KHOA HOC C b N G NGHE
CHUYEIM D O I G I O I T l l V H , IVUOI V O THAIMH T H I J C , 5 I I \ I H SAIM V A UOIMG IMUOI THAIMH COIMG CA
SOIMG C H U O T [CROMiLEPTES ALTiVEUS\
T6MTAT
U: Xan\ Nguyin Hiiu Tich^ Nguyin Diic Tu^^
Ca song chuot (mii chuot) Cromileptes altivelis Valencienes 1828 la loai ca ran san h6 vira dugc sfr dung lam thuc pham, vfra la loai ca canh dep, co gia tri cao so voi nhieu loai ca khac. Tong sd 250 con ca bd me dugc tuyen chpn tir dan ca buong (3 cm) nhap tir Indonexia nam 2003 va dugc nu6i v6 tai Cat Ba, Hai Phong. Sau qua trinh nu6i v6, ty le thanh thuc cira ca cai dat 91,8% va ca dtrc 94,6%. Sfr dirng hooc mon 17a- Methyltestosterone chuyen ddi gioi tinh dat ty le ca chuyen doi gioi tinh thanh due la 96,4%. Trong dieu kien nhiet do tti 25-32''C, do man 26-32%o, pH 7,4-8,4, uong nu6i sir dtrng thtic an la ban tning va nauplius (vo giap) cua artemia, ty le sdng ctia ca sau 45 ngay uong nu6i tir ca bot len ca huong (3,5 cm) dao dong tir 3,5- 6,2%. Ket qua thanh c6ng ctia nghien ctiu nay da dua Viet Nam gia nhap mot trong sd it qudc gia san xuat nhan tao thanh c6ng gidng ca song chuot.
Tir khod: Cd song chuot, nuoi vo thdnh thtic, sinh sdn, uong nuoi.
I. MO DAU
Ca song chupt, cac tinb phia Nam gpi 11 c l mii chudt, ten tiing Anh 11 mouse grouper; ngudi Uc goi 11 Panther grouper hay Polkadof grouper; fen khoa hoc Cromileptes altivelis Valencienes 1828. Ind6nexia la nudc cd san lugng c l song chudt nu6i ldn nhat fhl gidi. Ngudi Indonexia ggi c l song chudt l l Humpback grouper hay Barramundi cod. Cl song chuot phan bd chu ylu b cac nudc nhiet ddi nhu:
Ind6nexia, Philippines, Malaysia... Trong fu nhien, c l song chupt sdng frong cic vuc nudc tuong ddi nong (tii 2- 40 m), frong cic vfing d i m pha, vinh dio ven bd cd dly 11 ran dl, ran san h6 cd nudc bien frong sach, diiu kien m6i frudng if bien dong.
Tai fhi frudng Hdng Kong - thi frudng c l sdng ldn nhlt fhl gidi, c l song chudt cd gia b i n cao nhlt so vdi hlu b i t cic loai ca bien k h a c Gil b i n hien nay dao ddng tii 60-70 USD/kg (Hongkong news, 2009).
Ngoli muc dich fhtrc pham, c l song chuot cdn 11 loli c l canh do mlu sic dep. Cac nudc A Rap nhap tdi 60% sd lugng c l xuat khiu cua Indonexia d l b m c l canh. Hien nay, gia c l song chudt giai doan c l huong (3 cm) dugc bin tai Indonexia tfr 1,0-1,2 USD/con.
Vdi su hd frg vl ky thuat v l b i chmh cua Nhat Bin GICA), Ind6nexia smh san nhan tao c l song chudt thanh cong tfr nam 1999. Tfr dd, Indonexia lu6n 11 nudc din diu v l san xult gidng vl nu6i c l song chuot. Nam 2003, c6ng nghe sin xult gidng ca ' TS, ^ CN: Vien Nghien cifu Nuoi trdng Thuy san 1.
song chuot cua Indonexia da k h i dn dmh, ty le sdng khi uong d i n c l 45 ngly tudi dao dgng tfr 3- 20%, cao nhlt dat tdi 40%.
Malaysia va Ausfralia ciing da nghien ciiu san xuat gidng nhan tao c l song chudt. Nam 2005, Australia san xult dugc 100.000 con ca gidng. Thii Lan nghien cim tii nam 2005 nhung chua fhlnh cong (McBride,2005).
