Isolation of Escherichia coli from cellulitis and other lesions of the same bird in broilers at slaughter

Cellulitis results in substantial losses to the broiler industry due to condemnations at slaughter. This study was conducted to clarify the association between Escherichia coli isolated from cellulitis and other lesions caused by E. coli in individual birds. Fourteen flocks were sampled and 118 birds with cellulitis were examined. Escherichia coli was isolated from all but 2 of the cellulitis lesions, and serogroups O78, O1, and O2 predominated. Thirty-six birds had at least 1 other lesion in addition to the cellulitis lesion. Isolation of E. coli from cellulitis and other lesions occurred in 7 of the 14 flocks. Escherichia coli of the same serogroup were isolated from cellulitis and other lesions in some birds, suggesting that a single E. coli may sometimes be responsible for both types of lesions.

A study of electrocardiographic patterns in a population of commercial broiler chickens

A study was completed to characterize the electrocardiographic (ECG) patterns of male broiler chickens. Data were collected from 300 commercial broilers. ECG readings were collected from all birds between 12 and 15 days of age and then twice more at 10-day intervals. The measurements. included heart rate and rhythm, QRS complex duration, amplitude and mean electrical axis (MEA), incidence of ascites and incidence of sudden death syndrome (SDS). Eight birds died from SDS and 4 birds died from ascites. Twelve birds were condemned for ascites at the processing plant. The overall population heart rate declined with age. Birds that died of SDS had a higher heart rate, whereas those that developed ascites had a lower heart rate than the remainder of the population. The normal MEA was found to be between 0 degree and 180 degrees. On average 30% of birds showed left or right QRS axis deviation, and this pattern was observed in 14 of the 16 birds that developed ascites. Several types of cardiac arrhythmias were observed, the most common being premature ventricular contractions (PVC). The incidence of PVC increased with age, ranging from 1% at 12-15 days of age to 8.9% at 32-35 days of age. QRS axis deviation was present in 5 SDS birds. It is concluded that some 30% of the broiler flock tested was at risk of developing heart failure or heart-related disease.

Experimental reproduction of Escherichia coli cellulitis and septicemia in broiler chickens

Experimental reproduction of avian cellulitis was conducted by subcutaneous inoculation of 25-day-old broiler chickens with a field isolate of serogroup O78 Escherichia coli. Development of the cellulitis lesion occurred as early as 24 h post-infection. Reproduction of cellulitis occurred in 98% of inoculated birds, and E. coli was isolated from > 75% of cellulitis lesions. In addition to cellulitis, other lesions, including pericarditis, airsacculitis, osteomyelitis, arthritis, and perihepatitis, occurred in > 80% of birds inoculated with E. coli. Bacteremia occurred as early as 6 h post-infection and dramatically declined by 5 days post-infection. Seventeen of 59 (29%) birds inoculated with E. coli developed a fatal infection between 1 and 6 days post-infection, and bacteria were isolated from lesions in 98% birds. In contrast, E. coli was not isolated from lesions in birds that survived until days 7-14 post-infection. Birds that survived with cellulitis and other lesions until day 14 post-infection had a significantly lower body weight compared with the control group. This avian model of cellulitis and other lesions will be useful for studying the development of vaccination strategies for E. coli in broilers.

Escherichia coli cellulitis in broiler chickens: clonal relationships among strains and analysis of virulence-associated factors of isolates from diseased birds

