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Mycoplasmas in wild turkeys living in association with domestic fowl.

One hundred and nineteen Merriam's wild turkeys (Meleagris gallopavo merriami) and 31 domestic chickens coexisting on a ranch in west-central Colorado (USA) were surveyed for mycoplasmosis by serologic and cultural methods. Although no clinical signs were apparent in any wild turkeys tested, 51 (43%) had positive rapid plate agglutination (RPA) reactions for M. gallisepticum (MG) and/or M. synoviae (MS); 37% of 56 adults and 48% of 63 subadults were classified as positive reactors to MG and/or MS. No turkeys tested in 1992 (n = 61) and 17 (29%) of 58 turkeys tested in 1993 were RPA-positive for M. meleagridis (MM). Hemagglutination inhibition (HI) test results were negative for MG, MS and MM as were most enzyme-linked immunosorbent assay (ELISA) test reactions (MG = 99%, MS = 93%, MM = 87%). Immunoblotting showed mild to moderate reactivity to MG proteins in 49% of 41 samples tested. Most chickens were strongly positive for MS by RPA (81%), HI (58%) and ELISA (87%); 48% also were positive for MG by RPA but all were MG-negative by HI and ELISA. No pathogenic mycoplasmas were isolated from either group of birds. Mycoplasma gallopavonis was commonly identified from the wild turkeys, and M. gallinaceum was isolated from both the chickens and wild turkeys. In a transmission study conducted in 1994, disease-free domestic turkeys failed to seroconvert when co-housed with wild turkeys from this population that were RPA-positive for MG. Collectively, the results of this study were inconclusive regarding the status of pathogenic mycoplasmas within this wild turkey population.

Agglutination Tests↗

Experimental studies of interactions between wild turkeys and black-legged ticks.

Wild turkeys are increasing in abundance and distribution in eastern North America, but their potential role as hosts for ticks, or as predators on ticks, is unknown. We performed two experiments, one to determine whether juvenile black-legged ticks (Ixodes scapularis) feed successfully on turkeys, and the other to determine if turkeys depredate adult black-legged ticks in forest habitats. Of 550 larval ticks placed directly on 5 captive wild turkeys, none engorged and only 7 (1.3%) were recovered; the remainder apparently were consumed during preening. Of 165 nymphal ticks placed on the turkeys, 5 engorged and 8 unengorged ticks were collected; 152 (93.3%) were apparently consumed. Of 250 adult ticks introduced into forest enclosures exposed to turkey foraging, 89.5% were recaptured, which was not significantly different from the 92.2% recaptured in control enclosures from which turkeys were excluded. We conclude that wild turkeys are unlikely to host juvenile black-legged ticks in nature, and that turkey foraging is unlikely to reduce local density of adult ticks.

Animals↗

Experimental and serologic observations on avian pneumovirus (APV/turkey/Colorado/97) infection in turkeys.

An avian pneumovirus (APV) was isolated from commercial turkeys in Colorado (APV/Colorado) showing clinical signs of a respiratory disease. The results of virus neutralization and indirect fluorescent antibody tests showed that the APV/Colorado was partially related to APV subgroup A but was unrelated to APV subgroup B. Turkeys experimentally inoculated with the APV/Colorado were observed for signs, lesions, seroconversion, and virus shedding. Thirty-six 7-wk-old turkeys were distributed into three groups. Eighteen turkeys were inoculated oculonasally with APV/Colorado, six were placed in contact at 1 day postinoculation (DPI), and 12 served as noninoculated controls. Tracheal swabs and blood samples were collected at 3, 5, 7, 10, 14, and 21 DPI. Tissues were collected from three inoculated and two control turkeys on aforementioned days for pathologic examination and APV isolation. Inoculated turkeys developed respiratory disease, yielded APV at 3, 5, and 7 DPI, and seroconverted at 10 DPI. Contact turkeys yielded APV at 7 and 10 DPI. No gross lesions were observed in the turbinates, infraorbital sinuses, and trachea. However, microscopic examination revealed acute rhinitis, sinusitis, and tracheitis manifested by congestion, edema, lymphocytic and heterophilic infiltration, and loss of ciliated epithelia. The inflammatory lesions were seen at 3 DPI and became extensive at 5 and 7 DPI. Active regenerative changes in the epithelia were seen at 10 and 14 DPI. Serologic survey for the presence of antibodies in commercial turkeys (24,504 sera from 18 states) and chickens (3,517 sera from 12 states) to APV/Colorado showed seropositive turkeys in Minnesota, North Dakota, and South Dakota and no seropositive chickens. This report is the first on the isolation of an APV and APV infection in the United States.

