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At least 19 recordsLinked to original sources
PubMed1992

Trace element distribution in growing feathers: additional excretion in feather sheaths.

The use of feathers is a non-invasive and repeatable method for biomonitoring trace element levels in birds and their ecosystems. Trace element levels were examined in different parts of growing flight feathers from young common terns (Sterna hirundo) to determine distribution of heavy metals and selenium, potential bias from using partially grown feathers, and whether additional heavy metals and selenium are excreted in feather sheaths that are sloughed before feathers are usually sampled. Lead and mercury levels were significantly higher in the distal fully formed portion of the growing feather (with no residual blood supply) compared to the proximal, growing portion of the feather with a residual blood supply, but no significant differences were evident for cadmium and selenium. These results suggest that using partially grown feathers underestimates the amount of lead and mercury in fully formed feathers and that higher levels of lead and mercury are sequestered in feathers than are present in the blood at any one time. Significantly higher concentrations of lead and cadmium, and significantly lower levels of mercury were in the sheath compared to the whole feather blade. These data suggest that birds excrete more lead and cadmium during molt than previously thought.

Animals↗
PubMed1991

A novel DNA virus associated with feather inclusions in psittacine beak and feather disease.

The nature of feather inclusions was characterized in 32 psittacine birds (30 cockatoos, one peach-faced lovebird (Agapornis roseicollis), and one red-lored Amazon parrot (Amazona autumnalis autumnalis] with naturally-acquired psittacine beak and feather disease. Intranuclear inclusions within feather epithelial cells and intracytoplasmic inclusions within macrophages in the feather epithelium and pulp cavity contained psittacine beak and feather disease viral antigen when stained by the avidin-biotin complex immunoperoxidase technique. Ultrastructurally, inclusions were observed primarily within macrophages and to a lesser extent within epithelial cell nuclei. Macrophage inclusions appeared as paracrystalline arrays of viral particles. Intranuclear inclusions were less well defined, although scattered viral particles were present. Intracytoplasmic and intranuclear particles in ultrastructural preparations were identified by colloidal gold labeling as psittacine beak and feather disease virus. Feather epithelium was more frequently and severely involved in the disease process than was adjacent follicular epithelium. Plucked feathers with an intact epidermal collar and feather epithelium were preferred to follicular biopsies for histopathologic examination.

Animals↗
PubMed1975

The properties of bird feathers as converse piezoelectric transducers and as receptors of microwave radiation. II. Bird feathers as dielectric receptors of microwave radiation.

The characteristics of bird feathers as receptors of microwave fields were investigated in the 10- to 16-GHz region. Experiments were conducted coupling the specimen (feather) to a length of waveguide which served, together with other microwave components, as a primary detector. Microwave power radiation patterns were measured both in the presence and in the absence of the specimen. Results indicated a substantial increase in the microwave power collected in the forward direction and a decrease of the radiation pattern beam width when the feather was present. Fruthermore, some experiemental evidence indicated the possibility of inducing piezoelectric effects in the specimen by audiofrequency pulse-modulated microwave fields. These results are important in view of (i) the fundamental role that feathers play in the life of birds and (ii) the influence of environmental factors on bird behaviour.

Animals↗
PubMedDate not supplied

A feather-trap system for the removal of chicken feathers from laboratory sewage.

A simple feather-trap system is described for use on the drain lines of buildings housing poultry for research or other purposes where floors are frequently washed. The trap uses disposable plastic-mesh bags that can efficiently remove almost all feathers from the water, preventing sewer lines from being blocked by compacted feathers. Critical measurements and operational procedures are described.

Animals↗
PubMed1991

The influence of ev6 on the immune response to avian leukosis virus infection in rapid-feathering progeny of slow- and rapid-feathering dams.

