P. Balachandran

Bacteriological and pathological studies of egg peritonitis in commercial layer chicken in Namakkal area

OBJECTIVE To detect the various bacteriological agents and pathological changes in commercial layer chicken affected with egg yolk peritonitis in Namakkal region of India. METHODS A total of 6 572 layer chicken from 85 commercial farms were subjected for the study, out of which 1 715 showed various types of oviduct abnormalities. Among the 1 715, 264 birds from six farms were identified as egg peritonitis on the basis of postmortem examination. Trachea, lung, heart blood, liver, peritoneal exudate, oviduct (infundibulum, magnum, uterus) and cloacal swabs were collected from the 264 birds with egg peritonitis lesion for screening of bacterial agents. Signalment, clinical signs and pathological changes were recorded in the affected flocks. RESULTS The results of the present investigation indicated that the E. coli associated egg peritonitis was responsible for 15.39% of the reproductive tract abnormalities in commercial layers between 21 and 80 week of age. In the affected flocks egg production drop and mortality varied from 3% to 20% and 0.5% to 7.0% respectively. It was noticed during peak egg production (21 to 60 week) and southwest monsoon season (58%). Statistical analysis of age, season and egg production by Chi square test of independence revealed highly significant difference. E. coli was isolated as a pure culture and concurrent with other bacterial agents in 226 and 38 birds respectively. Among the fifteen E. coli serotypes identified serotype O166, O64 and O111 were predominant. Necropsy examination of affected birds revealed the presence of amorphous or insipissiated yolk material in the abdominal cavity with inflammatory changes in the ovary, oviduct and intestine. Microscopically the oviduct surface epithelium showed degeneration and desquamation, moderate to marked infiltration of inflammatory cells especially heterophils and lymphocytes in various regions and lumen contained serofibrinous exudate, inflammatory and desquamated epithelial cells with bacterial microcolonies. Ovarian follicles revealed hyperemia, degeneration of granulosa cells and infiltration of inflammatory cells. Intestine showed degenerative, necrotic and inflammatory lesion. CONCLUSION The findings of this study showed that the egg peritonitis might be caused by either the translocation of intestinal E. coli into the peritoneal cavity or by the movement of cloacal E. coli into the oviduct followed by ascension of these bacteria up the oviduct, through the infundibulum, and into the peritoneal cavity. To control the egg peritonitis faecal contamination with E. coli should be minimized.

Pathomorphological studies of polyserositis in commercial caged layer chicken

OBJECTIVE To detect etiological agents and pathological changes associated with polyserositis in commercial layer chicken. METHODS Ten commercial layer flocks which had a sudden increase in mortality and a drop in egg production with lesions suggestive of colisepticemia were investigated. Flock details and pathological changes were recorded in affected flocks to assess the prevalence and impact of polyserositis on commercial layer chicken. Trachea, heart blood, liver, oviduct, cloacal swab, poultry house environment samples, water and feed samples were screened for bacteriological agents. Pooled tissue (trachea, lung, spleen, caecal tonsil, kidney and oviduct) samples from colisepticemia cases were screened for viral agents. Serum samples collected from affected flocks were screened for Newcastle disease virus, infectious bronchitis virus and egg drop syndrome-76 virus by haemagglutination inhibition test, and for Mycoplasma gallisepticum and Mycoplasma synoviae by enzyme linked immunosorbent assay. RESULTS On necropsy examination of dead birds, fibrinous polyserositis and congestion of various visceral organs were noticed. Microscopically, deciliation and hypertrophy of mucus glands showed in the tracheal epithelium. Vascular derangements and infiltration of inflammatory cells showed in the lungs and air sac. Fibrinous polyserositis, focal necrosis and infiltration of inflammatory cells showed in parenchyma of heart and liver. Inflammatory changes were observed in the ovary and oviduct. Escherichia coli (E. coli) was isolated as a pure culture from 108 birds and from the poultry house environment of the ten affected flocks. Among the eight E. coli serotypes, identified serotypes O78 and O111 were predominant. In colisepticemia affected flocks egg production drop and mortality varied from 3%-10% and 2%-5%, respectively and occured during the peak egg production (21 to 40 weeks) and southwest monsoon season (June to September). CONCLUSIONS The present study revealed that the colisepticemia inducing E. coli isolates were derived from the layer house environment. Hence, the incidences of colisepticemia can be minimized by effectively reducing the bacterial load in the layer house environment through appropriate biosecurity measures.