O r i n g bien Viet Nam, c l song chudt phan bd tu nhien, nhung sd lugng rif if v l chua cd cong trinh nao nghien ciiu. Vdi muc dich tim bilu dac diem smh hoc, smh sin, b o din c l bd me, tiin tdi nghien ciiu cong nghe san xuat gidng c l song chuot, Vien Nghien ciiu Nuoi frdng Thuy sin I da nhap 3.000 con ca huong (2,5-3,0 cm) tii hid6nexia. Nam 2007, 250 con c l bd me hau hi dugc tuyin chpn phuc vu nghien ciru. Bii bio nly frmh bIy k i t qua nghien ciiu vl chuyin gidi tinh, sinh san nhan tao vl uong gidng c l song.
II. PHUONG PHAP NGHIEN CUU 1. Chuyin doi gidi tinh
Tuong fu nhiiu loli c l song khic, c l song chuot cd dac diem tu biln ddi gidi tinh frong giai doan ca sinh frudng vl phlf friln. Tfr c l gidng den ca sinh sin lan diu vl mdt sd lan k l tiep (khoang 4-5 tudi) din c l tu nhien chu ylu 11 ca cai. O tudi thii 6-7 mdt sd c l cii mdi chuyin sang ca due. Do vay, frong tu nhien lu6n luon thieu c l due phuc vu sinh san. Day cung ll mgt frong nhiing nguyen nhan din d i n quan fhl cic loli c l song luon cd sd lugng kh6ng nhiiu.
Vdi hlu b i t cic loli cl, de cd the smh sin nhan tao
K H O A HOC C b N G N G H £
vl cd ty le cl de, ty le trimg thu tmh cao nhat, cic nghien cuu cua nhiiu tie gia diu cho rang d n duy fri ty le due d i 1:1. Dl cd du sd lugng cl due, nu6i vd chuyin ddi gidi tmh b viec d n thilt dau tiin d n phii tiin hinh.
Theo doi chuyin ddi gidi tinh fu nhien: do dac diim sinh hpc cua c l cd fhl chuyin gidi tinb mgt d c h tu nhien tuy theo diiu kien m6i trudng, thffc an vl qui frmh phat friln cua d nen viec theo doi ty le chuyen ddi gidi tinh tu nhien vdi muc dich 11 bm ddi chiing cho fhi nghiem chuyen ddi gidi tinh bing hodc mon. Sd lugng cl theo doi chuyin ddi tu nhien 11 55 con, CO' cl tfr 900-1000 g/con.
Chuyin ddi gidi tinh bang hodc m6n 17a- Methyltestosterone (17a-MT): Thi nghiem filn h i n h fren 55 con cl, co c l thi nghiem tfr 900-1000 g/con.
Kit hgp chuyin gidi tmh bang phuong phip tiem true tilp k i t hgp vdi cho an. Lilu lugng hodc m6n tiem cho c l 115 m g / k g c l , tiem b m 3 lln v l thdi gian tiem 11 1 l l n / t h l n g vio thing 2, 3 v l 4. Hodc mon dugc frgn hoac tiem vio thuc an vdi h l u lugng 2 m g / k g cl, cho an 1 lan/ 6 ngay vio thing 2, 3 v l 4.
Trgn hodc m6n vdi thuc an b i n g d c h frdn hodc m6n vdi hot mi, sau dd dua hot mi vio bung cua c l b m thirc an (cl Nham, c l Nuc, Muc).
2. Nudi v6 thanh thuc
Khdi lugng c l bd me nu6i vd 900-1000 g/con, do tudi 4 - 5*. C l bd me dugc nu6i frong long cd kich thudc 3 X 3 X 4 m, cQf m i t ludi 2a = 3 cm. Nu6i v6 vdi mat do 1,5 kg c l nu6i/m^. Sir dung c l Nham, c l Nuc... b m thfrc an cho ca; h i n g ngly cho an 3% khdi lugng CO fhl, cho an 2 l l n / n g l y . Ngoai ra, frong q u i frinh nuoi vd cd bd sung them fhiic an chit lugng cao
Ngay tuoi
0 3 20
nhu Muc dng phdi frgn vitamin (Vtm) A, B, C v l vitamin tdng hgp (TH). Thdi gian nu6i vd fir giua thing 12 nam trudc d i n gifia thang 4 nam sau.
