The use of tunicate (Ciona intestinalis) as a sustainable protein source in fish feed – Effects on the extrusion process, physical pellet quality and microstructure

The aim of this research was to study the effect of the replacement of fishmeal (FM) or soy protein concentrate (SPC) by tunicate meal (Ciona intestinalis) on the extrusion process, physical pellet quality, pellet expansion, and microstructure. The experiment was based on a 3-component simplex-centroid mixture design. Models with R2 in the range of 0.574–0.999 (P = 0.03 to < 0.0001) were established for specific mechanical energy (SME), temperature behind extruder die (Tdie), apparent dough viscosity in the extruder die (Vdie), pellet hardness, durability, expansion, and microstructure parameters. Increase in SME and Tdie were mainly explained by the reduced lipid content in the feed mix due to the replacement of FM with tunicate or SPC. Reduced Vdie was mainly an effect of increased tunicate level and with the lowest value found for the pure tunicate blend. There was an increase in volumetric expansion and open porosity by replacement of SPC with tunicate, explained by this decrease in Vdie. Reduced hardness and durability were found for blends high in SPC due to incomplete plasticisation. Extrudate expansion, fat adsorption capacity and leakage were explained by the extrudate microstructure measured by X-ray microtomography. Within the boundary of the chosen design, 64% of the FM can be replaced by tunicate meal without compromising physical feed quality. Due to its viscosity behaviour, tunicate meal can improve pellet expansion and fat absorption capacity of extruded feed.publishedVersio

Performance of novel low trophic raw meterials in Atlantic salmon Salmo salar diets

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Atlantic Salmon (Salmo salar) Performance Fed Low Trophic Ingredients in a Fish Meal and Fish Oil Free Diet

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Genetic variation in growth in atlantic salmon when fed conventional and innovative diets

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Growth performance of gilthead seabream (Sparus aurata) fed low fishmeal diets with innovative ingredients

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A full factorial design to investigate interactions of variable essential amino acids, trace minerals and vitamins on Atlantic salmon smoltification and post transfer performance

To contribute in knowledge for the development of safe, efficient and sustainable functional salmon diets, we ran a feeding trial applying a 23 full factorial design to investigate combined effects, on Atlantic salmon smoltification and post transfer performance, of variable supplementation levels of essential amino acid (Lys, Met, Thr and Arg), essential trace mineral (Zn, Fe and Se) and vitamins (E, C and astaxanthin as provitamin A) premixes in low fishmeal diets, using crystalline amino acids, organic trace minerals and synthetic vitamins, respectively. The nutrient levels used in our study were chosen to meet the known requirements of fish reflecting the variation in commercial feeds. Fish performance, nutrient digestibility, skin, and intestinal health were evaluated in Atlantic salmon parr-smolt, the latter by means of qPCR, global transcriptomics, and immunohistochemistry. The results revealed the potential for significant improvement of salmon post smoltification growth by simultaneous dietary level increase of Met, Lys, Thr and Arg (5% higher body weight increase). Significantly negative effect on fish post transfer growth and survival (22.5 % lower body weight growth and 2.6 times higher mortality) was observed in the high dietary vitamin supplementation treatments which was not present in the simultaneous high trace mineral and vitamin supplementation treatments (8% higher body weight increase and 2.8 times lower mortality in the high trace mineral supplementation treatments). In the high trace mineral supplemented dietary treatments was also observed improved FCR (8.5 %) and a further improvement in performance was seen in the treatments with simultaneous high essential amino acid and trace mineral supplementation levels (12.6 % higher body growth increase). Redox-sensitive gene and extracellular matrix components’ gene transcription effects and compensatory mechanisms on protein and energy metabolism, immune modulation, skin repair systems and erythropoiesis were observed by transcriptomic and histological analyses in response to the variable dietary essential nutrient levels.publishedVersio

Feed and nutrition in organic aquaculture

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Fishmeal, plant protein, and fish oil substitution with single-cell ingredients in organic feeds for European sea bass (Dicentrarchus labrax)

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Welfare and performance of ballan wrasse (Labrus bergylta) reared at two different temperatures after a preparatory feeding trial with enhanced dietary eicosapentaenoic acid

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Optimization of the Balance between Protein, Lipid and Carbohydrate in Diets for Lumpfish (Cyclopterus lumpus)

The aim of this study was to investigate how the dietary balance between protein, lipid, and carbohydrate affects growth, welfare, and health with focus on immune responses, in lumpfish of body weight ranges 1.7-10 g and 15-50 g. A three-component mixture design, with simultaneous variation of the three macronutrients was applied. Growth, tissue and plasma nutrient composition, welfare, cataract frequency, and immune responses in leukocytes isolated from the fish head kidney were studied. Most responses were linear and driven by dietary lipid level, with minor effects of carbohydrate and protein. The growth in 1.7-10 g fish followed a special cubic model with no clear optimum. The fastest growth in the 15-50 g fish was obtained with the diet containing 55% protein, 17% fat, and 6% carbohydrate. The high dietary levels of lipid also gave high lipid levels in the tissues and a trend of improved welfare score, but there were no effects on cataract. The diets with minimum and maximum protein gave suboptimal immune responses in isolated head kidney cells of the 15-50 g fish, while the fastest growing fish showed normal immune responses. We propose that diets for lumpfish from 10-50 g body weight should contain approximately 55% protein, minimum 10% lipid, and maximum 10% carbohydrate. These diets will also be suitable for lumpfish of 1.7-10 g.publishedVersio