KHOA HOC KY THUAT THt Y TAP XXVII S6 1 - 2020
NGHIEIU ctfu M O T SO flAC flIEM LAM SANG VA YEU TO niGUY COf CUA BENH VIEM PHE QUAN TRUYEN N H I I M fli GA THIT
TAI DONG BANG SONG CUfU LONG
Nguyen Thf Cdm Loan', TrSn Ngpc Bich\
Nguyin Phuc Khdnh^, Huynh Thi Ngoc Dun^
TOM TAT
NghiSn cuu ty Ie nhilm vims viem phi quan tiiyin nhilm (IBV) dugc thuc hien qua viec khao sat trilu chimg, benh tich dai the va kit hgp xet nghiem PCR tir 20 dan ga thit c6 bieu hien benh duong ho hip tai tinh Vinh Long va Soc Trang. Ket qua nghien ciiu cho thay co 7 dan ga duong tinh vai IBV (35%), Ch^n doan Iam sang da dugc khang dinh vai ket qua xet nghiem PCR (vi qua bieu bien Iam sang chi dat 53,84%
do chinh xac). Trieu chimg va benh tich dai the chii yeu tap trung o ducmg ho bap, bao gim: am rit khi quan khi ther, hiit hoi, kho tho, chay nuoc miJi, viem ket mac, viem xoang mui, toan bp khi quan xuat huylt dilm, CO dich nhay, phoi sung huyet, xuat huyet, viem tiii khi va simg than. Ty Ie chet o ga duong tinh vai IBV la 14,93%. Ty Ie nhilm IBV cao nhat o nhung dan ga co bieu hien benh ma truoc do chi dugc phong ngiia bing vacxin 1 lln hoac 2 lan voi cimg 1 serotype vacxin chiing Massachusetts - H120 (50%), nhimg dan ga dugc phong ngira bing vacxin 2 lan voi 2 serotype vacxin khac nhau (Massachusetts - H120 va 793B -4/91) CO ty Ie nhilm thip hon (25%)). Ty Ie IBV cao nhat la a ga 5-7 tuan tuoi (71,43%o) so voi cac Iiia tuoi con Iai.
Khong CO su khac biet vl ty Ie dan ga nhilm IBV giiia cac kilu chuing nuoi cung nhu o miia kho, nhung benh co xu huong tang o nhom ga nuoi kieu chuong kin va vao miia mua.
Tif khoa: Ding b^ng song Cim Long, IBV, ga thit, viem phi quan tmyIn nhilm Investigation on some clinicai characteristics and r\sW factors for infectious broncliitis in broiler chickens in the Mekong Delta area
Nguyen Thi Cam Loan, Tran Ngoc Bich, Nguyen Phuc Khanh, Huynh Thi Ngoc Dung
SUMMARY
An investigation on the prevalence of infectious broncliitis virus (IBV) in the broiler chickens was carried out by symptom and gross lesion observations, and combining with PCR test from 20 chicken flocks suffering from respiratory problems in Vinh Long and Soc Trang provinces. The studied results showed that there were 7 chicken flocks infected with IBV (35%). Clinical diagnosis was determined combining with PCR assay because clinical signs showed only 53.84% of accuracy in diagnosis. The symptoms and gross lesions were mainly found in the respiratory tract, including tracheal rales when breathing, sneezing, dyspnea, nasal discharge, sinusitis, conjunctivitis, tracheal petechial hemorrhage with exudate mucus, pulmonary hemorrhage and congestion, airsacculitis and swollen kidney. The mortality of the IBV infected chickens was 14.93%. The higher IBV infection rate was found in the chicken flocks vaccinated only one or two times with 1 vaccine serotype (Massachusetts - H120) (50%), followed by the chicken flocks vaccinated two times with 2 serotypes (Massachusetts - H120 and 793B - 4/91) (25%). The comparison of different age groups showed that the highest infection flocks rate was from the chickens at 5 to 7 weeks of age (71.43%). There was no significant difference for the infection rate of the chickens in the different farm types as well as in the dry seasons, but the IB disease of chicken showed the tendency to increase in the captive farms and in the rainy season.
Keywords:lhe Mekong Delta, IBV, broiler chickens, infectious bronchitis.
' Cao dang Cong ding Vinh Long
^ Dai hoc can Tho
So Nong nghiep va Phat triln nong thon thanh phi Cm Thu
KHOA HOC KY THUAT THU Y TAP XXVn SO 1 - 2020
I. MO BAU
Hien nay, phuong thiic chan nuoi ga thit theo huong cong nghiep dang rat pho bien a dong bang song Ciru Long nham dap iing kip thoi nhu cau tieu thu thjt gia cam ngay cang tang ciia nguai tieu dimg. Tuy nhien, chan nuoi theo huang cong nghiep voi viec tang dang ke so lugng gia cam dan den dich benh thuong xuyen xay ra ngay ca khi da phong ngira bang vacxin. Mot trong cac benh gay ton that nang ne tren ga moi noi gan day chinh la viem phe quan truyen nhiem vol han 50 chimg virus da dugc cong nhan (Ignjatovic va Sapats, 2000), trong khi do, cac cong bo nghien ciru khoa hpc ve benh nay a khu vuc dong bang song Cuu Long chua nhieu.
