Health and welfare of Atlantic salmon in FishGLOBE V5 -a novel closed containment system at sea

Closed-containment (CCS) systems offer several advantages in controlling the production environment for Atlantic salmon (Salmo salar) aquaculture, especially at sea, where fish are more exposed to challenging environmental conditions. Here, we report the health and welfare of Atlantic salmon in FishGLOBE V5, a 3500 m3 semi-closed containment system. A group of 200,000 post-smolts was followed from a recirculating aquaculture system (RAS) facility, then for three and a half months in FishGLOBE V5, and three months after release in net pens. Fish samples were collected at four time points during the production period, while water quality was evaluated when the fish were in FishGLOBE V5. The water quality in FishGLOBE V5 was within the recommended range for salmon post-smolts. The mortality rate was 1.4% in FishGLOBE V5 and 4.9% in net pens. There was an increase in the prevalence of eye, snout and dorsal fin damages before the fish left the FishGLOBE V5 phase. The plasma level of magnesium was slightly elevated during this phase as well, indicating osmotic imbalance and stress. Histological evaluation of skin and gills showed sporadic cases of non-specific pathologies. In particular, the transitory stay in FishGLOBE V5 partially improved skin health, but not gill health. Gene expression profiling of some biomarkers showed that rearing fish in FishGLOBE V5 could influence the expression of genes involved in stress response, mucus production, and epithelial integrity. This study documented that rearing salmon for a certain period in FishGLOBE V5 during production affected different health and welfare indicators. These changes should be taken into consideration for the improvement of FishGLOBE V5 as a viable technology for post-smolt production at sea.Health and welfare of Atlantic salmon in FishGLOBE V5 -a novel closed containment system at seapublishedVersio

Molecular and physiological responses to long-term carbon dioxide exposure in Atlantic salmon (Salmo salar)

submittedVersio

The effects of ozone on Atlantic salmon post-smolt in brackish water — Establishing welfare indicators and thresholds

Ozone is a strong oxidant, and its use in aquaculture has been shown to improve water quality and fish health. At present, it is predominantly used in freshwater systems due to the high risk of toxic residual oxidant exposure in brackish water and seawater. Here, we report the effects of ozone on Atlantic salmon (Salmo salar) post-smolts (100 g), in a brackish water (12 ppt) flow-through system. Salmon were exposed to oxidation reduction potential concentrations of 250 mV (control), 280 mV (low), 350 mV (medium), 425 mV (high) and 500 mV (very high). The physiological impacts of ozone were characterized by blood biochemical profiling, histopathologic examination and gene expression analysis in skin and gills. Fish exposed to 425 mV and higher showed 33 % cumulative mortality in less than 10 days. No significant mortalities were recorded in the remaining groups. The skin surface quality and the thickness of the dermal and epidermal layers were not significantly affected by the treatments. On the other hand, gill histopathology showed the adverse effects of increasing ozone doses and the changes were more pronounced in the group exposed to 350 mV and higher. Cases of gill damages such as necrosis, lamellar fusion and hypertrophy were prevalent in the high and very high groups. Expression profiling of key biomarkers for mucosal health supported the histology results, showing that gills were significantly more affected by higher ozone doses compared to the skin. Increasing ozone doses triggered anti-oxidative stress and inflammatory responses in the gills, where transcript levels of glutathione reductase, copper zinc superoxide dismutase, interleukin 1 and interleukin were significantly elevated. Heat shock protein 70 was significantly upregulated in the skin of fish exposed to 350 mV and higher. Bcl-2 associated x protein was the only gene marker that was significantly upregulated by increasing ozone doses in both mucosal tissues. In conclusion, the study revealed that short-term exposure to ozone at concentrations higher than 350 mV in salmon in brackish water resulted in significant health and welfare consequences, including mortality and gill damages. The results of the study will be valuable in developing water treatment protocols for salmon farming.publishedVersio

Molecular and physiological responses to long-term carbon dioxide exposure in Atlantic salmon (Salmo salar)

submittedVersio

The effects of ozone on Atlantic salmon post-smolt in brackish water — Establishing welfare indicators and thresholds

