E ec s o wa e empe a u e on g ow h, heal h and diges i e p ocesses o
he hicklip g ey mulle Chelon lab osus
Ma kel Sanz-La o e
a,b,*
, Manu So o
a,b
, U zi Izagi e
a,b
, Xabie Lekube
a,b
a
Resea ch Cen e o Expe imen al Ma ine Biology and Bio echnology PIE, Uni e si y o he Basque Coun y UPV/EHU, A ea za 47, Plen zia, Basque Coun y, Spain
b
CBET Resea ch G oup, Depa men o Zoology and Animal Cell Biology, Facul y o Science and Technology, Facul y o Science and Technology, Uni e si y o he Basque
Coun y UPV/EHU, Sa iena z/g, Leioa, Basque Coun y, Spain
ARTICLE INFO
Keywo ds:
Aquacul u e di e si ica ion
Wa e empe a u e
Me abolism
Diges i e enzymes
Mugilidae
ABSTRACT
This s udy aimed o iden i y he e ec s o wa e empe a u e on he ea ing o he omni o ous eleos Chelon
lab osus and o de e mine he op imal empe a u e o he cul u e o his in e es ing candida e o he di e si-
ica ion o Eu opean aquacul u e. The ish (ini ial weigh 26.81 ±6.2 g) we e held a ou wa e empe a u es
(18, 22, 26 and 30 ◦C) in iplica e o 90 days in 100 L eci cula ing anks (n =14 / ank). The e ec s o said
empe a u es we e assessed on g ow h, in es inal heal h and he diges i e p ocesses o he ish. A 18 ◦C, ene gy
consump ion was low, leading o a high accumula ion o ese es and slow g ow h, a ypical o e win e ing
s a egy. The bes g ow h esul s we e ob ained a 22 ◦C, ollowed closely by 26 ◦C, which esul ed in low ene gy
ese es. The ac ha he ish a 26 ◦C g ew less han he ones a 22 ◦C while ha ing simila ene gy consump ion,
sugges ed ha his empe a u e was close o he end o he op imal ange, bu no signs o s ess we e de ec ed.
Howe e , a 30 ◦C he ish had lowe ene gy ese es bu g ew signi ican ly less, which can be conside ed
indica i e o s ess. Heal h impai men a his empe a u e was con i med by he epi helial lesions ound in his
g oup. The g ow h and ene gy a ailabili y o he di e en g oups is discussed in he ligh o he ac i i ies o
α
-amylase, pepsin and alkaline p o eases. As an in eg a ion o all hese esul s, a quad a ic eg ession model
esul ing om g ow h alues (SGR) in ela ion o wa e empe a u e was pe o med, and i allowed p edic ing an
ac ual op imal wa e empe a u e o 22.8 ◦C o g ow h o C. lab osus. This is he i s assessmen o he op imal
wa e empe a u e o he cul u e o C. lab osus, and i will be highly aluable o he de elopmen o i s in ensi e
cul u e.
1. In oduc ion
Ambien empe a u e is conside ed he mos impo an abio ic ac o
in luencing he me abolism and bioene ge ics o poikilo he mic ani-
mals, such as ish (Hawkins, 1995; Ny ø e al., 2014; Sun and Chen,
2014). Tempe a u e modula es he a es o biochemical eac ions ha
occu wi hin an animal, inc easing he oxygen and ene gy consump ion
as body empe a u e inc eases (Schul e, 2015). This aise o ene gy
consump ion in ela ion o empe a u e, hough, pla eaus and e en u-
ally declines apidly when eaching a c i ical empe a u e. This phe-
nomenon is mos ly explained by con o ma ional changes in he
enzymes, al hough o he p ocesses a e also impo an , as e iewed by
Schul e (2015). Ano he ac o playing a pi o al ole in he
de e mina ion o he “ene gy budge ” is he minimum amoun o ene gy
an animal has o expend in o de o main ain essen ial biological unc-
ions, which inc eases a highe empe a u es (Cla ke and F ase , 2004;
Fa ell, 2009; Schul e, 2015). The di e ence be ween hese wo a i-
ables de e mines he a ailable amoun o ene gy o di ec owa ds
p ocesses such as locomo ion, g ow h, immune esponse o ep oduc-
ion, c ea ing bell-shaped pe o mance cu es in ela ion o wa e
empe a u e in ishes (Fa ell, 2009).
In he case o cul u ed ishes, iden i ying he op imal wa e em-
pe a u e ange o maximum g ow h is essen ial o op imize p oduc ion
and ensu e he well-being o he animals, as subop imal en i onmen al
condi ions could e en ually lead o s ess, ha ing a nega i e impac on
ish heal h (Wang e al., 2019; Islam e al., 2021; Dawood e al., 2022).
* Co esponding au ho a : Resea ch Cen e o Expe imen al Ma ine Biology and Bio echnology PIE, Uni e si y o he Basque Coun y UPV/EHU, A ea za 47,
Plen zia, Basque Coun y, Spain.
E-mail add esses: [email p o ec ed] (M. Sanz-La o e), [email p o ec ed] (M. So o), [email p o ec ed] (U. Izagi e), [email p o ec ed]
(X. Lekube).
Con en s lis s a ailable a ScienceDi ec
Aquacul u e
jou nal homepage: www.else ie .com/loca e/aquacul u e
h ps://doi.o g/10.1016/j.aquacul u e.2024.741537
Recei ed 13 May 2024; Recei ed in e ised o m 6 Augus 2024; Accep ed 28 Augus 2024
Aquacul u e 595 (2025) 741537
A ailable online 30 Augus 2024
0044-8486/© 2024 The Au ho (s). Published by Else ie B.V. This is an open access a icle unde he CC BY-NC license ( h p://c ea i ecommons.o g/licenses/by-
nc/4.0/ ).
The e o e, e ec s o wa e empe a u e and op imal cul u ing condi ions
ha e been success ully iden i ied o comme cially impo an aquacul-
u e species such as A lan ic salmon (Jonsson e al., 2001), Eu opean sea
bass (Pe son-Le Ruye e al., 2004), gil head sea b eam (Segine , 2016),
u bo (Aydın e al., 2021, 2022a), Black Sea lounde (Aydın e al.,
2012) o yellow ail king ish (Bowye e al., 2014).
Tempe a u e can al e diges i e p ocesses such as inges ion, gu
passage ime o ood (Bendiksen e al., 2002; Handeland e al., 2008), as
well as he ac i i ies o diges i e enzymes (Papou soglou and Lyndon,
2005; Ahmad e al., 2014; Hani e al., 2018), which di ec ly in luence
eed e iciency. The a y acid p o ile o he edible pa o he ish is
ano he ele an aspec ha can be in luenced by ambien empe a u e.
Due o he homeo iscous adap a ion o cell memb ane luidi y, a lowe
empe a u es o ganisms end o syn hesize mo e unsa u a ed a y acids
wi h lowe mel ing poin s in o de o compensa e he loss o luidi y
caused by cold empe a u e (Hazel, 1995). As a esul , wa e empe a-
u e can di ec ly a ec ish quali y om he poin o iew o he con-
sume , conside ing he impo ance unsa u a ed a y acids ha e in
human die .
