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PubMed1993

The anatomy of the cloacal bursa (bursa of Fabricius) in the helmeted guinea fowl (Numida meleagris galeata).

The cloacal bursa (bursa of Fabricius) in the guinea fowls appeared either as an oval blind sac with a short thick stalk in one group or had a pointed cranial blind end with a slightly bulging middle part that was followed by a thick caudal stalk in the other group. Both groups of bursae originated from the proctodeal wall of the cloaca and were placed dorsal to the rectum. The average length of the bursa was 18 mm while the average width at the mid section was 15 mm. The internal surface showed about 12-14 primary folds. Histologically, the outline of the bursa was well established by day 18 of incubation. The primary folds had also been formed. Lymphocytes had already been encountered within the framework of the bursa at this day. The epithelium bordering the tunica propria was composed principally of two layers of cuboidal cells. Epithelial buds had also formed and some were already detached from the epithelial lining. The blood vessels present were positioned just beneath the outer covering. At day 19 of incubation, most of the epithelial buds had two layers of cells arranged in a circumscribed manner while a few had three layers of cells. Blood vessels had increased in number and were deeper placed inside the bursa than previously. At day 20, the cells of the upper layer of the epithelium were dorsoventrally flattened and stained paler than the cells of the lower layer. It was possible to distinguish the cortex from the medulla and the basement lining between both zones was distinct. Tiny vesicles within the cytoplasm of the epithelial cells at the mucosa and follicles were observed. Macrophages were also observed within the gland. At day 21, blood vessels were observed in the cortex of the follicles. The maximum number of primary folds (14) had been formed. At day 22, several follicles had severed connections with the mucosal epithelium. The mucosal lining had dropped to a single layer of cells in some areas. Goblet cells were observed amongst the mucosal cells. A plasma cell had first appeared. By day 25, dead cells had increased quite in number and there was also an increase in number of medium and small-sized lymphocytes within the gland. By day 26, the upper layer of the surface epithelium was composed primarily of tall columnar cells with numerous large vacuoles. Macrophages had suddenly increased within the thin interfollicular spaces and most of them were crowded internally with various sizes of debris.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Regularities and irregularities in the structure of the seminiferous epithelium in the domestic fowl (Gallus domesticus). II. Co-ordination between germ cell associations.

It was investigated in the domestic fowl, whether a mechanism for a synchronous start of the proliferation of the differentiating spermatogonia in a transversely cut seminiferous tubule (called the "co-ordination" between germ cell association) operates effectively in this species. A trapezoid-shaped cellular association demarcated by two perpendiculars from the tubular lumen to the basement membrane was the unit of observation (provisionally called a "column" Each column is composed of a bundle of elongate spermatids and the neighbouring, various types of germ cells). The extent of closeness of the co-ordination was examined in a total of 2,650 columns, based on the continuity of the spermiogenic step-number of the youngest generation of spermatids within adjacent columns. In no case did all columns in a tubular cross section show the same-step spermatids. In most cases (50.2% of 2,650 columns), the same number was kept in only 2 to 6 adjacent columns. The arrangement of different but consecutive numbers (e.g., 1-2-3 or 1-2-1) was observed in a total of 882 columns. The co-ordination mechanism, therefore, is considered to work, albeit incomplete, among a limited number of adjacent columns in this species.

Animals↗
PubMed1994

The thymus of the guinea fowl from the eighteenth day of incubation until maturity.