Nghien cuu va danh gia tinh hinh nhiem virus viem phe quan trayen nhiera (Infectious bronchitis virus - IBV) a ga nuoi theo huang cong nghiep dugc tien hanh nhara gop phan tao co sa xay dung quy trinh phong benh hieu qua. Chiing toi khao sat cat ngang a nhimg dan ga nhiem IBV tai VTnh Long va Soc Trang de ghi nhan nhimg dac diem dich te CO ban, trieu chimg va benh tich dai thi kit hgp voi chan doan chinh xac IBV bing ky thuat PCR. Voi khuon kho bai bao nay, chiing toi chi trinh bay kit qua ghi nhan tinh hinh nhiem IBV trong thai gian khao sat.
n . VAT LIEU VA PHirONG PHAP 2.1. ThM gian va dia diem nghien cihi
Nghien cihi dugc thuc hien tir thang 2 din thang 8 nam 2018.
Mau benh pham dugc lly tai cac trang Uai chan nuoi ga thit theo huong cong nghiep co quy mo tu 1000 con tra Ien a tinh Vmh Long va Soc Trang.
Dia diem xet nghiem la Vien Cong nghe sinh hoc, Vien Han Iam Khoa hpc va Cong nghe Viet Nam.
2.2. D6i tirtmg nghiin cihi
Cac dan ga thit dugc nuoi theo huong cong nghiep, da dugc chiing ngira vacxin phong benh IB thupc serotype Massachusetts (HI20), 793B (4/91), CO bieu bien benh IB the ho hip cdp tinh trong vong 7 ngay dau khi bat dau xuSt hien benh.
Sl dan: 20 dan. Loai mhi benh phim: Khi quan ga.
2.3. Dieu tra cSt ngang mot s6 dac dilm dich te Cff bao tren nhimg dan ga benh
Chiing toi ghi chep mgt sl thong tin co ban lien quan din dan ga khao sat bao gim: giong ga, lira tuli, tmh uang phong ngira vacxin IB, phuong thiic chan nuoi, miiavu, so ga benh va soga chet,...
2.4. Phutrng phap chan doan dua vao trieu chirng va benh tich
Tat ca cac bieu hien ve the trang va trieu chiing cua ga dugc ghi nhan, sau do mo kham. Ga nghi nhiem IBV co nhung bieu hien nhu u rii, kem an, kho tho, ho, hat hoi, co am rit khi quan, so miii, tieu chay, tich nuac xoang bung, sung dau, viem ket mac mat, than sung, khi quan xuat huyet, phoi tu huyet, xuat huyet, viem tui khi va viem xoang mui (Nguyen Thi Loan, 20 i 8).
Nhiing dan ga co bieu hien kho tho nhtmg khong nghi nhiem IBV trong nghien ciiu ciia chiing toi la nhimg dan co bieu hien dac trung ciia benh sung phii dau-Coiyza, benh chi khu tni o viing dau gom dau sung phu, chay nhieu nude mil!, nuoc mat, mat viem nang, mu, viem xoang tran, ma, miii, hgng ga c6 nhieu mu hoac chat casein boa.
Sau khi co ket qua xet nghiem bang phan iing RT-PCR la duang tinh voi IBV, chiing toi tiln hanh mo kham de tong ket tin suat trieu chiing, benh tich ga benh IB. Sl lugng ml kham la 10 con/dan.
2.5. Phuong phap chSn doan IBV b5ng ky thuat PCR
Thu nhan va bao quan mlu: Mlu benh phSm lajthi quan cua ga nghi nhilm IBV bao gom 39 raau ciia 13 dan (3 ga/dan). Tiln banh ghi ten mSu, ngay lay mau va dia dilm. Mlu duoc bao quan lanh o -20°C cha xet nghiem PCR.
Tach chilt RNA ting sl va chuyin cDNA:
RNA tong so dugc tach chilt tir mlu benh phSm su dung bg sinh pham RNeasy Mmikit cua QIAgen, theo huang dan cua nha san xu4t. RNA ting sl dugc chuyen doi cDNA sir dung „^|i ^^^ suit hexamer (Thermo Scientific).
