Cytochrome P450-dependent metabolism of midazolam in hepatic microsomes from chickens, turkeys, pheasant and bobwhite quail

In vitro putative cytochrome P450 3A mediated activity, and inhibition thereof, were measured in four avian species using midazolam (MDZ) as a substrate and ketoconazole as an inhibitor. All species produced 1-hydroxymidazolam (1-OH MDZ) to a much greater extent than 4-hydroxymidazolam (4-OH MDZ). Calculated Vmaxapparent values for formation of 1-OH MDZ were 117+/-17, 239+/-108, 437+/-168, and 201+/-55 pmol/mg protein*min and Kmapparent values were 2.1+/-0.8, 2.4+/-1.6, 6.7+/-5.1 and 3.2+/-2.1 microm for chicken, turkey, pheasant and bobwhite quail, respectively. For the formation of 4-OH MDZ the Vmaxapparent values were 21+/-10, 94+/-46, 144+/-112, and 68+/-30 pmol/mg protein*min and Kmapparent values for 4-OH MDZ formation were 12.4+/-10.1, 18.0+/-10.8, 38.6+/-34.7 and 29.1+/-10.1 microm for chicken, turkey, pheasant and bobwhite quail, respectively. In all four species, ketoconazole inhibited the production of both major metabolites of MDZ, with 4-OH MDZ formation more sensitive to inhibition than 1-OH MDZ. Pheasant and bobwhite quail appeared most sensitive to ketoconazole inhibition.     

A PBPK model for midazolam in four avian species

A physiologically based pharmacokinetic (PBPK) model was developed for midazolam in the chicken and extended to three other species. Physiological parameters included organ weights obtained from 10 birds of each species and blood flows obtained from the literature. Partition coefficients for midazolam in tissues vs. plasma were estimated from drug residue data obtained at slaughter. The avian models include separate compartments for venous plasma, liver, kidney, muscle, fat and all other tissues. An estimate of total body clearance from an earlier in vitro study was used as a starting value in the model, assuming almost complete removal of the parent compound by liver metabolism. The model was optimized for the chicken with plasma and tissue data from a pharmacokinetic study after intravenous midazolam (5 mg/kg) dose. To determine which parameters had the most influence on the goodness of fit, a sensitivity analysis was performed. The optimized chicken model was then modified for the turkey, pheasant and quail. The models were validated with midazolam plasma and tissue residue data in the turkey, pheasant and quail. The PBPK models in the turkey, pheasant and quail provided good predictions of the observed tissue residues in each species, in particular for liver and kidney.     

Pathogenicity of embryo-adapted serotype 2 OH strain of infectious bursal disease virus in chickens and turkeys

The pathogenicity of serotype 2 OH strain of infectious bursal disease virus (IBDV) to specific-pathogen-free (SPF) chicken embryos and 2-wk-old SPF chickens and turkey poults was investigated. The virus was pathogenic for chicken embryos after five passages as evidenced by pathologic changes in inoculated embryos. The embryo-adapted virus was not pathogenic for 2-wk-old SPF chickens and turkey poults as indicated by lack of clinical signs, gross or microscopic lesions in the bursa of Fabricius of inoculated birds. Bursa-to-body-weight ratios of the inoculated chickens and turkey poults were not significantly different from those of uninoculated controls. Virus-neutralizing antibodies to serotype 2 IBDV were detected in inoculated chickens and turkeys. Results of this study indicated that the embryo-adapted serotype 2 OH IBDV isolate that is pathogenic for chicken embryos is infectious but not pathogenic in chickens and turkeys.     

