Specific mucosal IgA immunity in turkey poults infected with turkey coronavirus

The objective of this study was to elucidate the kinetics and magnitudes of specific IgA antibody responses in intestines of turkey poults infected with turkey coronavirus (TCV). Turkey poults were orally inoculated with TCV at 10 days of age. Intestinal segment cultures were administered for duodenum, jejunum, and ileum and the IgA antibody responses were analyzed at 1, 2, 3, 4, 6, or 9 weeks post-infection (PI) in two different experiments. The kinetics of virus-specific IgA antibody responses in duodenum, jejunum, and ileum were similar: gradually increased from 1 week PI, reached the peak at 3 or 4 weeks PI, and declined afterward. The virus-specific IgA antibody responses in duodenum, jejunum, and ileum showed negative correlation with duration of TCV antigen in the corresponding locations of intestine with Spearman's correlation coefficient of -0.85 (p=0.034), -0.74 (p=0.096), and -0.75 (p=0.084), respectively. Moreover, the virus-specific IgA antibody responses in serum were positively correlated with that of duodenum (coefficient=0.829, p=0.042), jejunum (coefficient=0.829, p=0.042), and ileum (coefficient=0.771, p=0.072) segment cultures, suggesting that the induction of specific IgA response in serum was predictive of an IgA response in intestine. The results indicate that intestinal mucosal IgA antibodies to TCV are elicited in turkeys following infection with TCV. The local mucosal antibodies may provide protective immunity for infected turkeys to recover from TCV infection.     

Brain monoamine concentrations in turkey poults infected with Bordetella avium

Six hours post-hatch, large white turkey poults were inoculated intranasally with 5 X 10(7) organisms of the "W" isolate of Bordetella avium. Three hours after inoculation and subsequently on days 7, 10, 14, 21, and 28 postinoculation, 30 infected and 30 uninfected control poults were injected intramuscularly with alpha methylparatyrosine (AMPT, 250 mg/kg), and an additional 30 of each group received a saline vehicle. Three hours after AMPT injection, whole brains from treated and untreated poults from both infected and control groups were removed, weighed, and frozen until assayed for norepinephrine (NE), dopamine (DA), and serotonin (5-HT). B. avium-infected poults had a significant reduction in steady-state NE and Da and a greater depletion of NE and DA after AMPT treatment compared with control poults. Infected poults had significantly reduced whole brain 5-HT concentrations, which persisted through 21 days postinoculation. Altered brain NE, DA, and 5-HT concentrations suggest that the B. avium-infected poults may be less able to cope with additional stressors.     

Rickets in turkey poults

Fifteen outbreaks of rickets were diagnosed in turkey poults in Saskatchewan between 1978 and 1981. No relationship to farm, source of poults, or source of feed was apparent. Most outbreaks started when the poults were between 10 and 14 days of age, and they had recovered by 28 days of age. Losses varied from 1% to 14% of poults started. Skeletal lesions were characteristic of a vitamin D or calcium deficiency. On the basis of chemical analyses, adequate levels of calcium and phosphorus and proper amounts of vitamin premixes were present in the feed, but in five outbreaks biological feed tests implicated feed as a causative factor. The severity of rickets in poults fed defective feeds was markedly reduced by providing the poults with extra vitamin D in the drinking water or by injection. Two premixes used in different feeds contained adequate available vitamin D on the basis of biological testing. In some of the outbreaks, the rickets may have resulted from inadequate distribution of vitamin D in the feed, destruction of vitamin D during feed processing, or some unknown factor in the feed interfering with vitamin D utilization.     

Characterization of turkey coronavirus from turkey poults with acute enteritis.

The present study was to characterize turkey coronavirus associated with turkey poult enteritis and mortality. Intestinal contents or intestines from affected turkey poults and inoculated turkey embryos contained coronaviruses as revealed by electron microscopy or were positive for turkey coronavirus by immunofluorescent antibody assay. Sucrose density gradient ultracentrifugation of the virus-containing intestinal homogenate yielded two opalescent bands corresponding to the buoyant densities of 1.14-1.15 and 1.18-1.20 g/ml, respectively. Coronaviral particles from intestinal contents or the sucrose density gradient preparation were mainly spherical in shape and had envelope and central depression. They were surrounded by a fringe of regularly spaced petal-shaped projections attached to the particles by a short stalk. Purified viruses hemagglutinated rabbit erythrocytes with a titer of 16. Major protein bands of purified viruses analyzed by SDS-PAGE were located at 200, 100-110, 50-60, and 30-35 kDa. The patterns of protein bands were consistent with those of Minnesota or Quebec turkey coronavirus isolates. A 568 bp nucleotide fragment of turkey coronavirus spike protein gene was amplified from RNA of inoculated turkey embryo intestine or purified virus. Sequence analysis of the 568 bp PCR product revealed high degree of identity with the corresponding spike protein gene sequence of human and bovine coronaviruses. The results indicated that turkey coronavirus was associated with turkey poults with acute enteritis.     