The hicklip g ey mulle Chelon lab osus has been iden i ied as an
in e es ing ish o he di e si ica ion o aquacul u e (Ben Khemis e al.,
2006; Zoui en e al., 2008; Ga cía-M´
a quez e al., 2021; Ga cia-Ma quez
e al., 2022). Due o i s low- ophic na u e, i has g ea po en ial o he
usage o al e na i e eed ing edien s, helping in he de elopmen o he
aquacul u e indus y wi hou inc easing i s consump ion o ishmeal
(Naylo e al., 2000). G ey mulle s ha e been cul i a ed in he Medi-
e anean egion in adi ional ex ensi e sys ems since he an iqui y and
hey a e highly alued o human consump ion in se e al coun ies o
said a ea (C ose i, 2016). Howe e , he e a e se e al knowledge gaps
abou C. lab osus ha pose a challenge o he de elopmen o i s in en-
si e cul u e. Ve y li le is known abou he g ow h a es o g ey mulle in
he wild, bu i has been desc ibed ha hey al e na e a slow-g owing
phase in au umn-win e and a as e g owing one in sp ing-summe ,
which lead o he conclusion ha he species was no compe i i e o
aquacul u e in he ea ly 90s (A uda e al., 1991). Howe e , conclusions
om newe s udies a e mo e p omising, al hough he epo ed da a a y
g ea ly depending on he size o he ish conside ed. Speci ic G ow h
Ra es (SGR) om 0.4 o 1.15 ha e been ob ained in nu i ion esea ches
pe o med wi h ju eniles in he ange o 46 o 100 g (Vílchez-G´
omez
e al., 2017; Ga cia-Ma quez e al., 2022; Ga cía-M´
a quez e al., 2023),
p o ing he po en ial o he species when ea ed unde con olled con-
di ions. The es ablishmen o op imal cul u ing condi ions is o upmos
impo ance in o de o u he imp o e he a o emen ioned esul s.
Many e o s a e being di ec ed owa ds inc easing he knowledge abou
he nu i ion o he species (Oja ee e al., 1996; Da ies e al., 1997;
Pujan e e al., 2015; Pujan e e al., 2017; Al unok and ¨
Ozden, 2017;
Ga cia-Ma quez e al., 2022, Ga cía-M´
a quez e al., 2023; Qui ´
os-Pozo
e al., 2023). Howe e , li le esea ch has been conduc ed abou op i-
mising o he aspec s o cul u ing, apa om he e ec s o salini y and
s ocking densi y (De las He as e al., 2015; Pujan e e al., 2018). E en
hough wa e empe a u e is one o he mos impo an ac o s o ish
g ow h (Ny ø e al., 2014; Sun and Chen, 2014), no esea ch has been
published on C. lab osus o ou knowledge, aside om a pape ocusing
on he e ec s o empe a u e on osmo egula ion (Lasse e and Gallis,
1975) and he a o emen ioned a icle by A uda e al. (1991), whe e
g ow h in wild condi ions was oughly es ima ed.
In ou p e ious expe ience wo king wi h his species, we obse ed
he bes g ow h esul s we e ob ained du ing summe mon hs a wa e
empe a u e close o 22 ◦C (unpublished da a), and he e o e we could
expec his o be he op imal empe a u e o he ea ing o C. lab osus.
Hence, he objec i e o he p esen esea ch was o de e mine he e ec s
o di e en wa e empe a u es on g ow h, ene gy me abolism (plasma,
li e and muscle me aboli es), in es inal heal h (his opa hological
analysis), diges i e p ocesses (diges i e enzyme ac i i ies) and p oduc
quali y ( a y acid p o ile o muscle) o he hicklip g ey mulle
C. lab osus in o de o es ablish he op imal empe a u e condi ions o
i s cul u e, always ensu ing animal wel a e.
2. Ma e ials and me hods
2.1. Expe imen al design
The ish used in his expe imen ( hicklip g ey mulle , C. lab osus)
we e wild specimens caugh a he U ola es ua y (Zumaia, Basque
Coun y, Spain) and acclima ed o labo a o y condi ions o eigh
mon hs in h ee 300 L open- low anks, wi hou empe a u e con ol,
ensu ing na u al he mal condi ions o he acclima ion phase. The ish
(n =168, ini ial o k leng h 13.35 ±0.9 cm, ini ial weigh 26.81 ±6.2
g) we e andomly sepa a ed in o 12 anks (14 indi iduals pe ank, n =
3) 30 days p io o he beginning o he expe imen and main ained a
oom empe a u e (19 ◦C). Du ing ha pe iod and he en i e expe i-
men , ish we e ed a comme cial die (Gemma diamond 1 mm; Sk e -
ing, S a ange , No way) wi h 57 % o p o ein and 15 % lipid con en s.
The pelle size chosen (1 mm) was smalle han he ypical one o ish o
his size. I was decided based on he expe ience o he esea ch eam
wi h his species, as he sedimen il e ing eeding beha iou o mugilids
does no allow he applica ion o adi ional aquacul u e eed size ables
(Ca dona, 2016). Fish we e ed manually wice a day, wi h a o al
amoun ha accoun ed o 2 % o he o al biomass o each ank. A he
end o he acclima ion pe iod (0 D), wa e empe a u es we e adjus ed o
he desi ed expe imen al ea men s (±0.5 ◦C), which we e 18, 22, 26
and 30 ◦C (g oups 18, 22, 26 and 30). Each empe a u e ea men was
pe o med in iplica e. The expe imen al pe iod las ed 90 days. The
ini ial a e age s ocking densi y was 4.48 ±0.28 kg / m
3
. The s ocking
densi y o each pa icula ank can be ound in he Appendix (Table A1).
The expe imen was pe o med in 12,100 L cylind ical-conical anks.
The anks we e eci cula ing sys ems, each equipped wi h a Sun Sun HW
- 302 canis e il e (WilTec, Eschweile , Ge many). The wa e low o
he il e s was o 540 L / h. Each canis e con ained a mechanical il e
consis ing on h ee oam laye s, and a biological il e consis ing o
ce amic and plas ic subs a e o ni i ying bac e ia. Each ank was
equipped wi h a wa e coole o hea e , depending on he expe imen al
ea men . The anks we e p o ided cons an ae a ion o keep adequa e
oxygen le els o a ound 6 mg / L. A e ca e ul examina ion o he
eeding beha iou o C. lab osus, i was decided o close he il e s o 15
min a e e y eeding ime, in o de o ensu e su icien ime o an
adequa e eeding. A e said ime, a 10 L wa e change was pe o med,
and hen il e s we e e-opened. This p ocedu e allowed eco e ing
much o he le o e eed, bu no all. This accoun ed o a daily change
o 20 % o he wa e . A e e y sampling ime, all he wa e was enewed.
Ammonia, ni i e and ni a e le els we e checked weekly using com-
me cial ki s (SERA, Heinsbe g, Ge many). Ammonia le els we e kep a
0–0.5 mg / L, ni i e a 0–2 mg / L, and ni a e a 0–50 mg / L.
2.2. Sample collec ion
Biome ical da a ( o k leng h and body weigh ) we e collec ed a day
0 (0 D), 30 (30 D), 60 (60 D) and 90 (90 D). Fo handling (weighing and
measu ing), ish we e caugh wi h a ne and in oduced in a wa e ba h
con aining 100 mg / L T icaine me hanesul ona e MS 222 (Sigma-
Ald ich, Sain Louis, USA) anaes he ic. Fo sac i ice, he ish we e
in oduced a a wa e ba h o he same compound a a concen a ion o
300 mg / L. Fou indi iduals o each ank we e sac i iced and dissec ed
a 30 D (n =48), and he es a 90 D (n =120). Blood was collec ed om
he caudal ein wi h a hepa inized 1 mL sy inge wi h a 25 G needle, and
cen i uged o 15 min a 10000 pm. The plasma was collec ed, lash
ozen in liquid ni ogen and s o ed a −80 ◦C o me aboli e analysis.
Whole muscle o ishes we e lash ozen a −80 ◦C o me aboli e and
a y acid p o ile analyses. Li e and gas oin es inal ac s we e
ex ac ed, weighed and lash ozen a −80 ◦C o he measu emen o
me aboli es (li e ) and diges i e enzyme ac i i ies (gas oin es inal
ac s). A sec ion o p oximal in es ine was ixed in o malin o u he
M. Sanz-La o e e al.
Aquacul u e 595 (2025) 741537
2
his o(pa ho)logical analysis (See Sec ion 2.7).
2.3. Calcula ions
The ollowing calcula ions we e made acco ding o Ga cia-Ma quez
e al. (2022):
Weigh gain (WG) = Final weigh (g) − ini ial weigh (g).