Animals↗

An epornitic of fatal chlamydiosis (ornithosis) in South Carolina turkeys.

An unusual epornitic of fatal chlamydiosis occurred in a flock of 10,283 domestic turkeys in South Carolina. Total mortality over a 2-week period was 483 birds (4.7% of the flock). The principal gross lesion was severe pericarditis, but there was little or no airsacculitis, an observation at variance with many previous reports of chlamydiosis. Furthermore, an unusually heavy infestation of the turkeys with sanguivorous black flies (Simulium slossonae and S congareenarum) was observed at the time of the epornitic, an occurrence that may have permitted rapid transmission of chlamydiae between turkeys in the affected flock. The strains of Chlamydia psittaci isolated from naturally infected turkeys caused pericarditis and heptopathy as well as occasional airsacculitis, with a 41% mortality in intravenously (IV) inoculated turkeys. Turkeys inoculated intramuscularly (IM) or intraperitoneally (IP) did not die; however, airsacculitis was observed in more than 85% of turkeys inoculated intraperitoneally or exposed to infection by pen contact with inoculated turkeys. The strain was highly infectious but not lethal by the latter method of transmission. The strain was similar to other virulent chlamydiae isolated from turkeys, in that small numbers of the organism caused fatal infection in guinea pigs when inoculated IP.

Air Sacs↗

Effects of high and low environmental temperatures on clinical course of fowl cholera in turkeys.

Turkeys inoculated with Pasteurella multocida either in the palatine air spaces or via drinking water were maintained t high (33.4-37.4 C), low (2.6-5.3 C), and moderate (19.8-22.4 C) temperatures in temperature-controlled chambers to determine the influence environmental temperature had on the pathogenesis of fowl cholera. In inoculated turkeys maintained at high temperatures, there was a delay in the onset of depression and, in most instances, in mortality in relation to those at low or moderate temperatures. In turkeys inoculated via drinking water and maintained at low temperatures, there was a higher mortality than in those at high or moderate temperatures. In turkeys maintained at low temperatures during the preinoculation period, the onset of depression was accelerated more after inoculation than in those maintained at moderate temperatures before inoculation. The percentage of leukocytes in the hematocrit was higher in turkeys inoculated int he palatine air spaces and maintained at low temperatures than in turkeys similarly inoculated but maintained at high or moderate temperatures. Cloacal temperatures were higher in all inoculated turkeys maintained at high temperatures than in those at low or moderate temperatures, and decreased markedly when turkeys became moribund. In turkeys inoculated in the palatine air spaces, deaths from pneumonia occurred more frequently at low temperatures and torticollis occurred more frequently at high temperatures than at the other temperatures.

Administration, Oral↗

Transmission of marble spleen disease in turkeys and pheasants.

Marble spleen disease (MSD) of ring-necked pheasants (Phasianus colchicus L.) was transmitted in the laboratory to pheasants and turkeys (Meleagris gallopavo L.) by oral, colonic, and intravenous routes of inoculation, using cell-free supernatant fluids of splenic suspension from birds with naturally occurring MSD. Gross lesions consisted of large mottled spleens, a lesion more prominent in infected pheasants than in turkeys. The only microscopic lesion and also the criterion of infection were the presence of typical intranuclear inclusions of MSD. Similar to microscopic observations in naturally infected birds was the presence of inclusions in cells of spleen, bone marrow, liver, lung, bursa of Fabricius, and intestine-associated lymphoid tisse (IALT) OF EXPERIMENTALLY INFECTED BIRDS. Ultrastructural examination of splenic cells with intranuclear inclusions from turkey and pheasant with experimentally transmitted disease revealed viral particles and inclusions morphologically indistinguishable from those observed in naturally infected birds. Results of viral isolation procedures in turkey embryo chorioallantoic membrane (CAM) and yolk sac, as well as in turkey embryo fibroblast (TEF) and turkey kidney cell (TKC) cultures, were negative. Serologic assay by agar gel immunodiffusion tests indicated cross-reactivity between splenic MSD antigen and spleinic hemorrhagic enteritis (HE) of turkey antigen. Lines of fusion were formed between the splenic antigen from naturally occurring MSD in pheasants, experimentally transmitted MSD in turkeys, and HE of turkeys, using the homologous serum antibody to each of the 3 antigens.

