Tap chi Khoa hgc - Cone nghe ThOy sdn So 3/2013
KET QUA NGHIEN CLfU D A O TAO SAU DAI HOC
ANH HlTOfNG CUA MAT DO, LOAI THlTC AN VA KHAU P H A N AN LEN SINH TRU'CNG, TY LE S O N G CUA CA CHIM VAY VANG
(Trachinotus blochii Lacepede, 1801) GIONG l/ONG BANG GIAI DAT TRONG AO DAT
INFLUENCE OF DENSITY, FOOD AND FEEDING RATION ON GROWTH, SURVIVAL OF SNUB-NOSE POMPANO (Trachinotus blochii Lacepede. 1801)
FINGERLING CULTURED IN POND NETCA GE
Than Thi Hdng', BS Thj Hoa' Ngay nhan bai: 17/9/2012, Ngay phan bi?n thong qua- 28/02/2013, Ngay duy?i dSng: 10/9/2013
TOM T A T
Ket qud cua thi nghiem uang cd chim vdy vdng (Trachinotus blochii) ca 3 - 4cm bdng giai ddt trong ao dat trong 4 tudn a cdc mgt dp khdc nhau (100, 200, 300, 400 vd 500 con/m').vd thi nghi?m chocddn cdc loai thucdn (INVE, UPvd cd tgp) ket hcrp v&i cdc khdu phan dn (4, 6, 8 vd 10% khdi luang thdn (BW) da chira rang cdc mdt dg uang khdc nhau co dnh huang (p<0.05) len sinh truang, ndng sudt vd he so tieu ton thuc dn (FCR), trong do mat dg trang tir 400-500 con/m' dd cho ket gud tot nhdt Khi 2 yeu to Id logi thuc dn vd khdu phdn an khdc nhau cung tdc dpng dd dnh huong (p<0.05) len sinh trudng ve khoi lugng vd FCR cua cd chim vdy vdng, trong do thirc dn tong hgp INVE vai khdu phan dn tit 8 - 10% BW cho ket qud ucmg nuoi tot nhdt. Ngodi ra, ty IS song cua cd uang a tdt cd cdc nghiem thuc deu cao vd khong co sif khdc bift (p>0,05).
Tir khoa: mat do ucmg, logi thitc dn vd khdu phdn dn, ty le sdng, cd chim vdy vdng ABSTRACT
Experiments of cultured snub-nose pompano (Trachinotus blochii) 3 • 4cm in net cages located in pond during 4 weeks, with different densities (100, 200, 300, 400 and 500 individuals/m' and experiment grOe eating fish, foods (as INVE.
UP and trash fish) combine rations (4. 6, 8 and 10% BW) indicated that significant differences were observered (p<0.05) on growth, yield and feed conversion ratio (FCR). Also, the densities of 400-500 individuals/m' showed the best cultured results. When two elements including foods and ration both impacted on fish, significant effects on the body weigh growth and feed conversion ratio (FCR) of Trachinotus blochii were obser\'ed Specifically, the best cultured result was observed in experiment using Inve commercial food with diets 8 - 10% BW In addition, significant differences on survival rate of fish were noted in al the experiments.
Keywords: density, food, feeding ration, survival, snub-nose pompano
I. OAT V A N ot va hien dang dugc nufli thuang phim d nhieu nude Gd chim vay vdng {Trachinotus blochii nhu Hong Kong, Singapore, Sai Loan, Trung Qudc, Lacepede, 1801) td doi tugng nudi ed gia tri kinh t l Malaysia vd Viet Nam,... (Situ va CTV, 2004).
