Water requirements for optimal Atlantic salmon smoltin ...smoltproduksjon.no/Bilder/TidlKonf 2012/19...

Water quality requirements for optimal growth of Atlantic salmon smolt in

recirculating aquaculture systems (RAS)

FREMTIDENSSMOLTPRODUKSJONAndre konferanse om resirkulering av vann i akvakulturSunndalsøra 23. – 24. oktober 2012

Fremtidens Smoltproduction, Sunndalsøra 23 - 24 October 2012

Parameter ValuepH (tank inlet) 6.2 ‐ 7.8

Oxygen partial pressure not over 100%

Oxygen (tank outlet) > 80%

Total gass pressure in the tank water not over 100%

CO2 <15 and 10 mg l‐1, salmon and trout

Aluminium (free) < 5 µg l‐1

Aluminium (gills) < 15 µg g‐1 gill tissue (dry mass)

Nitrite (fresh water) < 0.1 mg l‐1

Nitrite (sea water) < 0.5 mg l‐1

Total ammonia nitrogen (TAN) < 2 mg l‐1

Ammonia < 2 µg l‐1

Legislation on water quality (Norwegian Food Safety Authority)

http://www.kystlab.no/nedlasting/Settefisk/Mattilsynet%20‐%20Aktuelt.pdf

At pH 7.8, optimum nitrification.,can have a maximum 0.2 mg / L TAN to keep the 2 µg / L NH3‐N

No information about Cl‐

requirements

At pH=6.8 and 12°C


How does this relate to RAS?

HOW DO ATLANTIC SALMON (Salmo salar) PARR COPE WITH LONG TERM SUBLETHAL AMMONIA EXPOSURE?

Kolarevic J.* , Takle H.¤, Ytteborg E. ¤ , Selset R.* , Felip O. •

Good C. # , Snekvik K.▪ , Bæverfjord G.* , Åsgård T.E.* , Terjesen B.F.*

* Nofima, Sunndalsøra, Norway¤ Nofima, Ås, Norway• University of Barcelona, Department of Animal Physiology, Barcelona, Spain# The Conservation Fund’s Freshwater Institute, Shepherdstown, USA▪College of Veterinary Medicine, Washington State University,Washington, USA

How does he do it?

I haven’t got a clue

In rainbow trout, ammonia appears to promote growth

15°C

6.5°C

Wood, C.M., 2004. Dogmas and controversies in the handling of nitrogenous wastes: Is exogenous ammonia a growth stimulant In fish? J. Exp. Biol. 207, 2043‐2054.

• Only when fed to satiation, and at a pNH3 around 23 µTorr

• In FT. Must be confirmed in RAS

• If so, should TAN removal and/or pH be dimensioned in trout RAS to produce this situation?

• What about Atlantic salmon?

• Two objectives:‐ Chronic effects of increased NH3‐N on physiology, welfare‐ Any differential growth effects

NH3‐N ~ 15‐18 µg L‐1

NH3‐N ~ 0 µg L‐1

NH3‐N ~ 15‐18 µg L‐1

NH3‐N ~ 0 µg L‐1


H high conc. (32‐35 µg l‐1 NH3‐N)

M medium conc. (14‐17 µg l‐1 NH3‐N)

L low conc. (8‐9 µg l‐1 NH3‐N)

C control ( 0.1 µg l‐1 NH3‐N)

• Done in FT, since NCRA not finalized

• 105 days of exposure

• 8 treatments (4 NH3‐N levels X 2 feeding rations)

• 24 tanks and 55 fish per tank; start weight 17g

• 12oC; pH = 6.8; oxygen >85%; ~400 µS/cm.

• Examined parameters:

‐Welfare indicators (e.g. growth & gill histopathology)

‐ Biochemical indicators (plasma urea and ammonia, brain FAAs)

‐Molecular indicators (mRNA expression of several genes in gills)

Experimental design


Days of exposure0 20 40 60 80 100

Bod

y w

eigh

t (g

ind-

1 )

0

20

40

60

80

100

35 µg/L restricted 32 µg/L full-fed 17 µg/L restricted 14 µg/L full-fed 9 µg/L restricted 8 µg/L full-fed Control restricted Control full-fed

• Fish grew well at all treatments, also at 32 µg/L NH3‐N

• When entire exp. tested, no sign. differences in BW (or SGR)

• Tendencies to higher BW at NH3‐N of 14 µg/L ( 20 µTorr), full fed, but not significantly so

• Same effect on feed intake, hence no difference in FCR

Weight development in Atlantic salmon parrchronically exposed to ammonia

Full‐fed

1/3 restricted

pNH3 = 20 µTorr

Kolarevic, J., et al. Influence of long‐term ammonia exposure on Atlantic salmon parr (Salmo salar L.) growth and welfare. Aquaculture Res, http://dx.doi.org/10.1111/j1365‐2109.2012.03170.x, in press.



