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Biomedical subjects

J N Beasley

Publications and source records attributed to J N Beasley.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

In vivo studies with dimethyldithiocarbamate, a possible new antimicrobial for use against Aspergillus fumigatus in poultry.

Dimethyldithiocarbamate (DmDTC), the carbamate analogue, was tested for therapeutic efficacy in a series of in vivo challenge trials using 5- and 10-week-old white leghorn chickens. Challenge organisms were Pasteurella multocida X-73, Escherichia coli O1:K1, and Aspergillus fumigatus. Birds were evaluated for survival rates, lesion scores, and the rate at which the bacteria or mold could be reisolated following challenge. Results showed DmDTC to be ineffective against P. multocida and E. coli at the treatment levels and in the form used in these trials, but DmDTC significantly reduced lesion scores and inhibited the rate of isolation of A. fumigatus compared with untreated infected birds.

Animals↗
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Efficacy of thiabendazole (Mertect 340-F) in controlling mold in turkey confinement housing.

Mertect 340-F (thiabendazole) was evaluated as a mold inhibitor for litter in turkey confinement housing using green oak wood shavings heavily contaminated with mold spores. One day before the addition of shavings, two environmentally controlled rooms were sprayed with Mertect 340-F at a rate of 51.0 ml in 11.37 liters of water (16 fl. oz./6000 sq. ft.). After the litter was added, it was treated with Mertect 340-F at a rate of 33.0 ml in 75.8 liters of water (32 fl. oz./6000 sq. ft.). The litter was treated again at 6 and 12 weeks. Mertect 340-F-treated litter had significantly lower mold spore counts than water-treated litter. Turkeys reared on Mertect 340-F-treated litter displayed no adverse effects. No obvious differences between groups were noted post mortem. Microscopically, however, lungs from turkeys on water-treated litter had a higher incidence of granulomas and mycelia than lungs from birds on Mertect 340-F-treated litter.

Animals↗
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Efficacy in turkeys of spray vaccination with a temperature-sensitive mutant of Bordetella avium (Art Vax).

Broad-breasted white turkeys were vaccinated with a temperature-sensitive mutant of Bordetella avium (Art Vax) at 2 and 15 days of age and challenged at 22 days of age by contact with infected birds. Necropsy was performed at 35 days of age. Two vaccination protocols (eyedrop/oral and spray cabinet/spray bottle) and two challenge isolates (Arkansas 105 and North Carolina [NC] isolates) were used. Neither the spray nor the eyedrop/oral methods of vaccination prevented infection of the anterior trachea with either of the virulent challenge strains. The spray and eyedrop/oral methods of vaccination were equally effective in reducing the severity of gross lesions in the trachea. The vaccine reduced the severity of gross lesions in the tracheas of turkeys challenged with the NC isolate to a level approximately equal to that observed in unchallenged vaccinated controls, but the vaccine only moderately reduced the severity of lesions in birds challenged with the 105 isolate.

Administration, Oral↗
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The efficacy of a temperature-sensitive mutant vaccine against Northwest Arkansas isolates of Alcaligenes faecalis.

The efficacy of a commercially produced temperature-sensitive mutant Alcaligenes faecalis vaccine was evaluated in turkeys contact-challenged with one of three strains of A. faecalis. In the vaccinated control group, the vaccine strain of A. faecalis colonized the nasal turbinates but not the trachea, caused no clinical signs of turkey coryza, and induced humoral antibodies. In the vaccinated challenged groups, the vaccine reduced both the severity of lesions and the number of birds exhibiting lesions compared with unvaccinated challenged groups, but it did not prevent colonization of challenge strains of A. faecalis.

Alcaligenes↗
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Neoplasms in the oviducts of turkeys.

The reproductive tracts of turkey breeder hens from five flocks were examined grossly and histologically. Hens from one flock had a normal reproductive history, but hens from the four other flocks had poor records in both egg production and hatchability. Nodular growths occurred in the oviducts of birds in all five flocks. The incidence of lesions varied from flock to flock and from bird to bird. In four flocks, lesions were small and consisted of areas of dysplasia with adenomatous change. Histologically, the lesions in some birds in the fifth flock were adenocarcinomas. No metastases were observed.