d cdc quoc gia thudc khu vgc Thai Binh Duang. Doi Trong vai nam g i n ddy, san xuat gilng nhan tugng nay lan dau tien dugc nghidn ciru san xuat tgo ca chim vay vang da thanh cflng d Vigt Nam, gilng thanh edng d Dai Loan vdo nhung nam 1989 tuy nhien de dap ung dugc nhu eau ciia ngudi nudi
' Thdn Th| Hang: Cao hpe Nu6i trfing thuy sdn 2009 - Tnrd-ng Oai hpe Nha Trang ' PGS TS. 05 Th! Hda- Vi$n Nu6i tr6ng thOy sSn - Tnrdng Dgi hpe Nha Trang
TRUONG DAi HOC NHA TRANG • 95
Tap chi Khoa hoc - Cong nghe Thuy sdn ed biln ve kich thudc vd chat lugng eon giong. can cd nhirng nghidn ciru sdu hon v l mat dp. loai thirc an vd khiu phan dn ciia cd chim vdy vang a giai dogn ea eon dac bigt id giai dogn giong. Ngodi ra, ky thuat uang ca biln trong cae be t h i tieh nhd cd nhilu hgn ehe nhu khd uang mdt dp cao, ca sinh tnrdng chdm, nang suit thip va gid thanh cao, vide ap dung ky thuat uang ed biln bing ao dat hay bdng giai dat trong ao dat da mang lai nhilu uu diem nhu: mgt dfl uang cao, hgn c h i djch hgi.
d l quan ty thirc dn, kich cd va dich bflnh, van hdnh dan gidn vd c4n it nhdn edng, tdn dung nguIn thuc an tu nhidn cd trong ao (Schipp vd CTV, 1996). Bdi bdo nay dugc vilt nhdm cdng bo k i t qua nghien cuu ve anh hudng cOa mdt dfl uang, logi thuc dn va khiu phin an ldn sinh tnjdng. ty Id sing cua ca chim vay vdng gilng uang bang giai dat trong ao dlt.
It. VAT LIEU VA PHU'aNG PHAP NGHIEN CD'U 1. Dja d i l m vd vgt ligu nghidn ci>u
Dia diem: Thi nghi$m dugc thye hien tai Vign nghien euu Nudi trdng thuy s^n, My TTianh, Cam Thinh Dflng. Cam Ranh. Khdnh Hda.
V$t li^u nghi4n ciru: D l i tirgng nghidn ciru Id ed ehim vay vdng (Trachinotus blochii Lacepede, 1801) giong. cd 3 - 4cm. duge mua tir trgi thye nghigm, thuflc Khoa Nufli trdng thijy sdn, Tnrdng Dai hpe Nha Trang.
Giai thi nghidm Idm bdng vgt lidu polyme, t h i tich cua mli giai Id 1 m' (kich thude ehieu eao, chieu rflng, nap vd ddy cOa giai lan lugt la lm). He thong 30 giai dung eho thi nghidm dugc dgt trong 1 ao dat cd dign tich 500m^, sdu 1,2m, 4 gdc cua day mdi giai dugc huge vdi 1 bao cdt nhd dgng trong tui nilon d l ddm bdo cho giai dirge vudng gdc vdi ddy. Djnh ky hang tuin thay 20% nude trong ao.
2. Phirvng phap bo b i cdc thi nghidm 2.1. Th! nghidm 1: Anh huvmg cua m^tdd uong l^
sinh tnrong, ty 1$ s6ng vi miec tfd phin din ciia c6 chim viy ving giai do^n giong 3 - 4cm
Ci chim vay vang giong (kfch thudc 3,97 t 0,25) dugc chuyin v l nai thi nghidm bdng phinmg phdp vdn chuyen kin, tha nufii dudng trong 1 gj^
tdn, sau 5 ngdy cd dirge t i l tri vdo cdc nghi^
thire (NT). Thi nghigm nay cd 5 nghidm thuc \m^
vdi cdc mgt dg: 100, 200, 300, 400 vd 500 con/m^, trong cdc giai cd the tich 1m^ va dugc tdp tgi 3 l4n Thirc an tong hgp cua hdng INVE dugc diing dio cd an vdi khau phan 6% BW trong suit thdi gian ttil nghiflm keo ddi 4 tuin. m i l ngdy eho dn 2 iln vSo 7h vd 16h. De tang cudng oxy hda tan, mdy qu^
nude ddt if gdc ao hoat dflng hdng ngdy tir 11h30 d i n 14hvatir 15hdln8hsdnghdmsau. Sau4tuln thi nghidm, cac ehi so ve sinh trudng. ty Id sing vS (FCR) duge xdc djnh d l danh gid dnh hudng ciia mdt dfl nufli len sinh tnrdng vd t^ tfl sing cOa cd.