3. Sinh san
Mua vu sinh san cua c l song chudt tfr thing 4-6.
VIo cudi thing 4 tien h i n h kiem fra chpn c l bd me fhlnh thuc d l cho sinh san. Ddi vdi c l d i , dung que fham trimg lay trimg ra quan s i t chgn nhiing con cd tning cang frdn diu. C l due, chon nhiing con khi vudt kilm fra cd se mau frlng d u e
Nghien ciiu da filn h i n h hai phuong phip kich thich smh san: (1) kich thich smh sin tu nhien bing tao ddng nuac chay; (2) kich thich sinh san str dung kich due fd HCG k i t hgp vdi LRHa, tiem mdt lan vdi lilu lugng 1000 UI HCG + 2 mg LRHa cho 1 kg c l cai, hlu tiem cho c l due b i n g 1/2 so vdi c l d i . Cl dugc cho de d' vinh Lan Ha, Cit Bl, Hai Phdng.
4. Uong nudi iu trung
Tning fhu tinh chuyin v l ap tei Trung flm Qudc gia gidng hii san miin Bic b i xa Xuan Dim, Cat Ba, Hii Phdng. Sau khi c l nd, c l bdt dugc uong frong b l dung tich 10 m^, do sau 1,2 m, b l dat frong n h i cd mii che, cudng dd anh sang 1200 - 1200 lux, frinh Inh sing true tilp. Mat do au trung ban diu 20 - 30 con/1.
Cham sdc quan ly (chi tilt b hinh 1): Giai doan diu sue khi nhe, diiu chinh sue khi tang din tuy theo tudi c l vio xi-ph6ng 2 l l n / n g l y vio 10 gid vl 17 gid. Trong giai doan diu (din 11 ngay tudi) kh6ng thay nudc. Khi c l bat diu an fhiic an nhan teo thay 20-30% nudc/ngly. CIc ylu td m6i trudng dugc kilm fra hang ngly vio 6 gib vk 14 gid. Duy fri mat dp teo Isochrysis galbana vk Nannochloropsis oculata 3x10^
t l bao/ml frong b l uong d l b m thitc an.
25 30 45 50
EE^^muishiojvpsis oculata 3-5 iffib/mLi^
Luan triing 7-1 Oct/ml
Artemia l-2ct/nil
Thirc an tong hgrp Thay nnCic.
20%/ngay
Thay nudc 50%/ng4y
W&:^'
Thay nudc 100%/ngay
Xi-phong day be
Thay nucrc 200%/ngay
Hinh 1. Tdm tit d c c l n g vile cham sdc quan ly frong qua frinh uong d song chuOt
KHOA HOC CONG NGHE
5. Phan tich va xu ly s6 li$u
Sd lieu vl ty le chuyin ddi gidi tinh dugc so sinh va kilm dinh b i n g gia fri x^ phan tich thdng ke m6 b fren phin m i m Excel vdi muc y nghia P<0,001.
lU. KET QUA NGHEN CUU VA THAO LUAN
1. Chuyin d6i gidi tinh va nudi v6 ihanh thuc a. Chuyen ddi gi&i tinh
Trong 55 con c l thi nghiem d l chiing tu chuyin ddi gidi tinh tu nhien, chi cd 5 (9,09%) c l fhl chuyin gidi tinh fhlnh d d u e Trong khi dd, 55 c l fhl dugc bd sung hodc m6n sinh due due 17a-
Bkng 1. Ty II chuyin d6i gidi tinh d song
Methyltestosterone (17a-MT) vdi lilu lugng tiem 0,5 mg/kg c l (tiem 3 lan, khoing d c h giffa hai lln tiem 11 mgt thing) k i t hgp vdi cho an 2 m g / k g c l (cho an 6 lln/ngly) d l chuyin ddi gidi tinh da cd 53 ca fhl chuyin thanh c l due (96,4%) (BIng 1). Kit q u i nly cho thay sir dung hodc m6n iZa-MTklf hgp vdi c h i dd nu6i vd fich cue tdt cd fhl hoan toln chu dpng sd lugng c l due cho sinh san nhan teo. Kit q u i nghien cuu chuyin ddi gidi tinh b c l song chudt b thi nghiem nly (96,4%) cao hon so vdi k i t q u i nghien Cliu chuyin ddi gidi tmh c l song cham nau (80-90%) khi Le Xan (2004) tiin h i n h d diiu kien tuong tu.