KHOA HQC KY THUAT T H O Y TAP XXVII SO 1
Thu nhan gen N bSng PCR: Phan iing PCR thuc hien vcri mii xuoi va mii ngugc: IBF (5'TTTTGGTGATGACAAGATGAA 3'), IBR (5'CGCATTGTTCCTCTCCTC 3'), thu viing gen N, kich thuac khoang 0,4 kb. Tinh sach bang bp sinh ph§m QIAquick PCR Purification kit (QIAGEN) va gui dpc hinh tu true tilp. Sau idii giii hinh hr, thu nhan phin gen N co kich thuac 403 bp cua m§u benh phim va khing dinh dan ga nhiem IBV (Le Thi Kim Xuyen va ctv., 2019). Mlu doi chimg ducmg trong phan iing nay la chiing IBV-KN do phong Mien dich hpc, Vien Cong nghe sinh hgc cung cap.
2.6. PhuoTig phap xu Iy thing ke
So ligu th6 dugc xir Iy bing phin mlm Excel.
Ty Ie dan ga nhilm IBV va ty ie ga chit giua cac giong. Ilia tuli, phuong thiic chan nuoi, tinh trang pbong ngira, mua vu dugc so sanh bing phep thii Chi-square cua phin ralm Minitab 17.
III. KET QUA VA THAO LUAN 3.1. Ket qua xac dinh nhilm IBV fr dan ga khao sat dira tren sir ket hop chin doan ISm sang va xet nghiem hing ky thuSt PCR
Ket qua xac dinh tinh hinh nhilm IBV bing ky thuat PCR dugc the hien 6 bang 1.
Bang 1. Ket qua xac djnh ga nhiem IBV
Ket qua xac dinh So Qkn ga khao sat (dan) Ty le (%) Nghi nhilm IBV (truac xet nghiem PCR)
Nhiem IBV (sau xet nghiem PCR)
Trong th6i gian nghien cim, chiing t6i ghi nhan c6 20 dan ga co bieu hien benh duang ho hap dugc yeu c3u chan doan benh. Qua chan doan lam sang, Ioai tni nhiing dan ga co bieu hien dac tnmg ciia b?nh Coryza nhu da neu thi so dan nghi nhiem IBV la 13 dan, chilm ty Ie 65%. Sau khi kit hgp chan doan bang ky thuat sinh hpc phan tii PCR tit 13 dan neu tren thi c6 7 dan cho ket qua duong tinh vai IBV. Dieu nay chung to c6 su luu hanh ciia IBV tren dan ga thit tai 2 tmh VTnh Long va Soc Trang thupc khu vuc Dong bang song Cuu Long, Ty I? dan ga nhilm IBV la 35% (7/20 dan) va so vcti viec kit hgp xet nghiem PCR thi phuong phap chan doan Iam sang xac dinh tinh hinh nhiem IBV chi d^t 53,84% (7/13) dp chinh xac. Qua day, chiing toi khang dinh viec ket hop chan doan Iam skg va ling dung ky thuat sinh hgc phan tir PCR g6p phan kit luan chinh xac trong chin doan IBV.
Ket qua phan nhom chiing IBV da dugc cong bl 0 bdo cao tmdc, cu the la qua phan tich gen N cua IBV dugc phan l^p tai Vinh Long va Soc Trang cho thiy co ba nhom chiing IBV gim 4/91 (793B), Massachusetts - M41 va LX4 (QX - like) va co sir da nhilm cac chung IBV tren cung mgt ca thi ga (Le Thi Kim Xuyin va ctv., 2019).
Cavanagh va Gelb (2008) cho biet IB la mgt trong nhiing b^nb gSy nhieu ton that voi ty Ie benh CO the Ien den 100%). 6 Viet Nam, theo bao cao cua Vo Thi Tra An va ctv. (2012), ty Ie nhilm IBV trgn ga thit tai tinh Lam D6ng la 16,6%; Nguyin Thi Loan (2018) bao cao ty Ie mac benh 6 dan ga huang trimg (quy mo >1000 con) tai mpt so tinh phia Bic la 20,25% va tinh hmh benh IB co lien quan den cac yeu to nhu phuong thiic chan nuoi, quy mo chan nuoi, tinh trang phong ngua, nguon glc gilng, vi tri trai va ve sinh chuong trai. Day la bao cao diu tien vl tinh hinh nhiem IBV tai VTnh Long va Soc Trang cho tbay ty Ie dan ga nhiem IBV cao hon (35%). Dilu nay chimg to tinh hinh djch tl ciia benh IB co xu huang pho bien o ga thit dugc nuoi theo huong cong nghiep tai hai tinh Vinh Long v^ Soc Trang.
Sau khi liy mlu xet nghiem PCR va cho kit qua duang tinh vai IBV, chung toi tiln hanh mo kham dl ting kit tin suit hieu chiing va benh tich.
s l ga (n) trong khao sat nay la 70 con tir 7 dan duong tinh vol IBV.
Ket qua khao sat tri?u chiing benh IB dugc thi hi?n a bang 2.
