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NG DNG MODIFIED LIVE VACCINES TRONG NUI TRNG THY SN

GVHD: Th.s Phm Minh Nht SVTH: L Th Lan Chi (08DSH3)

L Phm Trc Qunh (08DSH3) Mai Lin (08DSH3) Tn Phi Lin (08DSH4)

LI M U Vaccines l mt chin lc qun l quan trng c s dng duy tr sc khe con ngi v ng vt trn ton th gii.Mc d c p dng cho cc loi ng vt trn cn t lu, nhng i vi ng vt thu sinh, cng ngh ny ch c lch s rt ngn ngi. Trong nui trng thy sn, s ra i ca hng lot m hnh nui thm canh dn n s mt cn i v mi trng, sinh thi, iu th hin r qua hng lat dch bnh v ang xy ra, lm tn tht khng nh n ngh nui c cng nghip. Vic s dng khng sinh cha bnh cho c ngy cng nhiu v dn n hin tng khng thuc ca vi khun, nhng tn lu khng sinh khng mong mun Vi hin trng nh th, s dng vaccine phng bnh cho c c xem nh mt gii php ti u nht cho s pht trin bn vng ca ngh nui thy sn.

GII THIU Trong nui trng thy sn, vaccines c bt u nghin cu v pht trin t nm 1973 nhng mi n nm 1987 mi c a vo s dng cho h thng nui cng nghip.

Modified Live Vaccine (MLV) L vaccine sn xut da vo vic bin i gene ca chng vi khun gy bnh. Cng vic quan trng nht l xc nh gene c lc v loi b gene c lc trc khi s dng vi khun vn cn sng. Mt cch khc sn xut MLV l chn chng vi khun khng gy c nhng c cu trc t bo gn ging vi chng vi khun gy bnh v quan trng l chng vi khun phi kch thch c h min dch chng li tc nhn gy bnh.

Tng quan v s dng vaccine trong NTTS trn th gii Vaccine u tin c s dng l loi vaccine bt hot dng ngm nhm chng li Yersinia ruckeri l tc nhn gy bnh xut huyt di hu c. Sau s thnh cng ca sn phm ny,vaccines dng ngm s dng formalin git cht vi khun c p dng cho c hi phng bnh do Vibriosis c pht trin. Theo nguyn l tng t phng php ngm vaccine cng c p dng c hi Atlantic, Salmo salar, chng li A. salmonicida. Tuy nhin, vic ngm vaccine khng hiu qu v vy vaccine s dng theo phng php tim ra i

Vi nm tip sau , nhiu loi cht b tr cng nhng khng nguyn ti t hp c tin hnh th nghim. n nm 1995, vaccine phng bnh do virus chnh thc c iu ch thnh cng. T y m ra mt hng i mi cho ngnh thy sn th gii. Hin nay, ba loi Vaccines c ch c lc vi khun c quyn s dng Hoa K, bao gm vaccine chng li bnh thn vi khun (Renogen1), nhim trng huyt rut ca c nheo M (AQUAVAC-ESC ) v bnh Columnaris (AQUAVAC-COL )

AQUAVAC-ESC AQUAVAC-COL

PHNG PHP NGHIN CU Nghin cu trong phng th nghim:

Phng php to MLV n gin nht l cy chuyn nhiu ln trong phng th nghim bng vic nui cy cc VSV hoc nui cy m trn cc mi trng khng m bo iu kin cho s pht trin ca chng dn n s suy gim ca cc tc nhn gy bnh. Thnh tu u tin ca k thut ny c thc hin trn c nheo M, Ictalurus punctatus, bng virus (CCV) (Hart-man v Noga 1980). Gn y hn, Daly et al.(2001) s dng laboratory lm suy yu chng Renibacterium salmoninarum chng nga cho c hi i Ty Dng. Itano et al.(2006) cng cho thy vic s dng Nocardia seriolae (mt chng phn lp c c lc thp) nh l mt chng vaccine tim nng

Channel catfish

Vim da do Renibacterium salmoninarum.

Vi khun mi trng: S dng mt loi vi khun mi trng m phng cu trc khng tc nhn gy bnh ng dng thnh cng nht ca chin lc ny trong nui trng thy sn l s dng Arthrobacter davidanieli c cho tim vo bo v c hi khi vi khun gy bnh thn gy ra bi R. salmoninarum (Griffiths et al 1998; Salonius et al.2005) Gn y hn, Itano et al.(2006) th s dng mt chin lc tng t (tc l, Quan h pht sinh loi v phn ng khng nguyn cho) xc nh vaccines thch hp chng li N. seriolae.

