A Preliminary Field and Laboratory Investigation Report on Out Break of Sudden Death Syndrome in Broiler Chicken Above 6 Week Age in Kathmandu Valley

Background Field situation:

An unexpected Sudden Death of broiler of above 6 week striked in Kathmandu valley from mid July to yet. On field observation in Dharmasthali,Jitpurphedi,Krtipur,Indrayany,Thali,Danchhi,Mulpani,Brahmakhel area was investigated. On field investigation following condition was observed. Broilers those died of sudden death syndrome showed no specific premonitory abnormalities. Birds affected were usually broilers, appear healthy and are often above average flock body weight. Just before death birds appear normal and it is common to observe that these birds will be feeding, drinking or walking normally. Birds in flock appeared trmbling,ataxic,brooding posture,gasping,prostation, dead birds were found dead in poultry shade in different part of shade in all flock that were observed, Birds exhibit clinical signs such as extending their neck, squawk and start wing beating as well as leg extension before fall back on their back or lyining on breast or by there side.Generally all flocks were diagnosed  being affected by either CRD,Cocci, IBD and all flocks were found treated with drugs like Tylosin,Enroxin,Cholistin,Anticoccicidal drugs with liver tonic with miltivitamin Bcomplex.Most of the farmes were located in low marshy land and poultry house were constructed in rented land and were in temporary thatched in nature.Feed supply and birds were being supplied by common hatchery feed meal source and all birds were previously diagnosed for similar disease and similar treatment and preventive measure were advised. Death occurs within minutes. Birds in most of affected flock were observed havening leg deformity and difficulty in walking and standing.The condition was provisionally diagnosed as Sudden Death Syndrome probably due to involvement of systemic mycosis. Detail field and laboratory findings and suggestion is given below.

Table: 1. Epidemiology of Affected flock in Kathmandu Valley with sudden Death Syndrome in Month of August 2008:

Duration

no.of farm

Population at risk

Morbidity

(%)

Mortality

(%)

No. of samples examined

First week

22

16620

4250 (25.57%)

369

(2.22%)

44

Second week

14

15450

1235

(7.99%)

232

(1.50%)

28

Third  week

20

10260

848

(8.26%)

157

(1.53%)

40

Fourth week

30

15700

2380

(15.16%)

149

(0.94%)

60

Fifth week

13

16450

4750

(30%)

1650

(0.3%)

26

Sixth week

12

18850

4550

(25%)

876

(0.19%)

24

Total

111

93330

18013

(17.01%)

3436 (1.56%)

222

Postmortem finding of suspected  SDS birds:

Postmortem examination of birds that died of sudden death syndrome revealed showed no outstanding gross pathology. All birds were well fleshed, with muscle edema and general pulmonary congestion and edema. Feed was present along the entire digestive tract and the gall bladders of birds were distended usually filled with bile. The liver was pale to yellow enlarged molted appearance and kidneys were usually slightly congested and have patchy sub capsular hemorrhage. In most of the dead birds clotted blood was present in the atrium while ventricle was contracted .Usually, the proventriculus contains a milky fluid with hemorrhagic patches and intact food particles are present in gizzard. Crop in some bird was full with liquid intact food particles. Intestine was ballooning in appearance with thick mucous filled ingesta was present .Congestive spleenomegally was observed in almost all birds. Bursa was almost normal to atrophid.

Laboratory Finding of Mycobiota and Micro biota of Postmortem Tissue samples:

A total 222 tissue samples of lung, liver, spleen, proventriculus and gizzard, were collected during postmortem examination and were subjected for both bacterial and mycological culture. Results of microbiological examination done are given in Table 2.

Table: 2.

No. of samples

Bacterial isolated

Fungi isolated

Positive no

negative no

111

E.coli,

Streptococcus,

Staphylococcus

70

41

111

Aspergillus,

Penicillium,

Candida

80

31

222

150

72

Treatment and Preventive measure advised to the rest of birds in flock:

All birds remaining in flocks were subjected to restricted feed up to 8-10%, and feed to twice daily only. Supplementation with glucose containing electrolyte, liquid toxin binders, immunomodulater, and simple broad-spectrum antibiotics, acidifier, were provided in water. Antibiotics like tylosine, enroxin, cholistin, gentamycin, livertonic containing vitamin-B, anticoccicidal drugs and Vitamin B complex supplementation was totally withdrawn. All birds remaining in all affected farms responded well to the above management and there were marked improvement in the overall condition of the flock.

Discussion and Recommendations :

Sudden Death Syndrome (SDS) is an acute heart failure disease that affects mainly male fast growing chickens that seem to be in good condition. Although a common condition in fast growing birds, the pathogenesis remains unclear (Ononiwu et. al. 1979). Cardiac arrhythmias are involved in the pathogenesis of SDS with ventricular arrhythmias (VA) being the most common observation representing premature ventricular contractions and fibrillation (Olkowski and Classen, 1997; 1998). It has been reported that broilers fed with high vitamin D3 diet above the recommended levels in an attempt to prevent commonly occurring leg problems were 2.5 fold more likely to succumb to acute heart failure and die of SDS (Nain et. Al. 2007). SDS was also experimentally induced by feeding diets containing the

mycotoxin moniliformin that resulted to cardiac injury with subsequent alterations in cardiac electrical conductance (Reams et al, 1997) suggesting the possible role of chronic mycotoxicosis to the causation of SDS. Other implicated causes of SDS include continuous artificial lighting (Ononiwu et al, 1979b), deviations in dietary calcium and phosphorus (Scheideler et al, 1995),  feeding crumble-pellet diets (Proudfoot et al, 1982), dietary fat content (Rotter et al, 1985) and feeding frequency Bowes et al, 1988). The latter recommendation of restricted feeding supports well the previous observation that abdominal fat deposition increases the risk of SDS such those restrictions on calorie: protein ratio decreases the incidence of SDS (Mollison et al, 1984) The SDS seems to be worse when biotin is marginal and other Vitamin B are in excess. Among many drugs used in poultry the role of anticoccidial drugs perhaps have received more attention than other drugs. There is some evidence of higher SDS mortality when anticoccidial drugs are used. (Dr.H.A.Upendra.www.vetcareindia.com/halchal_Sudden death Syndrome.htm 2008)

.

The present investigation indicates that broilers in good body weight condition when not harvested timely and remain in poultry shade for prolonged periods suffer stressful events and even sudden death. Also, it is possible that the increased humidity and hot season favors the growth of mold and fungus in stored feeds increasing the risk of birds to mycotoxicosis. And laboratory finding of CVL revealed the presence of systemic fungus like Penicillium and Aspergillus in substantial no. of postmortems tissue samples and feed samples of all sources .This incidence of sudden death syndrome in birds in Kathmandu Valley was reported for the first time and needs to be investigated further for involvement of moldy feed in its occurrence in SDS and a suitable preventive measure need to be advised to the poultry sector.