Time filter

Source Type

Winkelbach A.,Leibniz Institute of Freshwater Ecology and Inland Fisheries | Winkelbach A.,University of Kiel | Gunzel D.,Charite - 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.

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.

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.

Discover hidden collaborations