Endogenous virus (EV) locus ev6 encodes only virus envelope glycoprotein. The influence of ev6 on the immune response to contact infection with hatchmates infected with avian leukosis virus (ALV) was compared in replicate hatches. The ALV Subgroup E-resistant, rapid-feathering (RF) female chickens produced by slow-feathering (SF) and RF dams with and without ev6 were exposed at hatch to hatchmates infected with ALV Subgroup A (Strain RPL-40). The RPL-40 viremia, shedding, and virus neutralizing antibodies were measured among pullets from two hatches at 22 wk of age. Although significant (P less than .05) differences between hatches in the immune response to contact infection were noted among ev6+ pullets, significantly fewer ev6+ pullets seroconverted than their ev6- hatchmates. At 22 wk of age, significantly more lymphomas were also found among ev6+ pullets than among ev6- hatchmates. In flocks wherein both parents and progeny were homozygous resistant to Subgroup E virus, there was no deterimental maternal effect on RF progeny from SF dams that carried ev21. These results also confirm that selection for genetic cellular resistance to Subgroup E ALV infection eliminates congenital transmission of EV21.

Animals↗
PubMed1975

The properties of bird feathers as converse piezoelectric transducers and as receptors of microwave radiation. I. Bird feathers as converse piezoelectric transducers.

An investigation was made of the properties of bird feathers as piezoelectric transducers in the audiofrequency range and as dielectric receptors of electromagnetic radiation in the microwave region. In the first case, cartridges of the ceramic and magnetic type and an electromagnetic transducer probe were used as detecting devices. Results show piezoelectric resonances in the 1 to 20-kHz region for the calami of feathers.

Animals↗
PubMed1991

Hydrolysis time as a factor affecting the nutritive value of feather meal and feather meal-blood meal combinations for growing calves.

The objectives of this research were to determine 1) the effects of hydrolysis time on feather meal (FTH) protein digestion and ruminal escape and 2) whether adding blood meal (BM) to FTH evoked a complementary response in animal performance. A lamb digestion trial was conducted to estimate true protein digestibility of soybean meal (SBM), BM, and FTH hydrolyzed for 10, 12, 15, or 18 min. Ruminal escape was estimated in situ. Two 94-d growth trials were conducted using 60 growing calves (226 kg) per trial to evaluate urea, FTH, BM, and 87.5:12.5, 75:25, and 50:50 combinations (CP percentage basis) of FTH:BM. There were small numerical differences in estimated escape of protein from the rumen and DM and protein digestibilities due to hydrolysis time. True protein digestibility of the 10- and 18-min samples was 5% higher (P less than .05) than for the 12- or 15-min FTH samples. In the growth trial, the slope-ratio technique showed that the most efficiently used protein supplement was 100% BM (protein efficiency = 2.45 +/- .19). No differences (P = .30) in protein efficiency were observed among supplements containing various combinations of FTH:BM. There was a quadratic (P less than .01) response to the level of BM, indicating a complementary effect. The largest complementary effect occurred at the 12.5% level of the BM addition. There were no nutritionally important effects of hydrolysis time between 10 and 18 min. Furthermore, supplements can be formulated more economically using small amounts of BM with FTH without compromising biological efficiency.

Animal Feed↗
PubMed1977

Abnormal morphogenesis of feather structures and pattern in the chick embryo integument. II. Histological description.

The development of skin and feathers in highly feathered scaleless mutants and normal Single Comb White Leghorn chick embryos was analyzed histologically. In addition, the growth of mutant feathers in chorioallantoic membrane culture is reported as a verification of several inferences made from observations of serially staged fixed specimens. The most striking feature of scaleless high line feather development is the widespread appearance of condensed or nearly condensed dermis. The discrete arrangement of normal placodes with underlying condensed dermis is replaced in the mutant by a heterogeneously shaped group of extremely large islands of columnar ("placodized") epithelium as long as 3,000 micron. The shape and extent of the condensed areas of dermis reflect the shape and extent of the overlying "placodized" epithelium. The polarity of the epidermis in normal feather germs, i.e., thicker epidermis on the posterior surface, is absent in mutant feather germs. This absence of epidermal polarity is reflected in the aberrant outgrowth of the mutant feather primordial. In the mutant, the basal cell layer of the epidermis invades the dermal core of the aberrant feather germs and may form barb vane ridges or feather sheaths. This process had no counterpart in the development of normal down feathers.

Animals↗
PubMed1991

Adhesion molecules in skin development: morphogenesis of feather and hair.

