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PubMed1994

B haplotype influence on the relative efficacy of Marek's disease vaccines in commercial chickens.

The objectives were to investigate whether or not B haplotypes influence vaccinal immunity against Marek's disease (MD) in commercial chickens and to evaluate whether retrospective analysis would detect the influence. This method involved evaluating the B haplotypes of turkey herpesvirus (HVT)-vaccinated sick vs normal chickens from a flock afflicted with MD symptoms. An analysis of the retrospective data disclosed that MD symptoms were present in a higher proportion of B2B19 than B2B21 chickens. A prospective study was then conducted with blood-typed chickens of the strain vaccinated with HVT or HVT + 301B bivalent MD vaccines prior to inoculation of the very virulent Md5 virus. The bivalent vaccine provided better protection than HVT alone, but with either vaccine fewer B2B21 chickens developed MD lesions. We conclude that the B haplotype influence on vaccinal immunity against MD previously demonstrated in B-congenic strains of chickens is also significant in commercial chickens and that the influence can be detected through analysis of B haplotypes in sick vs normal chickens of an affected flock.

Animals↗
PubMed1994

Resistance to Marek's disease in chickens with recombinant haplotypes to the major histocompatibility (B) complex.

Genetic resistance to Marek's disease (MD) is associated with the B-F region of the MHC. The resistance of chickens possessing either of two MHC haplotypes to challenge with different strains of MDV was examined. Chickens with serologically similar MHC recombinants BR2 and BR4 (both BF2-G23) were backcrossed for four generations to the highly inbred UCD-003 line (B17B17). Heterozygotes (B17BF2-G23) were mated to produce BR2BR2 and BR4BR4 homozygotes with 93% background gene uniformity. Both genotypes were highly resistant to GA-5 MDV, having an incidence of 0 and 8% MD for BR2BR2 and BR4BR4, respectively, whereas the incidence of MD in the UCD-003 birds was above 80%. Challenge with the very virulent RB-1B strain caused 10% and 31% MD in the BR2BR2 and BR4BR4 chickens, respectively, compared with 100% and 52% in the B17B17 (UCD-003) and B23B23 (New Hampshire 105) lines, respectively. Viremia levels at 5 and 6 d postinfection were significantly lower in BR2BR2 and B23B23 than in B17B17 genotypes.

Animals↗
PubMed1996

The effects of alternative electrical and mechanical stunning methods on hemorrhaging and meat quality of broiler breast and thigh muscles.

Five trials were conducted to determine the effects of various alternative stunning and restraining methods on the quality of chicken broiler meat. The stunning methods used were electrical whole-body and head-only stunning with different voltages (25 vs 100 V) and frequencies (50 vs 200 Hz), and mechanical captive bolt stunning. Before being stunned, the broilers were restrained either by shackling them by the feet, restraining their heads while they were standing, or placing them in a cone. Convulsions during and after stunning were subjectively scored. At 1 d post-mortem, the pH, color, and the intensity and number of hemorrhages, of breast and thigh muscles were measured. Convulsions were, in order of increasing intensity, observed after whole-body stunning using 50 Hz, whole-body stunning using 200 Hz, head-only stunning, and captive bolt stunning. No differences in ultimate pH were measured. A consistent difference in color was observed between whole-body and head-only stunning. Head-only stunning resulted in darker and more red (P < or = 0.01) breast muscles. Head-only and captive bolt stunning resulted in hemorrhages that were located more distal in the breast muscle than those observed after whole-body stunning. Captive bolt stunning (in a cone) resulted in fewer (P < or = 0.01) hemorrhages in breast and thigh muscles than whole-body stunning (100 V, 50 Hz, shackled), and in a similar level of hemorrhaging as electrical head-only stunning (25 V, 200 Hz, in a cone).

Animals↗
PubMed1990

[Effect of mucociliary dysfunction on nasal viral infection].