Bod

y w

eigh

t (g

ind-

1 )

0

20

40

60

80

100


Increasedexpressionof Rhcg1 gill NH3‐pumps

Detoxificationto glutamine in brain, butdepletion ofGlu

Ammoniaaccumulates in plasma

Small, butsign. gilldamages

Reducedgrowth rate

Day 22

SGR

(% d

ay-1

)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5 0.1 µg/L NH3-N8 µgl/L NH3-N14 µg/L NH3-N32 µg/L NH3-N

AAB AB

BThe early responses of salmonduring chronic NH3‐N exposure

Day 22

Glu

tam

ine

(nm

ol m

g-1)

0

2

4

6

8

10

12

0.1 µg/L NH3-N8 µgl/L NH3-N14 µg/L NH3-N32 µg/L NH3-N

*


Tota

l am

mon

ia (m

mol

L-1

)

0.0

0.5

1.0

1.5

2.032 µg/L NH3-N14 µg/L NH3-N 8 µg/L NH3-N 0.1 µg/L NH3-N

*

Day 22R

elat

ive

gene

exp

ress

ion

0

1

2

3

4

5

6


*

*

*


Kolarevic, J., et al., Molecular and physiological responses to long‐term sublethal ammonia exposure in Atlantic salmon (Salmo salar). Aquat. Toxicol. (2012), http://dx.doi.org/10.1016/j.aquatox.2012.07.003



Bod

y w

eigh

t (g

ind-

1 )

0

20

40

60

80

100


Up‐regulationof NH3‐pumps continues

Detox to Glncontinues in brain, and nodepletion ofGlu

No ammoniaaccumulationin plasma

No significantgill damages

No detec. effect ongrowth rate

Day 105

SGR

(% d

ay-1

)

0.0

0.5

1.0

1.5

2.0 0.1 µg/L NH3-N8 µgl/L NH3-N14 µg/L NH3-N32 µg/L NH3-N

The responses of salmon afterlong‐term NH3‐N exposure


Tota

l am

mon

ia (m

mol

L-1

)

0.0

0.5

1.0

1.5

2.032 µg/L NH3-N14 µg/L NH3-N 8 µg/L NH3-N 0.1 µg/L NH3-N

*

Day 105

Glu

tam

ine

(nm

ol m

g-1)

0

2

4

6

8

10

12


*

Day 105R

elat

ive

gene

exp

ress

ion

0

1

2

3

4

5

6


*

**


Kolarevic, J., et al., Molecular and physiological responses to long‐term sublethal ammonia exposure in Atlantic salmon (Salmo salar). Aquat. Toxicol. (2012), http://dx.doi.org/10.1016/j.aquatox.2012.07.003


• Fish from all treatments PIT‐tagged and kept in commontanks during 12:12 LD

• From the start of 24:0 LD, SW‐tests done at 34 ppt for 72 h

• All fish had low CF and regulatedCl‐ (and Na+) well at SWT 3

• No significant effect of previous ammonia or feed ration treatment

Smoltification appears not to be affected by previous ammonia exposure

Day 105 SWT 1 SWT 2 SWT 3

Plas

ma

Cl- (m

mol

/L)

110

120

130

140

150

160

170 35 µg/L restricted 32 µg/L full-fed 17 µg/L restricted 14 µg/L full-fed 9 µg/L restricted 8 µg/L full-fed Control restricted Control full-fed

Day 105 SWT 1 SWT 2 SWT 3

Con

ditio

n fa

ctor

0.9

1.0

1.1

1.2

1.3

1.4



What do these results mean for the design and operation of RAS?

• Repeat the experiment in RAS at higher nitrite/CO2/TSS levels than in previous exposure study

• Aquaculture operation regulations: 2 mg/L TAN at pH 6.8‐7.2 = 3‐7 µg/L NH3‐N (12ºC)

• After a period of adaptation, Atlantic salmon parr showed tolerance up to 35 µg/L NH3‐N, with good growth and apparently good welfare

• No significant effect of elevated ammonia on salmon parr growth and examined welfare indicators

• No effects of exposure on smoltification and development of sea water tolerance (PIT tag)

• If verified in RAS these results can affect the sizing and flow in biofilters


Effects of sub‐lethal nitrite exposure at high chloride background during the parr stage of Atlantic salmon

Xavier Gutierrez1,*, Jelena Kolarevic1, Bjørn‐Steinar Sæther1, Grete Bæverfjord1, Harald Takle1, Matias Medina2, Bendik Fyhn Terjesen1

1 Nofima, NO‐6600 Sunndalsøra, Norway.2 AVS Chile SA, Puerto Varas, Chile.*Current address: NIVA Chile, Puerto Varas, Chile

Nitrite, a potentially problematic compound in RAS

Brit Tørud (2009). From the presentation «Praktisk fiskehelsetjeneste i resirkuleringsanlegg»

• Nitrite can be problematic in RAS for Atlantic salmon after large changes in feed load,pH/alkalinity, or too soon after biofilter start‐up

• NO2‐ has about equal affinity as Cl‐, in the

Cl‐/HCO3‐ gill transporter

• Thus, NaCl supplementation has been used for a long time to reduce toxicity of nitrite in RAS

• It has been recommended to supply Cl‐ at 20:1 (Cl:NO2 ‐N) weight ratio (catfish, tilapia, and trout)