Visce osoma ic index (VSI) = 100 x Visce al weigh (g)
To al weigh (g)(%).
Hepa osoma ic index (HSI) = 100 x Li e weigh (g)
To al weigh (g)(%).
Ful on condi ion ac o (K) = 100 x Fish weigh (g)
Leng h3(cm).
2.4. Me aboli e analyses
Me aboli e analyses we e pe o med in pooled samples o each ank
(n =3). Plasma glucose (Amplex Red Glucose / Glucose Oxidase Assay
Ki , In i ogen, Ca lsbad, USA), li e and muscle glycogen (ab65620 –
Glycogen Assay Ki , Abcam, Wal ham, USA) and plasma, li e and
muscle iglyce ides (ab65336 – T iglyce ide Assay Ki , Abcam, Wal-
ham, USA) we e measu ed (Pujan e e al., 2015) wi h comme cial ki s,
ollowing he ins uc ions p o ided by he manu ac u e s.
2.5. Diges i e enzyme ac i i ies
The ac i i ies
α
-amylase (ab102523 Amylase Assay Ki , Abcam,
Wal ham, USA), lipase (ab102524 Lipase Ac i i y Assay Ki , Abcam,
Wal ham, USA), pepsin and alkaline p o eases (ab112153 P o ease Ac-
i i y Assay Ki , Abcam, Wal ham, USA) we e measu ed (Pujan e e al.,
2017, 2018) using comme cial ki s. In he case o pepsin, he same ki
employed o alkaline p o eases was used by changing he p o ided
eac ion bu e wi h 10 mM HCl (pH 2.0), as ecommended by he
manu ac u e .
The samples we e p epa ed o analysis by homogenizing he s om-
achs and in es ines in liquid N
2
condi ions, using a SPEX Sample P ep
6770 eeze / mill (SPEX Sample P ep, Me uchen, USA). Enzymes we e
ex ac ed om he esul ing homogena es using a P ecellis 24 homog-
enize (Mon igny-Le-B e onneux, F ance) wi h h ee 60 s passes a 6500
pm a 4 ◦C, using he bu e ecommended by he manu ac u e o each
enzyme. The analyses we e pe o med in iplica e in pooled samples o
each ank (n =3). The p o ein con en o each pool was measu ed using
Pie ce BCA P o ein Assay Ki (The mo Fishe Scien i ic, Wal ham, USA).
Each enzyma ic ac i i y was measu ed wice, as ollows. Fi s , all he
pools we e analysed using he same incuba ion empe a u e (25 ◦C o
α
-amylase, 37 ◦C o lipase), as indica ed by he manu ac u e . Fo
p o eases, no incuba ion empe a u e was indica ed on he p o ocol, so
he op imum empe a u e was he one desc ibed by Pujan e e al.
(2017), ha is, 50 ◦C o alkaline p o eases and 40 ◦C o pepsin. This
measu emen was called “absolu e ac i i y”. Fu he , a second analysis
was pe o med by incuba ing e e y g oup a i s espec i e expe imen al
empe a u e. This measu emen was called “ac ual empe a u e”. The
enzyma ic ac i i ies we e de ined acco ding o he manu ac u e s. 1
Uni Amylase =amoun o amylase ha clea es e hylidene-pNP-G7 o
gene a e 1.0
μ
mol o ni ophenol pe min a pH 7.20 a 25 ◦C. 1 Uni
Lipase =amoun o lipase ha hyd olyzes iglyce ide o gene a e 1.0
μ
mol o glyce ol pe minu e a 37 ◦C. P o eases: alkaline p o eases and
pepsin ac i i ies we e compa ed o uni s o ypsin (uni no speci ied).
2.6. Fa y acid p o ile o muscle
The analysis o a y acids was pe o med by ACOI Coimb a Collec-
ion o Algae. The cha ac e iza ion o he a y acid p o ile o muscle was
pe o med in pooled samples o each ank (n =3). Muscle samples we e
homogenized in liquid N
2
, using a SPEX Sample P ep 6770 eeze / mill
(SPEX Sample P ep, Me uchen, USA). The ex ac ion o lipids om he
esul ing homogena e was pe o med by he MTBE me hod (Ma yash
e al., 2008).
Fo he cha ac e iza ion o a y acid p o ile, d ied samples we e
esuspended in 1 mL o hexane and 0.5 mL o me hanol. A e o exing,
400
μ
L o sodium me hoxide we e added. The op laye was il e ed wi h
a nylon memb ane and 150
μ
L o he il e ed solu ion was placed in a
ial, 100
μ
L o he in e nal s anda d me hyl nonadecanoa e (C19:0)
(Sigma-Ald ich, Sain Louis, USA) wi h a inal concen a ion o 0.3 mg /
mL we e added. The gas ch oma og aphy was pe o med in a NEXIS GC-
2030 (Shimadzu, Kyo o, Japan) ch oma og aph equipped wi h a lame
ioniza ion de ec o and a TR-CN 100 capilla y column (60 m ×0.25 mm
×0.20
μ
m). Helium was used as ca ie gas a a p essu e o 150 kPa a
he op o he column. The empe a u e o he injec o and de ec o was
260 ◦C and he spli a io was 1:25. The ini ial empe a u e o he col-
umn was main ained a 90 ◦C o 7 min a e he injec ion, inc easing
5 ◦C / min o 220 ◦C and held o mo e 15 min. Da a we e acqui ed and
analysed using Lab Solu ions da a analysis so wa e. Fa y acids (FA)
we e iden i ied by compa ing he ela i e e en ion imes wi h an
au hen ic ex e nal s anda d, Supelco 37 componen FAME mix (Sigma-
Ald ich, Sain Louis, USA). The quan i ica ion o FA was based on he
in e nal s anda d me hod (Assunç˜
ao e al., 2017). The esul s we e
exp essed in pe cen age o he o al FAME (%).
2.7. His ological analysis
In es ine samples we e p epa ed o his ological analysis ollowing
s anda d his ological p ocedu es. B ie ly, p oximal in es ine samples
we e ixed in a 10 % o malin solu ion bu e ed wi h seawa e o 24 h
(Ma oja e al., 1970). Once ixed, o malin was eplaced by 70 %
e hanol un il he p ocessing. Samples we e p ocessed wi h an au oma ed
issue p ocesso (LEICA ASP 300S; Leica Mic osys ems Nussloch GmbH,
Ge many) and embedded in pa a in wax blocks. Fi e
μ
m hick sec ions
we e ob ained wi h a mic o ome (Leica RM2125RTS; Leica Mic o-
sys ems Nussloch GmbH, Ge many), s ained wi h haema oxylin-eosin
(Ma oja e al., 1970)using an Au os aine XL (Leica Mic osys ems
Nussloch GmbH, Ge many), and moun ed wi h co e slip. The samples
we e obse ed unde an Olympus BX61 ligh mic oscope (Olympus-
Li escience, Tokyo, Japan).
2.8. S a is ical analysis
All s a is ical analyses we e pe o med using he IBM SPSS S a is ics
27 so wa e (IBM Co p. Released, 2020). No mali y o he da a was
Speci ic g ow h a e%(SGR) = 100 x Ln (Final body weigh ) − Ln (Ini ial body weigh )
Feeding days (%/day).
M. Sanz-La o e e al.
Aquacul u e 595 (2025) 741537
3
es ed using he Shapi o Wilk es . Homogenei y o a iances was es ed
using he Le ene’s es . In he case o da a wi h no mal dis ibu ions and
homogeneous a iances, S uden ’s - es was pe o med o compa e he
di e en a iables such as weigh , leng h, SGR, HSI, VSI, K, me aboli e
le els, enzyma ic ac i i ies, a y acids o his ological lesions (dependen
a iables) ac oss wa e empe a u e ea men s o sampling imes (in-
dependen a iables). When da a was no no mal and a iances no
homogeneous, he non-pa ame ic Shapi o-Wilk’s es was used.