Using mean infectious dose of high- and low-pathogenicity avian influenza viruses originating from wild duck and poultry as one measure of infectivity and adaptation to poultry

The mean infectious doses of selected avian influenza virus (AIV) isolates, determined in domestic poultry under experimental conditions, were shown to be both host-dependent and virus strain-dependent and could be considered one measure of the infectivity and adaptation to a specific host. As such, the mean infectious dose could serve as a quantitative predictor for which strains of AIV, given the right conditions, would be more likely transmitted to and maintained in a given species or subsequently cause an AI outbreak in the given species. The intranasal (IN) mean bird infectious doses (BID50) were determined for 11 high-pathogenicity AIV (HPAIV) isolates of turkey and chicken origin for white leghorn (WL) chickens, and for low-pathogenicity AIV (LPAIV) isolates of chicken (n = 1) and wild mallards (n = 2) for turkeys, and WL and white Plymouth rock (WPR) chickens, domestic ducks and geese, and Japanese quail. The BID50 for HPAIV isolates for WL chickens ranged from 10(1.2) to 10(4.7) mean embryo infectious dose (EID50) (median = 10(2.9)). For chicken-origin HPAIV isolates, the BID50 in WL chickens ranged from 10(1.2) to 10(3.0) EID50 (median = 10(2.6)), whereas for HPAIV isolates of turkey origin, the BID50 in WL chickens was higher, ranging from 10(2.8) to 10(4.7) EID50 (median = 10(3.9)). The BID50 of 10(4.7) was for a turkey-origin HPAIV virus that was not transmitted to chickens on the same farm, suggesting that, under the specific conditions present on that farm, there was insufficient infectivity, adaptation, or exposure to that virus population for sustained chicken transmission. Although the upper BID50 limit for predicting infectivity and sustainable transmissibility for a specific species is unknown, a BID50 < 10(4.7) was suggestive of such transmissibility. For the LPAIVs, there was a trend for domestic ducks and geese and Japanese quail to have the greatest susceptible and for WL chickens to be the most resistant, but turkeys were susceptible to two LPAIV tested when used at moderate challenge doses. This suggests domestic ducks and geese, turkeys, and Japanese quail could serve as bridging species for LPAIVs from wild waterfowl to chickens and other gallinaceous poultry. These data do provide support for the commonly held and intuitive belief that mixing of poultry species during rearing and in outdoor production systems is a major risk factor for interspecies transmission of AIVs and for the emergence of new AIV strains capable of causing AI outbreaks because these situations present a more diverse host population to circumvent the natural host dependency or host range of circulating viruses.     

Drug use and antimicrobial resistance among Escherichia coli and Enterococcus spp. isolates from chicken and turkey flocks slaughtered in Quebec,Canada

An observational study was conducted of chicken and turkey flocks slaughtered at federal processing plants in the province of Quebec, Canada. The objectives were to estimate prevalence of drug use at hatchery and on farm and to identify antimicrobial resistance (AMR) in cecal Escherichia coli and Enterococcus spp. isolates and factors associated with AMR. Eighty-two chicken flocks and 59 turkey flocks were sampled. At the hatchery, the most used antimicrobial was ceftiofur in chickens (76% of flocks) and spectinomycin in turkeys (42% of flocks). Virginiamycin was the antimicrobial most frequently added to the feed in both chicken and turkey flocks. At least 1 E. coli isolate resistant to third-generation cephalosporins was present in all chicken flocks and in a third of turkey flocks. Resistance to tetracycline, streptomycin, and sulfisoxazole was detected in > 90% of flocks for E. coli isolates. Antimicrobial resistance (AMR) was observed to bacitracin, erythromycin, lincomycin, quinupristin-dalfopristin, and tetracycline in both chicken and turkey flocks for Enterococcus spp. isolates. No resistance to vancomycin was observed. The use of ceftiofur at hatchery was significantly associated with the proportion of ceftiofur-resistant E. coli isolates in chicken flocks. In turkey flocks, ceftiofur resistance was more frequent when turkeys were placed on litter previously used by chickens. Associations between drug use and resistance were observed with tetracycline (turkey) in E. coli isolates and with bacitracin (chicken and turkey), gentamicin (turkey), and tylosin (chicken) in Enterococcus spp. isolates. Further studies are needed to provide producers and veterinarians with alternative management practices and tools in order to reduce the use of antimicrobial feed additives in poultry.     