The thymus gland of the guinea fowl appeared as a series of pink, irregular-shaped lobes along the jugular veins. These lobes were 13 in number with seven on the right and six on the left side. The third and sixth lobes on the right side were the largest. The largest lobe measured about 20.0 x 5.0 mm while the smallest measured about 5.0 x 4.0 mm. Histologically, it was encircled by a thin layer of poorly stained connective tissue from which strands penetrated the thymic tissue giving incomplete lobules peripherally as early as day 18 of incubation. Lymphocytes and reticular epithelial cells were the two types of cells occurring at this time. Reticular epithelial cells were observed to be vacuolated especially towards the centre of the gland. Macrophages were observed in the thymus on day 20 of incubation for the first time. The blood vessels had accompanied the interlobular septa into the thymus. By day 21 of incubation, blood vessels had actually penetrated the thymic tissue but most of these vessels were of the capillary size. The cortex also became quite distinct from the medulla. At day 22, vacuolation ceased to appear in the cells at the cortical zone. Macrophages were still less than 10 in the slide. At day 23, most blood vessels were within the medulla and they displayed compressed lumina. Mitotic figures became a common site amongst the large lymphocytes and reticular epithelial cells. By day one post-hatch, lobulation of the thymus was still poor and macrophages became difficult to identify. The small and medium lymphocytes had outnumbered the large lymphocytes throughout the thymic tissue except at the most peripheral zone of the cortex. Fine vacuoles had reappeared within the cytoplasm of the reticular epithelial cells in the cortex. By day five, the distribution of blood vessels was almost uniform between the cortex and medulla. At three weeks post-hatch, plasma cells and red blood cells were seen in the stroma of the gland for the first time and most of the red blood cells occurred in the medulla.

Animals↗
PubMed1995

[Fine structure of the trigeminal nerve nucleus of the domestic fowl].

The trigeminal nerve nuclei are examined light- and electron-microscopically in the adult domestic fowl. The nucleus sensibilis principalis nervi trigemini is formed by scarce, medium-sized, round-to-ovoid polygonal neurons. The Nissl bodies are concentrated around the nucleus and consist of short cisterns of the rough endoplasmic reticulum densely bordered with ribosomes. The nucleus tractus spinalis nervi trigemini extends to the first segments of the cervical cord. The rostral part of the nucleus is characterized by medium-sized polygonal neurons. Their cell bodies are densely packed with coarse Nissl bodies. Small multiforme cell types with large nuclei frequently showing two nucleoli predominate in the caudal part. The motorical main portion, nucleus motorius nervi trigemini consists of medium-sized as well as great polygonal neurons. The accessory portion, nucleus motorius dorsalis nervi trigemini, consists of medium-sized polygonal neurons. Both nuclei show the typical motoneuron cytomorphology. In the neuropil, the axodendritic synapses can be differentiated into five types. Occasionally, densely packed glial lamellae and giant mitochondria occur.

Animals↗
PubMed2005

Light and electron microscopic study of the thoracic respiratory air sacs of the fowl.

There are conflicting reports in the existing literature on the nature of the epithelial lining and the content of the supporting connective tissue of the respiratory air sacs of birds. The present study describes the light and electron microscopic structure of the thoracic air sacs of the fowl. A simple squamous epithelium lined the greater part of the thoracic air sacs. The squamous cells characteristically contained vesicles filled with lamellar or myelinoid material. Localized areas of cuboidal to columnar ciliated epithelium were randomly distributed and often associated with underlying blood vessels. Isolated ciliated cells first appeared on squamous or low cuboidal cells and increased in frequency as the cells became taller. Occasional basal and goblet cells were seen between the ciliated columnar cells. A fibrous connective tissue stroma supported the epithelium. Fine elastic fibres were particularly prevalent immediately below the epithelium. Isolated smooth muscle myocytes were present in the connective tissue stroma. A sheet of smooth muscle extended some distance into the membrane from the attachment of the latter to the body wall. Numerous small blood vessels, lymphatics and occasional nerve bundles were observed in the stroma.

Air Sacs↗
PubMed2006

The guinea fowl spleen at embryonic and post-hatch periods.

