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Results for “FOWLS, DOMESTIC”

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At least 163 records · Page 9Linked to original sources

PubMed1987

Opiate participation in thyroid hormone regulation in domestic fowl.

Administration of morphine sulfate (at 5 and 50 mg/kg) to immature domestic fowl lowered the circulating thyroxine (T4) concentration in a dose- and time-dependent manner. The inhibitory effect of morphine on T4 secretion was mediated via opiate receptors, since it was completely blocked in the presence of naloxone (50 mg/kg). The possibility that T4 secretion may be under tonic opioid inhibition was suggested by a stimulatory effect of naloxone on plasma T4 concentrations. Morphine sulfate (50 mg/kg) enhanced plasma triiodothyronine concentrations, an effect that was completely suppressed in the presence of naloxone. These results demonstrate differential effects of opiates on T4 and T3 concentrations and suggest that opiates tonically inhibit T4 release and accelerate its rate of peripheral monodeiodination.

Animals↗

PubMed1987

Are there hunger and satiety factors in the blood of domestic fowls?

The presence of blood-borne hunger and satiety factors in domestic fowls was investigated in two experiments. In the first, birds that had previously been fed ad libitum or fasted for 24 h ate less after their blood had been transfused with that of fed or fasted donors than they did after two control treatments. Blood from fed donors suppressed intake more than did blood from fasted donors, but not significantly so. In the second experiment, previously fed birds ate less in the first hour after intravenous injection of reconstituted plasma from 24-h fasted donors, than after control injections of saline. The same treatments had little or no effect with subjects that had previously been fasted for 24 h. These results consistently indicate an absence of any hunger factor, but are less conclusive with regard to the presence of a satiety factor, for which there is recent evidence in fowls from central administration of plasma. It is suggested that hunger and satiety may be associated with scarcity and abundance of the same humoral factor(s), and that monitoring of blood composition may provide the necessary feedback for longer-term adjustments in food intake, modifying short-term control based on emptying and filling of part(s) of the alimentary tract.

Animals↗

PubMed1976

Passive cutaneous anaphylaxis in the domestic fowl.

Passive cutaneous anaphylaxis (PCA) has been demonstrated in young and adult domestic fowl using antisera obtained from actively sensitized chickens on the day of their maximal susceptibility to systemic anaphylaxis. Young chickens are more sensitive to histamine and PCA reaction than adults. The PCA reaction was inhibited by the H1-histamine receptor blocker, mepyramine. In the PCA reaction of 2 h sensitization period, the main exudating cells were heterophils, mononuclear cells (lymphocytes, monocytes and macrophages) and some basophils. This study suggests a possible role for circulating basophils in the mediation of early acute inflammatory reaction of immunological origin.

Aging↗

PubMed1987

Effects of denervation on baroreceptor and chemoreceptor endings in the aorta and pulmonary trunk of the domestic fowl (Gallus gallus domesticus).

Denervation experiments were carried out on twelve adult domestic fowls in order to investigate the location of the cell bodies of baroreceptor and chemoreceptor endings of the aorta and pulmonary trunk. Soon after both distal vagal ganglionectomy and midcervical vagotomy, baroreceptor and chemoreceptor endings showed distinct signs of abnormalities. These abnormal signs included many irregular and deformed clear vesicles, large membranous whorls and vacuolated mitochondria. The endings which were severely affected became greatly swollen and almost empty except for a flocculent substance and disordered filamentous material. It is suggested that the cell bodies of the majority of baroreceptor and chemoreceptor endings are not in the distal vagal ganglion and may be in the proximal vagal ganglion and/or proximal or distal glossopharyngeal ganglia. The chief cells of the aortico-pulmonary bodies were also affected after denervation when their axonal endings degenerated. The degenerative changes took the form of many expanded membrane-bound empty spaces and increased size and number of the dense-cored vesicles. It is concluded that the axonal endings exert a trophic effect upon the granular cells.