KHOA HOC KY THUAT THU Y TAP XXVII S6 1 - 2020
B a n g 2. Tan s u a t t r i e u chi>ng b e n h o" ga n h i e m IBV (n=70) Trieu chiJng
Am rft khi quan 0 ru, giam an Hat hoi, kho tho Chay nude mui Chay nuoc mit
Tieu chay phan loang, nhilu nuac Sung dau
Tan suat 64 64 51 43 20 12 06
Ty le {'/.
91,43 91,43 72,86 61,43 28,57 17,14 8,57
Bieu hien Iam sang xuat hien thuang xuyen nhat la li rii, giam an va dac biet c6 am rit khi quan khi tho voi ty Ie 91,43% so ga mo kham. Ngoai ra, ga benh con co nhiing trieu chirng khac nhu hat hai, kho tha va chay nuoc miii voi ty Ie Ian lugt la 72,86% va 61,43%. Doi khi ga benh co bilu hien chay nuoc mat (28,57%), tieu chay phan trang hoac trang xanh loang, nhieu nuac (17,14%,) va hiem khi sung diu (8,57%). Kit qua khao sat ciia Nguyin Thi Loan (2018) cho thiy 100% dan ga mic benh IB co hien tugng ho hip kho khan, chay nhieu dich miii va kem theo sung diu. Theo TrinNgpc Bich va ctv. (2018), IBV nhan Ien o mo
duong ho hap chinh ia nguyen nhan ciia cac bieu hien ga tha bon hen, ho, am rit khi quan va chay nuac miii.
Bieu hien lam sang se thay doi tuy theo tuli cua ga, kha nang gay benh ciia chimg virus va miic do mien dich. Tuy nhien, bieu hien benh phi biln nhat doi vai benh IB chinh la o duong ho hip. Hon nira, trieu chiing ban dau do nhilm chiing IBV thi than ciing co dau hieu ho hap du a mire dp nhe va sau do CO bieu hien dac trung la li rii, xu long, it di chuyen, tieu chay, uong nhieu nuac va giam can nhanh (Ignjatovic va Sapats, 2000).
A r^'i.^-,^' a r . ^ i f " ' ? " ^ ^ f ' " ^ " c/7t>ng /am s a n g o-ga mic benh IB
A:Ga kho tha; B: Gabj viem ket mac mat, mat uat. co bot; C: Ga tieu chay phan trinq hoac trang xanh, loang, nhieu nu^c ^ ^ ^ •
Ket qua khao sat benb tich dai thi 6 ga nhilm IBV dugc the Men o bang 3.
Benh tich xuit hien thuang xuyen nhit (90%) dugc ghi nhan !a toan bp khi quan xuit huylt dilm, CO dich nhay, due. Boroomand va ctv. (2012) da gay nhiem chung IRF1BV32 (thugc serotype
793/B) cho ga, day la chiing gilng serotype a Viet Nam da dugc V6 Thi Tra An va ctv. dinh danh nam 2012, ket qua sau 1 - 3 ngay cho thiy khi quan sung huyet, niem mac phii va xuylt huylt diem, than sung, nhat man. Nhimg benh tich khac trong khao sat nay cung xuit hien kha thuong xuyen la phoi sung huyet, xult huylt va viem kit
KHOA HQC KY THUAT THU Y TAP XXVII SO 1 - 2020
mac (81,43%), viem hii khi - due (74,29%), viem xoang miii (61,43%) cung nhu sung than (60%).
>aiung biln dli benh ly nay phan biet ro vcri hien ta^ng niSm mac d ca thanh quan va khi quan bi xuit huyet, xuit tiet chit mau trang vang (chat ba diu), CO lan cue mau dong trong long Ing din din tic nghen mpt phan hoac toan bg thanh quan va a khi quan, phoi hi sung huyet, dong dac, gan
hoa o benh ILT (Sivaseelan va ctv., 2014) ciing nhu phan biet vai hien tugng khi quan tilt dich co bgt tring, hii khi day, phii, tilt dich co fibrin, co bgt hrang hay chit ba dau, phli sung huylt, phu va ciing tich tu fibrin do CRT {Ornithohacterium rhinotracheale) gay ra (Rahimi va Banani, 2007;
Hauckva ctv., 2015).
Bang 3. Tan suat benh tich dai the if ga nhiem IBV (n=70)
Benh tich dai t h i Khi quan xult huyet diem, co Phoi sung huyet, xuat huylt Viem kit mac Viem tlii khi Viem xoang mui Th|n su'ng Nieu quan tich urate
djch nhay
Tan suat 63 57 57 52 43 42 4
90,00 81,43 81,43 74,29 61,43 60,00 18,57
Theo Mahgoub va ctv. (2010), benh IB the h6 hSp xay ra pho bien nhat. Benh tich IB a duang ho hap chiem ty le cao la do IBV xam nhap va phat trien trong cac te bao bieu mo ho hap, a day IBV da lam cac te bao nay thoai hoa va chet. IBV pha hoai thanh buySt quan Iam tang tiet dich thim xuat va tham nhiem cac te bao lympho vao cac xoang ho hap (Nguyen Thi Loan, 2018). Thinh thoang, chi 18,57% ga benh IB c6 hien tugng tich urate o nieu quan.