chudt b i n g 17a-MTk6t hgp nudi v6 tich cue
TT Noi dung thi nghiem
Ca tu chuyen doi gioi tinb
So bang ca thi nghiem (con)
Tuoi Sd ca due (con)
% ca due
55 5* 9,09
Ca dugc bo sung iZa-MTde chuyen doi gioi tinh 55 5* 53 96,4*
^ * *; Kiem dinh / sai khac y nghia so vdi ddi chitng (P<0,001) b. Nudi vd thdnh thuc
D l cd t h i cho de vio cudi t h i n g 4, diu t h i n g 5, thdi gian nu6i v6 c l dugc b i t d i u tfr giffa t h i n g 12 nam frudc. Trong thdi gian nu6i vd, nudc bien cd nhiet dp tblp 19,5-22,4''C, do man cao (32-33%o), h l u h i t d c loli c l biln nu6i thudng hi d c benh do
Bang 2. K i t q u i nudi v6 d song chuQt
ngoai ky sinh trfing, sau dd \b b i t va chit. Tuy nhien, do c h i dd nu6i vd tdt va cd d c bien p h i p phdng benh nen ty le sdng cua c l song chuot due v l d i d i u cao: c l due 93,3%, c l d i 90%. Ty le d thanh fhuc dat 91,8% ddi vdi d due va 94,6% ddi vdi c l cai (BIng 2).
Gioi tinh Ti le sdng Ti le thanh thuc
Ca cai
Sd ca thanh thuc/ca nu6i v6 (con) 54/60
45/49
(%) 90,0 91,8
Caduc
Sd ca thanh thuc/ca nu6i v6 (con) 56/60
53/56
(%) 93,3 94,6 2. Sinh sin va uong nudi l u trung
a. Sinh sdn
Khi thi nghiem da tiin h i n h phuong phip smh san tu nhien bang viec kich thich smh fhli (teo ddng chly, phun nudc, d p 6xy), tuy nhien ty le c l de vin rat tblp (20%). Vdi ty le c l de thap thi phuong phip sinh san tu nhiln kh6ng dem lai hieu q u i kinh t l frong viec san xuat gidng vdi sd lugng ldn. Trong khi dd sir dung kich due fd HCG k i t hgp vdi LRHa lilu lugng 1000 UI HCG -i- 2 mg LRHa tiem cho c l thi thay ty le c l d l cao (trung bmh 92,4%), c l bd me sau khi de khoe manh.
b. Ty li sd'ng cd song chudt trong qud trinh bii'n thdi tie du triing (cd bdt) len cd huong
Tuong tu nhiiu loli c l biln khic, l u trfing c l song chudt cd ty le c h i t cao n h l t vio khoing thai gian 3-5 ngly tudi. Nguyen nhan chu ylu do giai
doan nly c l chuyin tfr tieu thu noan hoing sang fhiic an ngoli. Quan sat cho thay au trfing c l song chuot chit nhiiu d' giai doan nly cdn cd nguyen nhan do au trfing thudng tap trung q u i nhiiu d mot sd vi fri frong be uong vl chiing tilt ra chat nhly dmh quanh au tning. Chit nhay tu nhffng au tning nly se nhanh chdng b m dinh nhfing au tning khic Ilm mpt sd lugng ldn au tning bi c h i t frong thdi gian ngan.
Giai doan d tii vong nhiiu thii 2 b giai doan
"moc vl rung gai" khoang 5-17 ngly tudi. Mdi au frung diu cd gai d' vay lung, vay nguc dii gap 2-3 lan chieu dii toan than. Day 11 giai doan c l k h i nhay cam vdi m6i trudng v l ciing d l quan vao nhau do gai dii, gay chef sd lugng ldn.
