets were fed once daily at six feeding levels (per day 0.3%, 0.6%, 0.9%, 1.2%, and 1.5% of body weight [BW] and ad libitum) to a total of 432 fish of 48 g initial BW. No differences in the growth parameters were observed between diets at the same feeding level, except a lower feed to gain ratio (p < 0.05) at the highest feeding level at Diet B. Whole-body composition was not affected by diet, whereas muscle protein concentration was significantly lower for fish fed Diet B. Amino acid concentration in whole-body protein was affected by dietary treatment and fish fed Diet B showed lower concentrations of all essential amino acids. In fish muscle protein, lysine, methionine, leucine, isoleucine, and valine concentrations were significantly lower in Diet B. Efficiency of lysine utilisation for growth (klys) was determined by linear regression analysis and amounted for 0.69 for Diet B. The maintenance lysine requirement defined at zero lysine retention was 6.5 mg · kg-0.8 · d-1. Lysine intakes at zero protein retention were 13.0 mg and 12.9 mg · kg-0.8 · d-1 for Diet A and B, respectively. Growth and nutrient retention were similar for both diets and, therefore, a lysine deficiency in Diet B did not occur. In conclusion, a proportion of 330 g wheat gluten per kg feed did not influence growth performance and maintenance requirement for lysine in juvenile turbot. However, the effect of diet composition on the amino acid profile of body protein might be relevant for the derivation of the amino acid requirement from protein retention. © 2013 Copyright Taylor and Francis Group, LLC.


PubMed | University of Kiel and Gesellschaft fur Marine Aquakultur
Type: Comparative Study | Journal: The British journal of nutrition | Year: 2015

In the present study, a linear regression analysis between lysine intake and lysine retention was conducted to investigate the efficiency of lysine utilisation (k(Lys)) at marginal lysine intake of either protein-bound or free lysine sources in juvenile turbot (Psetta maxima). For this purpose, nine isonitrogenous and isoenergetic diets were formulated to contain 225-412 g lysine/100 g crude protein (CP) to ensure that lysine was the first-limiting amino acid in all diets. The basal diet contained 225 g lysine/100 g CP. Graded levels of casein (Cas), fishmeal (FM) and L-lysine HCl (Lys) were added to the experimental diets to achieve stepwise lysine increments. A total of 240 fish (initial weight 501 g) were hand-fed all the experimental diets once daily until apparent satiation over a period of 56 d. Feed intake was significantly affected by dietary lysine concentration rather than by dietary lysine source. Specific growth rate increased significantly at higher lysine concentrations (P< 0001). CP, crude lipid and crude ash contents in the whole body were affected by the dietary treatments. The linear regression slope between lysine retention and lysine intake (k(Lys)) was similar between all the dietary lysine sources. The k(Lys) values for the diets supplemented with Cas, Lys or FM were 0833, 0857 and 0684, respectively. The bioavailability of lysine from the respective lysine sources was determined by a slope-ratio approach. The bioavailability of lysine (relative to the reference lysine source Cas) from FM and Lys was 821 and 103 %, respectively. Nutrient requirement for maintenance was in the range of 167-234 mg/kg(08) per d, and did not differ between the treatments. There were no significant differences in lysine utilisation efficiency or bioavailability of protein-bound or crystalline lysine from the respective sources observed when lysine was confirmed to be the first-limiting nutrient.

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