Animals↗

PubMed1984

Intramural granular cells in the arteries of the carotid body region of the domestic fowl.

The major blood vessels of the carotid body region of the domestic fowl were examined with both the light and electron microscope. With the light microscope, argyrophilic cells were found in the wall of the common carotid artery, carotid body artery, oesophagotracheobronchial artery, and the common trunk for the latter two arteries. With the electron microscope, cells containing granular vesicles were found in all the above mentioned arteries. In the wall of the common carotid artery two types of granular cell were found, one with small granular vesicles (60-140 nm) and the other with large granular vesicles (100-300 nm). Capillaries were not present amongst these cells, apposed axonal endings were infrequently seen, and there were no synapses. It is concluded that these cells do not have a chemoreceptor function but may secrete amines or peptides with a local action. Since the cells are located in the baroreceptor zone of the common carotid artery their secretions may modulate baroreceptor activity. In the other three arterial sites and on the distal vagal ganglion there were groups of granular cells characterised by small (60-140 nm) granular vesicles. These granular cells, together with their associated fenestrated capillaries, apposed axonal endings with synapses, and cells resembling carotid body Type II cells were interpreted as aberrant carotid body tissue, presumably with a chemoreceptor function.

Animals↗

PubMed1983

Fusions within the mandible of the domestic fowl (Gallus gallus domesticus).

The articulations formed within the mandible of the domestic fowl by its constituent elements have been described and illustrated. The sutures identified were suturae angulosplenialis, angulosupra-angularis, articulare/pre-articulo-angularis, articulare/pre-articulosupra-angularis, dento-angularis, dentosplenialis, dentosupra-angularis and supra-angulosplenialis. Some degree of fusion was found to occur in all sutures except sutura supra-angulosplenialis. The range of fusion time and mean fusion time for each site was studied in a flock of Golden Comet pullets. Mean fusion times varied from 45-119 days post-hatching.

Animals↗

PubMed1982

Immunohistochemical localization of the luteinizing hormone releasing hormone (LHRH)-containing structures in the central nervous system of the domestic fowl.

The location of LHRH-containing neuronal elements was investigated in the domestic fowl by means of immunohistochemical techniques. LHRH antisera were raised against synthetic LHRH in the rabbit. The antiserum used in the present study cross-reacted with LHRH of mammalian and avian tissues. LHRH-immunoreactive perikarya are located in the preoptic and in the septal areas, and in the bulbus olfactorius; however, no LHRH-immunoreactive perikarya were found in the tuberal part of the hypothalamus. LHRH-immunoreactive fibers course from these areas toward the median eminence mainly along the wall of the third ventricle in the form of a periventricular network. Originating from the same cell groups other fibers run caudally immediately above the optic chiasma, forming the median bundle of the tractus preoptico-infundibularis. The third bundle running toward the OVLT is named the tractus preoptico-terminalis. In addition to these structures, LHRH-containing fibers and terminals were also present in different regions of the limbic system, in the dorsal part of the hippocampus, in the tuberculum and bulbus olfactorius, as well as in the optic lobe, nuclei commissurales tectales, organon subcommissurale, periaqueductal area, and pars ventralis mesencephali. The general distribution of the LHRH system in the chicken corresponds principally to that described previously in rodents (Sétáló et al. 1976, 1978). However, some subtle differences were demonstrated between the location of the LHRH system in birds and mammals.

Animals↗

PubMed1988

Immunogold identification of the somatotrophs of domestic fowl of different ages.