Ozone is a strong oxidant, and its use in aquaculture has been shown to improve water quality and fish health. At present, it is predominantly used in freshwater systems due to the high risk of toxic residual oxidant exposure in brackish water and seawater. Here, we report the effects of ozone on Atlantic salmon (Salmo salar) post-smolts (100 g), in a brackish water (12 ppt) flow-through system. Salmon were exposed to oxidation reduction potential concentrations of 250 mV (control), 280 mV (low), 350 mV (medium), 425 mV (high) and 500 mV (very high). The physiological impacts of ozone were characterized by blood biochemical profiling, histopathologic examination and gene expression analysis in skin and gills. Fish exposed to 425 mV and higher showed 33 % cumulative mortality in less than 10 days. No significant mortalities were recorded in the remaining groups. The skin surface quality and the thickness of the dermal and epidermal layers were not significantly affected by the treatments. On the other hand, gill histopathology showed the adverse effects of increasing ozone doses and the changes were more pronounced in the group exposed to 350 mV and higher. Cases of gill damages such as necrosis, lamellar fusion and hypertrophy were prevalent in the high and very high groups. Expression profiling of key biomarkers for mucosal health supported the histology results, showing that gills were significantly more affected by higher ozone doses compared to the skin. Increasing ozone doses triggered anti-oxidative stress and inflammatory responses in the gills, where transcript levels of glutathione reductase, copper zinc superoxide dismutase, interleukin 1 and interleukin were significantly elevated. Heat shock protein 70 was significantly upregulated in the skin of fish exposed to 350 mV and higher. Bcl-2 associated x protein was the only gene marker that was significantly upregulated by increasing ozone doses in both mucosal tissues. In conclusion, the study revealed that short-term exposure to ozone at concentrations higher than 350 mV in salmon in brackish water resulted in significant health and welfare consequences, including mortality and gill damages. The results of the study will be valuable in developing water treatment protocols for salmon farming

The effects of carbon dioxide on growth performance, welfare, and health of Atlantic salmon post-smolt (Salmo salar) in recirculating aquaculture systems

High carbon dioxide (CO2) concentrations negatively impact fish, which makes data on its tolerance especially relevant for production systems that can accumulate CO2 such as recirculating aquaculture system (RAS). The current study evaluates the effect of CO2 on the growth performance, welfare, and health of Atlantic salmon post-smolts in RAS. This study consisted of two phases. The first was a CO2 exposure phase, where eighteen tanks were used with six treatments in triplicate: 5, 12, 19, 26, 33 and 40 mg/L of CO2 during 12 weeks in a 12 ppt salinity RAS (hereafter RAS phase). In the second phase, PIT-tagged fish were transferred to a 34 ppt salinity single flow-through tank at CO2 2 was low and not related to treatments. The mean final body weight was significantly higher in the 5 mg/L treatment compared to CO2 treatments ≥12 mg/L at the end of RAS phase and to CO2 treatments ≥33 mg/L at the end of seawater phase. Moreover, regressions showed that growth significantly decreased linearly with increasing CO2 in the water. Eye cataracts and visible external damage on skin, operculum, and fins were inexistent and similar among CO2 treatments. Kidneys showed no signs of mineral deposits in any of the structures of the tissue. However, skin analysis showed that fish exposed to high CO2 concentrations had a significantly thinner dermis layer (both at the end of RAS and seawater phase) and a significantly thinner epidermis layer and lower mucus cells count (at the end of seawater phase). In conclusion, Atlantic salmon post-smolts cultured in brackish water RAS showed a maximum growth performance at CO2 concentrations below 12 mg/L. Except skin, no major effects of health and welfare were observed, including cataracts and nephrocalcinosis. Further studies should evaluate the molecular and physiological responses to both short-term and long-term carbon dioxide exposure.</p