Figure 9 summarizes the morphogenetic process of feather and hair. Hair of feathers are formed from a layer of homogeneously distributed mesenchymal cells. The mesenchymal cells start to condense to form foci in response to some unidentified induction signal (Fig. 9B). Several adhesion molecules, including L-CAM, N-CAM, integrin, tenascin, as well as proteoglycan, are involved. These adhesion molecules appear to have different roles in this process, because perturbation with specific antibodies leads to different aborted patterns. Hair or feather follicles then form following cell proliferation and epithelial invagination (Fig. 9C). The dermal papilla is enriched with N-CAM and tenascin, whereas the feather collar (equivalent of hair matrix) is enriched with L-CAM and PDGF receptor. Epithelial cells in the feather collar receive a signal from the dermal papilla and are able to continue to divide. Several growth factors, such as PDGF and EGF, may be involved. As epithelial cells are pushed upwards, they differentiate and keratinize in a cylindrical structure into hair. In feather, another morphogenetic event takes place to form the branched structure. The epithelial cylinder of the feather shaft invaginates to form rows of cells that die to become space and create the secondary branch or barbs (Fig. 9D). N-CAM is enriched in the cells destined to die and appears to form the border of cell groups within which the "death signal" is transmitted. In some, but not all, feathers the same process is repeated, in a way analogous to fractal formation, to form the tertiary branches or the barbules (Fig. 9E). Thus, in each step of the morphogenesis of feather and hair, different adhesion molecules are expressed and are involved in different functions: induction, mesenchymal condensation, epithelial folding, and cell death, depending on different scenarios. We have just begun to elucidate these molecular events.

Animals↗
PubMed1990

Gradients of homeoproteins in developing feather buds.

Homeoproteins are functionally involved in pattern formation. Recently, homeoproteins have been shown to be distributed in a graded fashion in developing limb buds. Here we examine the expression of homeoproteins in chicken feather development by immunocytochemical localization. We find that XlHbox 1 antigen is present in cell nuclei and is distributed in a gradient in the mesoderm of developing feather buds, with strongest expression in the anterior-proximal region. The gradient is most obvious in feather buds from the mid-trunk level. Feather buds from the scapular level express very high levels of XlHbox 1 and feather buds from the caudal region express no XlHbox 1, suggesting that a broad gradient along the body axis is superimposed on a smaller gradient within each individual feather bud. Feather ectoderm also expresses XlHbox 1 antigen but without an obvious graded pattern. Another homeoprotein, Hox 5.2, is also expressed in developing feather buds in a graded way, and its distribution pattern is partially complementary to that of XlHbox 1. These observations suggest that homeoproteins may be involved in setting up the anteroposterior polarity of cell fields at different levels, first for the body axis, then for the limb axis and finally for the feather axis.

Animals↗
PubMed1992

Metal levels in regrown feathers: assessment of contamination on the wintering and breeding grounds in the same individuals.

Birds are useful indicators of environmental contamination because they are relatively large, conspicuous, top predators in food chains. However, concentrations of contaminants in a bird's tissues reflect the bird's exposure over wide temporal and spatial scales. Birds are most useful as monitors of exposure when these scales are known. In this paper we report concentrations of lead, cadmium, mercury, and selenium in breast feathers of common terns (Sterna hirundo) and roseate terns (S. dougallii) trapped during incubation at breeding colonies in New York and Massachusetts. Terns arrived on the breeding grounds with breast feathers grown on their wintering grounds, and regrew certain feathers that were plucked for analysis. The regrown feathers were themselves plucked, and both sets of feathers were analyzed. For roseate terns at Cedar Beach and common terns at both sites there was a significant increase in mercury levels in the feathers grown on the breeding grounds compared to those grown on the wintering ground. The differences in mercury were far greater at Bird Island than at Cedar Beach. Selenium levels at Cedar Beach were higher for the regrown feathers than the initial feathers for roseate terns, but not for common terns. Lead and cadmium levels were not significantly different at either site for either species. These results suggest that terns are exposed to significantly higher levels of mercury in the northeastern United States than they are in the wintering grounds in South America.

Animals↗
PubMed1977

A feather abnormality in chicks fed diets deficient in certain amino acids.