2.2. Thi nghi$m 2: Anh huang cua lo§i thitc in, WiJu ph^n dn lin sinh truang, t^ 1$ sdng vi mtic d^ pMn din cOa ca chim viy ving giong ca 2- 3cm
Cd chim vdy vdng ed kieh thudc tmng binh 2.75
± 0,26cm duge dung cho thi nghidm ndy M$t Q() tA uang cho ket qua tot nhat cua thf nghiflm 11d 400 con/m^ dugc diing cho thf nghigm 2. Cd 2 logi thirc an tdng hgp diing d l nudi cd biln td UP (sdn xult fl' Vidt Nam) va INVE (nhap tir Thdi Lan) diing clu cd dn vdi 4 logi khau phan an khde nhau: 4. 6,8 vi 10% BW. cho an 2 lln/ngdy vdo tiic 7h vd 14h hdng ngdy. Cf nghigm thirc dot chirng, cd tgp dugc 5i>
dgng vdi 40% BW. Cac nghigm thuc dirge ldp l9 ding thdi 3 tin vd kdo ddi trong 4 tuin. Mdy qu^
nude de a gdc ao hoat dpng theo c h i dfl nhir 33 trinh bdy d thi nghigm 1. Sinh tnrdng, ty Id s6ng vd hd s6 phdn dan ciia ca d cdc nghigm thdc 6\jijc kiem tra 1 lan/tuan. Mot so y l u to mfli trudng nlw dfl m$n. nhigt dfl vd pH dugc kilm tra hdng ngdy.^
Bang 1. Bd tri thi nghigm dnh hirfling ciia loai thuc an vd k h i u phan an ten sinh tru'd'ng vd t^ 1$ song ciia cd chim vdy vdng Khau phan %
ThLFC an Inve Thijc an UP
4 % NT1 NT2
6 % NT3 NT4
8 % NTS NT6
10%
NT7 NTS 3. Phiramg phdp XCF ly so ligu
Xae djnh cdc ehi so sinh trudng, he so phdn dan. FCR. ty ifl sing vd nang suit thu duge sau 4 tuin nufli dugc theo cdc cdng thirc thflng dyng tren phim mIm Excel. Phin mIm thong ke SPSS dugc diing d l phdn tich phuang sai
mflt nhdn t l (oneway-ANOVA) vd hai nhdn tS (twoway-ANOVA), ham LSD test dugc diinfl a l kilm djnh sy sai khdc giu-a cdc nghidm thue thi nghigm vdi mirc y nghTa p<0,05. g\i W trinh bdy \i. gia tn tmng binh (TB) ± sai s4 chuin (SE).
96 • TRl/ONG OAt H(pC NHA TRANG
Tap chi Khoa hoc - Cong nghe Thuy s So 3/2013
III. K t T QUA NGHteN CUU VA T H A O L U A N 1. Anh huong cua mat dp ucng din sinh trtrdng vd ty tg sdng ciia cd chim vay vang cd" 3-4 cm uang bing giai dat trong ao dat
Sau 4 tuan uang bang giai dgt trong ao dat, vdi cdc mat dfl 100. 200, 300, 400 va 500 con/m^ sinh tnrdng v l chilu ddi (TL), (BW), tdc dfi sinh trudng khoi lugng theo ngdy (SGRw). hg sd phdn dan, nang suit (kg/m^), (FCR) va t / Ifl song (%) ciia ed chim vdy vdng a eae mat do nufii khac nhau dugc the hien d bang 2.