The spleen of the guinea fowl was bean-shaped but without a dented hilus. It is supplied by three short arteries that came from the ventral surface, two on the cranial end and one at the caudal end of the organ. The whole organ had a thin but tough capsule covering the outer surface except at the point of entry of the blood vessels. By day 18 of incubation, the spleen had a thin but well-defined capsule and internal to this been complete network of sinusoids filled with erythrocytes, lymphocytes and granulocytes. By day 19, dark and light staining zones, which could be termed red and white pulps, had appeared. By day 20, the granulocytes with a lot of granules within their cytoplasm, had become the biggest-sized cells in the spleen. At day 21, arteries and veins were noticed clearly in the spleen and many lymphocytes, few granulocytes and reticular cells surrounded these. Red pulp with its sinusoids was now distinct. A giant cell containing three nuclei was seen within the red pulp. At day 1 post-hatch, the capsule was at its greatest thickness so far and muscle cells were seen at the inner most part of the capsule. Granulocytes that had been a constant feature suddenly disappeared. At day 5, the small lymphocytes had dominated the large and medium-sized ones. By 2 weeks, the red and white pulps were virtually equal in distribution but by 3 weeks, the red pulp was convincingly greater. By 7 weeks, plasma cells had appeared in the peripheral splenic cords. Monocytes were observed in the sinusoids. Two germinal centres were identified for the first time in week 13 post-hatch.

Animals↗
PubMed1993

Vaccination of chickens with live fowl pox (FP) vaccine in oil.

Live fowl pox (FP) vaccine was adjuvanted in oil just prior to the subcutaneous (SC) vaccination of one day old chicks and adult chickens. The birds were challenged by the wing web (WW) method and absence of "takes" were considered as protection. On 21 day post challenge, 90%-100% of the chicks or chickens were protected while on day 9 post challenge 60% were protected. Full protection of the live-in-oil adjuvanted vaccine is probably somewhat delayed as compared to protection endowed by the liquid vaccine. Incorporation of live FP vaccine in two different kinds of commercial Newcastle disease (ND) killed vaccine in oil, was shown to endow full protection following SC administration.

Adjuvants, Immunologic↗
PubMed1993

Unexpected isolation of virulent Newcastle disease virus from commercial embryonated fowls' eggs.

The authors report a case of causal isolation of virulent Newcastle disease virus (NDV) from embryonated eggs. The virus was isolated from uninfected chicken embryo liver and fibroblast cultures prepared from commercial embryonated fowls' eggs. A serological and virological investigation carried out on the breeders which had laid those eggs showed high titres against NDV, and virus isolation from cloacal swabs. The virus was also isolated from the progeny of the same breeders which showed no clinical signs of ND, following episodes of mortality. Vertical transmission of the virus is discussed.

Animals↗
PubMed2005

Expression of calcineurin and its interacting proteins in epileptic fowl.

Calcineurin (CaN), a Ca2+-calmodulin (CaM)-dependent protein phosphatase, is important for Ca2+-mediated signal transduction. The main objective of this study was to examine the potential role of CaN in epileptic brain and its involvement in neuronal apoptosis. We investigated CaN expression and its interaction with various signaling molecules in normal, carrier and epileptic brain tissues of chicken. Our results revealed higher Ca2+-CaM-dependent phosphatase activity of CaN and a correspondingly strong immunoreactive band of CaN A in epileptic and carrier brain samples compared with normal brain. Furthermore, immunohistochemical analysis showed a higher level of expression of CaN in epileptic brain tissue. However, the intensity of immunoreactivity was less in carrier than epileptic brain. We observed that the interaction of CaN with m-calpain and micro-calpain was strong in carrier and epileptic chickens compared with that in normal birds. In addition, the interaction of CaN with Bcl-2, caspase-3 and p53 was greater in carrier and epileptic fowl than in normal chickens. The greater interaction of CaN with various apoptotic factors in epileptic chickens adds to our understanding of the mechanism of CaN signaling in neuronal apoptosis.

Animals↗
PubMed1961

The persistence of a depressor response to oxytocin in the fowl after denervation and blocking agents.