Cac thi nghiem nam 2008 vdi diiu kien nhiet dp nudc dao dgng tii 25-32^*0, do man 26-30,2%o, pH duy fri 7,8-8,4, ham lugng 6xy hda ten lu6n d' mtic bao hda cho k i t qua b : Au trfing d da phlf friln holn
KHOA HOC C d N G N G H l
toln fhlnh d huong vdi tdng chilu dii 2,0-2,2 cm sau 55 ngly. Giai doan d huong, cl song chudt ciing cd hien tugng an thit lln nhau nhtmg khdng nhiiu nhu mpt sd loli cl song khac Ty le sdng tfr cl hot (au tiling) len d huong frong nghien cim diu tien dat 3,5%.
Sang nam 2009, vdi diiu kien mdi trudng tuong tu rdiung cd mot sd diiu chinh ky thuat tfr giai doan nu6i vd cl bd me dl cd chat lugng trimg vl au trfing tdt hon, da duy fri tdt diiu kien moi trudng vl thuc an cho au frung nen thdi gian biln fhli tfr cl mdi nd din d huong chi cdn 45 ngay vl ty le sdng dugc nang len 6,2%.
-2008 -?009
25 29 33 45 49 S3
Ngay tuoi
Hinh 2. Ty 1§ sing ciia d song ehugt giai doan d hot lln d huong nam 2008 va 2009
Ty le sdng tii cl hot len cl huong dat tfr 3,5%
(2008) din 6,2% (2009) cdn thap ban so vdi ty le sdng ciia d song chudt do Ind6nesia san xult hien nay
(khoing 5-31%) (Sugama vl et al., 2004), nhimg frudc day Ind6nesia vdi su giup da ciia Nhat Ban cfing phai mat 4 nam (tii 1995-1999) mdi san xuat fhlnh c6ng gidng cl nly vl ty le sdng luc dau < 3%. O Viet Nam mdi budc diu nghien cim, muc tieu nghien ciiu dat ra 11 ty le sdng khi uong din giai doan cl huong dat 3,5-6,2% 11 nhfing kit qua ding khich le.
Trong qui frinh biln fhli tfr au frfing len d huong, cl song chuot thay ddi rat nhieu ve hinh dang. Khi mdi nd', au tiling cl cd tdng chieu dii khoing 2 mm. Din ngly thu 11-12, tdng chieu dii khoang 5 mm, cl xuat hien 1 gai vay lung vl 2 gai vay nguc dii. Nhiing gai nly bm cho au trfing rat dl dinh vio nhau vl chef. Song song vdi su phlf friln d c bd phan khic cua ca the, d c gai nly ngln din vl mat di. Cl "rung gai" fhl hien da kef fhuc qui frinh biln fhli. Liic nly cl da phat friln day du d c ca quan, frd fhlnh cl huong vdi hinh ding vl d u teo holn toln gidng cl trudng thanh.
Kit qua nghien cim cho thay au frfing cl song chupt phlf triln cham ban so vdi cl song cham Nau
(E. coioides). Trong cfing diiu kien nhiet dd, pH, 6xy hda ten va chi dd cham sdc, cl song cham nau cd thdi gian biln fhli khoang 40-45 ngly dl cd hinh dang vl d u teo nhu cl frudng fhlnh. Vdi cl song chuot, thdi gian biln fhli cua cl thi nghiem tii 45 ngly tudi (2009) din 55 ngly tudi (nam 2008). Cl da holn fhlnh giai doan biln fhli cd tdng chilu dii trung binh 3,5 cm.
K200S
• 2000
Ngay luoi
Hinh 3. Sinh trudng eiia ck song chuOt giai doan d bgt bn d huong nam 2008 va 2009
Chit lugng tning, chat lugng au tning, sd lugng vl chat lugng thuc an, chi do cham sdc quin ly va diiu kien m6i trudng tdi uu 11 nhiing ylu td co ban dl cd fhl nang cao ty le sdng vl nit ngan thdi gian biln fhli ctia au trfing. CIc bien phip ky thuat tec dgng vio d c ylu td fren frong d c fhi nghiem nam 2009 da dua din kit qua thdi gian biln fhli dugc nif ngln tii 55 ngay tudi xudng 45 ngly tudi vl sinh trudng cua cl nhanh hon (Hinh 3).
0 '"?<
•.•4!