The effects of Newcastle disease virus infection on the nasal mucociliary dysfunction after the mechanical stimulation, dehydration and cocaine application were investigated in the nonanesthetized in vivo chicken. Mucociliary transport rate and mucociliary wave frequency were measured simultaneously using the video monitor systems and electrophotometer connecting to the otomicroscope by the direct vision through the palatine cleft of the chicken which were placed in a specially designed plastic holder with mouth opener. Mucociliary transport rate was accelerated on the postnasal fossa adjacent to the mechanically stimulated side of the palatine cleft. The dehydration for 96 hours produced progressive decelerations of mucociliary transport rate, but not mucociliary wave frequency. Topical application of 20% cocaine to the postnasal fossa caused the ciliary paralysis within 5 minutes for more than one hour. The topical inoculation of Newcastle disease virus into the postnasal fossa induced the deceleration of mucociliary transport rate after 4 days and mucociliary wave frequency after 3 and 6 days significantly. We studied the effect of mucociliary transport rate and mucociliary wave frequency on the topical Newcastle disease virus inoculation after the mechanical stimulation, dehydration, and the application of 20% cocaine. Mucociliary transport rate in dehydration and cocaine groups were decelerated significantly 4, 7, 10, 13 days after inoculation, but not in the mechanical stimulation group. Mucociliary wave frequency in the dehydration group were decelerated significantly 3, 6, 12 days after inoculation, but not in the cocaine and mechanical stimulation groups. Therefore, the results suggest that the mucociliary dysfunction may increase and prolong the severity of viral infection.

Animals↗
PubMed1998

Evaluation of an avian-specific probiotic and Salmonella typhimurium-Specific antibodies on the colonization of Salmonella typhimurium in broilers.

Salmonella typhimurium colonizes the intestinal tract of poultry and causes food-borne illness in humans. Reduction of S. typhimurium colonization in the intestinal tract of poultry reduces potential carcass contamination during slaughter. The purpose of this study was to determine the effect of an avian-specific probiotic and S. typhimurium-specific antibodies on the colonization of S. typhimurium in broilers and on body weights. Broiler chicks were spray-vaccinated at the hatchery with the commercial product. Avian Pac Plus, which contains Lactobacillus acidophilus, Streptococcus faecium, ad S. typhimurium-specific antibodies. At placement, these chicks were administered Avian Pac plus in the water. Six hours postplacement, chicks were orally challenged with 1.8 x 10 (7) CFU of S. typhimurium. Chicks were administered Avian Pac Plus for two additional days postchallenge. Chicks were evaluated for S. typhimurium colonization and shedding every 3 to 4 days for the first 2 weeks and every 7 days for 6 weeks. The mean cecal and colonic concentration of S. typhimurium from the Avian Pac Plus-treated group was significantly lower at day 31 (P = 0.0001), day 38 (P = 0.0005), and day 43 (P = 0.0001) than the nontreated control group. These results indicated that a combination of Lactobacillus acidophilus, Streptococcus faecium, and S typhimurium-specific antibodies have a beneficial effect in reducing the colonization of S. typhimurium in market-aged broilers.

Abattoirs↗
PubMed1987

Myopathy associated with megaloschizonts of Haemoproteus meleagridis in a wild turkey from Florida.

Necropsy of an emaciated adult wild turkey (Meleagris gallopavo osceola) that died in captivity soon after capture revealed numerous macroscopic 1-2 mm white cysts in the pectoral muscles. Microscopic, aseptate protozoan megaloschizonts, 50-150 microns in diameter, corresponded to the cysts in histological sections. The megaloschizonts were surrounded by a thick, hyaline wall and packed with spherical merozoites less than 1 micron in diameter. Muscle fibers surrounding most of the megaloschizonts exhibited early signs of dystrophic calcification. The fibers were swollen, pale and hyaline and contained scattered basophilic granules. The megaloschizonts were morphologically distinct from sarcocysts of Sarcocystis sp. and Besnoitia sp. and the thin-walled tissue cysts of Toxoplasma gondii. They were identical in structure and host reaction to the second-generation megaloschizonts of Haemoproteus meleagridis, reported previously from experimentally infected domestic turkeys. While the precise cause of death of the wild turkey could not be determined, the most prominent lesions were associated with the numerous intramuscular megaloschizonts.