The effects of oxytocin and vasopressin on the blood pressure of the fowl have been studied after surgical or chemical interruption of parts of the central and peripheral nervous systems, and after the administration of stilboestrol and progesterone. An augmented and prolonged depressor response to oxytocin was seen after atropine, bretylium, tetraethylammonium or decapitation, but not after decerebration, dihydroergotamine or dibenamine. There was a tendency for the pressor action of vasopressin to disappear after decapitation, decerebration, and all the blocking agents used, except tetraethylammonium. The differences between these results and those which have been obtained in rats are discussed.

Animals↗
PubMed1961

Assay of substance P on the fowl rectal caecum.

The optimum conditions for the assay of substance P on fowl rectal caecum have been studied. Effective concentrations vary from 0.01 to 0.5 u./ml.; it is remarkably insensitive to other polypeptides, such as bradykinin. The test can be made more specific by using a bath fluid containing antagonists for known interfering substances. A suitable antagonist for acetylcholine is atropine or hyoscine, for 5-hydroxytryptamine, methysergide and for catecholamines, ephedrine. The effects of histamine and adenosine compounds can be abolished by specific tachyphylaxis, in which the bath fluid contains an excess of the active substance itself. The assay is reasonably accurate. Woolf's index of precision (L) was estimated as 15.5 with a range (9) of 9.2 to 29.4. Simplified methods of calculating L, and the fiducial range, are described.

Acetylcholine↗
PubMed1969

Spontaneous and evoked release of neurotransmitter substances in the longitudinal muscle of the anterior mesenteric artery of the domestic fowl.

1. Changes in length of the longitudinal muscle of the anterior mesenteric artery of the domestic fowl (LMAMA) were recorded isotonically.2. The actions of physostigmine and hyoscine suggest that the tone of the LMAMA is dependent on a resting release of acetylcholine within the tissue.3. Catecholamines inhibited the contractions obtained in response to stimulation of cholinergic nerves; this was a beta-receptor effect. After beta-receptor blockade, noradrenaline, but not isoprenaline, weakly facilitated the effects of stimulating cholinergic nerves.4. In the presence of hyoscine, nicotine relaxed preparations of the LMAMA in which the tone had been raised with barium chloride. These relaxations were considered to be due to a release of catecholamine probably from sympathetic nerves.

Acetylcholine↗
PubMed1970

An ultrastructural and histochemical study of the short-term effects of 6-hydroxydopamine on adrenergic nerves in the domestic fowl.

1. The effects of 6-hydroxydopamine (6-OHDA) on adrenergic nerves in the domestic fowl have been investigated with ultrastructural and fluorescence histochemical methods.2. 6-OHDA depletes the nerves of catecholamine, initially by displacing it from the storage vesicles. 6-OHDA enters large as well as small vesicles, indicating that large granular vesicles in adrenergic nerves are sites of amine storage.3. Doses of 6-OHDA, insufficient to cause degeneration, still cause loading of the vesicles.4. The effects of various drugs on the action of 6-OHDA indicate that this drug must be taken up by the nerves and reach a critical extragranular axoplasmic concentration before degeneration will occur; 6-OHDA bound in the vesicles plays no part in the degenerative process.

Amphetamine↗
PubMed1974

Effects of cholinomimetic agents given into the brain of fowls.

1 Effects of cholinomimetic agents, given into the IIIrd ventricle of adult fowls (Gallus domesticus) or infused into the hypothalamus of young chicks, were tested on behaviour, respiratory rate and body temperature.2 Carbachol evoked behavioural and electrocortical arousal but lacked postural and respiratory effects. Contrariwise, pilocarpine increased respiratory rate and induced postural changes, i.e. abduction of the wings, but lacked other behavioural effects and did not alter electrocortical activity. Benzoylcholine induced tachypnoea, postural changes and brief electrocortical arousal. Acetylcholine was ineffective unless given with physostigmine, when electrocortical arousal, postural changes and tachypnoea developed. Methacholine induced tachypnoea and postural changes.3 Effects of carbachol and pilocarpine were prevented by hyoscine and those of benzoylcholine by pempidine; hyoscine and pempidine were required together to prevent the effects of methacholine and to attenuate those of acetylcholine with physostigmine.