' ? J ^ -
Hmh 4. Ca song chudt gilng 80 ngay tu6i
IV. KET LUAN
Ca song chupt bd me nuoi frong diiu kien d Cat Bl (Hii Phdng) fhlnh thuc vl de frimg lan diu d- tudi 5^ Sir dung 17a-Methyltestosterone (kit hgp tiem vl frgn vio fhiic an) dl chuyin ddi gidi tmh cd hieu qui dat 96,4% cl due, cao ban y nghia (P<0,001) so vdi chuyin ddi gidi tinh due tu nhien (9,09%).
KHOA HOC CONG N G H l
Nu6i vd tdt ca bd me se cd chat lugng tning tdf, ty le nd cao, au trfing khde; che dd cham sdc quan ly tdf cd fhl nang cao dugc ty le sdng, nit ngln din mirc cd fhl dugc thdi gian biln fhli. Trong diiu kien nhbt dd 25-3200, do man 26-30,2%o, pH duy fri 7,8-8,4, h i m lugng 6xy hda tan d' muc bao hda, au frfing ca song chuot (2 mm) da hoan thanh q u i frinh bien fhli fhlnh d huong (3,5 cm) sau 45 ngly tudi. Ty le sdng khi uong tii c l hot (au tning) len c l huong dat 6,2%.
Cin tilp tuc nghien cim v l thuc an, dinh duong, anh hudng ctia diiu kien moi trudng, c h i dd cham sdc d l dn dmh vl nang cao ty le sdng tii c l hot len c l gidng.
Cl song chuot 11 mgt frong nhiing loli c l d l hi benh hoai tii thin kinh (VNN) gay c h i t h i n g Iqat frong qui frmh uong nu6i d gidng v l nuoi c l thif thuang pham. Do vay, d n loai bd nhifng d the c l bd me hi nhilm VNN trudc khi dua vio san xuat gidng.
TAI UEU THAM KHAO
(1) McBride, S., 2005. Ausfralian success witii barramundi cod (C altivelis). Aquaculture m Asia 3, p 23.
(2) Sugarma K, Ismi, S., Kawahara, S. and Rimmer, M., 2003. Improvement of larval rearmg technology for humpback grouper Crommileptes altivelis. World Aqua. 3, pp 34-37.
(3) Sugama K., Trijoko, S., Ismi, S. and Kawahara, S., 2004. Larval rearmg tank management to improve survival of early stege humpback grouper
(C. altivelis) Larvae. Advances m Grouper Aquaculture. Ausfralian Cenfre for International /Agriculture Research Canberra, pp 61-67.
(4) Le Xan, 2004. Kit qua nghien cim cdng nghe sin xult gidng va nuoi thuong pham mgt sd loli c l song (Epinephelus sp) phuc vu xuat khau. Bao clo tdng k i t d l tei KHCN d p N h i nudc KC06.13.NN.
Vien Nghbn cuu NTTS I.
(5) Hongkong News, 2009. http//:enaca.org/fishprice.
SEX REVERSE, BROODSTOCK MANAGEMENT AND SEED PRODUCTION OF MOUSE GROUPER (CROMILEPTES ALTIVEUS)
Le Xan, Nguyen Huu Tieh, Nguyen Due Tuan Summary
Mouse grouper (Cromileptes altivelis Valencienes 1828) is coralfish that has highest price compare to many other species. The grouper is considered as one of the best foodfish and ornamental fish. Total of 250 brood fish were selected from the introduced fingerling stock in Catba, Haiphong that originally fingerlings (3.0 cm in length) were introduced from Indonesia in 2003. After four months of broodstock management, the ratios of mamre were 91.8% for female and 94.6% for male. The efficiency of sex reversal was 96.4% male by using 17a-Methyltestosterone. In tbe nursing conditions of temperature 25-32°C, salinity 26-32%o, pH 7.4-8.4, feeding by rotatoria and nauplius of artemia; survival rate of nursing from newly hatched larvae to fry of 45 days old ranged from 3.5% to 6.2%. The present results propose Vietnam fo limited number of countries whose are successfiiU in induced breeding of mouse grouper.
Keyvfords: Mouse grouper, broodstock management, spawning, nursing.
Ngudi phan bi^n: TS. Pham Anh Tuin