S l lidu bieu th| d bang 2, sau 4 tuan uang nufli cho thay, chieu dai todn than (TL) va khdi tugng (BW) trung binh cua ea d cdc mat dp nudi khdc nhau tir 100, 200, 300, 400 va 500 con/m^ da tSng dan, lan lugt tir 4.00; 6,97; 7.08, 7,38; 7,25 cm va 5.86; 6,96; 7,91; 8,66 vd 7,23 g/con. Trong dd. ca nudi d NT 400 va 500 con/m^ ed sinh trudng
Bdng 2. Cdc ch? sd ve sinh trudng vd hf sd phan dan ty te sdng (%) cua ca chim vdy vdng
v l chieu ddi tdn han (p<0.05) so vdi cac nghiem thuc cdn lgi. Trong khi d mgt dfi 400 con/m^
ed BW, SGRW cao han (p<0.05) so vdi cac NT edn lai. nhung tai khong cd su sai khdc (p>0,05) vdi NT 300 con/m^. K i t qua cung cho t h i y o- mgt dp 400-500 con/m3 cd nang suat (kg/m^) cao han (p<0,05) so vdi cac mat dp cdn tgi. Ty le sdng trung binh d t i t ca eae mat dp tir 98,66 -100% va khdng ed su sai khac giira eae nghigm thuc (p>0,05).
Nhu vay, ndn uang ca chim vdy vang bang giai dgt trong ao d l t d mat do 400 - 500 con/m^
dat hieu qua kinh te cao han so vdi cdc mgt dp cdn lai.
Sd ligu d bang 2 cting eho thay d mdt dfl 400 - 500 eon/m^ cd nang suat (kg/m^) cao han (p<0,05) so vdi cae mdt dfi edn lgi. Ty Ig sdng trung binh d t i t cd cae mgt dfl tir 98,66 - 100% va khflng cd sy sal khdc giCra edc nghiem thue (p>0,05).
(CV^ %) trung binh, nang suit {kglm% (FCR) va d- cac mgt dg nudi khac nhau
Cdc chi tieu T L M BW(g) SGR.(%hgay) (CV,%) Nang su^t (kglm^) FCR Tf 1$ song (%)
M|tll$tlli(co[irm>) 100
4.00 ± 0,00"
5,86 ±0,13"
4,40 ± 0,08' 7,30 ± 0,40' 0,58 ± 0 . 0 1 ' 0.53 ± 0.00"
98,66 ±1,33' 200 6,97 ± 0,02"
6,96 ± 0,38"
5,00±0,19»
6,10±0.05' 1,39 ± 0,07»
0,52 ± 0,00' 100,0 ±0,00"
300 7.08 ± 0,06"
7,9 1 ± 0,38"
5,46 ± 0 , 1 7 "
6,99 ± 0 , 1 9 "
2.37 ± 0,11' 0.45 ± 0,00 • 100,0 ±0,00-
400 7,38 ± 0,03"
8,66 ±0,16' 5,79 ± 0.06' 6,43 ± 0,26" • 3,46 ± 0.06' 0,40 ± 0,02"
100,0 ±0,00"
500 7,25 ± 0.05' 7.23 ± 0,20"
5.14 ± 0 . 1 0 "
8.23 ± 0,30' 3,61 ±0,10' 0,40 ± 0.01' 100,0 ±0,00"
Trong cung 1 fiang, c6c c^O'cA khic ntiau Iti4 ti4n sir sai ktiAc c6 f nghia (p<0.05}, Smfi khoi Itiii Imn Cau & c6c m4t do 100, 200, 300, 400 vA 500 con/m'lan Ivgtld 0.171. 0.342; 0,513:0.684 va 0.855kg/m"
2. Anh hird'ng cda logi thu'c an va khau phan an tdn sinh trud'ng, ty tg sdng, nang suit va hieu qua sir d^ng thirc an ciia ca chim vdy vdng gilng cd' 2-3 cm
2.1. Sinh truong vi h$ so phin dan cOa ci chim viy ving ca 2-3 cm nuoi bing dc lo^i thirc in va khiu phan in khac nhau
Chilu ddi toan than, khdi lugng, edc ehi tidu tdng trudng va he sd phan ddn CVL % eiia ca gilng vdi 2 logi thirc an vd 4 khau phan an khi k i t thiic thf nghigm duge trinh bdy d bdng 3. Khdng ed sy anh hudng tuang tac ciia loai thirc dn va khau phin dn Idn chieu ddi todn thdn ea TL em va he sd phdn dan CVL % (p>0,05).