Acetylcholine↗
PubMed1975

Central effects of clonidine 2-(2,6-dichlorophenylamino)-2-imidazoline hydrochloride in fowls.

1 The effects of clonidine infused into the IIIrd cerebral ventricle, the hypothalamus or intravenously were studied on behaviour, electrocortical activity, body, comb and leg temperatures, respiration and carbon dioxide elimination in adult and young fowls (Gallus domesticus). 2 Behavioural and electrocortical slow wave sleep were induced by clonidine infused into IIIrd cerebral ventricle, the hypothalamus or intravenously. Suprisingly, sleep elicited by intravenous clonidine was much longer-lasting than that induced by an identical dose given intraventricularly. 3 Body temperature was lowered by clonidine given intraventricularly or infused into the hypothalamus. Depending on initial comb temperature and ambient temperature, comb temperature was elevated, unaffected or lowered as body temperature fell; temperature of the unfeathered legs also rose as body temperature declined after clonidine. 4 Following clonidine, but before any considerable decline of body temperature, tachypnoea and wing abduction developed; during recovery of body temperature, the wings were lowered and applied closely to the trunk and the feathers partly erected. 5 CO2 elimination fell more swiftly than body temperature following intrahypothalamic clonidine in young chicks; initial recovery developed sooner than that of body temperature, but eventual recovery was delayed compared to that for body temperature. The effects of clonidine were much more marked in young chicks studied at an ambient temperature below thermoneutrality as compared to thermoneutrality. 6 The soporific effects of clonidine were attenuated by intraventricular phentolamine; its hypothermic effects were prevented by phenoxybenzamine and prevented or attenuated by phentolamine. Intraventricular atropine, haloperidol, methysergide and propranolol were ineffective. 7 Larger doses of intraventricular phentolamine elicited shivering, tachypnoea and wing abduction; body temperature was elevated, to the extent even of lethal hyperthermia. Intraventricular atropine also elevated body temperature. 8 Clonidine infused intravenously, intraventricularly or into the hypothalamus, replaced the behavioural and electrocortical arousal evoked with dexamphetamine, by sleep associated with slow wave electrocortical activity.

Animals↗
PubMedDate not supplied

Effect of the barring gene on eye pigmentation in the fowl.

Pigment cells of the iris, pecten, retinal pigment epithelium, and choroid of the wild-type jungle fowl (JF) and the barred Plymouth rock (BPR) breeds of adult chickens were studied at both light and electron microscopic levels. BPR choroidal tissues had 2.8 times fewer melanophores than the JF choroid, and BPR melanophores also contained 2.4 times fewer melanosomes, which tended to clump together in variously sized clusters. The melanosomes were often irregular in shape, smaller in diameter, and less mature (stage III) than those granules in the JF. The retinal pigment epithelium of both JF and BPR breeds contained a single epithelial layer of columnar cells. Rod-shaped melanosomes were present in the more apical regions of this cell type in both breeds. Both JF and BPR irides contained a multilayered posterior pigmented epithelium of columnar shaped cells that were densely filled with large spherical granules. Intercellular spaces with interdigitating cytoplasmic projections were present between pigment cells of both breeds. The pecten melanophores of both breeds were dendritic with melanosomes that were larger and fewer in numbers than those pigment cells of the iris and choroid. Intercellular spaces were present between cells in both breeds, with numerous villous-like pigment cell extensions. Choroid melanophores contained very little, if any, acid phosphatase activity. Approximately one-half of the retinal pigment epithelial cells observed contained small amounts of diffuse acid phosphatase activity in both breeds. The iris and pecten melanophores of both breeds contained profuse acid phosphatase activity scattered throughout their cytoplasms. Sparse tyrosinase activity was seen in iris and pecten pigment cells, whereas no tyrosine activity was observed in choroid melanophores or in retinal pigment epithelial cells in the two breeds, indicating that little new melanogenesis occurs in adult pigmented eye tissues. The results show that the barring gene reduces the number and melanin content of the choroidal melanophores in homozygous male BPR chickens as compared to the wild-type JF chickens. Whether this gene prevents the initial migration of embryonic neural crest cells (future melanophores) to the choroid or whether some of the choroidal melanophores prematurely degenerate in the embryo of young birds is yet to be determined. If the latter is the case, this choroid system may serve as a model for a genetic hypomelanotic disease such as vitiligo.