Vitamin A deficiency in turkey poults.

Vitamin A deficiency was diagnosed in a commercial flock of 13,000 4-6-week-old turkey poults in the summer of 2004. The birds were initially submitted for examination because of a 3% increase in the reported daily mortality of the flock. Clinically, affected birds had stunted growth and ruffled feathers, showed signs of incoordination, and were depressed. At necropsy, pale white pseudomembranous to mucoid material was observed on the mucosal surface of the tongue, oral cavity, portions of the esophagus, and the crop of some birds. Histologically, there was squamous metaplasia of the mucosal epithelium of the oral mucosa, esophagus, sinuses, nasal glands, bronchi, proventriculus, and the bursa of Fabricius. Vitamin A was not detected in the feed sample at a detection limit of 0.5 mg/kg. Serum vitamin A concentrations in 7 birds were very low and ranged from 0.05 to 0.1 mg/L. Vitamin A concentrations in livers were extremely low (0.1 mg/kg wet weight, 1/7 poults) or undetectable (< 0.1 mg/kg wet weight, 6/7 poults). A diagnosis of vitamin A deficiency was made based on gross and microscopic lesions and vitamin A concentrations in serum, liver, and feed. To the authors' knowledge, this is the first documented case of vitamin A deficiency in poults submitted from a commercial meat turkey producer comparatively depicting the gross and microscopic lesions with those found in other species of birds and mammals.     

Salt poisoning in turkey poults

A 4% mortality in 5-to-11-day-old turkey poults was attributed to 1.85% sodium chloride in the feed. The syndrome included peracute respiratory distress, ascites, and sudden death that resembled peracute heart failure. Clinical signs were observed only in the final phase of the toxicity, but progressive histologic lesions were found. Live, apparently unaffected poults showed increases in intracellular glycogen and cytoplasmic granularity, loss of striation, and early mild intercellular myocardial edema; similar but more severe histologic lesions were seen in live, ascites-affected poults. The ascites-affected poults had hydropericardium and hydrothorax which seemed to develop just minutes before death. Ultrastructurally, focal areas of myocardial cells exhibited myofibrillar disarray, lysis of myofilaments, widened Z-bands, and dilation of sarcoplasmic reticulum.     

In vitro cellular migration of leukocytes from turkey poults infected with Alcaligenes faecalis

The ability of peripheral blood leukocytes from young turkey poults to migrate in vitro was investigated. Migration from capillary tubes was relatively rapid and was usually complete in 2 hours. Leukocyte migration was significantly enhanced in Alcaligenes faecalis-infected turkeys compared with uninfected controls at 1, 2, 5, and 6 weeks of age.     

Tracheal cilia response to exogenous niacin in drinking water of turkey poults infected with Bordetella avium.

Niacin was added daily to the drinking water of control and Bordetella avium-infected turkey poults at a dosage of 0, 70, and 280 mg/liter over a 2-week experimental period. Fourteen days postinoculation, tracheal sections were examined by histological and morphometrical analysis of cilia, as well as agar plate isolation for bacteria. Infected poults exhibited a 96-97% loss of cilia along the tracheal epithelial border, compared with only a 4-5% loss in controls. Infected poults receiving niacin in the drinking water exhibited only a 61.0% and 76.0% loss of cilia at doses of 70 mg/liter and 280 mg/liter, respectively. The results indicate that niacin treatment may influence the pathogenicity of B. avium infection.     

Furazolidone toxicity in neomycin-treated turkey poults

Furazolidone (FZ) toxicity was evaluated in turkey poults treated with neomycin at a dose of 20 mg/kg body weight for 5, 10, or 26 days. Neomycin treatment had no effect on FZ-induced anorexia, delayed the onset of altered electrocardiographic patterns by approximately 1 week, and did not significantly affect the development of FZ-induced cardiomyopathy. Data indicated that FZ toxicity is not significantly altered by the gut microflora.     