Di e en linea eg ession models we e pe o med among SGR da a
om 0 D o 90 D (dependen ) and wa e empe a u e (independen ), and
he one wi h he bes i was selec ed. The signi icance o e e y s a is-
ical es was se a p <0.05. All da a a e p esen ed as mean ±s anda d
de ia ion.
2.9. E hical s a emen
All expe imen al p ocedu es complied wi h he Guidelines o he
Eu opean Union (2010/63/UE) and he Spanish legisla ion (RD53/2013
and law 32/2007) o he handling and use o labo a o y animals unde
he supe ision and accep ance o he E hics o expe imen a ion and
animal wel a e commi ee o he Uni e si y o he Basque Coun y
(UPV/EHU) and p o incial au ho i ies (CEEA: M20_2021_108-
Dipu aci´
on Fo al de Bizkaia).
3. Resul s
A he end o he expe imen , g oup 22 exhibi ed highe leng h and
weigh alues han he o he s. This di e ence was s a is ically
Fig. 1. leng h (cm) and weigh (g) o C. lab osus ea ed a di e en empe a u es o 90 days. G oups wi h di e en supe sc ip le e s show s a is ically signi ican (p
<0.05) di e ences.
Table 1
Speci ic G ow h Ra e (SGR) o C. lab osus ea ed a di e en empe a u es o 90
days. 30 D: day 30; 60 D: day 60; 90 D: day 90. G oups wi h di e en supe sc ip
le e s show s a is ically signi ican (p <0.05) di e ences. Capi al le e supe -
sc ip s: compa isons be ween empe a u e ea men s inside a gi en ime pe iod
( ow); lowe le e supe sc ip s: compa isons be ween ime pe iods inside a
gi en empe a u e ea men (column).
SGR
(%/day)
18 ◦C 22 ◦C 26 ◦C 30 ◦C
0 D - 30
D
0.92 ±
0.03
Aa
1.02 ±
0.09
Aab
1.01 ±
0.15
A
0.51 ±
0.14
Bb
30 D -
60 D
0.72 ±
0.14
Bb
0.96 ±
0.06
Ab
1.01 ±
0.16
AB
0.87 ±
0.43
ABab
60 D -
90 D
0.57 ±
0.17
Bb
1.16 ±
0.10
Aa
1.01 ±
0.21
A
0.79 ±
0.20
Ba
0 D - 90
D
0.80 ±
0.09
BC
1.01 ±
0.02
A
0.95 ±
0.09
AB
0.79 ±
0.06
C
M. Sanz-La o e e al.
Aquacul u e 595 (2025) 741537
4
signi ican (p <0.05) be ween g oup 22 and g oup 30 in bo h cases
(Fig. 1).
A he end o he expe imen , g oup 22 showed he highes SGR
alues, ollowed by g oup 26, he o he wo ha ing signi ican ly lowe
alues (Table 1). Du ing he expe imen al pe iod, he SGR alues o
g oup 18 signi ican ly dec eased, while he opposi e happened o g oup
30.
The eg ession model be ween SGR om he beginning o he end o
he expe imen (0 D – 90 D;dependen a iable) and wa e empe a u e
(independen a iable) wi h he bes i (R
2
=0.701) was he quad a ic
eg ession (Fig. 2). The maximum o he cu e was ound a 22.8 ◦C.
HSI showed he same pa e n a bo h samplings (Table 2), g oup 18
ha ing he highes alues, ollowed by g oup 22, while 26 and 30 g oups
had he lowes . The e we e no signi ican di e ences in VSI a 30 D, bu
a 90 D, a e y simila esul o HSI di e ences was ob ained. Rega ding
K alue, i was also highe in g oup 18 han in he 26 and 30 g oups a 30
Fig. 2. quad a ic eg ession be ween SGR (beginning o end o he expe imen ; 0 D – 90 D) and wa e empe a u e o C. lab osus ea ed a di e en empe a u es o
90 days.
Table 2
weigh (W), o k leng h (Fl), hepa osoma ic (HSI) and isce osoma ic (VSI) indexes, and Ful on condi ion ac o (K) o C. lab osus ea ed a di e en empe a u es o
90 days. 30 D: day 30; 90 D: day 90. Capi al le e supe sc ip s: compa isons be ween empe a u e ea men s a 30 D; lowe le e supe sc ip s: compa isons be ween
empe a u e ea men s inside 90 D. Signi ican di e ences (p <0.05) inside a gi en ea men o e ime (30 D s 90 D) a e highligh ed in bold.
18 ◦C 22 ◦C 26 ◦C 30 ◦C
30 D 90 D 30 D 90 D 30 D 90 D 30 D 90 D
W (g) 40.33 ± 7.85
A
52.59 ± 9.56
AB
40.25 ± 8.77
a
57.74 ± 11.86
A
38.41 ± 7.05
a
55.70 ± 10.28
AB
34.86 ± 7.36
b
49.13 ± 8.73
B
Fl (cm) 14.77 ± 0.91 16.15 ± 0.93
A
14.96 ± 1.04 16.78 ± 0.99
A
14.89 ± 0.88 16.65 ± 0.97
A
14.49 ± 0.91 15.76 ± 0.86
B
HSI 1.16 ± 0.04
a
1.03 ± 0.06
A
0.80 ±0.12
b
0.78 ±0.05
B
0.65 ±0.08
bc
0.65 ±0.03
C
0.63 ±0.09
c
0.69 ±0.04B
C
VSI 6.79 ±0.47 7.00 ±0.33
A
6.47 ±0.11 6.19 ±0.22
B
6.10 ±0.74 5.15 ±0.37
C
6.29 ±0.74 5.84 ±0.18
B
K 1.24 ±0.03
a
1.24 ±0.02
A
1.19 ±0.02
ab
1.20 ±0.04
AB
1.15 ±0.02
b
1.19 ±0.02
B
1.13 ± 0.03
b
1.24 ± 0.02
A
Table 3
plasma, li e and muscle biochemical da a o C. lab osus ea ed a di e en empe a u es o 90 days. 30 D: day 30; 90 D: day 90; Glu: glucose; Tg: iglyce ides; Gly:
glycogen. G oups wi h di e en supe sc ip le e s show s a is ically signi ican (p <0.05) di e ences. Capi al le e supe sc ip s: compa isons be ween empe a u e
ea men s a 30 D; lowe le e supe sc ip s: compa isons be ween empe a u e ea men s inside 90 D. Signi ican di e ences (p <0.05) inside a gi en ea men o e
ime (30 D s 90 D) a e highligh ed in bold.
18 ◦C 22 ◦C 26 ◦C 30 ◦C
30 D 90 D 30 D 90 D 30 D 90 D 30 D 90 D
Plasma
(mg/
dL)
Glu 63.56 ±35.37 84.63 ±16.49 58.58 ±23.59 81.39 ±18.03 54.10 ± 14.72 91.45 ± 9.12 64.78 ±28.23 80.68 ±14.89
Tg 178. 80 ±
20.89
a
243.34 ± 38.50
A
119.25 ±
12.80
b
175.04 ±
17.60
B
34.97 ±28.71
c
97.45 ±
41.28
C
38.13 ±
23.29
c
96.72 ± 7.62
C
Li e
(mg/g)
Gly 13.23 ±3.37 15.41 ±2.03
A
7.52 ±3.33 6.72 ±4.04
B
10.67 ±2.09 12.69 ±
3.42
AB
8.16 ±2.91 10.77 ±2.24
AB
Tg 86.01 ±9.05
a
101.35 ±25.62
A
55.54 ±14.22
b
61.56 ±7.18
AB
63.93 ±
26.17
ab
49.41 ±
10.16
B
47.46 ±
22.25
b
86.42 ± 15.61
A
Muscle
(mg/g)
Gly 2.35 ± 0.31
a
1.53 ± 0.20
A
1.33 ±0.18
b
1.30 ±0.08
AB
1.45 ±0.47
b
0.91 ±0.20
C
1.51 ±0.26
ab
1.12 ±0.12
BC
Tg 5.49 ±1.95 8.61 ±5.87 11.79 ±5.92 10.64 ±3.87 9.29 ±6.31 5.34 ±2.62 3.45 ± 0.52 9.93 ± 1.26
M. Sanz-La o e e al.
Aquacul u e 595 (2025) 741537
5
D, bu a 90 D, g oup 26 showed he lowes alue.
