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

Technical feed quality influences health, digestion patterns, body mineralization and bone development in farming of the stomachless cleaner fish ballan wrasse (Labrus bergylta)

Farmed ballan wrasse (Labrus bergylta) is an efficient cleaner fish used for non-medicinal delicing of Atlantic salmon in sea cages replacing to an increasing degree wild wrasse due to considerations for biodiversity and risk of overfishing local wrasse populations. Farming of ballan wrasse has been hampered by low growth rates, high prevalence of skeletal deformities and other welfare related pathologies. In this study we investigated how diets identical in composition but differing in their technical characteristics, by being prepared using different feed production technologies, affect fish performance, mineralization, bone development and gut health of the ballan wrasse larvae and juveniles. The different production technologies include the commonly used ‘high temperature’ extrusion, cold extrusion, and agglomeration, resulting in feed pellets with distinctive physicochemical properties. The results revealed that prolonged feeding periods with extruded pellets during ballan wrasse larvae weaning result in low body mineralization and the development of severe skeletal deformities. In juvenile ballan wrasse, the extruded pellet treatment resulted in higher mortality rates, fish with larger livers, indication for increased serum TAG and cholesterol in a similar manner, and increased activity of the digestive enzymes LAP and maltase, most probably as a compensatory mechanism to the assumed reduced availability of protein and carbohydrates of extruded pellets for this fish species. Smaller dietary effects were identified in terms of intestinal morphology and gene transcription rates.publishedVersio

pH indikatorar: Inkorporering av pH-indikatorar i porøse silikastrukturar, som er syntetisert direkte på substrat, og hydrogelar med pH-avhengig ekspansjon.

I dette prosjektet vart det sett på to alternative måtar å måle pH på med utgangspunkt i to ulike kolloidsystem; mesoporøse silikastrukturar og hydrogelar. Det vart laga mesoporøse silikastrukturar ved hjelp av stöberprosessen. Forsøka vart gjort multivariat, og nivåa til variablane vart endra etter kva resultat dei tidlige forsøka fekk. Elektron mikroskop (SEM og TEM) vart brukt til å karakterisere silikastrukturane. Det vart funne at lågare etanol konsentrasjon førte til mindre silikapartiklar og meir danning av silikafilm. Silikastrukturane vart inkorporert med pH-indikator. Den inkorporerte indikatoren skifta farge med ein gong den vart sett i bufferløysing, men det var store lekkasjar frå silikastrukturen og etter eit par minutt var det ikkje noko farge att i silikastrukturen. Hydrogelen poly(NIPAM-co-AAc) vart laga med multivariate forsøk. Det vart funne at høgare konsentrasjon av kryssbindaren førte til ein stivare hydrogel. Hydrogelane poly(NIPAM-co-AAc) og poly(NIPAM) vart laga. Desse vart òg laga med eit Na-alginat nettverk, og med eit Na-alginat/Fe³⁺ nettverk. Den pH sensitive svellinga til desse hydrogelane vart studert ved å rekne ut svellingsforholdet i ulike bufferløysingar. Det vart funne signifikant forskjellig svelling mellom poly(NIPAM-co-AAc) og poly(NIPAM). Poly(NIPAM-co-AAc), poly(NIPAM) og poly(NIPAM)/Na-alginat er pH-sensitive, det er ikkje dei andre hydrogelane. For å måle styrken på hydrogelane, vart det gjort målingar av lagringsmodulen ved hjelp av eit rheometer. Lagringsmodul mot frekvens vart plotta og det vart funne at Na-alginat gjorde hydrogelane sterkare. Poly(NIPAM-co-AAc)/Na-alginat vart svakare ved tilsetting av Fe³⁺, mens poly(NIPAM)/Na-alginat vart sterkare

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

Technical feed quality influences health, digestion patterns, body mineralization and bone development in farming of the stomachless cleaner fish ballan wrasse (Labrus bergylta)

Farmed ballan wrasse (Labrus bergylta) is an efficient cleaner fish used for non-medicinal delicing of Atlantic salmon in sea cages replacing to an increasing degree wild wrasse due to considerations for biodiversity and risk of overfishing local wrasse populations. Farming of ballan wrasse has been hampered by low growth rates, high prevalence of skeletal deformities and other welfare related pathologies. In this study we investigated how diets identical in composition but differing in their technical characteristics, by being prepared using different feed production technologies, affect fish performance, mineralization, bone development and gut health of the ballan wrasse larvae and juveniles. The different production technologies include the commonly used ‘high temperature’ extrusion, cold extrusion, and agglomeration, resulting in feed pellets with distinctive physicochemical properties. The results revealed that prolonged feeding periods with extruded pellets during ballan wrasse larvae weaning result in low body mineralization and the development of severe skeletal deformities. In juvenile ballan wrasse, the extruded pellet treatment resulted in higher mortality rates, fish with larger livers, indication for increased serum TAG and cholesterol in a similar manner, and increased activity of the digestive enzymes LAP and maltase, most probably as a compensatory mechanism to the assumed reduced availability of protein and carbohydrates of extruded pellets for this fish species. Smaller dietary effects were identified in terms of intestinal morphology and gene transcription rates