Adenocarcinoma↗
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The development of dermatitis (scabby-hip) on the hip and thigh of broiler chickens.

Broiler chicks grown on litter or in cages at high bird density developed skin lesions on the thigh and hip. Changes in bird denisty markedly influenced lesion incidence (100% at 0.0185 sq m of floor space per bird). The dermatitis was characterized by crusted dry "scabs" at the base of feather follicles and between follicles. The lesions often coalesced to cover wide areas. The scab consisted of a mass of pyknotic nuclei and cellular debris, and when the epidermis was intact there was little inflammatory reaction in the dermis or subcutaneous tissue. The epidermis was destroyed in some lesions, with heterophils penetrating into the subcutaneous tissue. Colonies of gram-positive cocci were present in the lesions.

Animals↗
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Studies on the use of a long-acting oxytetracycline in turkeys: efficacy against experimental infections with Alcaligenes faecalis and Pasteurella multocida.

A group of 2-week-old turkey poults was inoculated with a pathogenic strain of Alcaligenes faecalis. One week later, half the group was injected with a long-acting oxytetracycline formulation. Poults were examined post-mortem on days 3, 5, and 10 post-treatment. Swabs were taken of the trachea, sinus, and lung of each poult. Poults were observed closely for clinical signs, and appropriate tissues were taken for histopathology. Results showed no evidence of therapeutic effect on A. faecalis infection in vivo, even though the organism was highly sensitive in vitro. Six-week-old turkeys were inoculated intramuscularly with 3.7 X 10(3) organisms of the P-1059 strain of Pasteurella multocida. Immediately following inoculation, half the group was treated with the long-acting oxytetracycline. Ninety percent of the untreated poults were dead 72 hours postinoculation, whereas none of the treated turkeys died. No evidence of any clinical disease was observed in the treated group during the 8-day observation period. The long-acting oxytetracycline product was highly efficacious in preventing disease caused by experimental inoculation with the P-1059 strain of P. multocida.

Alcaligenes↗
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Digestion of feed by chicks with pale bird syndrome.

Unaffected chicks (normal) and chicks with pale bird syndrome (pale) were fed a control diet or a test diet obtained from the broiler house containing the pale chicks. Pale birds digested less (P less than 0.05) dry matter and ether extract than normal chicks, and the nitrogen content in their feces was greater. The chicks from both sources digested more (P less than 0.05) dry matter from the test feed but also excreted more (P less than 0.05) nitrogen than those fed the control diet. Neither diet resulted in differences in the digestion of ether extract. The cause of pale bird syndrome was related more to source of chicks rather than source of feed. Depigmentation may have resulted from decreased pigment absorption because of reduced absorption of dietary components, including ether extract.

Animals↗
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Effect of dietary citrinin on urine excretion in broiler chickens.

Eight 4-week-old broiler chickens were used to study the effects of dietary citrinin on water consumption, urine excretion, and fecal moisture. The birds were colostomized by exteriorizing the colon directly below the vent. Plastic bags were attached to collect feces. Corn containing the various levels of citrinin was fed for 4 hr. Water consumption and urine excretion were measured, and fecal samples were retained for moisture determination. Analysis of variance indicated citrinin increased (p less than 0.05) both water consumption and urine excretion. Regression analysis isolated the linear component as being significant (p less than 0.05) for both water consumption and urine excretion, identifying the responses as linear through the bounds of the treatment levels. Fecal moisture showed no changes (p less than 0.05). The correlation coefficients yielded significant relationships between treatment vs. water consumption, treatment vs urine excretion and water consumption vs urine excretion.

Animals↗
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Effect of humidity on infection of turkeys with Alcaligenes faecalis.