Dieu nay co the do mgt so ga nhiem chiing IBV the than. Cl nhiing con ga nhilm IBV thi than.
benh tich dai the gom than sumg, nhgt nhat, tich tu urate a ong than, nieu quan (Tran Ngoc Bich va ctv., 2018).
Nhin chung, nhiing con ga nhiem IBV trong khao sat nay co bieu hien Iam sang va benh tich dai thi chil yiu o ducmg ho hap. Cac chiing IBV CO sir da dang ve ai tinh mo (tissue tropisms) nhu chung M4I CO muc tieu la co quan ho hap, sinh san, chiing QX va 793B co ai tinh mo voi ca co quan ho hip, sinh san, tieu hoa va than (Tran Ngpc Bich va ctv., 2018).
Hinh 2. B§nh tfch dai the &ga mac benh IB
A: Xoang mui tich djch; B: Khi quan xuit huyit; C: Phoi sung huyet, xuit huyit; D: Than swng, nh^t m^u, CO diim xuat huyet
KHOA HOC KY THUAT THU Y TAP XXVII SO 1 - 2020
3.2. Ket q u a p h a n tich m o t so yeu t6 dich te c a b a n lien q u a n benh IB
3.2.1. Ket qua khdo sdt ty le chet do benh IB
N b i m danh gia miic dp thiet hai do benh IB gay ra, k i t qua khao sat t>' !e chit d u g c t h i hien 6 bang 4.
So dan (dan) 7
Bang 4. Ty le ga ch6t do benh IB
So ga khao sat (con) 85 ga chet (con) 80.200 11.976
Ty le chet (%) 14,93
Ket qua dugc trinh bay a bang 4 cho thay ty Ie ga chit do benh IB la 14,93% tinb tren toan dan. Dieu nay cho th^y benh IB c6 the gay ton that dang ke nen ciing can dugc chii tam kiera soat, phdng tri. Theo bao cao khao sat ciia Nguyen Thj Loan (2018), ty le ga huong tning duoi 17 tuin tuoi chet do benh IB la 7,52% trong ting s l gakhao sat (1.738/23.108 con), tinh rieng cho 4.060 con ga mac benb thi ga chet len din 42,81%. Theo Cavanagh va Gelb (2008), ty le chet 6 ga len den 30yo va tiiy thupc vao dpc Iuc cua vims, tuoi ga, tinh trang mien dich, stress lanh va nhiem khuan ke phat.
Thuc te trong khao sat nay, ty Ie chet do IB da
phan nao d u g c han cbe boi nguoi chan nuoi ^ sir dung thuoc dieu tri ngay khi phat hien benh nhu khang sinh phong bgi nhiem, vitamin tang siic de khang, thuoc long dom, dien giai, men tieu hoa, giai dpc gan than va dac biet la mpt so trai sir dung khang the khang virus (K.T.G).
3.2.2. Ket qud khdo sdt benh IB theo tinh trang cliung ngu'a vacxin chda virus serotype Mass vd 793B
Tinb hinb nhiem benh IB ciing c6 the chiu anh huong b a i cong tac chung ngira khong day dii quy trinh. Ket qua khao sat v e van de n a y dugc trinh bay o bang 5.