Plasma glucose (Table 3) did no show any signi ican di e ence
be ween ea men s a any o he sampling imes, bu i did ha e an
upwa ds end om 30 D o 90 D in e e y g oup, his di e ence being
signi ican in g oup 26. Plasma iglyce ide changed be ween g oups
and sampling imes. A bo h samplings, g oup 18 had he highes alues,
ollowed by g oup 22, while he o he g oups had he lowes alues.
Simila o wha happened wi h glucose, plasma iglyce ide also
inc eased o e ime, bu in his case he di e ences we e always sig-
ni ican be ween 30 D and 90 D, excep a g oup 26. Li e glycogen only
showed a signi ican di e ence a 90 D, when g oup 18 had he highes
alues and g oup 22 he lowes . A 30 D, g oup 18 showed a signi ican ly
highe li e iglyce ide con en han he o he g oups, bu a 90 D,
g oup 30 had he highes alues alongside g oup 18. In ac , g oup 30
showed he only signi ican inc ease in li e iglyce ides o e ime.
Muscle glycogen alues we e he highes in g oup 18 a bo h samplings.
Muscle iglyce ide le els did no show any signi ican di e ence be-
ween empe a u e ea men s a any sampling, bu hey did inc ease
o e ime a g oup 30.
When measu ing he amylase ac i i y o e e y g oup a he same
incuba ion empe a u e (absolu e ac i i y), g oup 18 showed he highes
alue a 30 D, bu a 90 D, g oup 22 had he highes ac i i y (Table 4).
G oup 18 was he only one whe e absolu e amylase ac i i y did no
inc ease o e ime. When measu ing he amylase ac i i y a he expe -
imen al empe a u es (ac ual ac i i y), g oups 26 and 30 showed he
highes alues a 30 D, bu a 90 D, he e we e no di e ences be ween
22, 26 and 30 g oups. Lipase ac i i y was below de ec ion limi a e e y
empe a u e es ed.
A 90 D g oup 18 had he lowes ac ual alkaline p o ease ac i i y,
despi e showing he highes absolu e ac i i y. In he case o pepsin,
g oups 18 and 22 had he highes absolu e ac i i ies a 90 D, while 22,
26 and 30 g oups demons a ed signi ican ly highe ac ual ac i i ies
han he g oup 18.
Fa y acid con en o ish muscle (Table 5) did no di e among
empe a u e ea men s in e ms o o al SFA con en , bu he e we e
sligh changes in MUFA and PUFA. The ish wi h he lowes MUFA
con en a he end o he expe imen we e he ones held a 22 ◦C, while
hey had he highes con en o PUFA.
ω
-3 and
ω
-6 PUFA con en we e
also equal ac oss all expe imen al ea men s. Full in o ma ion abou
a y acids can be ound a he Appendix (Table A2).
Mos o he analysed in es inal samples p esen ed he expec ed
s uc u e (Fig. 3A). This consis s o he se osa laye in he ou e mos
pa , muscula laye , submucosae and he mucosa, comp ised o he
epi helium and lamina p op ia (Raˇ
sko i´
c e al., 2011). In e es ingly, a
dis up ion o he mucosal ba ie cha ac e ised by he loss o en e ocy es
(Fig. 3B) was de ec ed in ce ain samples. Aside om he gaps in he
epi helium caused by he en e ocy e loss, some deb is could be seen
coming ou om hese lesions. These anomalies we e mos p e alen a
he end o he expe imen a g oup 30 (Fig. 3C).
4. Discussion
In he p esen esea ch, Chelon lab osus we e main ained unde ou
wa e empe a u es (18, 22, 26 and 30 ◦C) o assess he one ende ing
he bes yields in e ms o g ow h and animal wel a e. The highes leng h
inc ease, weigh gain and SGR alues o C. lab osus ju eniles we e
achie ed a 22 ◦C, closely ollowed by he ish ea ed a 26 ◦C. The o he
wo g oups (18 and 30 ◦C) showed signi ican ly lowe alues on all he
a o emen ioned pa ame e s a he end o he expe imen . The SGR
alues ob ained he ein a e wi hin he ange epo ed o C. lab osus in-
di iduals o simila sizes in p e ious esea ch, as SGRs om 0.89 o 1.15
we e ob ained in ju eniles weighing 46 g in a nu i ional esea ch
(Vílchez-G´
omez e al., 2017). These esul s sugges ha he op imal
empe a u e ange o a heal hy g ow h is be ween 22 and 26 ◦C o
C. lab osus, 26 ◦C being close o he uppe limi . The o he empe a u es
es ed a e sub-op imal o hicklip g ey mulle cul u e. In o de o
summa ize all hese esul s, absolu e SGR was used as a gene al ep e-
sen a ion o ish pe o mance du ing he expe imen , and i was co e-
la ed o wa e empe a u e. The eg ession model wi h he bes i was
ound o be he quad a ic eg ession, which accu a ely e lec ed he
dome-shaped g ow h cu es usually caused by wa e empe a u e on
ishes (Ny ø e al., 2014). The esul ing model allowed p edic ing he
ac ual op imal empe a u e o he ea ing o C. lab osus ju eniles, which
was 22.8 ◦C, a e y simila empe a u e o he o iginally expec ed one
(22 ◦C). In a esea ch ocusing on a y acids o C. lab osus unde
di e en cul u ing condi ions, he au ho s men ion “good g ow h a es”
a empe a u es om 26 o 30 ◦C (Rabeh e al., 2022), bu u he de ail
is lacking, as his is no he ocus o said pape . The accu a e in e p e-
a ion o hese esul s, hough, equi es conside ing he o igin o he ish
used. The expe imen al ish used he ein we e o iginal om he Can a-
b ian Sea, which a ely eaches empe a u es abo e 22 ◦C e en in
summe mon hs (Bo ja e al., 2019). Mo eo e , i is known ha op imal
wa e empe a u e o ish g ow h is ypically somewha highe han he
empe a u e no mally encoun e ed a hei na u al habi a (Handeland
e al., 2008), which suppo s ou obse a ions. Howe e , his species is
widely dis ibu ed ac oss he No h-Eas A lan ic Ocean om Mau i ania
o No way, Medi e anean and Black Seas (Tu an, 2016). Al hough he
exis ence o gene ically di e en ia ed subpopula ions has no been
p o en (Nzioka e al., 2023), i is concei able o popula ions inhabi ing
wa me a eas, such as he Medi e anean, o ha e adap a ions o cope
wi h he he mal cha ac e is ics o hei habi a , which ul ima ely could
a ec g ow h. Fo his eason, he p o enance o he ish has o be aken
in o accoun when a ming C. lab osus, and op imal empe a u e e-
e alua ed i necessa y. O he ish species o empe a e wa e s show an
Table 4
α
-amylase (Amy), alkaline p o eases (Alk P o ) and pepsin (Pep) ac i i ies o C. lab osus diges i e ac ea ed a di e en empe a u es o 90 days. 30 D: day 30; 90 D:
day 90; Abs: absolu e ac i i y measu ed as ecommended by he manu ac u e ; Ac : ac ual ac i i ies measu ed a he expe imen al empe a u es. G oups wi h di e en
supe sc ip le e s show s a is ically signi ican (p <0.05) di e ences. Capi al le e supe sc ip s: compa isons be ween empe a u e ea men s a 30 D; lowe le e
supe sc ip s: compa isons be ween empe a u e ea men s inside 90 D. Signi ican di e ences (p <0.05) inside a gi en ea men o e ime (30 D s 90 D) a e
highligh ed in bold.