Distribution patterns of influenza virus receptors and viral attachment patterns in the respiratory and intestinal tracts of seven avian species

ABSTRACT: This study assessed the presence of sialic acid α-2,3 and α-2,6 linked glycan receptors in seven avian species. The respiratory and intestinal tracts of the chicken, common quail, red-legged partridge, turkey, golden pheasant, ostrich, and mallard were tested by means of lectin histochemistry, using the lectins Maackia amurensis agglutinin II and Sambucus nigra agglutinin, which show affinity for α-2,3 and α-2,6 receptors, respectively. Additionally, the pattern of virus attachment (PVA) was evaluated with virus histochemistry, using an avian-origin H4N5 virus and a human-origin seasonal H1N1 virus. There was a great variation of receptor distribution among the tissues and avian species studied. Both α-2,3 and α-2,6 receptors were present in the respiratory and intestinal tracts of the chicken, common quail, red-legged partridge, turkey, and golden pheasant. In ostriches, the expression of the receptor was basically restricted to α-2,3 in both the respiratory and intestinal tracts and in mallards the α-2,6 receptors were absent from the intestinal tract. The results obtained with the lectin histochemistry were, in general, in agreement with the PVA. The differential expression and distribution of α-2,3 and α-2,6 receptors among various avian species might reflect a potentially decisive factor in the emergence of new viral strains.     

Passage of duck hepatitis virus in cell cultures derived from avian embryos of different species

An egg-attenuated strain of duck hepatitis virus was successfully passaged through cell cultures of avian embryos derived from goose, turkey, guinea fowl, Japanese quail, pheasant and chicken. Two field strains of the virus were passaged in a more limited range of species.     

Marek's disease in turkeys. II. Characterization of the viral glycoprotein B gene and antigen of a turkey strain of Marek's disease virus

Marek's disease virus (MDV) causes immunosuppression and tumors in chickens. As sporadic cases of Marek's disease (MD) were recorded in turkeys, the antigenic and genomic characteristics of the MDV glycoprotein B (gB) gene and antigen of turkeys were compared to the chicken MDV gB. The whole chicken and turkey gB genes were sequenced and found identical. By immunoblotting of infected-cell culture lysates using chicken convalescent and gB monoclonal antibodies, the antigenic epitopes of the chicken and turkey viruses were found to differ. The turkey MDV had a unique epitope, compared to the chicken MDV and compared with our previous findings. While the chicken MDV had two epitope types, heat-labile but dithiothreitol (DTT)-stable and heat-stable but DTT-labile, the turkey MDV gB epitope is both heat and DTT-labile.     

乌鸡、火鸡实验性组织滴虫病病理学比较

以组织滴虫病疫区鸡异刺线虫虫卵实验诱发火鸡、乌鸡组织滴虫病，分别在潜伏期、症状明显期、转归期对盲肠、肝脏等组织器官进行病理学比较观察，结果显示：盲肠卡他（乌鸡13/20；火鸡8/29）和纤维素性坏死（火鸡19/27，乌鸡7/20）。肝脏脂肪变性（火鸡8/27；乌鸡11/20）及局灶性坏死（火鸡19/27；乌鸡4/20）。此外，火鸡肝脏与盲肠见典型传染性肉芽肿。     

Pathogenicity of turkey coronavirus in turkeys and chickens

We designed this study to compare the replication potential of turkey coronavirus (TCV) and its effect in chickens and turkeys and to study the effect of singleand combined infection of turkey poults with TCV and astrovirus. We studied the pathogenicity of TCV in experimentally inoculated turkey poults and chickens by observing the dinical signs and gross lesions. Two trials were conducted with 1-day-old and 4-wk-old specific-pathogen-free turkey poults and chickens. One-day-old turkey poults developed diarrhea at 48 hr postinoculation. Poults euthanatized at 3, 5, and 7 days postinoculation had flaccid, pale, and thin-walled intestines with watery contents. The 4-wk-old turkeys had no clinical signs or gross lesions. One-day-old and 4-wk-old chicks developed no clinical signs or gross lesions although the TCV was detected in gut contents of the birds throughout the experimental period (14 days). In another experiment, mean plasma D-xylose concentrations in 3-day-old turkey poults inoculated with TCV, turkey astrovirus, or a combination of both viruses were significantly lower than in the uninoculated controls.     

Organic matrix composition and ultrastructure of eggshell: a comparative study.