Bang 5. Ty le benh IB theo tinh trang chung ngira vacxin
Chung ngCFa vacxin So dan khao sat
(dan) So dan
benh (dan)
Tyle {%)
So ga khao So ga Ty le sat 6* dan chet chet benh (con) (con) (%) Chljng ngira 1 lln,
hoac 2 iSn voi ciing 1 serotype Chiing ngira 2 iSn voi 2 serotype khac nhau
Tinh chung
28.450
51.750 80.200
5.021 17,65
11.976 14,93
Qua ket qua bang 5 cho thay a nhung dan ga dugc chiing ngira khong day dii (ngira 1 lin/2 lin vcri Cling 1 serotype vacxin - Mass) thi ty le m i c benh IB (50%) cao gap 2 Ian so voi nhiing dan dugc chimg ngira day du (ngira 2 lan voi 2 serotype vacxin khac nhau - Mass va 793B (4/91)) mac dii sir khac biet khong CO y nghTa thong ke (P = 0,251). D6ng thai ty le chet ciia ga o nhung dan chimg ngira khong d i y dli ciing cao hon co y nghTa thong ke so vai nhom con Iai (17,65%i so vai 13,44%). Dieu nay cho thiy
yeu to phong ngira b i n g vacxm gop p h i n dang kl vao viec giam ty le m i c va chit do benh IB. ^gayh Thi Loan (2018) cung bao cao i i n g nhiing dan khong chiing ngira vacxin diy dii co kha nang m k benh IB cao ban kha nang khong m i c benh 1,59 i k (OR=i,59). Ngoai ra, viec chimg ngira d i y du Iam giam kha nang mac benh ciing duoc Vo Thi Tra An va Nguyen Tbi Kun Yen (2014) khing dinh'qua thu nghiem qm Uinh chung ngira vacxin IB H I 2 0 va tai Chung IB 4/91 hoac IB 88 cho hieu qua phong benb
KHOA HOC KY THUAT THU Y TAP XXVII SO 1 - 2020
cao han v6i sl dilm ho hip ciia ga giam ban 25 diem so vai dan ga chi chiing ngita 1 lin chimg H120. Nbu vay, kit qua nghien ciiu cua chiing toi hoan toan phii h9p vai cac nghien ciiu truac day
Tuy nhiSn, dilu cin luu y la o nhiing dim ga chiing ngita diy du da khong dugc bao hg hoan toan, dich benh vln xay ra (25%. mac benh). Theo bao cao ciia Mahgoub va ctv, (2010), mac du da dugc chimg ngira, benh IB Ihe ho hip xay ra 7/24 trang trai ga ihit a Ai Cap (29,16%). Nguyen nh^n co the do IBV CO nhieu serotype khong co mien dich cheo voi nhau (Roussan va ctv., 2008) nhu Mass (dong
H120), 793B (dong 4/91, CR88) va ga lay nhilm cac chimg khac vai chimg vacxin. Do do, mac dii viec chiing ngira vacxin diy du giiip han chi thiet hai do benh IB nhung chua dam bao dat miic bao hp hoan toan cho dan ga ma chiing toi thilt nghT nghien ciiu djch tg hgc phan ttr vl cac chimg IBV thuc dia la rit can thiet de co ke hoach su dung vacxin IB phii hgp vcri chung virus a thuc dia do.
3.2.3. Kit qud khdo sdt benh IB theo kiiu chudng chdn nuoi
Ket qua khao sat ty Ie benh IB theo kieu chuong chan nuoi dugc the hien qua bang 6.
Bang 6. Ty le benh IB theo kieu chuong chan nuoi
Kilu chuong So dan khao sat (dan) So dan benh (dan) Tyle(%) Chuong kin
Chuong ho'
40,00 30,00
Kit qua bang 6 cho thay dan ga nuoi theo huong cong nghiep o ca chuong kin va chuong ho deu co the nhiem benh IB voi ty le lan lugt la 40% va 30%., trong do ga a chuong kin co ty Ie benh cao hon 10% so vol ga dugc nuoi cr chuong ho, nhung su khac biet nay khong co y nghia thong ke (P=0,639).
Cling nghien ciru ve benh IB o ga dugc nuoi theo huang cong nghiep nhu chiing toi, tac gia Nguyen Thi Loan (2018) ciing da ket luan rang chan nuoi theo phucmg thiic cong nghiep chinh la mot yeu to lien quan den benh do mat dp chan nuoi cao va giira cac chuong cung chua co su each ly va thong khi tot, CO kha nang lam cho nguy co benh cao han 1,68 Ian (OR=I,68) so voi phuang thirc chan nuoi chan tha va ty Ie tmng bmh dan ga huong tning a nhom chan nuoi cong nghiep mic benh IB la 18,94%.
(43/227 dan). Tuy nhien, tac gia khong neu cu the v6 mat do nuoi ciing nhu kieu chuong nuoi.
Trong nghien cuu aia chimg toi, nguyen nhan
nhilm benh o chuong kin co the do mat dp nuoi cao (lO-U con/m^ doi vai ga long trang, I2-I5con/m^d6i voi ga long mau) nen chat thai nhieu, nhiet dp chuong nuoi cao (28-31"C), su thong thoang giam theo sir phat tnen cua ga dii chuong co quat thong gio dan den niem mac ho hip ga dl bi kich img, tao co hpi cho mam benh xam nhap. Hem niia, giua cac chuong kin o cung trai ciing khong co su each Iy giong nhu trong nghien ciiu cua Nguyin Thi Loan (2018) din din ga dl bi lay nhilm benh qua duong ho hip trong khi chuing ha co do thong thoang tit va mat do nuoi thua han (6-7 con/
m^). Ngugc lai, a chuong ho phu thugc vao anh sang tu nhien va gio miia, trong dilu kien mira tat, gio lua ma chuing ho khong dugc che chan can than de am uot thi duong ho hip ciia ga yeu di, din den sire de khang giam, tao dilu kien virus xam nhap gay benh.