Animals↗
PubMedDate not supplied

Construction and evaluation of a delta cya delta crp Salmonella typhimurium strain expressing avian pathogenic Escherichia coli O78 LPS as a vaccine to prevent airsacculitis in chickens.

Avian pathogenic strains of Escherichia coli cause a number of extraintestinal diseases in poultry, including airsacculitis and colisepticemia. Expression of O78 lipopolysaccharide (LPS) is frequently associated with pathogenic isolates. Salmonella, a common poultry contaminant, is a major public health concern. The purpose of this work was to develop an E. coli vaccine for poultry with the use of an attenuated Salmonella typhimurium carrier that would benefit both the bird and the consumer. Orally administered attenuated S. typhimurium delta cya delta crp strains have been shown to provide excellent protection against wild-type Salmonella challenge in chickens. This work describes the construction of a delta cya delta crp derivative of an avian pathogenic S. typhimurium that expresses both the homologous group B determinants (O1,4,5,12) and the heterologous E. coli O78 LPS O antigens. This was accomplished by inserting the E. coli rfb region, which encodes the genes required for O78 expression, into the chromosomal cya gene of S. typhimurium, creating a defined deletion/insertion mutation. A delta crp mutation was introduced in a subsequent step. Expression of both O antigens was stable in vitro and in vivo. Vaccination of white leghorn chicks at day of hatch and 14 days with the recombinant vaccine strain induced serum immune responses against both S. typhimurium and E. coli LPS and protected the birds against subsequent challenge with an avian pathogenic E. coli O78 strain. Introduction of a mutation in rfc, which encodes the O antigen polymerase, reduced the chain length of the S. typhimurium LPS without affecting the expression of O78. The rfc mutation further enhanced the ability of the vaccine strain to protect chickens against E. coli challenge.

Air Sacs↗
PubMedDate not supplied

Renal Cryptosporidiosis (Cryptosporidium baileyi) in specific-pathogen-free chickens experimentally coinfected with Marek's disease virus.

Renal Cryptosporidiosis was experimentally induced during a study to investigate the pathogenicity of Cryptosporidium baileyi in specific-pathogen-free (SPF) chickens coinfected with Marek's disease virus (MDV). Cryptosporidium baileyi was administered orally at 4 days of age to chickens previously infected at hatching (day 0) with the HPRS 16 strain of oncogenic MDV. Three control groups received MDV at hatching, C. baileyi on day 4, or placebo consisting of distilled water. Renal cryptosporidiosis lesions were induced in the group coinfected with MDV and C. baileyi. The kidneys were markedly swollen and pale, with visible urate crystals in the ureters and surface tubules. Oocysts of C. baileyi were demonstrated in six of seven cases tested by a scoring method with modified Sheather's sugar solution on renal tissue scrapings and were confirmed in three cases by histologic examination of paraffin-embedded kidney sections. Histologic study also revealed subacute interstitial nephritis, acute ureteritis, and attachment of cryptosporidia on the epithelial cell surface of the ureters and collecting ducts, collecting tubules, and distal convoluted tubules. Various developmental stages of the parasite were present in the kidney sections. To our knowledge, this is the first report of experimentally induced renal cryptosporidiosis in SPF chickens coinfected with MDV.

Animals↗
PubMed1976

An animal model for the study of human alpha-1-antitrypsin deficiency.

Turkeys with "round heart disease" often have a deficiency in alpha1 globulin. Within their liver cells, PAS +, diastase resistant granules are present, and are remarkably similar to those of persons with inherited AAT deficiency. The electrophoretic patterns made according Fagerhol's method showed differences between the serum of healthy birds and the turkeys suffering from "round heart disease".