Thirty-nine Escherichia coli isolates from broiler chickens with cellulitis were serotyped and analyzed for clonal relationships by multilocus enzyme electrophoresis. The isolates were further characterized with respect to hemagglutination (HA); serum resistance; antibiotic susceptibility; production of aerobactin, colicin V, and hemolysin; expression of K1 or K5 capsule; sensitivity to cloacin DF13 after treatment with diphenylamine; expression of iron-regulated outer membrane proteins; and virulence in 1-day-old chickens. In addition, the isolates were examined for the presence of DNA sequences related to F1A (fim) and P (pap) fimbriae, aerobactin synthesis (iuc) and transport (iut), hemolysin operon hly, and TraT lipoprotein-induced serum resistance (traT). Only 38.4% of the isolates were typeable with standard O antisera, and of these, serogroups O25 and O78 were the most frequently observed. Multilocus enzyme electrophoresis, based on 20 enzymes, resolved 17 electrophoretic types, forming seven clusters. Isolates from four of these clusters fell into E. coli clone complexes that have been previously reported to be commonly associated with avian colibacillosis. All isolates expressed two to five iron-regulated outer membrane proteins, were resistant to serum and cloacin DF13, and possessed DNA sequences homologous to fim and iuc/iut. Most isolates (72%) were positive for traT, and a majority produced colicin V and aerobactin (92 and 82%, respectively). Assays for the presence of fim and pap DNA sequences, for HA, and for virulence gave variable results but suggest that cellulitis isolates may express F1A and/or other mannose-resistant HA fimbriae different from P and may be virulent in 1-day-old chickens. Our results support the hypothesis that cellulitis in broilers in many cases is caused by E. coli clones identical to other pathogenic avian E. coli strains. Certain clones may be specific to cellulitis, because 25% of the isolates tested belong to clusters not related to known clone complexes.

Live performance and health of broiler chickens fed diets diluted with whole or crumbled wheat

Broiler chicken diets were diluted with three levels of whole wheat and two levels of crumbled wheat to determine how feeding whole grain and diluting feed with wheat would alter the performance of male and female broilers. Grit was not used. The amount of extra wheat added increased from 5% at 11 d of age to a maximum level of 30% at 31 d of age. Body weight at 41 d of age averaged 2.130 kg for pullets and 2.422 kg for cockerels and was unaffected by diluting with wheat, in whole or crumbled form. Total mortality and cause of mortality were similarly unaffected by dilution and form of wheat. The feed:gain ratio from 11 to 41 d of age was increased significantly for cockerels from 1.75 at zero dilution to 1.84 at maximum dilution. Dilution did not affect the feed conversion of pullets and form did not influence the feed conversion of either sex. Dilution of broiler rations may be profitable because of the limited effect on bird performance. Pelleting all the wheat in poultry rations is unnecessary because bird performance is unaffected by feeding up to 30% whole grain in the finisher diets. Key words: Broiler chickens, whole wheat, pelleting

Esophagitis due to a herpesvirus associated with mortality in a psittacine aviary

In a disease outbreak at a psittacine aviary, eight Pionus sp. and Amazon parrots became sick. Three of four Amazon parrots died with severe esophagitis, and epithelial intranuclear inclusion bodies containing herpesvirus were prominent. Focal liver necrosis with rare hepatocyte intranuclear inclusion bodies were found in two of the dead Amazon parrots.

The approximate inverse and conjugate gradient: non-symmetrical algorithms for fast attenuation correction in SPECT

Hybrid methods have been known for a long time as very efficient algorithms for attenuation correction in single-photon emission computed tomography, but only recently have efforts been made to formulate them with more rigorous mathematics. This has allowed us to explain their efficiency in terms of approximate inversion, and to establish a convergence condition. The present study focuses on the convergence problem and emphasizes the question of symmetry. Hybrid method operators are not symmetrical; therefore the convergence condition is not easily verified. New schemes based on a modified conjugate gradient method are presented. Convergence is proved and performances are shown to be at least as good as the standard hybrid schemes on perfect and noisy simulated data.

Effect of infection with hemorrhagic enteritis virus on susceptibility of turkeys to Escherichia coli

The present study was designed to investigate hemorrhagic enteritis virus (HEV) as a predisposing factor influencing the susceptibility of young turkeys to Escherichia coli infections. In addition, the pathologic changes caused by administration of E. coli by various routes were compared. Following oral infection with HEV, groups of turkeys were inoculated with various doses of pathogenic E. coli by intravenous (IV), intra-air sac (IA), or intratracheal (IT) routes. A synergistic effect was observed in birds that were exposed to a combined HEV-E. coli challenge, resulting in higher mortality than that caused by either pathogen alone. This synergy was more evident when the bacteria were administered by the IT route than when it was administered by the two other routes. Turkeys infected with HEV and then inoculated IT with E. coli O78 had higher mortality (61%) and higher occurrence of gross body lesions (74%) than birds given E. coli alone (0% mortality and 16% gross lesions). After E. coli inoculation by the IA and IT routes, lesions observed were mainly pericarditis, perihepatitis, lung and air-sac lesions, splenic enlargement, and occasional arthritis. The incidence of lesions was affected by HEV exposure. In contrast, IV inoculation with E. coli O78 usually resulted in arthritis, and its incidence was independent of previous HEV exposure. The synergistic effect between HEV and E. coli administered IT can be used as a challenge model for testing E. coli vaccines.