Turkeys maintained at 75% to 80% relative humidity were more adversely affected by Alcaligenes faecalis infection than turkeys maintained at 20 to 35% relative humidity. Alcaligenes faecalis was reisolated earlier and more often from turkeys maintained at the higher humidity. Clinically, the turkeys maintained at high humidity exhibited both sinusitis and conjunctivitis earlier than the turkeys at low humidity. In both groups, antibody titers as determined by a microagglutination test developed by 2 weeks postinoculation and started to decline after the third week, lymphocytosis was demonstrated at 1 week postinoculation, and a lymphopenia developed at 5 weeks postinoculation.

Agglutination Tests↗
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A longitudinal study of green-liver osteomyelitis complex in commercial turkeys.

Two flocks of Nicholas tom turkeys from separate farms with histories of above-average condemnations for turkey green-liver osteomyelitis complex (TOC) were studied throughout a 16-week growout. Fifty birds from each farm were necropsied each week for 15 weeks, and birds that had green livers, osteomyelitis in the proximal tibia, or swollen joints were cultured for aerobic bacteria along with an equal number of control birds. At processing, TOC lesions and green livers were obtained for bacterial culture and histopathology. Green-liver-associated TOC was not observed until the turkeys were 9 or 10 weeks of age. The incidence of TOC was higher on one farm, which also had a higher incidence of airsacculitis, higher early and weekly mortality, seroconversion to Newcastle disease virus and Mycoplasma meleagridis, and significantly higher average body weights, relative spleen weights, and relative liver weights. Both farms had a high incidence of intestinal lesions and infestation with Ascaridia dissimilis. Histological evaluation of green livers revealed hyperplasia of bile ducts, dilation of sinusoids, and pigment-containing Kupffer's cells, some of which stained positive for iron. The bacterial isolates most frequently cultured from bones and livers were pleomorphic gram-variable coccobacilli, which grew visible colonies only after a series of subcultures and extended incubation.

Animals↗
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A survey of two commercial turkey farms experiencing high levels of liver foci.

Two turkey farms that had previously experienced high levels of liver condemnations at slaughter were monitored through one complete growout cycle. Liver foci appeared at both farms by week 2. More than 80% of the liver foci sampled did not have any aerobic or facultative bacteria isolated from the lesions. Low numbers of Ascaridia dissimilis larvae were found on both farms by week 3 in the growout. The patterns for the ascaridiasis at both farms were similar, although one of the farms had a higher number of ascarids earlier than the other. Neither farm had high levels of adult ascarids present, although the average larval burden was high. Piperazine was administered at both farms on multiple occasions, but there were no significant decreases in the level of adult ascarids following administration. There was no apparent development of immunity, since all stages of the life cycle remained stable, even late in the growout. The simultaneous appearance of the liver foci and the A. dissimilis indicate that the ascarids may be responsible for the hepatic pathology.

Animals↗
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Use of virulent hemorrhagic enteritis virus for the induction of colibacillosis in turkeys.

Three hundred fifty 1-day-old large white turkeys were reared in brooding batteries to 10 days of age, after which they were moved to floor pens on litter. At 7 weeks of age, poults were allotted into four treatment groups as follows: 1) virulent hemorrhagic enteritis virus (HEV) alone (100 turkeys), 2) Escherichia coli alone (100 turkeys), 3) HEV + E. coli (100 turkeys), and 4) negative controls (50 turkeys). HEV was given orally at 7 weeks of age, followed by E. coli challenge in the drinking water 2 days later for 10 consecutive days. All groups were observed daily for mortality, both during and after challenge. Turkeys that died or were moribund were necropsied, and cultures were taken from the liver and bone marrow for bacterial isolation. Total mortality rates were 23% in the HEV + E. coli group, 10% in the HEV-only group, 3% in the E. coli-only group, and 0% in the negative control group. Cumulative mortality values were significantly different from those of the negative controls (P < or = 0.05) for HEV only and the HEV + E. coli group. E. coli was isolated from the liver and bone marrow of almost all turkeys that died.

Adenoviridae Infections↗
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Determination of optimum formulation of a novel infectious bursal disease virus (IBDV) vaccine constructed by mixing bursal disease antibody with IBDV.