1. The avian eggshell is a biomineralised composite ceramic consisting of calcium carbonate embedded in an organic matrix. Matrix components are supposed to be involved in the control of mineralisation, crystallographic texture and biomechanical properties of eggshell. 2. The structure and eggshell matrix composition of various domesticated bird species were compared to gain insight into the universality of the eggshell mineralisation process. 3. The SDS-PAGE profiles of soluble eggshell matrix were specific within groups of birds (a: laying hen, breeder hen, quail, pheasant and possibly turkey; b: guinea fowl; c: duck and goose) but some of the protein bands were common to all groups. 4. Analogies between species were confirmed by Western blotting using hen protein antibodies. Ovocleidin-17 (OC-17) and ovalbumin were revealed in all species (except quail for OC-17). Lysozyme was present only in hen eggshell. Another egg white protein: ovotransferrin showed a positive signal in hens, turkey and quail. Osteopontin was observed in laying and breeder hens and quail. 5. Different proteoglycans were localised to discrete regions within the eggshell. Dermatan sulphate was observed within the matrix of the calcified shell of all species except quail which contained chondroitin-6-sulfate. Keratan sulphate was observed in mammillary bodies of breeder and laying hen, quail, pheasant and turkey while chondroitin sulphate was also present in guinea fowl and duck. 6. The general structural organisation of the different avian eggshells was similar but specific differences were observed in the ultrastructure of the mammillary layer. Species of the same taxonomic family could be grouped according to their structural analogies: breeder hen, turkey and pheasant resembled that of the domestic fowl. Guinea fowl was unique. Goose and duck were quite similar with large and confluent mammillary bodies. 7. Some matrix components are therefore common to eggshells of various species but more information is needed to relate differences in matrix composition between taxonomic groups with differences in ultrastructure.     

Pathogenesis of rotavirus infection in various age groups of chickens and turkeys: clinical signs and virology

Age-related susceptibility patterns of turkeys, broilers, and specific pathogen-free (SPF) White Leghorn chickens to experimentally induced infection with turkey or chicken rotavirus isolates were compared. The following determinants were evaluated: clinical signs, onset and duration of virus production, viral titers, involvement of intestinal villi in the replication of the virus, and the development of antibodies against the virus. Older turkeys and chickens were more susceptible than were their younger counterparts, turkeys were more susceptible than were broiler and White Leghorn chickens (regardless of age), and broiler chickens were slightly more susceptible than were age-matched White Leghorn chickens. Turkeys developed diarrhea, accompanied by high viral titers within 1 day after inoculation with virus. Viral antigen was found in the epithelial cells of the intestinal villi throughout the intestinal tract and some cells of the cecal tonsils. Antibodies could be detected as early as 4 to 5 days after inoculation. These findings were more pronounced in turkeys inoculated at 112 days of age than in birds inoculated at a younger age. Age-related susceptibility patterns were similar in White Leghorn and broiler chickens. Infection was subclinical in birds less than 56 days old, whereas older birds developed soft feces. Egg production in the White Leghorn chickens decreased after being inoculated with virus at 350 days of age.     

Immunization of chickens and turkeys against avian influenza with monovalent and polyvalent oil emulsion vaccines.

Chickens and turkeys vaccinated with inactivated virus oil-emulsion vaccines containing different concentrations of either 1 (monovalent) or 4 (polyvalent) strains of avian influenza virus (AIV) were challenged-exposed with virulent AIV A/chicken/Scotland/59 or A/turkey/Ontario/7732/66. Four of 6 vaccines protected completely against postexposure mortality. Vaccine valency did not alter the serologic and challenge-exposure responses of chickens vaccinated with AIV A/turkey/Wisconsin/68, which was the virus component common to both monovalent and polyvalent vaccines. The magnitude of the serologic responses and protection against challenge-exposure were dependent on the concentration of virus in the vaccines. These data indicate that control of virulent AIV in chickens and turkeys by vaccination with inactivated vaccines may be feasible.     