Animals↗

Experimental toxoplasmosis in turkeys.

Fourteen 2-3-wk-old turkeys were inoculated orally with 10(5) or 10(4) infective oocysts of the ME 49 strain of Toxoplasma gondii. Of the 8 turkeys given 10(5) oocysts in experiment 1, 3 died or were killed 12 or 14 days after inoculation (DAI) because of respiratory distress associated with a concomitant Aspergillus-like fungus infection. The remaining 5 turkeys remained normal and were killed 62 DAI. Toxoplasma gondii was isolated in mice from the heart of all 5, from the breast muscles of 2, leg muscles of 3, and from the brains and livers of none of the turkeys. All 6 turkeys fed 10(4) oocysts in experiment 2 remained clinically normal until necropsy on 41 DAI; T. gondii was isolated from pooled tissues from each turkey. All 14 turkeys developed high antibody titers to T. gondii in the modified agglutination test (MAT) using formalinized tachyzoites. The enzyme-linked immunosorbent assay (ELISA) was as sensitive as MAT for detecting T. gondii antibodies in turkey sera. The latex agglutination and indirect hemagglutination tests were less sensitive than the MAT and ELISA. No dye-test-measurable antibodies were found in sera of any turkey.

Agglutination Tests↗

Eimeria tenella and E. acervulina: differences in ability to elicit cross-species protection as compared with the turkey coccidium, E. adenoeides.

Repeated oral inoculation of turkey poults with large doses (1 x 10(6) oocysts) of the chicken coccidia, Eimeria tenella or E. acervulina, failed to prevent weight loss, poor feed conversion, and intestinal pathology in turkeys challenged with the turkey coccidium, E. adenoeides. Invasion by E. tenella in turkeys was significantly greater than invasion by E. adenoeides in chickens; by 24 hr postinoculation (PI), the numbers of E. tenella and E. adenoeides sporozoites in the ceca had decreased markedly as compared with the numbers that initially invaded, and they did not differ significantly from each other. At 24 hr PI, however, transfer of cecal scrapings from chickens or turkeys inoculated with E. adenoeides produced infection in 53% of the recipient turkeys, but transfer of scrapings from either chickens or turkeys inoculated with E. tenella failed to produce infection in 20 attempts with recipient chickens. Cultured chicken peripheral blood monocytes (PBMs) that were inoculated with E. adenoeides sporozoites contained numerous vesicles that were recognized by the refractile body-specific monoclonal antibody 1209; the number of vesicles was markedly decreased in PBM cultures inoculated with gamma-irradiated E. adenoeides sporozoites. Very few vesicles were detected in the cytoplasm of turkey PBMs that contained E. tenella sporozoites, and none were detected in turkey PBMs containing E. adenoeides sporozoites. The survival of infective sporozoites, along with the secretion of refractile body antigen, may be more critical to the development of cross-species immunity than the number of sporozoites that initially invade the foreign host.

Animals↗

Susceptibility of convalescent turkeys to pulmonary aspergillosis.

Pulmonary lesions resulting from Aspergillus fumigatus inoculation were assessed in convalescent turkeys and compared with those in previously noninoculated (control) turkeys. In addition, lesions observed in small Beltsville white (SBW) turkeys were compared with those in broad-breasted white (BBW) turkeys challenged with the same inoculum. Turkeys were challenged by unilateral posterior thoracic air sac (PTAS) inoculation, rechallenged via the contralateral air sac after 5 wk, and then necropsied 1 wk later. Pulmonary lesions induced by the initial challenge had resolved in 6 of 10 SBW and 9 of 10 BBW turkeys. However, convalescence did not protect against pulmonary aspergillosis subsequent to rechallenge; 10 of 10 SBW and 9 of 10 BBW developed granulomatous pulmonary lesions on the side of reexposure. A greater proportion of control SBW turkeys developed pneumonia and airsacculitis following challenge as compared with the BBW breed. Lesions were limited to the lower respiratory tract in all turkeys and were confined to the ipsilateral lung and PTAS in the singly inoculated control turkeys. This study demonstrates that convalescence from pulmonary aspergillosis does not confer protection against rechallenge but may, instead, decrease resistance to subsequent infection.

Animals↗

Response of specific-pathogen-free turkeys to vaccines derived from marble spleen disease virus and hemorrhagic enteritis virus.