Nocardia gy bnh nhim trng

Bnh thn do R. salmoninarum

Yellowtail

t bin ha hc v vt l: S dng phng php t bin ha hc hoc vt l m kt qu l s t bin ngu nhin trong tc nhn gy bnh.Sau chng vc-xin c la chn l chng b c ch c lc v khng gy hi cho ng vt ch (Linde et al 1990; Klesius v Shoemaker nm 1999; Shoemaker et al. 2007) V d in hnh l vic s dng rifampicin, mt loi khng sinh cho kt qu lm suy gim vi khun Gram m bng cch cm ng thay i trong lipopolysaccharide (LPS), mt yu t c lc quan trng (Schurig et al 1991; Klesius v Shoemaker 1999; Arias et al.nm 2003; Zhang et al.2006). S thay i ny lm mt mt chui O side ca LPS in hnh nh vaccine RB-51 (Brucella abortus).

Rifampicin

Nghin cu gn y m t t bin ca E. ictaluri RE33 chng minh s thay i l trong LPS. Hiu qu c chng minh trn 3 - 9 ging c tra khi s dng MLV khng E. ictaluri (Klesius v Shoemaker nm 1999; Lawrence Banes 2005). Liu vaccines c th nghim trong phm vi t 105 107 (CFUs) RE-33/mL v cho tip xc vi c bng cch ngm t 2 30 pht. Th nghim c chng minh l c hiu qu min dch i vi c nng 107 CFU/mL trong iu kin invitro v exvitro vi E. ictaluri.

K thut di truyn: Phng php th t l ng dng k thut di truyn in hnh bng cch chn vo, xa, gin on con ng chuyn ha hoc gen c lc m kt qu lm suy gim tc nhn gy bnh. Cooper et al.(1996) s dng mt on gen nhy mini (minitransposon) lm gin on vic sn xut ca chondroitin sulfatase (yu t nghi ng c tnh c lc) trong E. ictaluri. Mt n lc gn y l phng php to t bin bng gen nhy lm mt tc nhn gy c O polysaccharide khi phn lp E. ictaluri v c s dng nh mt loi MLV (Lawrenceet al 2001;. Lawrence v Banes nm 2005).

Igarashi v Iida (2002), vi cng ngh tng t, tm ra vaccine gim c lc E. tarda bng cch to ra mt chng t bin E. tarda (t bin gen nhy) vi vic sn xut siderophore thp hn bo v c r phi, Oreochromis niloticus S dng mt on gene nhy t bin ngu nhin (Tn917) chn vo on gen m ha cho enzyme phosphoglucomutase Streptococcus iniae (Buchanan et al 2005) trong c vc lai c sc (Morone chrysops X M. saxatilis).K thut di truyn

Mt trong nhng chin lc ph bin hn l bt hot gen cn thit cho qu trnh sinh dng ca vi khun trong vt ch.V d nh gen aroA ca tc nhn gy bnh c bt hot bng cch chn mt DNA cassette c cha mt gen nh du khng khng sinh.

K thut di truyn

U V NHC IM u im: i vi vaccine bt hot th chng vi khun sn xut vaccine khng b bt hot hon ton, vn cn kh nng gy bnh cho vt ch.Trong khi , MLV th chng vaccine khng cn kh nng gy bnh cho ng vt c tim vaccine. Frey (2007) a ra mt nh gi v khi nim an ton sinh hc v mt di truyn ca MLV khi ng dng trong sn xut thuc cha bnh cho ng vt, l nguyn tc c bn p dng trong vic s dng Modified live vaccines c ng dng trong ngnh nui trng thy sn.

MLV c kh nng tc dng lm kch thch hot ng ca t bo trung gian,th dch ( khng th) v nim mc min dch (Clack v Cassidy Hanley 2005). Modified live vaccines tn ti v c sao chp cng vi vt ch, chnh l kt qu ca s phn ng mnh ca t bo min dch nhm bo v n trong thi gian di. MLV d dng a vo c th vt ch bng nhiu con ng nh: nhng, ngm, tim.(Norqvis et al. 1989) Gi thnh ca MLV tng i mc trung bnh v d sn xut.u im

Nhc im i hi cng ngh sn xut cao Ch c tc dng phng nga c hiu i vi mt loi bnh Sai st trong qu trnh xc nh v loi b gen c lc c lc ca vi khun c th phc hi khi chng c tng sinh trong c th vt ch.

KT LUN MLV c ng dng thnh cng trn ngi, th y, v ng vt thy sn.Nu nguy c tim n i vi ng vt, mi trng v con ngi u mc thp hoc khng ng k th vic s dng MLV trong nui trng thu sn l chin lc thch hp. Ngoi ra cn xem xt k hn v vn an ton ca vaccines i vi mi trng khi khng c nhiu d liu khoa hc dn chng v c lc ca vi khun vn cn tim tng. Vaccines l cng c c dng bo v sc khe v an ton sinh hc mang n li ch ln cho cc nh nui trng thu sn.