Pharmacokinetics of midazolam in sevoflurane-anesthetized cats

ObjectiveTo estimate the pharmacokinetics of midazolam and 1-hydroxymidazolam after midazolam administration as an intravenous bolus in sevoflurane-anesthetized cats.Study designProspective pharmacokinetic study.AnimalsA group of six healthy adult, female domestic cats.MethodsAnesthesia was induced and maintained with sevoflurane. After 30 minutes of anesthetic equilibration, cats were administered midazolam (0.3 mg kg^–1) over 15 seconds. Venous blood was collected at 0, 1, 2, 4, 8, 15, 30, 45, 90, 180 and 360 minutes after administration. Plasma concentrations for midazolam and 1-hydroxymidazolam were measured using high-pressure liquid chromatography. The heart rate (HR), respiratory rate (f_R), rectal temperature, noninvasive mean arterial pressure (MAP) and end-tidal carbon dioxide (Pe′CO₂) were recorded at 5 minute intervals. Population compartment models were fitted to the time–plasma midazolam and 1-hydroxymidazolam concentrations using nonlinear mixed effect modeling.ResultsThe pharmacokinetic model was fitted to the data from five cats, as 1-hydroxymidazolam was not detected in one cat. A five-compartment model best fitted the data. Typical values (% interindividual variability where estimated) for the volumes of distribution for midazolam (three compartments) and hydroxymidazolam (two compartments) were 117 (14), 286 (10), 705 (14), 53 (36) and 334 mL kg^–1, respectively. Midazolam clearance to 1-hydroxymidazolam, midazolam fast and slow intercompartmental clearances, 1-hydroxymidazolam clearance and 1-hydroxymidazolam intercompartment clearance were 18.3, 63.5 (15), 22.1 (8), 1.7 (67) and 3.8 mL minute^–1 kg^–1, respectively. No significant changes in HR, MAP, f_R or Pe′CO₂ were observed following midazolam administration.Conclusion and clinical relevanceIn sevoflurane-anesthetized cats, a five-compartment model best fitted the midazolam pharamacokinetic profile. There was a high interindividual variability in the plasma 1-hydroxymidazolam concentrations, and this metabolite had a low clearance and persisted in the plasma for longer than the parent drug. Midazolam administration did not result in clinically significant changes in physiologic variables.     

Phylogenetic analysis of the sigma 2 protein gene of turkey reoviruses

The open reading frame of the S3 segment encoding the sigma2 protein of four turkey reovirus field isolates was analyzed for sequence heterogeneity. The turkey reoviruses we present here have a 97% amino acid identity to turkey NC 98. The S3 nucleotide and amino acid sequence similarity was < or =61% and 78%-80%, respectively, when compared to the chicken reovirus isolates. Comparison of amino acid sequences from chickens and turkeys with that of a duck isolate revealed a 53% and 55% similarity, respectively. Phylogenetic analyses, based on both nucleotide and amino acid sequence, resulted in three major groups among the avian reoviruses; these groups were clearly separated by species. The results of this study provide further evidence, based on the deduced sigma2 sequence, that turkey reoviruses form a distinct, separate group relative to chicken and duck isolates. In addition, as a result of the limited sequence identity with their avian counterparts, turkey reoviruses could potentially be considered a separate virus species within subgroup 2 of the Orthoreovirus genus.     

Prevalence and risk factors for Salmonella spp. and Campylobacter spp. caecal colonization in broiler chicken and turkey flocks slaughtered in Quebec, Canada

We conducted an observational study to estimate prevalence and risk factors for Salmonella spp. and Campylobacter spp. caecal colonization in poultry. Eighty-one broiler chicken and 59 turkey flocks selected among flocks slaughtered in the province of Quebec, Canada, were included in the study. Flock status was evaluated by culturing pooled caecal contents from about 30 birds per flock. Exposure to potential risk factors was evaluated with a questionnaire. Odds ratios were computed using multivariable logistic regression.

The prevalence of Salmonella-positive flocks was 50% (95% CI: 37, 64) for chickens and 54% (95% CI: 39, 70) for turkeys, respectively. Odds of Salmonella colonization were 2.6 times greater for chicken flocks which failed to lock the chicken house permanently. In turkeys, odds of Salmonella colonization were 4.8–7.7 times greater for flocks which failed to be raised by ≤2 producers with no other visitors allowed onto the premises, or origin from a hatchery.