Acid Phosphatase↗
PubMed1994

Growth of neural crest cells in vitro is enhanced by extracts from Silky Fowl embryonic tissues.

In the Silky Fowl (SF) breed of chicken, most of the internal organs are infiltrated with melanocytes. Previous studies have shown that this generalized mesodermal pigmentation is not due to a cell autonomous abnormality of the melanocytes but to environmental factors able to promote both the homing of pigment cell precursors in abnormal embryonic sites and their proliferation and differentiation. To analyse the mode of these environmental cues, we tested the effect of SF embryo extract (SFEE) on cultured quail neural crest cells as compared with that of EE from normal chickens of the JA57 strain (JA57EE). We found that SFEE enhances crest cell proliferation as judged by 3H-TdR incorporation and cell counting. In contrast, no effect of SFEE was observed either on the proportion of cultured cells that are engaged into the melanocytic differentiation pathway or on the amount of melanin produced by each differentiated pigment cell. The simple observation, however, reveals that SFEE has a significant effect on pigmentation of the cultured quail neural crest cells. This effect has therefore to be accounted for by the general increase in cell number induced by SFEE. The question is raised as to whether the in vivo SF phenotype is generated exclusively by this mechanism.

Animals↗
PubMed1994

Premature avian melanocyte death due to low antioxidant levels of protection: fowl model for vitiligo.

Feather melanocytes in the Barred Plymouth Rock (BPR) and White Leghorn (WL) chickens die prematurely in vivo when compared to the wild type Jungle Fowl (JF) chicken. Since these mutant melanocytes live in vitro, an environmental factor in the feather must precipitate their death. Results show that the addition of selected antioxidants, glutathione (GSH) and superoxide dismutase (SOD), can rescue these mutant melanocytes in vitro that have been placed under stress conditions that cause their premature cell death. Measurements of in vivo levels of GSH, catalase, and SOD show no significant difference in catalase activity between the JF, BPR, and WL feathers but do show a significant reduction in GSH activity in both the BPR and WL feathers to approximately 66% of the GSH concentration found in JF feathers. SOD activity in the BPR tissue is reduced significantly to approximately 50% of the JF activity and the WL SOD activity is reduced significantly to approximately 50% of the BPR SOD activity. Preliminary results of measurements of glutathione peroxidase activity indicate there is no difference in the levels of this enzyme in JF, BPR and WL feathers. A working hypothesis, based on current results, is proposed for premature cell death in BPR and WL feather melanocytes. The BPR melanocytes are genetically sensitive due to a defect in their SOD and GSH levels caused by the barring gene (B) and their death, due to reactive species of oxygen radicals, is precipitated in the poorly vascularized feather by the accumulation of oxygen radicals due to the low turnover of tissue fluids. The WL chicken carries the dominant white gene (I) in addition to the B gene. This gene directs the further reduction of the level of SOD and, when combined with the cell death mechanism already present in the BPR chicken, causes the WL feather melanocytes to die much earlier than the BPR feather melanocytes which in turn die much earlier than the wild type JF melanocytes. This same mechanistic hypothesis could apply as a cause of premature melanocyte cell death in human vitiligo wherein the vitiliginous melanocytes may have a genetic defect in their oxygen radical protection system.

Animals↗