The somatotrophs of the pituitary gland of the male domestic fowl were identified by means of an immunoelectron-microscopic method based on gold as the electron-opaque label and an antibody to growth hormone. Gold particles indicating sites of growth hormone were restricted to cells in which virtually all of the granules were labelled. Little, if any, gold label was found outside the granules in these cells designated as somatotrophs, or at sites outside these cells. The size of these gold-labelled secretory granules presumed to contain growth hormone decreased with age, from a mean sectional diameter of 256 +/- 6.2 nm (SEM) at 4-6 weeks to 221 +/- 5.7 nm at 11-18 weeks and 205 +/- 8.6 nm at 24-30 weeks of age. On the basis of these values for mean sectional diameters the change between the first two periods represents a decrease in granule volume of about 36%. However, during the same period the growth hormone concentration of the granules increased. Accordingly, growth hormone content per granule changed little if at all. In contrast, from 11-18 weeks to 24-30 weeks of age there was a decrease of 31% in growth hormone content per granule. These data indicate that growth hormone packaging in the chicken somatotroph changes with age. The first change results in the production of smaller granules of higher growth hormone concentration. During this period growth hormone content per granule remains relatively constant. The later change results in the production of granules of lower growth hormone content than that of younger animals.

Animals↗

PubMed1981

The hypothalamic magnocellular system in the domestic fowl. A golgi and electron microscopic study.

In the rostral hypothalamus of the domestic fowl, the magnocellular neurosecretory nuclei show a peculiar differentiation. Golgi studies of the supraoptic and paraventricular nuclei of the fowl reveal at least two major cell types: 1) large multipolar neurons, and 2) small interneurons. Golgi impregnations provide a detailed cytoarchitectural picture of the large-sized cells; the latter may well correspond to the neurosecretory cells demonstrated in the same regions by selective staining, and immunocytochemical and electron microscopical techniques. Electron microscopically, neuronal perikarya are observed to contain variable amounts of neurosecretory granules (100-200 nm in diameter; mean diameter of 160 nm) scattered throughout the cytoplasm. The diameters of these granules do not differ statistically in the two principal nuclear areas examined. The perikarya of these neurons display only a few axosomatic synapses containing electron-lucent and dense-cored vesicles (70-90 nm in diameter). Numerous nerve terminals of this type also end on the dendritic ramifications in the surrounding neuropil.

Animals↗

PubMed1979

Fine structure of the ependymal cells in the area postrema of the domestic fowl.

The ultrastructure of the ependymal cells in the area postrema of the domestic fowl was studied by scanning and transmission electron microscopy. The ependymal surface of the area postrema is covered with many furrows and ridges. These ridges consist of ependymal cells aggregated in a fan-like shape. The ependymal cell lacks clustered cilia, microvilli are few, and a long basal process extends through the parenchymal layer of the area postrema. Within the cytoplasm as well as in the basal process, a spherical body with a diameter ranging from 1.5 to 2 micron is occasionally observed.

Animals↗

PubMed1983

Partial retinal dysplasia and subsequent degeneration in a mutant strain of domestic fowl (rdd).

An inherited recessive form of retinopathy has been discovered in the domestic fowl (rdd) which is characterized by progressive deterioration of the retina, culminating in blindness by sexual maturity. Morphologically, the condition is recognizable by abnormalities in both the retinal pigment epithelium and the neural retina. Gaps in the pigment epithelium which are first detected macroscopically at nine days of incubation become larger and more numerous until the time of hatching, then disappear during the subsequent week. Undulations in the outer nuclear, outer plexiform, and inner nuclear layers are obvious by 11 days of incubation. There is a marked reduction of photoreceptors at 18 days of incubation as compared to normal controls. After hatching, the thickness of the retina decreases with age, primarily due to cell loss from the photoreceptor region and inner nuclear layer. Detachment of the atrophic retinas generally occurs in adults, and is followed in some adults by granulation and ossification of the vitreous. Problems concerning the site of the lesion are discussed.

Aging↗

PubMed1994

Construct validation of behavioral indices of isolation stress and inflammatory nociception in young domestic fowl.