Logi thirc an dnh hudng (p<0,05) len cae ehi tidu TL cm, BW, SGRW. Chieu ddi toan than ciJa cd
khi thu hoach dao ddng trong khodng 5,01±5,57 mm vd ed xu hudng tang d nhdm cd sir dung thirc an INVE. Tuy nhidn, loai thue an lgi khdng anh hudng ten he s6 phdn dan CVL % (p>0,05) dao dfing tir 5,47-5,60 % va cd xu hudng tang d nhom ca an thuc an UP.
S6 lieu d bang 3 cho thay, ca chim vdy vang eo- 2-3 cm nufli bang thdc an tdng hgp (UP hay INVE) ed chieu dai trung binh tdn nhat (p<0,05) d khau phan an la 8 vd 10% BW, khdi lugng trung binh va SGRW tang dan vd cd sy sai khac (p<0,05) khi khau phan thirc an tang tir 4 - 10% BW va eao n h i t d khau p h i n an 10% BW(p<0,05), tuy nhien ve hg s l phan dan (CVL%) lgi khflng khac nhau (p>0,05) gida cac nghidm thirc.
TRLTONG OAI HOC NHA TRANG - 97
Tap chi Khoa hgc - Cong nshe Thuy san So 3/2011 Bang 3. Cac chi tieu sinh tnpo-ng va he s6 phan dan cua ca chim vay vang vai cSc lo^i t h i i t in
va khau phan an ithac nhau (so fiSu trong bang la TB± SEt
Ngliiem Ihirc Chieu dai
Tl-(cm) CV, (%)
Khoi BW(g) Khau p h i n an (%) (n = 6)
4%
6%
8%
10%
5.02 ± 0.06"
5.16±0.06' 6.44 ± 0.06' 6.57 ± 0.06'
6,00 ± 0,22- 5,56 ± 0.22"
5.30 ± 0.22"
5.29 ± 0.22"
2.40 ± 0.04"
2.70 ± 0.04' 3.30 ± 0,04' 3,51 ± 0,04' Loaithi>can (n = 12)
Inve UP Ca tap
5,57 ±0,10=
5,01 ± 0,04' 5,42 ± 0,00-
5.47 ±0.10"
5.60 ± 0.2- 6.68 ± 0.24'
3,35 ±0,18' 2,60 ± 0,09' 3,23 ± 0,03"
i/Tng SGR(%/ngiv) 5,49 ± COS"
5,95 ± 0,06' 6,62 ± 0.06' 6.84 ± O.OP 6.67 ± 0.19"
5.7910.14' 6.59 ± 0.03- Khdc nhau co y nghTa thong l<e (p<0,05)
Loai thijc an Khau phan an Lopi thijc an * khiu phan an
* *
ns
ns ns ns
* *
*
• 4
' ^ • 1
ns (no signiiieant). si/ sai khic khdng co y ngtiia Ihong k§ (p>0,05):('} sif sai fchSc c6 ]> nghia thong ke (p<0.05), Tmng aing mttcft,^
cii khic nhau k^m theo thS hi$n sir sai khac cd y nghia thong ke (p<0.05): Chieu dii vi kh6i luvng ban (Jio lin lui?t 14 2,75t0.26 cm; 0,51i^
g, TL, BW. ch4u dii vi Midi luvng loan thin ci, CV^: h? s6 phan din chi4u dii va SGR,^ toe 60 smh trudng (S$c tnmg theo kh6l lupng. ^', 2 2. Tyle song, ning suit vi he so tieu tdn thiiv an cOa ci chtm viy ving khi du^ nuoi bing cic lo^ithikSn vi khau phan in khic nhau
Khi xem xet tdc dflng rieng biet eiia khau phin an (4, 6, 8 va 10% BW). hogc cua logi thirc dn (INVE hay UP), eae so ligu d bang 4 eho thay, ea chim vay vdng cd 2,0 - 3,0em uang bdng giai trong ao d l t cd t^ Id sfing eao, ty le song tnjng binh eua ea d eac nghiem thirc dat tir 99.66 - 100% va khfing cd sy khdc bidt (p>0,05}
glCra cac nghidm thirc. Tuy nhien, khau phdn an khac nhau lgi dnh hudng (p<0.05) len nang suat thu Sucfcll ede nghiem thirc sau 4 tuan uang nufii, trong do ca d NT nudi vdi khiu phan thirc an 10% BW dgt nang su^
ldn han (p<0,05) so vdi eac khau phan an cdn lgi. Tuang ty nhu vay (FCR) cung khdc nhau (p<0.05) giiia cde nghiem thirc va cao nhit a NT cho an 10% BW. Trong khi dd, ea d NT diing thue dn tong hgp Inve 6s c6 nang suit cao han (p<0,05) so vdi NT diing thirc an UP.