• Svobodoba et al (2005) recommends, based on nitrite episodes in tilapia and tench RAS, that the ratio should be higher (e.g. tilapia had MetHb at Cl:NO2‐N ratio of 150)

• Nitrite exposure has been little studied in Atlantic salmon, only acute exposure (MethHb occurred) on fasting fish

• We wanted to study long‐term effects of varying Cl:NO2‐N ratios


• Done in FT

• 4 week acclimatization, 84 days of exposure

• Varied NO2‐N (5), chloride constant @180 mg/l

• Exp. system produced Cl:NO2‐N ratios of 23:1,

43:1, 1081, 424:1 and :2x105:1 in control

• 15 tanks and 52 fish per tank; start weight

16.5±0.6 g

• 12°C; pH = 6.8‐7.2; O2>85%;

• Examined parameters:

‐ Growth

‐ Biochemical indicators (plasma nitrite)

Experimental design

Nominal exposure group

Control 0.5 mg/l 2 mg/l 5 mg/l 10 mg/l

NO

2-N

con

cent

ratio

n (m

g/L)

0

2

4

6

8

10

12

H

H

H

H

1 2 3

1 2 3

1 2 3

1 2 3

H: Header tank1,2,3: Exp. tanks(n=36 per unit)



Cl- :N

O2-

N (w

eigh

t bas

is)

0

100

200

300

400

500

600

200000

3000002x105: 1

424:1

108:1

43:123:1


Days of exposure0 20 40 60 80

Bod

y w

eigh

t (g

ind-

1 )

0

20

40

60

80

100

Control 0.5 mg/l NO2-N, 424:1 1.9 mg/l NO2-N, 108:14.6 mg/l NO2-N, 43:19 mg/l NO2-N, 23:1



Spe

cific

gro

wth

rate

(% B

W/d

ay)

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2x105: 1 424:1 108:1 43:1 23:1Cl:NO2-N ratio

Weight and growth in Atlantic salmon parr exposed to nitrite

Control 0.5 mg/l NO2-N, 424:1 1.9 mg/l NO2-N, 108:14.6 mg/l NO2-N, 43:19 mg/l NO2-N, 23:1

SGR day 1-21



Spe

cific

gro

wth

rate

(% B

W/d

ay)

0.01.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

2x105: 1 424:1 108:1 43:1 23:1Cl:NO2-N ratio

A

AB ABAB

B

SGR day 49-84



Spe

cific

gro

wth

rate

(% B

W/d

ay)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2x105: 1 424:1 108:1 43:1 23:1Cl:NO2-N ratio


• Only a ratio ≥ 108:1 protected the salmon parr against nitrite entry, compared to control

• Body size and/or compensatory mechanisms appear to reduce nitrite accumulation with time (ANOVA, p<0.05)

Does nitrite enter Atlantic salmon parr at 20:1 chloride:NO2‐N ratio?



Pla

sma

NO

2-N

(mg/

L)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5Control, day 210.5. mg/l, day 212 mg/l, day 215 mg/l, day 21 10 mg/l, day 21

2x105: 1 424:1 108:1 43:1 23:1Cl:NO2-N ratio

AA

AB

B

B



Pla

sma

NO

2-N

(mg/

L)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5Control, day 210.5. mg/l, day 212 mg/l, day 215 mg/l, day 21 10 mg/l, day 21Control, day 840.5 mg/l, day 842 mg/l, day 845 mg/l, day 8410 mg/l, day 84

2x105: 1 424:1 108:1 43:1 23:1Cl:NO2-N ratio

AA

AB

B

B

AA

A

B

B


Conclusions

• The commonly used ratio of 20:1 Cl:NO2‐N appears not to protect Atlantic salmon parr against an initial growth rate reduction or nitrite entry

• NO2‐N plasma concentration did not differ significantly from control, in the 108:1 ratio group, despite NO2‐N water levels being ~20x Norwegian guidelines

• Results suggested that a 108:1 ratio should be used to protect Atlantic salmon parr, at least during the first days of nitrite exposure

• It should be considered if water quality guidelines for NO2 should also include Cl‐ requirements

• Selected treatments in this study will be repeated in RAS. If confirmed, results may have impact on Atlantic salmon RAS dimensioning and management


Overall conclusions

• Atlantic salmon parr has the potential to sustain higher concentrations of water ammonia than that currently recommended

• Atlantic salmon parr can also manage higher nitrite concentrations then recommended if adequate level of chloride is available

• These findings should be confirmed in RAS

• Establishment of more specific set of water quality parameters for RAS dimensioning and operation during smolt production is a necessity



Thank you for your attention!

[email protected]: Kjell Merok, Nofima

… and a BIG thank you to:all researchers that took part in the presented studies and technical staff at Nofima Sunndalsøraand Ås for taking good care of the experimental fish and for help with laboratory analyses.

Funded by Nofima and The Research Council of Norway

Water requirements for optimal Atlantic salmon smoltin ...smoltproduksjon.no/Bilder/TidlKonf 2012/19...

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Transcript of Water requirements for optimal Atlantic salmon smoltin ...smoltproduksjon.no/Bilder/TidlKonf 2012/19...