18 ◦C 22 ◦C 26 ◦C 30 ◦C
30 D 90 D 30 D 90 D 30 D 90 D 30 D 90 D
Amy
(U /
μ
g p o ein)
Abs 100.40 ±
11.13
a
81.35 ±
5.35
B
71.20 ±
10.84
b
104.29 ± 9.50
A
73.20 ±
6.57
b
88.18 ±
3.00
B
71.46 ±
4.34
b
94.12 ± 10.89
B
Ac 68.82 ±
10.74
ab
53.18 ±
7.16
B
57.62 ±
11.24
b
83.98 ± 6.14
A
74.24 ±
9.49
a
85.38 ±5.62
A
78.84 ±
3.58
a
119.49 ± 28.39
A
Alk P o (mU/
μ
g
p o ein)
Abs 1.74 ±0.24 1.78 ±0.19
A
1.80 ±0.16 1.64 ±0.22
AB
1.60 ± 0.14 1.21 ± 0.20
B
1.34 ±0.40 1.30 ±0.27
AB
Ac 0.93 ±0.12 0.73 ±0.10
B
1.08 ±0.08 1.16 ±0.06
A
1.29 ±0.25 1.26 ±0.19
A
0.91 ±0.29 1.13 ±0.31
AB
Pep
(U / g p o ein)
Abs 54.37 ±1.52
a
55.11 ±7.84
A
52.72 ±3.62
a
49.56 ±0.97
A
45.91 ±
7.81
a
11.44 ±
2.11
B
13.70 ±
7.94
b
10.57 ±3.74
B
Ac 10.63 ±2.44
b
7.42 ±3.31
B
14.27 ±
3.81
ab
16.01 ±3.03
A
21.37 ±
3.38
a
16.16 ±2.28
A
11.42 ±
4.18
b
14.74 ±2.48
A
M. Sanz-La o e e al.
Aquacul u e 595 (2025) 741537
6
op imal he mal ange simila o C. lab osus, al hough species-speci ic
a ia ions exis . Yellow ail king ish exhibi s a e y na ow op imal
empe a u e ange peaking a 24 ◦C, e y simila o C. lab osus (Bowye
e al., 2014). The pe o mance cu e o he Eu opean sea bass is sligh ly
displaced owa ds highe empe a u es, as i pe o ms be e a em-
pe a u es close o 26 ◦C, and g ow h s a s o be dep essed a 29 ◦C
(Pe son-Le Ruye e al., 2004). Gil head sea b eam also exhibi s highe
op imal empe a u es, close o 25 ◦C (Segine , 2016). The opposi e
happens in he case o u bo , as i s op imum empe a u e is close o
18 ◦C (Aydın e al., 2021), which has been iden i ied as sub-op imal o
C. lab osus. Compensa o y g ow h is a phenomenon ha could make he
in e p e a ion o hese esul s mo e di icul . I consis s o accele a ed
g ow h appea ing when eco e ing op imal condi ions a e a pe iod o
ad e si y like ood dep i a ion o sub-op imal empe a u e (Py e al.,
2022). Wa e empe a u e du ing he acclima ion phase was a ound
19 ◦C, close o he 18 ◦C iden i ied as sub-op imal o C. lab osus ea ing.
The e o e, inc easing wa e empe a u e o 22 and 26 ◦C, in he op imal
ange o he species, could igge compensa o y g ow h, and he e ec s
obse ed would be a p oduc o he empe a u e change, no o he
expe imen al empe a u e i sel . Howe e , compensa o y g ow h is
known o be s onge a e pe iods o se e e ad e se condi ions, when
ene gy ese es o he ish ha e been s ongly exploi ed (Py e al., 2022).
As seen in he p esen s udy, ish a 18 ◦C had he highes ene gy e-
se es, so he sub-op imal condi ions o he acclima ion pe iod p obably
Table 5
summa y o a y acid con en s o C. lab osus muscle ea ed a di e en empe a u es o 90 days (exp essed as % o he o al a y acid me hyl es e s). 30 D: day 30; 90
D: day 90; SFA: sa u a ed a y acids; MUFA: monounsa u a ed a y acids; PUFA: polyunsa u a ed a y acids;
ω
-3 PUFA: omega-3 polyunsa u a ed a y acids;
ω
-6
PUFA: omega-6 polyunsa u a ed a y acids. G oups wi h di e en supe sc ip le e s show s a is ically signi ican (p <0.05) di e ences. Capi al le e supe sc ip s:
compa isons be ween empe a u e ea men s a 30 D; lowe le e supe sc ip s: compa isons be ween empe a u e ea men s inside 90 D. Signi ican di e ences (p <
0.05) inside a gi en ea men o e ime (30 D s 90 D) a e highligh ed in bold. Full in o ma ion abou a y acids can be ound a he Appendix (Table A2).
18 ◦C 22 ◦C 26 ◦C 30 ◦C
30 D 90 D 30 D 90 D 30 D 90 D 30 D 90 D
ΣSFA 43.00 ±1.65 43.33 ±1.86
AB
41.95 ± 0.33 44.26 ± 0.85
A
43.12 ±2.23 42.99 ±0.83
AB
40.23 ±3.32 42.17 ±1.07
B
ΣMUFA 30.76 ±0.97 31.33 ±0.97 30.39 ±1.73 27.54 ±2.02 30.49 ±1.00 29.31 ±1.71 32.12 ±2.86 31.59 ±1.73
ΣPUFA 26.24 ±2.61 25.34 ±0.92
B
27.81 ±1.68 28.20 ±1.20
A
26.38 ±1.23 27.70 ±0.99
A
27.62 ± 0.47 26.24 ± 0.66
AB
Σ
ω
-3 PUFA 14.26 ±2.63 15.91 ±1.29 16.57 ±1.99 19.63 ±2.45 15.64 ±0.24 18.36 ±2.33 14.78 ±2.53 16.12 ±1.64
Σ
ω
-6 PUFA 10.61 ±1.76 8.12 ±0.82 9.87 ± 0.31 7.35 ± 0.83 9.40 ±1.13 7.76 ±0.92 11.04 ±2.41 8.37 ±0.81
Fig. 3. A) no mal s uc u e o in es inal illi. 1: se osa laye . 2: muscula laye . 3: submucosae. 4: lamina p op ia. 5: epi helium; B) example o in es inal illi wi h
epi helial lesions (highligh ed wi h a ows). No e he gap caused by en e ocy e loss and he deb is coming ou o he lesion; C) incidence (lesions pe sample) o
epi helial lesions in C. lab osus in es ine ea ed a di e en empe a u es a day 90.
M. Sanz-La o e e al.
Aquacul u e 595 (2025) 741537
7
we e no se e e enough o induce a compensa o y g ow h esponse.