Effect of lighting treatment on the productivity, health, behavior and sexual maturity of heavy male turkeys

1. Turkey poults (1620) were used to compare the effects of three lighting programmes on heavy strain males reared to 188 d: constant light (24L:0D, CON); increasing light (6L:18D at 7 d gradually increasing to 20L:4D by 63 d, INC); a pattern identical to INC followed by a decrease in daylength from 84 d to 10L:14D at 112 d (DID). 2. Lighting affected growth pattern but had no effect on body weight at 118 d or overall food to gain ratio. 3. Both INC and DID lighting reduced overall mortality in comparison to CON light primarily because of a reduction in the incidence of skeletal disease and spontaneous cardiomyopathy. INC and DID lighting increased the incidence of cannibalism. 4. Turkeys given INC or DID lighting had a superior ability to walk in comparison to those birds given CON light. 5. INC and DID males stood, ate and drank more frequently, and sat less often than CON turkeys during behavioural observation. 6. There were no lighting effects on carcase composition except that INC and DID birds had heavier keel bones. The ultimate force per cm2 (stress) required to break femora was greater for turkeys given INC and DID lighting (P = 0.065). 7. Plasma testosterone concentrations at 117 d were 272.5, 115.2 and 29.5 pg/ml for turkeys given CON, INC and DID lighting, respectively (P = 0.072). Testosterone concentration was not related to growth rate.

A retrospective study of circovirus infection in pigeons: nine cases (1986-1993)

Circovirus infections were diagnosed in 12 pigeons from the United States 4 pigeons from Australia, and 1 pigeon from Canada (1986-1993). Circovirus was identified by electron microscopic examination of basophilic botryoid cytoplasmic inclusions that had a histologic appearance similar to that of psittacine beak and feather disease virus inclusions. Inclusions were seen in splenic, bursal, gut-associated, and bronchus-associated lymphoid tissue macrophages and in bursal epithelial cells. Inclusions were composed of paracrystalline arrays of tightly packed, nonenveloped icosahedral virions 14-17 nm in diameter. Histologic changes in the spleens ranged from lymphofollicular hyperplasia with mild discrete lymphocellular necrosis to lymphoid depletion and diffuse histiocytosis. Lesions in the bursa of Fabricius ranged from mild lymphocellular necrosis to severe cystic bursal atrophy. Remaining histologic findings coincided with concurrent bacterial, viral, fungal, and parasitic infections. Immunoperoxidase staining and DNA in situ hybridization demonstrated that pigeon circovirus is distinct from psittacine beak and feather disease virus; however both viruses apparently share some homologous DNA sequences. Clinical and diagnostic findings indicate that pigeon circovirus may be similar to psittacine beak and feather disease virus with respect to acquired immunodeficiency and subsequent multiple secondary infections.

Correction of attenuation in SPECT with an attenuation coefficient map: a new method

Attenuation coefficient (mu) maps, measured from transmission scan, are now becoming available. A simple method of attenuation correction is needed for routine implementation, however. Significant attenuation compensation can be mathematically obtained by dividing each actual pixel value of emission projections by the average of all the attenuation factors [exp (-sigma mu)] of all voxels along the same projection ray. This simple method, compatible with filtered back projection algorithms, was tested on simulations of cardiac and cerebral transaxial images on a Vax computer using the RECLBL library. In the models, the different structures received different activity and mu values. Three types of emission projections were generated: the ideal projections obtained by summation of the activity along each projection ray, the corresponding attenuated projections, and the projections corrected for attenuation. Comparison of projections on a pixel by pixel basis showed differences of less than 20% between the corrected and ideal projections. After reconstruction, both absolute and relative quantification were greatly improved by the correction of attenuation. Further validation of the method is in progress with actual patient data.