A feather abnormality was observed in chicks during bio-assay investigations with eleven essential amino acids. As dietary valine, leucine, isoleucine, glycine or phenylalanine and tyrosine levels decreased, a similar progressive feather abnormality became apparent. The outstanding feature of the feather abnormality was the concave structure of the feathers as they bent upward from the body. This structure gave the feathers a ragged appearance. The feather abnormality is described and illustrated. The percentage of dietary amino acids used were: valine, 0.40, 0.50, 0.60, and 0.70; leucine, 0.60, 0.68, 0.76, and 0.82; isoleucine, 0.32, 0.38, 0.44, and 0.50; glycine, 0.30, 0.35, 0.40, and 0.45; or phenylalanine and tyrosine, 0.65, 0.70, 0.75, and 0.80. Chicks fed the highest level of valine (0.50%), histidine (0.15%) or methionine to cystine ratio of 1:1 (0.30%) had normal feathers. In contrast, chicks fed the highest levels of either leucine, isoleucine, glycine or phenylalanine and tyrosine had abnormal feathers.

Amino Acids, Essential↗
PubMed1992

Hydrocortisone perturbs the cell proliferation pattern during feather morphogenesis: evidence for disturbance of cephalocaudal orientation.

In this study, we have monitored the spatial distribution of S-phase cells during successive stages of normal feather morphogenesis using the specific marker BrdU. We also disturbed the development program by administration of hydrocortisone on the chorioallantoic membrane of 6.5-day chick embryos and examined the resulting pattern of BrdU incorporation. Our results show that a specific spatio-temporal pattern of cell proliferation occurs during successive stages of feather development and that this pattern accounts for the growth of feather buds according to the cephalocaudal orientation. Our experimental analysis showed that the stage-dependent alteration of feather morphogenesis (as shown by Züst, Ann. Embryol. Morphogen. 4, 1971 and confirmed by Démarchez et al., Dev. Biol. 106, 1984), is based on a stage-dependent alteration of the proliferation pattern in the epidermis. Forty-eight hours after treatment, non-induced epidermis ceases DNA synthesis and is unable to form placodes. Induced epidermis at the placodal and dermal condensation stages fails to produce the cohorts of S-phase cells responsible for the caudal outgrowth and the slanting shape of the buds. These young buds display anarchic proliferation in the whole epidermis possibly resulting in the appearance of "curly" feathers. Together, these results show the importance of the spatial pattern of ectodermal and mesodermal cell proliferation during the normal feather morphogenesis. Moreover, they corroborate the particular role of epidermis both in the establishment of feather rudiments and in the cephalocaudal orientation of the feathers.

Animals↗
PubMed1978

Feather-forming capacities of the avian extra-embryonic somatopleure.

Blocks of 12.5- or 13.5-day embryonic mouse upper-lip dermis were introduced under the ectoderm of the extra-embryonic area of 2- to 3-day chick or duck embryos. Two kinds of ectopic cutaneous appendages were produced: either arrested feathers alone, or arrested feathers and full-grown feathers. The former developed in the ectoderm overlying the implanted mouse dermal cells, the latter formed in their close vicinity, but contained host dermal cells exclusively. Thus, avian extra-embryonic somatopleure, both ectoderm and mesoderm, possesses the information for feather development: the extra-embryonic ectoderm, if it is brought in contace with an appendage-forming dermis, is able to respond to the dermal induction by initiating feather morphogenesis; the extra-embryonic mesoderm, if it is experimentally transformed into a dense dermis, can express its feather-forming capacity by specifying feather tract morphology and barb-ridge number, thus leading to the acievement of feather morphogenesis.

Animals↗
PubMed1976

Abnormal morphagenesis of feather structure and pattern in the chick embryo integument. I. Macroscopic description.

The development of feathers in embryos from a profusely feathered line derived from a homozygous scaleless mutant stock was compared with that of embryos from a standard White Leghorn stock. The time of appearance of feather primordia, their structure and their arrangement all were altered in mutant embryos. Unit structures ranging in size from hillocks of 300 mu diameter (the size of normal primordia) to ridges 8 mm long were found in varying numbers in the different tracts of the mutant embryos. the hexagonal pattern characterizing feather primordia in normal embryos was disrupted in scaleless high line embryos. Differential growth and morphogenetic sculpting, as evidenced by the appearance of clefts, generate the form of and subdivide the variable shaped unit structures of the mutant as they elongate. Selection for high feather number was successful in dramatically increasing the total amount of feathering but the absence of coordinate controls of pattern and feather structure development led to the aberrant arrangement of tracts and of structures within the tracts. The basic pattern thus appears to have been destroyed by the scaleless mutation, and the alteration of the phenotype accomplished by selection has not apparently restored its control.