I is wo h no ing ha while he pe o mance o g oups 22 and 26
was cons an ac oss he en i e expe imen al pe iod, he o he wo g oups
showed ema kable al e a ions o e ime, as e idenced by he changes
in SGR ac oss he di e en sampling imes. In he case o g oup 30, he
pe o mance imp o emen obse ed o e ime migh be a esul o
acclima ion a e a sha p inc ease in wa e empe a u e. A wide ange o
mechanisms o he mal acclima ion exis in eleos ishes, some o hem
being almos ins an aneous while o he s can ake se e al weeks o
ac i a e (Johns on and Dunn, 1987). Howe e , despi e he abili y
showed by C. lab osus o acclima e o empe a u es up o 30 ◦C and
imp o e hei pe o mance o e ime, hei compensa o y mechanisms
a e no enough o o e come he challenge posed by his ex eme
ambien empe a u e comple ely. Feed in ake da a could allow o a
be e unde s anding o he dec ease o g ow h obse ed a g oup 18
om he beginning o he end o he expe imen , bu un o una ely, i
was no eco ded. I is known ha eed in ake can a y depending on
se e al ac o s, including wa e empe a u e, al hough he unde s and-
ing o appe i e egula ion on ish is s ill a “wo k in p og ess” (Volko
and Rønnes ad, 2020). In gene al, ood in ake in ishes inc eases
alongside wa e empe a u e un il eaching a maximum, usually a a
empe a u e a bi highe han he op imal one o g ow h (Bu el e al.,
1996). A dec ease in eed in ake when lowe ing wa e empe a u e has
been obse ed in ishes such as he yellow ail king ish Se iola lalandi
(Miegel e al., 2010), Asian ca ish Cla ias ba acus (Ahmad e al., 2014),
u bo Scoph almus maximus (Gue ei o e al., 2016), cobia Rachycen on
canadum (Sun and Chen, 2014) o A lan ic salmon Salmo sala
(Bendiksen e al., 2002). This hypo he ical low eed in ake o he ish a
18 ◦C does no comple ely explain he dec ease in he g ow h a e
obse ed a e he i s 30 days. Excessi e a ese e accumula ion can
hinde eed in ake by p o iding nega i e eedback on he ood in ake
egula ion cen es (Jobling and Johansen, 1999) and cause e a da ion
o g ow h (Jobling e al., 2002). In his expe imen , pe i isce al a was
ex ac ed and weighed alongside he diges i e ac , so VSI could be
used as an app oxima ion o pe i isce al a ese es in his pa icula
case. This index was highe on g oup 18, and his high a accumula ion
could lead o lowe eed in ake and consequen ly, a dec ease in he
pe o mance o his g oup o e ime. Howe e , he e is no enough e -
idence in o de o suppo his hypo hesis.
As expec ed, wa e empe a u e also had an impac on he bio-
ene ge ics o he ish. The ish held a 18 ◦C had he highes le els o
iglyce ides, in bo h plasma and li e , as well as glycogen in li e and
muscle. The e o e, he slow g ow h obse ed on his g oup canno be
a ibu ed o low ene gy a ailabili y. High ene gy s o age was also e-
lec ed on HSI, as his g oup had he highes alues o said index, and on
VSI, as p e iously men ioned. In win e , ood a ailabili y migh be
comp omised, and some ishes do exhibi a ese e accumula ion
beha iou a cold empe a u es (Schul z and Cono e , 1997), coupled
wi h a dep essed me abolic ac i i y (Ree e e al., 2022). On a esea ch
conduc ed on ju enile oach Ru ilus u ilus i was seen ha g ow h was
comple ely s opped a 12 ◦C, and ha he ene gy ese es we e highe in
win e han in summe , especially in ish acclima ed a 4 ◦C (Van Dijk
e al., 2005). The ex en o his beha iou and he empe a u e a which
i akes place is a iable among species and esponds o he en i on-
men al ac o s hey encoun e in hei na u al habi a (Schul z and
Cono e , 1997). In he case o ou expe imen al ish, 18 ◦C seems o be
oo high o igge an o e win e ing beha iou , because his empe a-
u e is high o win e in hei na u al habi a a he Can ab ian Sea
(Bo ja e al., 2019). In a esea ch abou wild g ey mulle popula ions o
he A lan ic coas o Po ugal, i was seen ha mos o he g ow h
expe ienced by C. lab osus happened du ing sp ing and summe , when
wa e empe a u e was abo e 14 ◦C (A uda e al., 1991). Pe haps, in
na u al condi ions, 18 ◦C could be close o he h eshold a which his
ish s a s o eo ganize ene gy pa i ioning, wi hd awing ene gy om
g ow h owa ds ese e accumula ion, as a p epa a ion o win e
do mancy. The esul s o plasma, li e and muscle me aboli es, as well
as HSI and VSI sugges ha ish o g oup 26 had a highe ene gy
expendi u e han he ish o g oup 22, which was no e lec ed as a
g ow h inc ease. This could imply ha a his empe a u e, he ish a e
s a ing o de ia e ene gy om g ow h in o de o uel he mechanisms
o he mal s ess compensa ion (Al onso e al., 2021), a s a egy ha
could be conside ed success ul a his empe a u e, as i did no
comp omise g ow h. A simila bu mo e p onounced esponse was seen
a 30 ◦C, we e highe ene gy expendi u e did no cause g ow h
imp o emen , his being he g oup wi h he lowes SGR. In e es ingly,
a e 30 D, an inc ease in lipid ese es was no ed, as seen by he high
li e iglyce ide le els and VSI, coinciding wi h he momen whe e he
g ow h in his g oup s a ed o aise.
In a p e ious s udy abou he ac i i y o diges i e enzymes o ish
ea ed a di e en wa e empe a u es, he enzyma ic ex ac s o e e y
expe imen al g oup a he same eac ion empe a u e we e es ed o
es ima e enzyme sec e ion le els (Na a o-Guillen e al., 2022), called
“absolu e ac i i y” he ein. Howe e , he enzyma ic ac i i ies measu ed
a he expe imen al empe a u es a e mo e ele an o elucida e he
ac ual diges i e capabili ies o he ish, as hey a e poikilo he ms and
s ic empe a u e con o me s (Volko and Rønnes ad, 2020), wi h he
excep ion o some species wi h big body sizes ha can p oduce and keep
enough hea so as o inc ease hei empe a u e abo e said h eshold
(Ca ey e al., 1971). The o e all low lipase ac i i y ound in he p esen
esea ch is in conco dance wi h he esul s ob ained by Pujan e e al.