Tissue-culture-propagated marble spleen disease virus (MSDV-TC) and two preparations of spleen homogenate (MSDV-SH and MSDV-SH-TC) were compared as anti-hemorrhagic enteritis virus (HEV) vaccines in specific-pathogen-free turkeys. Both types of vaccines spread horizontally among turkeys, induced anti-HEV antibodies, and protected turkeys against challenge with virulent HEV. Antibody development and horizontal spread of virus occurred earlier in turkeys given MSDV-SH or MSDV-SH-TC than in those given MSDV-TC. Virulent HEV was serially passed in MDTC-RP19 cells. The 30th passage virus (HEV-P30) was nonpathogenic for turkeys but was immunogenic. Turkeys exposed to HEV-P30 had viral antigen in the spleen, developed neutralizing antibodies, and resisted virulent HEV. The principal difference between MSDV-TC and HEV-P30 vaccines was that MSDV-TC caused well-defined splenomegaly in turkeys, whereas HEV-P30 protected turkeys without causing spleen enlargement.

Animals↗

Lung growth of the turkey, Meleagris gallopavo: II. Comparison of two genetic lines.

Comparisons of lung growth in two genetic lines of turkeys, one unselected and one selected for increased body mass, were used to evaluate the lung's alteration in structure with changes in body form or physiology. Seventy-two male turkeys, 36 genetically selected for early rapid growth and large pectoral musculature, and 36 unselected birds, were killed at 12 different ages to compare lung growth in the two lines. Body weights and lung volumes were determined. A three-level cascade sampling system was used to prepare lung tissue for qualitative and quantitative observation by light microscopy. Allometric equations describing growth of lung volume and lung compartments relative to body weight in two phases (tissue proliferation and equilibrated growth) were compared between lines of turkey for differences in slopes or intercepts. Means of data for 112- and 420-day-old birds were also compared. There were no qualitative histological differences observed between lungs of the two lines of turkey, yet there were morphometric differences in lung growth relative to body weight. During equilibrated lung growth, there was less rapid growth of air and blood capillary volumes and surfaces relative to body weight in the selected than in the unselected turkey. The gas-exchange compartment did not enlarge concomitant with the large increase in muscle mass of the selected turkeys, while large-vessel volume and small-airway volume grew similarly to body weight in both turkey lines. We conclude that the lung of the selected line of turkeys did not show an enlarged gas-exchange compartment relative to the greater body muscle mass, but it did show enlarged vessels and conducting airways.

Animals↗

Modulation of the prolactin response to thyrotropin releasing hormone by ovarian steroids in ovariectomized turkeys (Meleagris gallopavo).

The effect of thyrotropin releasing hormone (TRH) administered intramuscularly (im) on serum levels of prolactin (Prl) in ovariectomized (ovx) adult turkeys before and following the onset of photostimulation, before and during daily administration (im) of progesterone (P; 0.1, 0.4, or 1.0 mg/kg), estradiol benzoate (EB; 0.01, 0.1, or 0.2 mg/kg), or their combination (1.0 mg/kg EB + 0.1 mg/kg P) were studied. Ovariectomy reduced Prl levels in the serum of photostimulated turkeys, and blunted the Prl response to TRH administration. Progesterone treatment had no effect on basal serum Prl levels but the Prl response to TRH was higher in P-treated turkeys than in non-treated ovx turkeys. Basal serum Prl levels were higher (P less than 0.05) in the EB-treated ovx turkeys than in the untreated birds. The Prl response to TRH in ovx EB-treated turkeys was greatly increased (P less than 0.05). Progesterone treatment of EB-primed ovx turkey did not alter the basal levels of serum Prl or the Prl response to TRH administration. These results suggest that ovarian steroids may be responsible for the increased Prl secretion in the female turkey associated with laying.

Animals↗

Myocardial high-energy phosphate levels in cardiomyopathic turkeys.

A congestive cardiomyopathy (CCM) model occurs in inbred broad-breasted turkeys and is manifested by reduced hatchability and a high mortality within a week of hatching. In the survivors, cardiac dilation begins by 3-4 weeks of age and further mortality occurs from chronic congestive heart failure. The mechanisms behind these changes is unknown, and, therefore, we investigated what role, if any, myocardial energy metabolism might play in these events. Ventricular myocardial samples were obtained for analysis of adenine nucleotides (ATP, ADP, AMP) and creatine phosphate (CP) in control and CCM turkeys, 1-31 days old. The adenine nucleotide energy charge (EC) was calculated using the formula EC = ATP + 1/2ADP/(ATP + ADP + AMP). We found the myocardial ATP levels and EC in CCM hearts at 1-2 days were reduced. In control turkeys, no significant age-related differences were found in myocardial high-energy phosphate compounds or in the EC. This depression in the energy metabolism of CCM turkeys may also be reflected in their poor hatchability. By 6-10 days, however, ATP levels had recovered and remained normal despite the onset of cardiac dilation and failure at 3-4 weeks of age in CCM turkeys. Because CP levels in control and CCM turkey hearts were similar in all age groups, significant ischemia did not appear to be present after hatching in CCM turkeys. Our results suggest, therefore, that an insult probably prior to hatching produced depressed myocardial energy levels in CCM turkeys and led to reduced hatchability. This early insult appears to be significant, in that late cardiac dysfunction resulted despite the recovery of myocardial ATP levels.