The influence of diet on necrotic enteritis in broiler chickens

Necrotic enteritis was reproduced in broiler chickens by mixing cultures of Clostridium perfringens in the feed. Mortality due to necrotic enteritis was higher among chickens fed rations based on wheat, rye, barley, and oat groats than among chickens fed corn-based rations. Addition of pentosanase to a wheat-based diet did not affect the level of mortality due to necrotic enteritis. Addition of pectin and guar gum to different rations severely reduced growth rate and eliminated necrotic enteritis from test birds. Addition of glucose to a corn-based diet caused a small increase in mortality due to necrotic enteritis.

Effects of increasing photoperiod length and anticoccidials on performance and health of roaster chickens

Male broiler chickens were raised to 63 days of age under different lighting and anticoccidial treatments. A constant-light program was compared with two interrupted and increasing-light programs in which the photoperiod length was 6 hours between 7 and 14 days of age and then increased gradually to continual light by 49 days of age in the first program and more gradually to 18 hours by 49 days of age in the second program. By 63 days of age, the increasing-light programs significantly increased body-weight gain and decreased feed/grain ratio, but not significantly. The increasing-light programs reduced the incidence of skeletal disease from 7.56% to 2.88% in the first program and to 3.53% in the second program, reduced the incidence of acute death syndrome from 5.94% to 3.37% in the first program and to 4.65% in the second program, and reduced total mortality from 18.81% to 11.71% in the first program and to 11.38% in the second program. The lighting programs had no effect on the incidence of ascites and right heart failure, the ratio of right ventricular weight to total ventricular weight, the incidence of clinical and subclinical tibial dyschondroplasia, and the number of cartilaginous and osseous nodules in the lungs. The anticoccidials compared were monensin and amprolium/ethopabate, from 0 to 35 days of age. These treatments had no significant direct effects on any of the parameters measured.

Viral tracheitis in goslings in Saskatchewan

Up to 12% mortality occurred in goslings between 4 and 11 days of age in two sequential hatches from a single breeder flock. Respiratory signs were noted before the birds died. The most consistent necropsy finding was a white opaque plug of fibrin and cellular debris in the trachea. The tracheal epithelium was hyperplastic and metaplastic with intranuclear inclusion bodies present in superficial cells. An adenovirus was isolated in both chicken and goose embryo liver cells.

Inflammation of the nasal gland in domestic turkeys

A prominent swelling above the eye of range-reared tom turkeys was found to be due to severe inflammation and hyperplasia of the nasal or salt gland. The incidence of affected turkeys was sporadic, and no mortality or other lesions were associated with the condition.

Effects of increasing photoperiod length on performance and health of broiler chickens

1. Broiler performance and health were compared from 0 to 42 d for lighting programmes consisting of near-continuous light 23L:1D (23L), a lighting programme where photoperiod gradually increased from 6 to 23 h between days 4 and 35 (INC) or an increasing-lighting programme with 1 h of light mid-way through the scotophase (INC + 1). 2. The increasing lighting programmes reduced growth rate and increased gain:food ratio from 0 to 21 d; INC + 1 growth rate was intermediate to the 23 L and INC treatments. From 0 to 42 d there were no differences in growth rate or gain:food ratio among lighting treatments. Males grew faster, ate more food and converted food more efficiently than females. 3. The increasing-lighting programmes (INC and INC + 1) resulted in less skeletal disease than the 23L control. The incidence of sudden death syndrome (SDS) and mortality other than SDS were numerically lower for the increasing lighting treatments. More males died as a result of SDS and were affected by skeletal defects than females. 4. In terms of health, increasing lighting programmes were superior to near-continuous light for broiler chickens.

A study of hepatic lesions in broiler chickens at processing plants in Saskatchewan

A detailed descriptive study was done on broiler chickens with abnormal livers found at processing. Two syndromes were evident: those birds with enlarged, pale, firm livers, designated hepatosis, with Clostridium perfringens type A often isolated; and ascitic birds with cobblestone-appearing livers. Livers with hepatosis had marked proliferation of bile ducts; ascitic livers had normal architecture. Hearts from birds with ascites had elevated right ventricular/total ventricular weight ratios, whereas hearts from normal birds and birds with hepatosis did not. Two isolates of C. perfringens produced necrotic enteritis in experimental birds; an attempt to reproduce hepatosis with these isolates was unsuccessful.