FishGLOBE – a new S-CCS concept for farming salmon

Denne rapporten beskriver vannkvalitet og ytelse og velferd hos post-smolt som har gått i det semilukkede anlegget FishGLOBE. I tillegg har FishGLOBE V3 og V5 blitt modellert med CFD modellering. Fire ulike caser ble modellert i V5. Modelleringen viste at det originale designet uten vannavdelere ga best vannhastighet og fordeling. En fiskegruppe på 200 000 post-smolt ble fulgt fra RAS anlegg, så fire måneder i FishGLOBE, og tre måneder etter sjøutsett i åpen not. Vannkvalitetsvariable ble målt rett etter innsett i globen, mens biologiske målinger av fisk ble utført ved alle fire tidspunktene. Vannkvaliteten i FishGLOBE var innenfor det anbefalte. Dødeligheten var 1,4 % i globen og 4,9 % i sjøfasen. Veksten i FishGLOBE viste TGC på 4,0 og SGR på 1,3. Fisken hadde litt forhøyede nivåer av Mg i FishGLOBE, noe som kan bety at den var i osmotisk ubalanse og stresset. Det var økt ekspresjon av hsp90 og Mucin hos fisk i globen, noe som kan tyde på stress. Mucin-nivået kan også øke når skinnet styrkes. Histologisnitt av skinn og gjelle viste en bedring hos fisken i globen. Bedring i gjellestatus kan forklares med god vannkvalitet, lav turbiditet og TSS. Det ble registrert en stor andel av øyeskader hos fisken i FishGLOBE. Det er ukjent hva dette skyldes.Two-hundred-thousand post-smolts were followed from RAS, to four months in FishGLOBE, and three months after transfer to sea cage. Water quality in FishGLOBE was as recommended. Mortality in the globe was 1.4 % and 4.9 % in sea cage. The growth; TGC = 4.0 and SGR = 1.3. The fish had slightly elevated levels of Mg in FishGLOBE and increased expression of hsp90 and mucin. Histology showed that skin and gills status improved in the globe. A large proportion of eye injuries were registered in FishGLOBE. It is unknown what caused this.publishedVersionpublishedVersio

Nytt S-CCS konsept for oppdrett av laks - Postsmoltproduksjon i FishGLOBE

Denne rapporten beskriver vannkvalitet og ytelse og velferd hos post-smolt som har gått i det semilukkede anlegget FishGLOBE. I tillegg har FishGLOBE V3 og V5 blitt modellert med CFD modellering. Fire ulike caser ble modellert i V5. Modelleringen viste at det originale designet uten vannavdelere ga best vannhastighet og fordeling. En fiskegruppe på 200 000 post-smolt ble fulgt fra RAS anlegg, så fire måneder i FishGLOBE, og tre måneder etter sjøutsett i åpen not. Vannkvalitetsvariable ble målt rett etter innsett i globen, mens biologiske målinger av fisk ble utført ved alle fire tidspunktene. Vannkvaliteten i FishGLOBE var innenfor det anbefalte. Dødeligheten var 1,4 % i globen og 4,9 % i sjøfasen. Veksten i FishGLOBE viste TGC på 4,0 og SGR på 1,3. Fisken hadde litt forhøyede nivåer av Mg i FishGLOBE, noe som kan bety at den var i osmotisk ubalanse og stresset. Det var økt ekspresjon av hsp90 og Mucin hos fisk i globen, noe som kan tyde på stress. Mucin-nivået kan også øke når skinnet styrkes. Histologisnitt av skinn og gjelle viste en bedring hos fisken i globen. Bedring i gjellestatus kan forklares med god vannkvalitet, lav turbiditet og TSS. Det ble registrert en stor andel av øyeskader hos fisken i FishGLOBE. Det er ukjent hva dette skyldes

Health and welfare of Atlantic salmon in FishGLOBE V5 -a novel closed containment system at sea

Closed-containment (CCS) systems offer several advantages in controlling the production environment for Atlantic salmon (Salmo salar) aquaculture, especially at sea, where fish are more exposed to challenging environmental conditions. Here, we report the health and welfare of Atlantic salmon in FishGLOBE V5, a 3500 m3 semi-closed containment system. A group of 200,000 post-smolts was followed from a recirculating aquaculture system (RAS) facility, then for three and a half months in FishGLOBE V5, and three months after release in net pens. Fish samples were collected at four time points during the production period, while water quality was evaluated when the fish were in FishGLOBE V5. The water quality in FishGLOBE V5 was within the recommended range for salmon post-smolts. The mortality rate was 1.4% in FishGLOBE V5 and 4.9% in net pens. There was an increase in the prevalence of eye, snout and dorsal fin damages before the fish left the FishGLOBE V5 phase. The plasma level of magnesium was slightly elevated during this phase as well, indicating osmotic imbalance and stress. Histological evaluation of skin and gills showed sporadic cases of non-specific pathologies. In particular, the transitory stay in FishGLOBE V5 partially improved skin health, but not gill health. Gene expression profiling of some biomarkers showed that rearing fish in FishGLOBE V5 could influence the expression of genes involved in stress response, mucus production, and epithelial integrity. This study documented that rearing salmon for a certain period in FishGLOBE V5 during production affected different health and welfare indicators. These changes should be taken into consideration for the improvement of FishGLOBE V5 as a viable technology for post-smolt production at sea