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Evaluation of effluent waste water from salmonid culture as a potential food and water supply for culturing larval Pacific lamprey Entosphenus tridentatus Texte intégral
2020
Barron, James M. | Hanson, Kyle C. | Headley, Racheal R. | Hawke, Kelli A. | Twibell, Ronald G. | Gannam, Ann L.
The Pacific lamprey is an iconic native fish of great importance to the ecosystem and indigenous cultures in the U.S. Pacific Northwest. Pacific lamprey populations have declined in abundance from historic levels, and conservation aquaculture has been proposed as a technique to restore these populations. The present research focused on expanding the culture methods for larval lamprey. The larvae filter feed and cohabitate with juvenile salmonids in the wild, therefore the effluent water from rearing salmonids may be a viable source of water and food for culturing lamprey. This approach could be a sustainable method for raising lamprey at existing salmonid hatcheries. A nine week trial investigated the effects of rearing in effluent water from salmonid culture on the growth, survival, proximate composition, and fatty acid profile of larval lamprey. This trial also explored the potential of this rearing strategy to improve the water quality by removing nutrients from the effluent. The trial included three treatments testing the use of the effluent from steelhead trout (Oncorhynchus mykiss), a conventional lamprey diet (control diet), or both combined as a means for rearing lamprey. A fourth treatment where lamprey were excluded served as a water quality control to test the effect of lamprey presence on effluent quality. Lamprey survival was not affected by treatment. Lamprey reared solely on the effluent waste matched the survival and growth of fish fed the conventional diet. Lamprey fed the combination treatment grew faster than the conventional diet fed fish. Whole body lipid levels were elevated in lamprey from the combination treatment relative to the conventional diet fed lamprey. Crude protein in the whole bodies of effluent fed lamprey was low compared to fish from either of the treatments where the conventional diet was fed. Lamprey offered the effluent nutrients were high in saturated fats relative to the control fed fish, which reflected the lipid profile of this diet. However, lamprey from the combination treatment were lower in long chain polyunsaturated fatty acids relative to the control or the effluent treatment lamprey. There was no measureable improvement in water quality due to the presence of lamprey, though lamprey were able to sequester approximately 1.3% of the effluent dry matter as lamprey biomass. Overall, it appears the larval stage of lamprey can be effectively reared on salmonid effluent, and this method provides superior growth when used in combination with a conventional lamprey diet.
Afficher plus [+] Moins [-]Food grade water-in-oil microemulsions as replacement of oil phase to help process and stabilization of whipped cream Texte intégral
2016
Mitsou, Evgenia | Tavantzis, George | Sotiroudis, George | Ladikos, Dimitris | Xenakis, Aristotelis | Papadimitriou, Vassiliki
Food grade W/O microemulsions were developed and characterized to be used in blends with sunflower oil as replacers of palm kernel oil in whipped cream alternatives. Creams for whipping are oil-in-water (O/W) emulsions containing significant proportions of partially hydrogenated solid fat. With the addition of sunflower oil and W/O microemulsions up to 6.8% w/w in the final confectionary product we achieved the decrease of saturated fats and also the decrease of the energy required for the formulation. More specifically, by replacing 20% w/w of the oil phase by the proposed edible W/O microemulsions, the homogenization time was reduced from 7 to 5min under the same experimental conditions. In addition solid fat partial replacement permitted the modification of structural and textural characteristics. Droplet size and size distribution measurements were performed using dynamic light scattering (DLS). The existence of rather polydisperse oil droplets with diameters of approximately 1μm upon palm kernel oil partial replacement was detected. Structural characterization of the proposed alternative systems with confocal laser scanning microscopy (CLSM) showed the existence of air bubbles of diameter 6–94μm stabilized by globular oil droplets having diameters ranging from 4.2 to 5.9μm adhered to their surface. Firmness and consistency of the proposed alternative formulations were evaluated using a Stevens-texture analyzer. As a result emulsions after whipping gave products with lower density (362±9g/mL) but higher consistency (208±7g) as compared to the standard whipped cream preparation (150±5g).
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