Metastatic malignant melanoma in dog - A case report

A three year old male Labrador dog was presented with history of anorexia, dyspepsia, respiratory distress and weakness. On physical examination, the dog showed small round lumps on the skin. Ultrasonography examination of heart, lung, liver and kidney depicted multifocal abnormal tissue. Multifocal neoplastic growths in different organs were tentatively diagnosed and the dog was symptomatically treated until death. On postmortem examination, multiple dark black masses varying from 0.5 to 3 cm in diameter were detected in heart, lung, liver, kidney, bladder and intestine. Histopathologically, these masses were diagnosed as malignant melanoma and variable melanin pigments within the neoplastic cells were confirmed by Fontana-silver method of staining technique. These tumors were considered to have originated from the primary site of skin or intestine.

Spontaneous Occurrence of Oviduct Infundibular Adenocarcinoma in a Layer Chicken

The present communication reports a spontaneous case of non-viral, metastatic infundibular adenocarcinoma in a 74 week old commercial layer chicken. On necropsy examination, mesentery, serosal surface of intestine and pancreas were studded with 5 mm grayish white nodules. Fimbrial region of oviduct contained varying sizes of multiple single to lobulated grayish white nodules. Serosal surface of tubular neck region showed tiny pearl-like nodules and the mucosal surface was diffusely thickened. Microscopically, cuboidal neoplastic cells were arranged in acinar and tubular pattern in the serosal layer of infundibulum. The cells appeared as variable sized cuboidal cells with indistinct cell borders, eosinophilic granular cytoplasm, round nuclei, indistinct nucleoli and fine chromatin granules. Transcoelomic nodules showed neoplastic cells and structures similar to those of the oviductaltumor.

An outbreak of pulmonary aspergillosis in emu (Dromaius novaehollandiae) chicks

Pulmonary aspergillosis in 5 week old emu chicks with 60 and 53.33 per cent of morbidity and mortality was reported. On gross examination, numerous small greyish yellow nodules were seen on the lungs and air sacs. Microscopically a granulomatous inflammatory reaction associated with fungal hyphae was observed in lung parenchyma and air sacs. The gross and microscopic lesions, in combination with the mycological identification provided the diagnosis of pulmonary aspergillosis due to A. fumigatus. Contaminated litter was identified as a source of infection. The disease was controlled by removal of primary source of infection and treating the affected birds with copper sulphate through drinking water.

Pathomorphological changes of oviduct in spontaneous cases of Newcastle disease in layer chicken

Newcastle disease is a major constrain to commercial layer production in India due to high mortality and egg production loss. The disease was found to be one of the predominant cause affecting oviduct with an overall prevalence rate of 27.23% and commonly noticed in the age group of 21 to 50 weeks during the summer season. In the affected flocks drop in egg production, morbidity and mortality were in the range of 5 to 40, 2 to 35 and 0.5 to 15%, respectively. Grossly, in acute death, the visceral organs revealed marked congestion and petechial haemorrhages on the proventricular papillae. Oviduct was congested and the uterus contained partially or fully formed eggs. Cyanosis of comb, congested tracheal mucosa with catarrhal exudate, petechial haemorrhages on the proventricular papillae and caecal tonsils were noticed in chronic cases. The ovarian follicles were misshapened, congested, haemorrhagic and ruptured with yolk materials in the abdominal cavity. Mild to moderate reduction in the size of the oviduct, congestion of the serosal vessels and pale and dry less prominent mucosal folds were observed. Microscopically, in birds died of acute disease, the oviduct showed congestion, edema and haemorrhages, and necrotic changes in the surface epithelia and glandular epithelial cells resulting in desquamation and accumulation of cellular debris in the lumen. In chronic cases, along with the above changes, focal to scattered lymphocytic and plasmacytic infiltration in the interstitium was noticed throughout the oviduct, however more pronounced in the magnum and uterus region. In immunoperoxidase test, NDV antigen appeared as moderate to dark golden brown fine granular material in the cytoplasm of surface epithelium, tubular glands and adjoining to the damaged epithelial cells.