In vivo mechanical and in vitro electromagnetic side-effects of a ruminal transponder in cattle.

This work was undertaken to assess the long-term impacts of a ruminal transponder, used for electronic identification, on ruminal motility and on health and performance of cattle, as well as to study the electromagnetic effects on ruminal bacteria in vitro. A passive transponder (51.4 g, 67 x 17 mm) was delivered into the forestomachs of 8 calves, 32 bulls, 10 heifers, and 40 dairy cows. Final readability was 87.5% in calves, 96.9% in bulls, 90% in heifers, and 100% in cows at 481, 360, 650, and 601 d, respectively, after transponder administration. The transponder did not affect production or reproduction of cows over a 2-yr period, or performance of bulls, or mortality compared with control animals. Chewing movements per bolus were lower (P <0.01) in treated animals than in controls (49.6 vs. 52.2, 51.2 vs. 63.6, and 57.0 vs. 59.7 for bulls, heifers, and cows, respectively). Regurgitation frequency (number of boluses/10 min) tended to be greater in treated cattle: 12.4 vs. 11.3 (P = 0.07), 11.3 vs. 10.6, and 11.3 vs. 10.7 (P = 0.08) for bulls, heifers, and cows, respectively. Rumination patterns of calves fitted with transponders within the first weeks of life were similar to controls. During the experiment, 43 treated animals (8 calves, 29 bulls, and 6 cows) were slaughtered. Thirty transponders were localized in the reticulum (3 calves, 24 bulls, and 3 cows), 11 in the rumen (4 calves, 4 bulls, and 3 cows), and 2 were not recovered (1 calf and 1 bull). Within the calves, 57% of the boluses were found in the rumen. In 8 reticula (2 calves and 6 bulls) and 1 rumen (1 cow), an impression left by physical contact of the transponder was observed, although histological examination did not reveal specific lesions in the mucosa of the dystrophic areas. In strained, whole ruminal contents incubated in vitro, pH values were lower after 24 and 48 h (P <0.001) of continuous exposure to an electromagnetic field induced by the transponder-reading system. After 48 h of incubation, total bacterial numbers and NH3-N concentration were greater (P <0.001) in exposed flasks than in controls. These data indicate that the transponder may alter, via mechanical action, the reticuloruminal mucosa and rumination patterns. Furthermore, the transponder may increase, via its electromagnetic action, the growth rate and metabolic activity of ruminal bacteria.

Development of a polymerase chain reaction-based in vivo method in the diagnosis of subclinical pigeon circovirus infection.

This paper describes a polymerase chain reaction (PCR)-based method performed on blood samples and intestinal content to detect subclinical pigeon circovirus (PiCV) infection in live pigeons. In addition, two sets of primers (primer set 1 and 2), designed in two different regions of the viral genome, were used to provide evidence of possible differences in PCR responses. Blood and intestinal content samples were randomly collected from a total of 50 apparently healthy meat pigeons, aged 1 to 5 wk, which came from central Italy. Samples of primary lymphoid organs were also collected. Results showed a high level of PiCV infection, although clinical signs were not present. The results obtained with the two sets of primers showed that primer set 2 was able to detect a higher number of PCR-positive pigeons (45 of 50 pigeons) than primer set 1 (11 of 50 pigeons). In both cases an increase in positive results with pigeon age indicates that the major direction of transmission is likely horizontal. In these circumstances feces can play an important epidemiologic role, as supported by the consistent circovirus detection in intestinal content. The high sensitivity of this PCR test, which is able to detect very low amounts of viral DNA (5.5 x 10(-3) fg of plasmid containing the cloned PiCV genome), makes it suitable for possible application as an epidemiologic tool for identifying virus carriers for subsequent removal from lofts.

Atrophy of the primary lymphoid organs of meat pigeons in Italy associated with circoviruslike particles in the bursa of Fabricius.

During a survey effected in a meat pigeon slaughterhouse of central Italy, atrophy of primary lymphoid organs (bursa of Fabricius and thymus) and hypoplasia of bone marrow were observed. Histologic, ultrastructural, and hematologic examinations were performed on a total of 80 randomly selected 30-day-old meat pigeons. By histologic studies, lymphocytic depletion and necrosis with cyst formations in the bursa of Fabricius were detected in all subjects that showed thymus and bursa atrophy at necropsy. Basophilic intranuclear inclusions were also observed in bursal cells. After ultrastructural studies, these inclusions were proved to be viral particles resembling circoviruslike particles in morphology and size. Severe lymphocytic depletion of the bursa was plausibly associated with the presence of the viral particles.