Animals↗
PubMedDate not supplied

Protective immunity to infectious bronchitis in broilers vaccinated against Marek's disease either in ovo or at hatch and against infectious bronchitis at hatch.

Two experiments were conducted using commercial broiler chickens to determine if Marek's disease (MD) vaccines HVT/SB-1 and HVT plus CVI-988 given either in ovo or at hatch adversely affected the efficacy of infectious bronchitis (IB) vaccines (Ark and Mass serotypes) given by eyedrop on the day of hatch. Nonvaccinated negative controls and controls that received only IB vaccines were included in each study. Birds were challenged with either infectious bronchitis virus (IBV) Mass-41 or IBV Ark-99 on either day 26 or 27 of age. Protection was assessed 5 days post-IBV challenged by virus isolation from the trachea. The day of hatch mean antibody titer to IBV was 12,668 +/- 4704 and 2503 +/- 3243 by enzyme-linked immunosorbent assay in experiments 1 and 2, respectively. In each study, nonvaccinated controls had a significantly higher (P < or = 0.05) incidence (88%-100%) of IBV challenge virus isolation than did controls vaccinated for IB but not for MD. Analysis of data from both studies showed that protection to IB in groups that received only IB vaccines at hatch ranged from 55.0% to 77.3%, whereas protection to IB in groups receiving both MD and IB vaccines ranged from 50.0% to 95.5%. In both experiments and within IBV challenge serotype, broilers given MD vaccines (in ovo or at hatch) and IB vaccines at hatch had protection rates to IBV challenges that were not significantly less (P < or = 0.05) than IB protection rates of groups that received only IB vaccines at hatch. Analysis of these data shows that administration of high-titered MD vaccines either in ovo or at hatch did not affect the efficacy of an IB vaccination (serotypes Ark and Mass) given by eyedrop at hatch.

Animals↗
PubMedDate not supplied

Turkey knockdown in successive flocks.

Turkey knockdown was diagnosed in three of five flocks of hen turkeys on a single farm within a 12-mo period. The age of birds in the flocks affected ranged from 6 wk 2 days to 7 wk 4 days. The attack rate ranged from 0.02% to 0.30% with a case fatality rate in affected birds ranging from 0 to 74%. The diagnosis was made on the basis of clinical signs and histopathologic lesions associated with knockdown. The feed in all flocks contained bacitracin methylene disalicylate and monensin (Coban). Affected birds were recumbent, demonstrated paresis, and were unable to vocalize. Postmortem examination revealed few significant lesions although pallor of the adductor muscles and petechiation in adductor and gastrocnemius muscles were noted. Birds that had been recumbent for extended periods were severely dehydrated. Consistent microscopic lesions included degeneration, necrosis, and regeneration of adductor, gastrocnemius, and abdominal muscles. No lesion in cardiac tissue was noted. Results of our investigation indicated that changes in water consumption, vitamin E status, and brooder to finisher movement correlated with the occurrence of knockdown. Turkey knockdown was defined in 1993 as any condition identified in a turkey flock that has affected the neuromuscular system to a degree that a turkey is unable to walk or stand. This definition was later modified to...neuromuscular or skeletal systems to a degree that a turkey is unable to walk or stand properly. Knockdown may be associated with numerous feed, management, or disease factors alone or in combination. Dosage of monensin, feed restriction/gorging, water restriction, heat stress, copper, mycotoxins, sodium chloride in feed, and sulfa drugs have all been suggested as contributing factors; however, laboratory studies to duplicate this have not been successful. This report presents observations from a single farm at which three of five hen flocks in a single year experienced knockdown. When a flock was reported as affected, a detailed investigation was initiated within 3 hr. The fifth flock was followed on a twice weekly basis from 0 to 8 wk of age to determine if initiating events were evident, but knockdown did not occur.

Animals↗