Enteric viruses in diarrheic turkey poults

Thirty-three intestinal samples from 10-to-21-day-old diarrheic turkey poults were examined for the presence of enteric viruses by electron microscopy. Samples originated from 32 flocks in six commercial operations located in six states. Mortality in these flocks ranged from 3 to 15%, and birds from recovered flocks varied greatly in size. Rotavirus-like agents (RVLA) were the most common viruses associated with diarrhea outbreaks in the flocks examined, occurring in five out of six operations. Other viruses detected either singly or in combination, in order of prevalence, were astroviruses, reoviruses, rotaviruses, enteroviruses, and adenoviruses. With the exception of RVLA and rotaviruses, the other viruses were identified solely on the basis of morphology. Salmonellae were isolated from only one of the intestinal samples. By electron microscopy, RVLA were morphologically indistinguishable from rotaviruses, occurring as both 55-nm single-shelled and 70-nm double-shelled particles. However, immune electron microscopy was useful for antigenic differentiation of these two viruses. Turkey rotaviruses reacted with antisera to porcine and bovine rotaviruses, whereas turkey RVLA did not. Neither turkey rotaviruses nor RVLA reacted with antisera to porcine para-rotavirus or an antigenically distinct bovine rotavirus (bovine rotavirus-like agent). Similarly, convalescent anti-turkey RVLA serum (from recovered specific-pathogen-free poults) reacted with homologous virus but did not react with mammalian or avian rotaviruses or reoviruses. Further, RVLA were found to possess RNA electrophoretic migration patterns unlike those of conventional rotaviruses or reoviruses. This trait was used as an additional means of differentiating these viruses.     

Effect of fasting on plasma thyroid and adrenal hormone levels in turkey poults infected with Bordetella avium.

Plasma triiodothyronine (T3), thyroxine (T4), and corticosterone (CS) were measured in fasted and nonfasted control and Bordetella avium-infected poults. The stress of B. avium infection increased plasma CS, and fasting for 24 hours caused a further significant increase in CS levels. Plasma T3 was not affected by the infection, but fasting caused a significant reduction in both control and infected poults. Plasma T4 of fasted poults was increased in both control and infected groups, but infection attenuated the plasma T4 response. Total iodothyronines were increased in the control-fasted poults more than in infected-fasted poults, indicating a reduced responsiveness to stress by the thyroids of infected poults. Changes in plasma thyroid hormones and CS partially explain the decreased body weight gain and decreased body temperature after exposure to B. avium.     

Protection of turkey poults from Bordetella avium infection and disease by pili and bacterins

The role of pili in protection against Bordetella avium infection in turkey poults was studied. An isolate that produced the largest number of pili under growth conditions developed in our laboratory was used for preparation of pili and bacterin and for challenge. The pili were isolated, purified, examined by electron microscopy, and tested for purity by gel electrophoresis. Poults were vaccinated with oil-adjuvant pili, formaldehyde- or merthiolate-inactivated bacterins, or a commercial bacterin. Poults were vaccinated once or twice subcutaneously at different ages and challenged intranasally with a pathogenic B. avium isolate 5 days following the last vaccination. A few vaccinated birds had very mild clinical signs. B. avium was isolated from the sinuses of a few vaccinated birds, and growth was scanty. The mean colony counts from tracheal sections was significantly higher (P less than 0.1) in unvaccinated challenged poults than in vaccinated challenged poults. It is postulated that B. avium pili are important immunogens in turkey poults.     

The infection of turkey poults with Histomonas meleagridis by contact with infected birds or contaminated cages