Animals↗
PubMed1977

Epidermal-dermal tissue interactions between mutant and normal embryonic back skin: site of mutant gene activity determining abnormal feathering is in the epidermis.

The site of the scaleless gene's activity in the development of abnormal feathers was determined by reciprocally recombining epidermis and dermis between normal and scaleless chick embryos and culturing the recombinants for seven days on the chorioallantoic membrane. When recombined with a common dermal source, feather development is enhanced by scaleless high line as compared to scaleless low line epidermis. Against a common responding tissue, 7-day normal back epidermis, significant differences were not found in feather inducing ability between normal, scaleless high line and scaleless low line dermis. It was concluded that, in relation to abnormal feathering, these tissue interactions reveal that the site of the scaleless gene's activity is the epidermis. A model of tissue interaction in the development of normal and abnormal feathers is presented. According to the model, the focus of the scaleless mutation and the genes accumulated by selection for high or low feather numbers is the epidermis, the effect being that the reactivity of the epidermis to dermal stimuli is altered. Subsequently, the epidermis controls the morphogenetic organization of the dermis. The scaleless dermis is presumed to contain normal positional information for the determination of feather structure and pattern.

Animals↗
PubMedDate not supplied

Abnormal feathers of the micromelic syndrome in White pekin ducks.

In an effort to provide further information concerning the pleiotropic effects of the gene mutation responsible for micromelia in White Pekin ducklings, a histological examination was made oq the abnormal feathers associated with the mutation. Abnormalities found in mutant feathers included decreased overall size, absence of prelumulae and prefiloplumulae feathers, an abnoramlly small rhachis with a disproportionally small medulla, thickening of the feather-sheath, and increased abundance of pulp cells. Embryos having the most abnormally developed feathers and the thickest periderm and feather-sheaths. The nature of many of the abnormalities found in mutant feathers suggests a common source in defective embryonic mesoderm.

Animals↗
PubMed1992

Structural variants of the neural cell adhesion molecule (N-CAM) in developing feathers.

The neural cell adhesion molecule (N-CAM) is expressed in a specific spatiotemporal pattern during feather development, suggesting that adhesion mediated by this molecule is involved in feather morphogenesis. To begin to investigate N-CAM's function in developing feathers, we determined what forms of N-CAM polypeptide are present and the distribution of polysialic acid (PSA), a carbohydrate moiety that decreases N-CAM-mediated cellular adhesion. N-CAM in skin appears as a Mr 145-kDa polypeptide compared to the 140-kDa brain N-CAM polypeptide, and is encoded by a 6.4-kb mRNA, compared to the 6.1-kb mRNA in brain. Polymerase chain reaction analysis of the exon splicing pattern of skin N-CAM shows that the 6.4-kb mRNA band represents two transcripts, with and without a 93-bp insert between exons 12 and 13. Thus, two N-CAM polypeptides are expressed in skin, but the 93-bp insert does not account for the larger size of the skin mRNAs and polypeptides. We show that the size difference of the polypeptides is instead due to N-linked oligosaccharides attached to the skin N-CAM proteins. The larger size of the skin mRNAs may be due to use of a different transcriptional start site. Staining of skin sections and wholemounts confirms previous descriptions of N-CAM in developing feathers, but reveals that N-CAM is also present at low levels on epidermal cells as early as stage 29 (E6). We find that PSA is expressed only on a subset of the cells that express N-CAM, in particular on dermal cells in the feather rudiments from stage 35-36 (E9-10) and on smooth muscle cells at the base of the filaments from stage 37 (E11) until the latest stage examined (stage 44, E18). The known effects on cell-cell adhesion of amount of N-CAM and PSA suggest that the variations we observe in skin may regulate cell-cell interactions that are important in feather development.

Animals↗