Adenine Nucleotides↗

Turkey beta 2-microglobulin--II. Physiological parameters investigated by radioimmunoassay.

A competitive binding radioimmunoassay (RIA) was developed utilizing 125I-labeled turkey beta 2-microglobulin (beta 2m), rabbit anti-turkey beta 2m serum and polyethylene glycol for separation of bound and free antigen. The antibody-antigen reaction was demonstrated to be monospecific by immunofixation electrophoresis. Characteristic parameters of the RIA were: nonspecific binding, 5.5%; linear dose-response range, 0.24-64.0 ng turkey beta 2m; dose-response correlation coefficient, -0.995; assay sensitivity, 0.52 ng; upper limit of precision, 40.4 ng. RIA analysis of adult turkey tissue and organ homogenates revealed highest amounts (greater than 10 micrograms turkey beta 2m/g) in liver and kidney and intermediate levels (2-10 micrograms/g) in lymphoid organ (thymus, spleen, caecal tonsil, bursa), skin and lung extracts. Erythrocytes and peripheral blood lymphocyte extracts contained 8.0 and 5.1 micrograms/10(9) cells respectively whereas all other tissues examined expressed greater than 2.0 micrograms/g. The beta 2m content in turkey serum was 192.5 micrograms/ml. The molecular weight distribution of turkey beta 2m in serum determined by gel permeation chromatography consisted of a minor component of approximately 60,000 daltons and a major fraction eluting at a position characteristic of free beta 2m. A cross-reaction between turkey and mammalian beta 2ms was not observed.

Animals↗

Development and characterization of expressed sequence tags for the turkey (Meleagris gallopavo) genome and comparative sequence analysis with other birds.

Twenty-one randomly selected clones from a turkey (Meleagris gallopavo) pituitary complementary DNA (cDNA) library were sequenced to develop expressed sequence tags (ESTs) for this economically important avian species whose genome is among the least understood. Primers specific for the ESTs were used to produce amplicons from the genomic DNA of turkey, chicken (Gallus gallus), guinea fowl (Numidia meleagris), pigeon (Columba domestica), and quail (Corturnix japonica). The amplicons were sequenced and analyzed for sequence variation within- and similarity among-species and with GenBank database sequences. The proportion of shared bases between the turkey sequence and the consensus sequence from each of the other species ranged from 72% to 93% between turkey and pigeon and quail and between turkey and chicken, respectively. The total number of single nucleotide polymorphisms (SNPs) observed ranged from 3 in quail to 18 in chicken out of 4898 and 5265 bases analyzed, respectively. The most frequent nucleotide variation observed was a C-->T transition. Linkage analysis of one such SNP in the backcross progeny of the East Lansing reference DNA panel, localized TUS0005, the chicken sequence derived from primers specific for turkey TUT2E EST, to chromosome 4. The ESTs reported, as well as the SNPs may provide a useful resource for ongoing efforts to develop high utility genome maps for the turkey and chicken. The primers described can also be used as a tool in future investigations directed at further understanding the biology of the guinea fowl, pigeon and quail and their relatedness to the turkey.

Animals↗

FHF-2 in the turkey (Meleagris gallopavo).

A cDNA clone homologous to the fibroblast growth factor homologous factor (FHF-2) was isolated and sequenced from the turkey (Meleagris gallopavo). The DNA sequence of the turkey was almost identical to that of the chicken (99% similarity) differing at only 8 of 770 nucleotides in the coding region resulting in a single amino acid difference between these poultry species. The 3'UTR of the turkey FHF-2 gene was 445 nucleotides in length and included an imperfect CT microsatellite (ms) repeat. The sequence of the 3'UTR was amplified from genomic DNA of the chicken and found to be highly conserved differing at only three nucleotides when compared to the turkey. Length of the CT repeat was indifferent in a sample of 52 turkeys (monomorphic) however, the number of CT repeats was greater in the turkey than in the chicken. No inter-individual polymorphism was detected in multiple sequences of the 3'UTR of the FHF-2 gene in the turkey. Based on comparison of the turkey and chicken sequences, the mutation rate for coding and associated non-coding (3'UTR) regions of FHF-2 are approximately equal.