(2017) on he same species, which was almos negligible. This is in
ag eemen wi h he expec ed lipase ac i i y o he bi o ous ish, which
heo e ically would ha e a low in ake o die a y lipids in he wild
(Opuszynski and Shi eman, 2019), and i sugges s ha C. lab osus has a
limi ed abili y o diges lipids (Pujan e e al., 2017), independen ly o
wa e empe a u e. As a esul , hese species would ely mo e on ca -
bohyd a es as ene gy sou ce. One o he mos impo an ca bohyd ases
in ishes is
α
-amylase (Kaushik e al., 2022). When measu ing absolu e
ac i i y, all g oups excep g oup 18 showed an inc ease in
α
-amylase
ac i i y in he gas oin es inal ac o e ime. I has been epo ed ha
α
-amylase ac i i y o C. lab osus inc eases alongside he size o he ish
(Pujan e e al., 2017), and he aise o ac i i y o e ime ound in he
p esen expe imen could espond o he same p inciple. E en hough
no s a is ically signi ican , he
α
-amylase ac i i y o he 18 ◦C g oup
dec eased o e ime. This could po en ially lowe ca bohyd a e di-
ges ibili y, and i could pa ially explain he dec ease o SGR expe i-
enced o e ime. Al hough eed diges ibili y was no measu ed, he
al e a ion o he pa e n obse ed on he es o he g oups seems ele-
an , and he possibili y o a dec ease on ene gy diges ibili y canno be
uled ou . When measu ed a hei espec i e physiological empe a-
u es, g oups 22, 26 and 30 showed simila
α
-amylase ac i i ies, while
g oup 22 showed he highes absolu e ac i i y o said enzyme. Enzy-
ma ic ac i i ies inc ease wi h eac ion empe a u es (Schul e, 2015), so
i is plausible o g oup 22 o be p oducing a highe amoun o
α
-amylase
in o de o compensa e o he lowe ac i i y a said empe a u e. E en
hough his mechanism has been obse ed a some cases (Sa oie e al.,
2008), i does no seem o be a widesp ead s a egy. Despi e being a
gene al end, he inc ease o he
α
-amylase ac i i y a 30 ◦C om 30 D
o 90 D was he mos p onounced and may explain he imp o emen o
pe o mance du ing he expe imen al pe iod, as well as he inc ease o
lipid ese es. P o ease ac i i ies showed simila pa e ns o
α
-amylase,
bu he e we e no any ema kable di e ences o e ime. A 18 and
22 ◦C, highe absolu e pepsin and alkaline p o ease ac i i ies we e
ound, sugges ing a highe concen a ion o said enzymes, bu when
measu ing a he physiological empe a u es, ac ual ac i i ies we e
simila a g oups 22, 26 and 30, and lowe a 18. The highe p oduc ion
o p o eases a 18 and 22 ◦C could espond o he same compensa ion
mechanism p e iously hypo hesized o
α
-amylase, bu wi h di e en
e ec i eness. A 22 ◦C, he inc eased enzyme p oduc ion would be
enough o each he same physiological ac i i y han a wa me em-
pe a u es, whe eas a 18 ◦C would no . The pepsin ac i i y measu ed
he ein is ema kably low when compa ed o alkaline p o ease ac i i y,
M. Sanz-La o e e al.
Aquacul u e 595 (2025) 741537
8
con a y o he indings by Pujan e e al. (2017), who ound ha hese
ish do ha e a ela i ely high pepsin ac i i y a ea ly li e s ages, which is
almos los du ing de elopmen . The e o e, ou esul s align be e wi h
he expec ed p o ease p o ile o olde ish, as he expe imen al ish o
he p esen esea ch we e e en younge /smalle han he ish analysed
by Pujan e e al. (2017). This disc epancy dese es mo e a en ion in
u u e esea ch, and he unde s anding o he di e en expe imen al
s a egies, p o ocols, eeding, o igin o he ish and sampling would
make he compa ison be ween esea ches easie .
E en hough g oup 30 was no he only one showing epi helial
damage in he in es ines, he p e alence o such lesions was signi ican ly
highe han a o he empe a u es. I is known ha s ess ul condi ions
can al e ish diges i e epi helial in eg i y by damaging en e ocy e
junc ions (Olsen e al., 2002). The obse ed en e ocy e damage could be
a esul o such weakening o he epi helia, and i could lead o a
dis up ion o i s ba ie unc ion, endange ing he osmo ic balance and
acili a ing pa hogen in ec ion (Del-Pozo e al., 2010). This condi ion
s ongly sugges s ha 30 ◦C a e s ess ul o C. lab osus, and he heal h
and well-being o he ish could be comp omised a his empe a u e.
Wa e empe a u e did no ha e a p o ound impac on C. lab osus
muscle a y acid p o ile. E en hough cell memb anes show he abili y
o al e hei a y acid composi ion depending on ambien empe a u e
(Hazel, 1995), o he bio ic ac o s such as phylogeny, die , age, ep o-
duc i e s a us o ploidy ha e been ound o be mo e ele an when
explaining he a y acid p o ile o a gi en ish species (Kaushik e al.,
2006; Skalli e al., 2006; Senso e al., 2007; Sushchik e al., 2018, Aydın
e al., 2022b). Among abio ic ac o s, wa e salini y o pH can also ha e
a p o ound impac on ish ille a y acid p o ile (Rabeh e al., 2022).
This would suppo he lack o di e ences ound among g oups in he
p esen esea ch when i comes o muscle a y acids. In any case, g oups
22 and 26 did show a highe con en o PUFA, especially o he
ω
-3
g oup. Con e sely, Rabeh e al. (2022) epo ed signi ican changes in
C. lab osus a y acid p o ile depending on wa e empe a u e and
salini y, bu he in e ac ion be ween hose wo abio ic a iables make
compa isons wi h ou esul s di icul .
5. Conclusions
In conclusion, op imal wa e empe a u e o ea ing C. lab osus ju-
eniles was ound o be 22.8 ◦C. Colde empe a u es o a ound 18 ◦C
caused g ow h delay and high ene gy ese e accumula ion. A 30 ◦C,
ish exhibi ed a high ene gy expendi u e ha did no lead o as g ow h.
This, coupled wi h he epi helial lesions obse ed in in es ines o hese
ish, e idences ha 30 ◦C a e s ess ul o C. lab osus ju eniles. E en
hough he exac wa e empe a u e we e said s ess s a ed could no be
elucida ed, a 26 ◦C he ish showed simila g ow h alues o he ones
ea ed a 22 ◦C, bu hey spen mo e ene gy o ha , he e o e, i is no
ecommended o inc ease wa e empe a u e abo e 26 ◦C. Howe e , ish
pe o mance in ela ion o wa e empe a u e and, concomi an ly,
op imal empe a u e o g ow h, is highly a iable no only ac oss
di e en species, bu also ac oss di e en li e s ages o a gi en one
(McCauley and Huggins, 1979). Consequen ly, he esul s ob ained in
his esea ch canno be ex apola ed o he en i e li e cycle, and con-
duc ing simila expe imen s o he p esen one is ecommended wi h
indi iduals a di e en de elopmen s ages in o de o ob ain mo e ac-
cu a e in o ma ion abou he op imal wa e empe a u e o C. lab osus
ac oss i s en i e li e cycle. The esul s ob ained he ein a e pa icula ly
in e es ing o he ex ensi e cul u e o he hicklip g ey mulle , as he
lack o empe a u e con ol manda es a deep unde s anding o he
esponse o he ish o said a iable, in o de o adjus a ming condi-
ions, eeding p o ocols o ha es ing s a egies acco dingly.
Funding sou ces
This esea ch was unded by he Basque Go e nmen [00007-
INA2019–33, 00003-INA2022–33, 00010-PIT2020–22, 00005–2,101,0
22,023, GIC19/IT-1302-19]. Ma kel Sanz-La o e had a p edoc con ac
inanced by he Basque Go e nmen (IKERTALENT g an P og amme)
The unding ins i u ions did no ha e any inpu in he design, da a
collec ion and in e p e a ion, w i ing o publica ion o he in es iga ion
p esen ed he ein.
CRediT au ho ship con ibu ion s a emen
Ma kel Sanz-La o e: W i ing – o iginal d a , Visualiza ion,
Me hodology, In es iga ion, Fo mal analysis, Da a cu a ion. Manu
So o: W i ing – e iew & edi ing, Valida ion, Supe ision, Resou ces,
P ojec adminis a ion, Me hodology, Funding acquisi ion, Concep u-
aliza ion. U zi Izagi e: W i ing – e iew & edi ing, Valida ion, Su-
pe ision, Resou ces, Me hodology, Concep ualiza ion. Xabie Lekube:
W i ing – e iew & edi ing, Valida ion, Supe ision, Resou ces,
Me hodology.
Decla a ion o compe ing in e es
The au ho s decla e he ollowing inancial in e es s/pe sonal e-
la ionships which may be conside ed as po en ial compe ing in e es s.
Ma kel Sanz-La o e epo s inancial suppo was p o ided by Bas-
que Go e nmen . Manu So o Lopez epo s inancial suppo was p o-
ided by Basque Go e nmen . I he e a e o he au ho s, hey decla e
ha hey ha e no known compe ing inancial in e es s o pe sonal e-
la ionships ha could ha e appea ed o in luence he wo k epo ed in
his pape .
Da a a ailabili y
Da a will be made a ailable on eques .
Acknowledgemen s
The au ho s a e hank ul o he echnical and human suppo om
he ACOI Coimb a Collec ion o Algae a he a y acid analysis, and om
Ka dala LHII a ish cap u e and deli e y.
Appendix A. Appendix
Table A1
ini ial s ocking densi y o e e y expe imen al ank a he beginning o he expe imen . T: empe a u e ea men (◦C); SD: s ocking densi y (kg / m
3
).
T (◦C) 18 22 26 30
Tank 18.1 18.2 18.3 22.1 22.2 22.3 26.1 26.2 26.3 30.1 30.2 30.3
SD (kg / m
3
) 4.73 4.85 4.38 4.85 4.35 4.42 4.74 4.10 4.15 4.45 4.58 4.10
M. Sanz-La o e e al.
Aquacul u e 595 (2025) 741537
9