3.2.4. Kit qud khdo sdt binh IB theo mua vu Kit qua khao sat ty le benh IB theo mua vu dugc the hien a bang 7.
Bang 7. Ty le dan ga benh IB theo mua vu
Mua kho(Thang 2-4) Miia mu-a (Thang 5-8)
So dan khao sat (dan) S6 dan benh (dan) Ty le (%) 27.27
KHOA HOC KY THUAT THU Y TAP XX\TI SO 1 - 2020
Qua ket qua bang 7 cho thay benh IB xuat hien quanh nam, o ca miia kho (ty le benh 27,27%) cho den mua mua (ty Ie benh 44,44%). Tuy nhien, ga dugc nuoi vao mua mua co ty Ie benh IB cao hon ga dugc nuoi vao miia kho 17,17%. Dieu kien thai tilt khi hau vao miia mua a day gan giong voi dieu kien miia dong d nhirng khu vuc khac va nhirng bao cao truac day cung da cho thay tinb hinh benb IB cao vao mua dong (Ignjatovic va Sapats, 2000) Nguyen Thi Loan (2018) bao cao rang ga hucmg tning dugc nuoi 6 mpt so tinb phia bac Viet N a m vao miia dong co ty Ie ga mac benh IB cao nhat so voi cac miia vu con Iai (20,5% so con khao sat).
D i l u nay do IBV c6 the ton tai rat lau a dieu kien
ngoai trai co nhiet dp t h i p , t i n tai den 12 ngay vao miia xuan va 56 ngay vao miia dong ( C a v a n a ^ va Gelb, 2008). 6 d i n g b i n g song C u u Long yao nhung ngay m u a , nhief dp khong k h i tai chuong nuoi giam con 22-26''C, i m dp cao tren 80%, tham chi len d i n 9 8 % lam siic d l khang c u a ga y i u di va c h u i n g trai i m uot ( o chuong ho), kem thong thoang ( a c h u i n g km) da tao dieu kien cho vuus phat triln manh va d l dang x a m nhap gay benh cho ga.
3.2.5. Kit qud khdo sdt binh IB theo lira tuoi Ket qua ty le ga nhiem benh I B theo Ilia tuoi dugc trinh bay a bang 8.
Bang 8. Ty le ga nhiem IB theo li>a tuoi
Tuan tuoi So dan khao sat (dan) So dan benh (dan) Ty le (%)
< 4 tuan 5 -7 tuSn
> 8 tuan
20,00*
71,43^
12,50"
Cdc so trong cimg mot cot CO mang chir mu khde nhau thi khac biet coy nghia thong ke, p<0,05
Qua ket qua bang 8, mpi Iiia tuoi ga deu man cam voi benh IB, lira tuoi bi nhiem IBV nhieu n h i t la 5-7 tuan (71,43%), ket qua nay phii hgp voi cong bo ciia Cavanagh va Gelb (2008), k l d i n la ga con cho den 4 tuan tuoi chiem ty le 20% va thap nhit la ga til 8 man moi trir Ien (12,50%). Mahgoub va ctv. (2010) ciing da bao cao ty Ie n h i l m benh IB tai cac ffang trai ga thit a Ai Cap dugc ghi nhan chii yeu sau 4 man feoi, cao nhat liic 5 - 6 tuin t u l i (37,5%). Sir khac biet giua ty Ie dan ga m i c benh IB a giai doan 5-7 tuin va ga n i 8 tu^n t u l i tro Ien CO y nghTa thong ke (P = 0,04) bai o ga lan ban thi he mien djch da dan hoan chinh nen kha nang d l khang a duong ho hap doi voi benh IB cao hon, ty le mac benh thap hon. Rieng ga con cho d i n 4 m i n tuoi, da so ga con khang the thu dgng tir me truyin bao ve va chuong trmh chiing ngira liic 1 ngay m i i a trai giup bao ho ga trong vong 3 man (Cavanagh, 2007) nen ty Ie benh cung thap, ga o lira moi nay nhiera benh IB co the do Iich chiing ngiia vacxin chua day du, chua nghiem ngat.
IV. KET LUAN VA DE NGHI Benh IB la mpt benh truyen tihiera pho bien va gay ton that dang ke tren dan ga thit tai Vinh Long va Soc Trang thuoc dong bang song Ciiu Long voi ty le dan ga duong tmh thong qua xet nghiem PCR la 3 5 % , ty le ch6t 14,93%. Trieu chiing va benh tich dai the chu yeu tap trung a dirong ho h i p gom am rit khi quan khi t h a vcri ty le 91,43%, hk hoi, kho tho (72,86%), chay nircrc miii (61,43%), toan bo khi quan xuSt huylt d i l m , co dich nhSy, due (90%), phoi sung huyet, xudt h u y l t va viem kit mac ( 8 1 4 3 % ) , viem tiii khi - due (74,29%), viem xoang miii (61,43%) v a stmg than (60%). B i i vcri cac y i u 16 nguy c o , ty lc d a n ga n h i l m B V
* nhom chi phong ngiia ! Uu duy n h i t hoac 2 lin voi cimg 1 chung virus vacxm (50%), ga 5-7 tuin tuoi (71,43%). Khong co su khac biet v l ty le dan ga nhiem IBV giiia cac kilu chudng nuoi ciing nhtr giua cac mua vu, nhung benh co xu h u o n g tang a nhom ga nuoi kieu chuong kin va vao m u a m m Do do, can tiep tue nghien =mi quy trinh phong benh va lua ebon loai vacxin p h i hop vM chimg
KHOA HOC K-? THUAT T H C Y TAP XXVII SO 1 - 2020
vims thyc dia dl phong benh IB cho ga thit nuoi theo hucmg cong nghiep.