Monoclonal antibodies PG-B6a and PG-B6p recognize, respectively, a highly conserved and a formol-resistant epitope on the human BCL-6 protein amino-terminal region.

The human BCL-6 gene, which is rearranged in approximately 30% of diffuse large B cell lymphomas, encodes a 706-amino-acid nuclear protein of the Kruppel-type zinc finger transcription factors mainly expressed in normal germinal center B cells and related lymphomas. Four monoclonal antibodies (PG-B6, PG-B6a, PG-B6p, and PG-B6m), specifically directed against the human BCL-6 protein, were generated by immunizing BALB/c mice with a recombinant protein corresponding to the BCL-6 amino-terminal region (amino acids 3 to 484). The PG-B6 monoclonal antibody reacted with a BCL-6 epitope sensitive to fixatives and preserved in all mammalian species. PG-B6a (a is for avian) recognized the most evolutionarily conserved BCL-6 epitope (expressed in all animal species including avian). PG-B6p (p is for paraffin) recognized a fixative-resistant epitope of BCL-6 that was detectable on paraffin sections after microwave heating in 1 mmol/L EDTA buffer. PG-B6m (m is for mantle) was the least specific monoclonal antibody as, in addition to BCL-6, it reacted with a yet undefined antigen selectively located in the cytoplasm of mantle and marginal zone B cells. All monoclonal antibodies detected strong nuclear expression of BCL-6 in follicular lymphomas, diffuse large B cell lymphomas, Burkitt's lymphomas, and nodular, lymphocyte-predominance Hodgkin's disease. In diffuse large B cell lymphomas, BCL-6 expression was independent of BCL-6 gene rearrangements and did not correlate with expression of other markers or the proliferation index. BCL-6 was not expressed in B-CLL, hairy cell leukemia, mantle-cell- and marginal-zone-derived lymphomas. Labeling of paraffin sections with PG-B6p proved useful for differentiating proliferation centers in B-CLL (BCl-2+/BCL-6-) from trapped germinal centers in mantle cell lymphomas (BCL-2-/BCL-6+) and for identifying neoplastic cells in cases of nodular, lymphocyte-predominance Hodgkin's disease. Because of their high specificity, wide reactivity in humans and animal species including avians (PG-B6a), and suitability for labeling routine paraffin sections (PG-B6p), the reagents described in this paper should prove valuable in both research and diagnostics.

Isolation and characterization of an adenovirus associated with inclusion body hepatitis in psittacine birds.

An outbreak is reported of inclusion body hepatitis in psittacines from a private aviary, in which several birds aged between 35 and 75 days had died without showing any clinical signs. Histological examination of the livers revealed severe hepatic damage with presence of large basophilic intranuclear inclusion bodies. Avian adenoviruses were isolated from the affected livers. Characterization of the isolates by means of restriction endonuclease analysis showed that they were similar to reference strain SR49 (serotype 3) which is associated with inclusion body hepatitis in chickens. This finding was confirmed by the virus neutralization test.

Naturally occurring nephroblastomas in light meat broilers.

Twenty-seven cases of nephroblastoma were observed in 54 culled light meat broilers during a 1-year period. The tumours were generally unilateral and varied in size. Metastases were not observed. Histopathological studies showed epithelial and mesenchymal structures at different stages of development. Ultramicroscopy and immunohistochemistry findings revealed viral particles in intercellular spaces and in the lumen of the tubules not morphologically unlike avian leukosis/sarcoma viruses.

Vitamin E as adjuvant in emulsified vaccine for chicks.

Mineral oil was partially replaced with D, L-alpha-tocopheryl acetate (vitamin E) in bacterial and viral inactivated emulsified vaccines. Vitamin E increased the immune response to the viral antigen (Newcastle disease virus) used but not to the bacterial antigen (Escherichia coli) when its presence in the oil phase did not exceed 30%. Inoculated vitamin E may have enhanced the immune response by interacting with the immune-competent cells involved in the inflammatory reaction that followed inoculation of emulsified vaccines.

Evaluation of the efficacy of apramycin against Salmonella pullorum infection in chickens.

The efficacy of apramycin given orally at dose levels of 225, 150 and 75 mg/litre for five days to chicks experimentally infected with Salmonella pullorum has been evaluated. The results show that this drug, when utilised at the dose level of 225 mg/litre for five days, totally suppresses mortality and significantly reduces Salmonella excretion in comparison with non-treated chicks.