Tuy nhien. vdi sy tac dgng ddng thai ciia 2 y l u td la loai thuc an (Inve hay UP) va khau phan an (4,6,8vS 10% BW) cd nang suat uang nudi (kg/m*) va FCR da cd sg sai khdc (p<0,05).
Bang 4. Ty le sdng, nang s u i t va he sd tidu tdn thiPC an (FCR) cua ca C W khi irang bdng logi thuc in va khau phan an khac nhau (s6 li^u trong bang la TBtSE)
Nghiem thiJc Khau phan an (%} (n=6) 4'A
6 % 8 % 10'/.
Loaithlj>can (n=12) Inve
UP Cat^p
Khac nhau co y nghTa (p<0.05) Loai thijc an
Khau phan an Loai thi>c an ' khau phin an
Cac chi lieu ddnh gi^
Tyle song (%) | Nang suat (kg/m'J | FCR (%|
99.66 ± 0.12"
99.83 ±0.12""
100.00 ±0.12' 99.83 ± 0 . 1 2 "
0,96 ±0,01"
1,08 ± 0 , 0 1 ' 1.32 ± 0 . 0 1 ' 1.40 ± 0 . 0 1 '
0,22 i 0,00"
0,27 ± 0,0^
0,42 ± 0,00- 0.54 ± O.OC 99.91 ± 0.08"
99,75 ± 0,11"
100,00 ±0,00"
1.34 ±0.07' 1.04 ± 0.03"
1.29 ± 0 . 0 1 '
0.36 ± 0.04"
0.37 ± 0,03"
2,52 ± 0,02' ns
ns ns
* *
*
ns
* *
nsfno significani)- su sai khac khong co y nghia thdng ke (p>0.05); (') sy sai khic c6 y nghia Uiong k6 (p<0,05); Tmng ciing mftcftd*
cii khic nhau thSh^nsy sai khac cof nghia thdng ke(p<0,05);Ch4u dii vakh^ tirong ban dAu lin luvtli2.75±0,26 cm: 0,51±0.Xg:Tl- BW li chiiu dai va khdi lining loin thin ca. CV^. h$ SD phan dan chieu dai, SGR^ t6c d? sinh tnrdng d$c tnmg theo kh6i lu^ng.