Ldi cdm cm: Be tdi ndy duac tdi tra bdi Du an Ndng cdp Trudng Dgi hoc Cdn Tha VN14-P6 hang nguon von vay ODA tir chinh phu Nhat Bdn.
TAI LIEU THAM KHAO
1. Bich, T.N., Khanh, N.P. and Loan, N.T.C., 2018. Pathogenesis of infectious bronchitis vims (IBV) and laboratory test methods available to detect IBV in chickens. Can Tho University Journal of Science. 54(2): 40-45.
2. BoroomandZ.,Asasi K., MohammadiA., 2012.
Pathogenesis and Tissue Distribution of Avian hifectious Bronchitis Virus Isolate LRFIBV32 (793/B Serotype) in Experimentally Infected Broiler Chickens. Scientific World Journal.
3. Cavanagh, D., 2007. Coronavirus avian infectious bronchitis virus. Veterinary Research, BioMed Cenhral, 38 (2), pp.281-297.
4. Cavanagh, D., Gelb J.J., 2008. Chapter 4:
Infectious Bronchitis. In: Y. M. Saif (Editor in Chief). Diseases of Poultry, I2th Edition.
Blackwell Publishing. Pp 117-130.
5. Hauck R, Chm R.P, Shivaprasad H.L., 2015. Retrospective Study on the Isolation of Ornithohacterium rhinotracheale from Chickens and Turkeys in Central California:
294 cases (2000-12). Avian Z)/5.;59(I):130-7.
6. Ignjatovic, Sapats, 2000. Avian infectious bronchitis vims. Rev. sci. tech. Off. int. Epiz., 2000,19 (2), 493-508
7. Mahgoub, K.M., Bassiouni A.A.; Manal A.Afify and, Nagwa Rabie, S., 2010. The Prevalence of Infectious Bronchitis (IB) Outbreaks in Sorae Chicken Farms. I. Spotlight on the Stahis of IB Outbraks in Some Chicken Flocks. Joumal of American Science;6(9).
8. Rahuni, M., Banani, M., 2007. Isolation of
Omitbobacterium rhinotracheale from the chickens of a broiler farm in Kermanshah province, west of Iran. Iranian Journal of Veterinary Research, University of Shiraz, Vol.
8,No. 4, Ser.No. 21.
9. Roussan, D.A., W.S. Totanji, G.Y. Khawaldeb, 2008. Molecular subtype of infectious bronchitis virus in broiler flocks in Jordan.
Poultry science, 87: 661-664.
10. Sivaseelan, S., Rajan, T„ Malmarugan, S., Balasubramamam, G.A., Madheswaran, R., 2014. Tissue tropism and pathobiology of infectious laryngotracheitis vuus in natmal cases of chickens. Israel Journal of Veterinary Medicine. Vol. 69 (4).
11. Le Thi Kim XuyIn, Nguyin Thi Cim Loan, Trin Ngoc Bich, Doan Thi Thanh Huong, Le Thanh Hoa, 2019. Xac dinh phan nhom virus gay benh viem phe quan tmyen nhiem tren ga nam 2018 6 ding bing song Cim Long. Tap chi Khoa hoc Ky thuat thiiy. so 5:trang 5-13.
12.Nguyen Thi Loan, 2018. Ngbien ciiu dich te hpc benb viem phe quan truyen nhiera (infectious bronchitis - IB) a ga nuoi tai mgt so tinh phia bac Viet Nam. Luan an tien sT. Nhd xudt bdn Hoc vien nong nghiep.
13.V5 Thi Tra An, Nguyin Thi Kim Yin, H6 Hoang Dung, 2012. Phan lap, dinh serotype virus viem phe quan truyen nhiem hi ga thit.
Tap chi Khoa hoc Ky thugt Thiiy 19:5-9.
14. Vo Thi Tra An, Nguyin Thi Kim Yin, 2014.
So sanh hieu qua phong benh viem phe quan truyen nhilm cua ba quy trinh chimg ngira vacxin tren ga. Tgp chi Khoa hoc Ky thugt Thii y so 5: trang 21-25.
Ngay nhan 9-8-2019 Ngay pban bien 11-9-2019 Ngay dang 1-1-2020