The prevalence of Campylobacter-positive flocks was 35% (95% CI: 22, 49) for chickens and 46% (95% CI: 30, 62) for turkeys. Odds of colonization were 4.1 times higher for chicken flocks raised on farms with professional rodent control and 5.2 times higher for flocks with manure heap >200 m from the poultry house, and also increased with the number of birds raised per year on the farm and with the age at slaughter. For turkeys, odds of Campylobacter flock colonization were 3.2 times greater in flocks having a manure heap at ≤200 m from poultry house and 4.2 times greater in flocks drinking unchlorinated water.     

Failure of Heterakis bonasae to transmit Histomonas meleagridis

Studies were conducted to determine whether Heterakis bonasae eggs from bobwhite quail infected with Histomonas meleagridis would transmit histomoniasis to turkeys. Fifteen helminth-free bobwhites were inoculated per os with embryonated H. bonasae eggs. Each bobwhite was then infected with H. meleagridis via rectal inoculation. Bobwhites that developed cecal lesions rarely retained mature H. bonasae. H. bonasae eggs recovered from bobwhites exposed to or known to have concurrent H. meleagridis infections were inoculated per os to eleven helminth-free turkeys. None of the turkeys developed H. meleagridis infections.     

Determination of chicken and turkey plasma and serum protein concentrations by refractometry and the biuret method

Plasma and serum protein concentrations were determined in chickens and turkeys by refractometry (with human and veterinary refractometers) and by the biuret method. Chicken and turkey serum protein values were significantly lower than respective plasma protein values according to both methods. Refractometer readings for both plasma and serum correlated closely with the results of the biuret test (r2 = 0.72 to 0.97). These findings indicate that plasma and serum protein values may be determined accurately in chickens and turkeys with a handheld refractometer.     

Cloning of comparative gene identification-58 gene in avian species and investigation of its developmental and nutritional regulation in chicken adipose tissue

Adipose triglyceride lipase (ATGL) is the rate-limiting enzyme of lipolysis in chicken adipose tissue. Its regulation is not fully understood. Recent studies suggest ATGL may be regulated by physical protein-protein interactions. Comparative gene identification 58 (CGI-58) has been identified as an activator of ATGL in mice. The purpose of the current study was to clone and sequence the CGI-58 gene in avian species and to investigate its regulation during development, fasting, and refeeding. Here, we report the cloning and sequencing of the complete coding sequence of CGI-58 and the deduced AA sequences for the domestic chicken, turkey, and Coturnix quail. The CGI-58 protein is a 343-AA protein in the chicken and quail, and a 344-AA protein in the turkey. Sequence comparisons with the human and mouse show that the CGI-58 gene is highly conserved among avian and mammalian species, with complete identities at the predicted lipid-binding site. Cell fractionation of chicken fat cells and stromal-vascular cells revealed that CGI-58 is expressed primarily in mature adipocytes (P < 0.01). When compared in multiple organs and tissues, avian CGI-58 is expressed predominantly in the adipose tissue (P < 0.001), similar to ATGL. To understand CGI-58 expression during adipose tissue development, its mRNA expression was measured along with ATGL and stearoyl CoA desaturase (SCD-1) mRNA, an adipogenic marker, in embryos and adults. Messenger RNA expression of CGI-58 increased (P < 0.05) immediately after hatching, concurrent with peak ATGL expression. It is interesting that CGI-58 remained somewhat increased at posthatch d 11 and 33 as SCD-1 mRNA expression increased (P < 0.05). To evaluate the response of CGI-58 to nutritional status, chickens and quail were fasted for 24 h and subsequently refed. After the fasting period, CGI-58 mRNA was induced (P < 0.05) for both chickens and quail and was returned to control levels upon refeeding. The ATGL mRNA responded similarly, increasing dramatically after fasting and quickly decreasing with refeeding. The direct relationship between CGI-58 and ATGL mRNA expression indicates a role for CGI-58 in activating ATGL-mediated lipolysis in avian species.