The conditions under which infection with Histomonas meleagridis could spread from directly inoculated turkey poults to uninoculated poults without the aid of invertebrate hosts or vectors was investigated in several experiments. In three experiments in battery cages, uninoculated poults were commingled with directly infected birds on pine-shaving litter. Directly exposed birds were inoculated per cloaca with H. meleagridis by means of a plastic pipette tip attached to a 10-ml syringe or orally gavaged with fresh cecal droppings from donor turkeys 4 days postinoculation (PI). Of the cloacally inoculated controls in these experiments, 31 of 44 (70.5%) birds had severe lesions ofhistomoniasis at 14 days PI, whereas none of the orally gavaged birds became infected. Histomoniasis developed in 11 of 36 (30.5%) birds allowed to commingle with inoculated birds. In other treatments, poults were allowed only contact with droppings from directly inoculated birds after the infected birds were removed from the cages. This was done for a single period of 1 hr or repeated five times. Four of 32 birds (12.5%) became infected in this way after the single exposure, whereas only four of 44 birds (9.1%) exposed five times developed lesions. In a comparison of floor materials, 35 of 35 control birds inoculated per cloaca developed severe liver and cecal lesions, irrespective of litter. Uninoculated birds allowed to commingle with infected birds on paper or pine shavings became severely infected in all cases (12/12 and 12/12 birds, respectively), whereas only 33% of those on wire-floored cages became infected (4/12). These results suggest that transmission of infection is more likely to occur as a result of direct contact between birds than from contact with litter or fecal material.     

Effect of Bordetella avium infection on electrocardiograms in turkey poults.

Electrocardiograms (ECGs) were recorded from turkey poults infected with the W isolate of Bordetella avium. Strip chart data (amplitudes and intervals) were measured at 7, 14, 21, and 28 days postinoculation and compared with data from uninoculated controls. B. avium infection altered P-, RS-, and T-wave amplitudes, as well as P-R and S-T intervals throughout the 4-week experimental period. Heart rates were similar over the 4-week period in control poults, while rates in the infected birds were variable. Alterations in ECGs associated with B. avium infection appeared to be the result of disturbances in the cardiovascular system and may be associated with the pathogenicity of the organism in turkey coryza.     

Oral challenge of turkey poults with Mycoplasma iowae

Day-old poults were inoculated orally each day for 7 days with 0.2 ml of Mycoplasma iowae, strain D112, 10(8) colony-forming units/ml. Cloacal swabs were taken from each poult during the inoculation period and at selected intervals until 21 days after the last inoculation. Most poults shed mycoplasmas persistently after inoculation. Cloacal swabs from eight out of ten poults were positive at 21 days after the last inoculation. Feces of poults in the infected group were normal, and there was no significant rise in cloacal temperature. At necropsy, mycoplasmas were recovered from tissues of the respiratory tract, gastrointestinal tract, spleen, and kidney. In the gastrointestinal tract, the most frequent recoveries were from the wall of the distal portion of the small intestine, cecum, and large intestine. Recovery of M. iowae from these organs and tissues indicated infection following oral challenge.     

The effects of stray voltage on turkey poults

Three successive flocks of turkey poults experienced cumulative mortality of 10% to 26% through the fifth week of brooding. Stray electrical voltage was suspected after no definitive laboratory diagnosis could be made and no evidence of management deficiency was found. Alternating current voltages of 0.2 to 2.5 volts were detected between waterers and the floor and between the water line and gas line. When the water line was equipment-grounded to the electrical service entrance, the subsequent flock had no mortality problem. A series of experiments was conducted to determine the sensitivity of turkey poults to alternating current. Based on these experiments, the voltage levels measured at the farm probably did not cause the mortality experienced in the three flocks. The reason for the farm problem could have been 1) the poults experienced higher voltage than was present when measurements were taken, 2) the voltage may have been intermittent, or 3) there was a difference between the farm environment and the cage battery environment in the experiments.     

A survey of enteric viruses of turkey poults

Intestinal samples from 91 turkey flocks between 1 day and 5 weeks of age were examined for enteric viruses using electron microscopy and electropherotyping. These flocks originated from eight operations in six states. Individual flocks were sampled only once. At the time of sampling, 31 flocks were considered normal/healthy and 60 were considered to have enteric disease. The most frequently identified viruses from diseased flocks were astroviruses (78%) and rotavirus-like viruses (RVLVs) (67%). Far less frequent were rotaviruses (22%), atypical rotaviruses (12%), enteroviruses (5%), and reoviruses (2%). Only 10% of the samples from diseased flocks were negative, but 48% of the samples from normal/healthy flocks were negative. Astroviruses and RVLVs were far less frequent in normal/healthy flocks than in diseased flocks, but rotaviruses were identified slightly more often. No viruses were detected from flocks sampled within the first few days of life. Astrovirus infections seemed to occur at an earlier age than other virus infections. Seldom was only one type of virus identified. Astrovirus + RVLV was the most frequently identified combination in diseased flocks.