Amino Acid Sequence↗

Myocardial lipid composition in turkeys with dilated cardiomyopathy.

OBJECTIVE: The aim was to determine if reduced heart lipid peroxidation in turkeys with two forms of dilated cardiomyopathy, previously reported, was related to an alteration in the lipid composition of the ventricle. METHODS: Myocardial lipid composition was measured in turkeys with two types of dilated cardiomyopathy. Twenty six turkeys with naturally occurring dilated cardiomyopathy, six with furazolidone induced dilated cardiomyopathy, and 18 age matched control birds were used at 1 day, 9-10 days, and 38-78 days of age. Left ventricular fatty acid composition of the phospholipid, triglyceride, free fatty acid, and cholesterol ester fractions was analysed using gas chromatography. RESULTS: Significant age related changes were identified in the fatty acid composition of the heart. In the phospholipid fraction, linoleic acid (18:2 omega 6) values increased with age, while arachidonic acid values decreased. The saturated to unsaturated fatty acid ratio in control hearts was unchanged as a function of age in the phospholipid fraction. In the triglyceride fraction, however, this ratio decreased substantially between newly hatched and nine day old birds and then markedly increased in two month old controls. There was a striking alteration in the saturated to unsaturated fatty acid ratio in the triglyceride fraction of 2 month old cardiomyopathic birds; this ratio was markedly increased in the furazolidone induced cardiomyopathic turkey hearts (5.14 v 2.79 in controls) and markedly diminished (ie, 0.97 to 1.21) in the spontaneously cardiomyopathic turkeys. A significant increase in myristic (14:0) and decrease in linoleic (18:2 omega 6) acid concentration in the furazolidone group v control and a marked decrease in myristic and increase in linoleic acid concentrations in the spontaneously cardiomyopathic group v controls was present. CONCLUSIONS: (1) There is an age related alteration in the fatty acid composition of control turkey hearts. (2) Previously identified reduced lipid peroxidation in furazolidone induced and spontaneous cardiomyopathy in turkeys does not appear to be related to reduced concentration of polyunsaturated fatty acids. (3) The two forms of dilated cardiomyopathy are associated with markedly disparate alterations in the concentration of polyunsaturated fatty acids in the triglyceride fraction of 1-2 month old turkey hearts. The changes may be related, in part, to the pathogenesis in these two different forms of dilated cardiomyopathy.

Aging↗

Evidence for multiple prolactin receptor transcripts in the turkey.

Multiple prolactin receptor (PRL-R) mRNA transcript isoforms have been identified in mammals, but there are conflicting reports concerning the number of avian PRL-R isoforms. We hypothesized that multiple turkey PRL-R transcript isoforms exist and that PRL-R mRNA abundance may be related to reproductive status. Two turkey PRL-R cDNA fragments were generated using reverse transcriptase polymerase chain reaction (RT-PCR) that displayed a high degree of similarity to mammalian and avian PRL-R. Northern blot analysis of poly A+ mRNA hybridized to a turkey PRL-R riboprobe revealed a 3.1-kb band in the liver, oviduct, and testes. Additional 1.5- and 10.7-kb transcripts were found in the liver and testes, respectively. Hybridization of the same Northern blot to a chicken PRL-R probe verified the presence of a 3.1-kb transcript in all three tissues. A Northern blot was used to examine turkey PRL-R transcript isoform expression in laying hens. A 3.1-kb band was found in the pineal, infundibulum, magnum, isthmus, kidney, and intestine. In addition, 10.7- and 7.3-kb bands were detected in the pineal, magnum, isthmus, and intestine. Turkey PRL-R transcript isoforms were also examined throughout the reproductive cycle. The 10.7-, 7.3-, and 3.1-kb isoforms were detected in the oviduct, intestine, and pineal during each reproductive state. Turkey PRL-R mRNA levels were also compared during the reproductive cycle. Turkey PRL-R mRNA levels were greatest in laying hen pineal glands (P<0.05) and in incubating hen oviducts. This study provides the first evidence for multiple PRL-R mRNA transcript isoforms in turkeys.

Animals↗