98 • TRUONG OAI HOC NHA TRANG
Tap chi Khoa hoc - Cong nghe Thiiy sdn So 3/2013 3. Thdo luan
Trong thf nghigm 1, khi uang ca chim vay vang cd 3 - 4cm bang giai dat trong ao dat vdi cac mat do khac nhau: 100, 200, 300, 400 va 500 con/m^
da the hign sy anh hudng (p<0,05) len sinh trudng, nang suit va FCR, NT uang cd vdi mgt dfl 400 - 500 con/m^ cd sinh trudng nhanh, nang suit uang nudi Idn nhat va FCR thip nhat (p<0,05) so vdi cae NT con lai. K i t qua nghidn ciru nay tuang tg nhu cdc thflng bao tren ea chem chau Au Dicentrarchus labrax (Hatziathanasiou va CTV, 2002), tren ea Ban Paralichthys califomicus (Merino, 2007), cd Chem mom nhgn Psammoperca waigiensis (Nguyin Trpng Nho, 2004). Tuy nhien, da phan cdc tae gia ndy deu eho rang khi mgt dfl tang thi sinh trudng eua cd nufli giam, nhung ket qua nghidn ciru d ca chim vdy vang tgi eo xu hudng nguac Igi. Mat dfl cao nhit {400 - 500 con/m^) trong nghiflm thirc nay tdng trudng nhanh han. Sy khdc nhau ndy cd the lien quan tdi tap ti'nh b i t mdi bay dan cOa ed chim vay vang, uu the ciia md hinh uang ca bing giai dgt trong ao dat vd thang mgt dp bd tri trong thf nghidm nay chua cao, ndn khi mgt dfl nufli cao, kha nang bit moi ciia cd tai tang ten, k i t qua ndy eung da dugc not d i n trong nghien ciru eiia Rowland va CTV (2004). K i t qua thf nghigm 1 eung dd cho thiy, d cae mgt dfl nuoi khac nhau da khong anh hudng d i n ty Id song ciia ca sau 4 tuin irang nuoi.
tuang ty nhu cac thdng bao ciia Ly va CTV (2005), Rowland vd CTV (2004). Nhu vdy, mgt dp uang ca chim vay vang bdng giai dat trong ao d l t d mgt do 400 - 500 con/m^ dgt hidu qua kinh te cao han so vdi mgt dp 100, 200 va 300 eon/m^
Trong thi nghidm 2. ket qud thu dugc ehung td rang, logi thirc an khac nhau (INVE, UP) va cae khau phan an khae nhau (4, 6. 8 vd 10% BW) cd anh hudng tdi sinh trudng ve ehieu dai, khoi lugng, nang suit vd FCR eiia ea ehim vdy vang eo 2 - 3cm khi uang bang giai trong ao dlt, trong dd logi thuc an INVE vdi khau phan an ttr 8 - 10% BW dem lgi higu qua nang xuat cao (P<0,05) so vdi thirc an UP va eae khau phin an cdn lai.
IV. K f T LUAN
1. Mgt dp nufli khdc nhau (100, 200, 300, 400 va 500 con/m^) eo anh hudng idn sinh trudng, (CVL
%), nang suit va FCR, nhung khflng anh hudng tdi ty id sdng ciia ea. Sinh trudng ve ehieu dai, BW cao nhdt, CVL %, va FCR thip nhat d mgt dfi uang 400 eon/m^, nhung nang suit ca thu hogch dgt cao nhat a mat dfl 400-500 con/m'
2. Logi thire an tdng hgp (INVE, UP) va cac khau phan an (4, 6,8 va 10% BW) cd anh hudng ldn sinh trudng ve BW, SGR (%/ngdy) va (FCR) ciia ca Trong dd, thirc an INVE vdi khiu phan an 8 - 10%
BW dgt higu qua eao trong thf nghigm nay.
TAi H | U THAM KHAO Tieng Viet
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Tieng Anh
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3, Ly M. A., Cheng A. C , Chien Y. H and Liou C. H , 2005. The effects of feeding fiequency, slocking density and fish size on growth, food consumption, feeding pattern an size variation of juvenile groUPer Epinephelus coioides. J. Fish. Soc Taiwan, 32(1), p 19-28
4, Menno G. E , Piedrahita R H., Conklm D E , 2007. The effect offish stocking density on the growth cyf California halibut (Paralichthys califomicus) juveniles. Aquaculture 265: 176-186.
5 Schipp G., 1996. Barramundi farming in the Northern Territory. Aquaculture Branch Fishenes Division, Depamnent Pnmary Industry and Fishenes, GPO Box 990 Darwin NT 0801 44 p
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TRUONG OAI HOC NHA TRANG • 99