A novel vaccine against infectious bursal disease virus (IBDV) has been developed. The new vaccine was constructed by mixing bursal disease antibody (BDA) contained in whole antiserum with live IBDV before lyophilization. To establish various formulations of BDA and IBDV, several BDA doses between 5 units and 80 units of BDA/50 microliters were mixed with 100 EID50/50 microliters of IBDV suspension in Expt. 1; in Expt. 2, several IBDV doses between 10 EID50/50 microliters and 977 EID50/50 microliters of IBDV suspension were mixed with 24 units of BDA/50 microliters. Vaccine preparations were administered subcutaneously to the nape of 1-day-old specific-pathogen-free (SPF) chicks. Safety, potency, and immunogenicity of the different vaccine formulations were evaluated using bursal weight, bursal gross examination, and IBDV antibody titer. Some bursae were examined histologically to confirm gross examinations. Several vaccine formulations were safe and efficacious and met the safety, potency, and immunogenicity criteria. A vaccine construct of 100 EID50 mixed with 24 units of BDA was selected as the release dose. When administered at 1 day of age, the novel vaccine allows for delayed infection of the bursa until after days 6-8 of age in SPF chicks, while initiating potency and immunogenicity to an IBDV challenge. The addition of BDA to the IBDV results in a complex vaccine that allows for safer immunization in SPF birds than under administration of the vaccine virus without BDA.

Animals↗
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A survey of sixty turkey flocks exhibiting hepatic foci taken at time of processing.

Fifty turkey flocks including 24 16-week-old male flocks and 26 20-week-old male flocks were sampled at time of processing. Hepatic foci were cultured for aerobic and anaerobic bacteria. The majority of these did not have any bacteria recovered from the lesions. Of the bacteria that were recovered, most were facultative anaerobes, with Escherichia coli and Salmonella sp. comprising the most common isolates. All of the birds examined (300 total) for parasites were infected with varying levels of Ascaridia dissimilis. The highest average worm burden was found in the 20-week-old flocks. Heterakis gallinarum were found in only a few of the younger turkeys (16 weeks old) and not in any of the older birds. An analysis of the spatial distribution of the hepatic foci performed in an additional 10 turkey flocks (500 birds) revealed that, although present on the surface of all regions of the liver, 56.12% of the lesions were found on the left hepatic lobe and 43.88% were found on the right hepatic lobe.

Aging↗
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Pathogenicity studies of an Arkansas variant infectious bursal disease virus.

A variant infectious bursal disease virus (IBDV), IBDV-s977, was blind passaged in cell culture, plaque purified, and attenuated by serial passage at a high multiplicity of infection (MOI) in chick embryo fibroblasts (CEF). Cell culture passages of virus caused less bursal atrophy and splenomegaly than did the original isolate and retained immunogenicity; however, virus tended to persist for a longer time in the bursa and spleen of birds infected with the highest CEF passages. Antibody to both low MOI and high MOI passages of IBDV-s977 poorly neutralized virus that was isolated from bursal tissue 28 days postinfection (PI). The spleens of chickens infected with the eighteenth CEF passage were negative for virus at 3 and 7 days PI but had high titers of virus at 14 and 28 days PI. There was also more virus in the bursa of birds infected with the fifteenth and eighteenth CEF passages at 28 days PI than at 7 or 14 days PI. Defective interference (DI) was demonstrated when cell cultures were coinfected with a constant amount of low MOI virus and serial dilutions of high MOI virus. There was an increase in interference score with increased passage number in CEF, and there was more interference in virus passaged at a high MOI. There was an inverse relationship between interference score and bursal lesion score and splenomegaly at 7 days PI, indicating that DI particles may be involved in virus attenuation. There was a positive relationship between interference and viral persistence in the bursa and spleen at 28 days PI. Antiserum to s977 was shown to enhance the nonlytic replication of s977 in CEF, presumably within macrophages, providing a possible mechanism for the pathotypic variation seen in emerging strains of IBDV.

Animals↗