Isolation from conspecifics can elicit a variety of behavioral responses in young domestic fowl that include increased vocalizations (VOC), ventral recumbency posturing (VRP), hypoalgesia, and hyperthermia. During tests of acute inflammatory nociception, chicks not only display several pain-related behaviors (i.e., footpecks and lifts), but also VOC and VRP. However, systematic evaluation of whether these behaviors reflect converging indices of stress and nociception remains to be conducted. In two separate experiments, 7-day-old chicks received intraplantar formalin (0.05%) or saline (0.05 ml) and were placed in sound-attenuating chambers with or without two conspecifics for a 3 min observation period. The following measures were recorded: VOC, footlift frequency (LFT), and duration (DUR, Experiment 2 only), pecks (PKS), ventral recumbency latency (VRL), body temperature (BTMP), and body weight (WGT). Principal component analyses revealed the presence of two oblique and nonmonotonically related components, one consisting of pain-related measures (i.e., LFT, DUR, and PKS) and the other consisting of stress-related measures (VOC, VRL, and BTMP). A third component, consisting of BTMP and WGT ostensibly reflects maturational variability in thermoregulatory capability. These findings support the construct validity of these behavioral indices of isolation stress and inflammatory nociception and are consistent with the notion of stress effects on nociceptive processing.

Animals↗

PubMed1990

Ultrastructural localisation of alkaline phosphatase in the intertubular tissue of the testis in the domestic fowl.

Alkaline phosphatase activity in the intertubular tissue of the testes of the domestic fowl was examined using an ultracytochemical technique based on the lead capture method. In the interstitial tissue, the Leydig cells, transitional cells and the fibroblasts displayed enzyme activity on their cell membranes. Vacuoles located in the transitional cells were lined by reaction products of enzyme activity, whereas the vacuoles representing extracted lipid droplets and present mainly in the Leydig cells were free of enzyme activity. In the peritubular tissue the cell processes of fibroblasts showed enzyme activity on the cell membranes and in pinocytotic vesicles. Cell processes lying adjacent to blood vessels showed pronounced activity. In the blood vessel itself some activity was present in the basement membrane and the endothelium. The surface of the red blood cell showed moderate activity. The possible role of alkaline phosphatase in the transfer of hormone from the Leydig cells to the seminiferous tubules and from the seminiferous tubules to the interstitium is discussed. The myoid cells and their processes were devoid of enzyme activity.

Alkaline Phosphatase↗

PubMed2002

Mineral status of embryos of domestic fowl following exposure in vivo to the carbonic anhydrase inhibitor acetazolamide.

Eggs of domestic fowl were given daily injections of vehicle (DMSO) or vehicle plus acetazolamide, a potent inhibitor of the enzyme carbonic anhydrase, beginning on day 12 of incubation. Embryos were removed from eggs on days 16 and 18, and carcasses and yolks were analyzed for calcium, magnesium, and phosphorus. Treatment with acetazolamide did not affect the quantity of calcium or phosphorus in carcasses and the effect, if any, on magnesium in carcasses was small. However, calcium content of yolk was reduced substantially by acetazolamide both on day 16 and day 18. The reduction in calcium content of yolk led, in turn, to a reduction in the total quantity of calcium in eggs on days 16 and 18. Embryos exposed to acetazolamide seemingly mobilized less calcium from the eggshell than did control embryos. When faced with a shortfall in the availability of calcium from the eggshell, embryos defended carcass calcium, and the shortfall was reflected in a reduction in the quantity of calcium deposited in yolk. The results of this study support the concept that the enzyme carbonic anhydrase plays a role in solubilization of the eggshell and provision of calcium to embryos.

Acetazolamide↗

PubMed1979

An improved transbuccal approach for hypophysectomy in the domestic fowl.

The present paper describes an improved transbuccal approach for hypophysectomy in the domestic fowl. With this technique, the operative procedures are the same as in the transbuccal approach of Hill and Parkes (1934), except that the drilling angle is the same as in the oral approach of Rothchild (1948a,b), since the present anatomical investigation indicates that the hypophysis lies at an angle of 45 degrees to the surface of the palate. An apparatus that was made to restrain the fowl head facilitates the operative procedure; even a novice can perform fowl hypophysectomy in more than 70% of the cases.

Animals↗

PubMed1994

Mechanoreceptors in the crop of the domestic fowl.

Electrophysiological "single fiber" experiments were conducted on the vagal nerves of the domestic fowl to confirm the presence of mechanoreceptors in the crop and to study their properties. The afferent activity of the left vagus nerve was recorded in nine anaesthetized laying hens with and without the crop being artificially distended. Twenty-two units were found to respond to the crop inflation, 18 of them being slowly adapting mechanoreceptors. The discharge rate of these slowly adapting units increased as the pressure inside the crop was raised. Twelve units were localized and the responses of three units to different doses of acetylcholine, epinephrine, and norepinephrine were obtained. Mechanoreceptor discharges were enhanced when the crop was distended and during drug-induced contractions of its smooth muscle, suggesting an "in series" location within the muscle layers. Such receptors may provide the afferent limb of a reflex regulating crop motility and may be involved in the regulation of feed intake.

Acetylcholine↗

PubMed1990

The development of pneumatisation in the skull of the domestic fowl (Gallus gallus domesticus).

The development of pneumatisation in the skull of the domestic fowl has been studied in a series of chick embryos from 7-20 days incubation (Hamburger & Hamilton Stages 29-46) and in birds from hatching to 126 days posthatching. During the embryonic period primary pneumatisation developed by 3 routes. (i) The tympanic cavity directly invaded surrounding bones-squamosal, parietal, supraoccipital and prootic. (ii) Extensions of the tympanic cavity invaded the bones in which these occurred-the caudal pneumatic antrum in the exoccipital and the rostral pneumatic antrum in the parasphenoid/basisphenoid. (iii) A tubular diverticulum from the tympanic cavity grew rostrally and invaded the quadrate and pterygoid. A similar diverticulum grew rostrally towards the cartilaginous mandible but was only found to invade it in one case after the time of hatching. In most instances onset of pneumatisation occurred three stages subsequent to the onset of ossification. In bones in which ossification is intramembranous bone tissue often formed around small air sac outgrowths, resulting in multiple sites of invasion while, in bones ossifying perichondrally, cartilage resorption was a necessary prerequisite and air sac invasion frequently occurred in common with a vascular bud resulting in a single pneumatic foramen. After hatching secondary pneumatisation spread from the already pneumatised bones to involve the whole cranium. Spread throughout the parietal and frontal was preceded by the establishment of dipole within these bones and the final extent of pneumatisation was variable. Spread to the most distal parts of the cranium was only accomplished after the intervening sychondroses had fused.

Air↗

PubMed1986

Respiratory responses of the domestic fowl to low level carbon dioxide exposure.

Respiratory function in the restrained, conscious domestic fowl was measured using a non-invasive technique and computer aided analysis to examine respiratory flow, and in-dwelling arterial catheters to monitor blood carbon dioxide levels. The effects of two low ranges of inspiratory carbon dioxide (0.2 to 1.0 per cent and 0.25 to 2.25 per cent) were studied, simulating levels of carbon dioxide that may occur in commercial poultry units and representing a mild environmental stress for the birds. A linear increase in minute volume with inspiratory carbon dioxide was observed, due primarily to increases in tidal volume. Arterial carbon dioxide (PaCO2) tension also rose as the inspiratory carbon dioxide concentration was raised, but higher inspiratory carbon dioxide levels were required to affect significantly blood carbon dioxide concentration than to modify respiratory parameters. Variation was observed in the individual bird's response to carbon dioxide (bird X carbon dioxide interaction), suggesting that resting values of the respiratory parameters measured were important in determining the bird's ventilatory response to carbon dioxide.

Analysis of Variance↗