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PubMed1977

Ultrastructural studies on the endogenous development of Eimeria brunetti. IV. Formation and structure of the oocyst wall.

The ultrastructural changes occurring during wall formation in the oocysts of E. brunetti were studied in tissue from the small intestine of young domestic fowls. The process of oocyst wall formation was initiated by a separation of the limiting membranes of the cytoplasmic mass of the macrogamete, to form a loose veil, consisting of 2-3 membranes, around the organism. Concomitant with the appearance of the veil, changes were observed in the Wall Forming Bodies of Type I (WFB I) and Type II (WFB II) which were present in the cytoplasm of the macrogamete. The outer layer of the oocyst wall seemed to be formed by a combination of membranes released from the surface of the organism and the contents of the WFB I. A 700 nm thick layer was thereby formed and, at this stage, the WFB I had disappeared from the cytoplasmic mass. The outer layer further condensed into a structure 250-350 nm in thickness in which 3 zones of different densities could be distinguished. The formation of the inner layer of the oocyst wall appeared to be associated with material from the WFB II and these disappeared from the cytoplasmic mass as the inner layer became evident. This inner layer was homogeneous in appearance and 80 nm thick. Comparison of the ultrastructure of the walls of oocysts obtained from chicken faeces with that of oocysts observed within the intestine showed only minor differences. The loose veil was not present in oocysts isolated from faeces and some changes were also noted in the outer zone of the outer layer of the oocyst wall. These differences could result from the mechanical and chemical treatments used for processing the faeces.

Animals↗
PubMed1977

Cytochemical electron microscopy on polysaccharide granules in the endogenous forms of Eimeria brunetti.

The endogenous stages in the life cycle of Eimeria brunetti were tested for polysaccharide material by electron microscopical cytochemistry using the periodic acid-thiocarbohydrazide-osmium tetroxide (PATO)-method. The parasites were observed within the epithelial cells of the small intestine of infected domestic fowls. Two types of granules reacted positively for polysaccharide. The first was large, approximately 500 nm by 250 nm. These granules had an appearance similar to the polysaccharide granules reported for other coccidian parasites. They were observed in mature merozoites, macrogamonts, and developing oocysts. The second type of granule was smaller (15-30 nm in diameter) and was only observed at the periphery of the residual cytoplasmic mass of mature microgamonts. It was more similar in appearance to metazoan glycogen than the former. However, since the PATO-method does not differentiate between different polysaccharides it can not be proven if these granules in fast contain glycogen. The WFBI of the macrogamete and the outer layer of the oocyst wall gave a slight positive reaction but after examination of the controls it appeared that this was not a specific reaction for polysaccharides.

Cytoplasmic Granules↗
PubMed1978

Pharmacological study of chicken airway smooth muscle.

Isolated chicken bronchus contracts to carbachol, PGF2alpha, histamine, 5-HT, bradykinin and phenylephrine. The bronchial strips from the horse plasma sensitized domestic fowl contracted to specific sensitizing antigen in vitro (Schultz-Dale anaphylactic reaction) and were 5 to 10 fold more reactive to PGF2alpha, histamine and 5-HT compared with the bronchi from normal chickens. Second antigen challenge was inactive or produced a weak response (desensitization). Allowing the bronchi to rest for 1 h resulted in partial recovery of anaphylactic response. Bronchi which had partially contracted submaximally to carbachol, antigen or PGF2alpha, relaxed to isoprenaline, adrenaline and PGE1 and E2.

Airway Resistance↗
PubMed1978

Iron metabolism in pigeons.

Several haematological parameters such as haemoglobin concentration, haematocrit, erythrocyte number, reticulocyte concentration, plasma iron and total iron binding capacity were determined in 118 urban pigeons of both sexes. No statistically significant sex differences among these parameters were found. In 36 specimens (23 males and 13 females), the plasma iron turnover was determined using 59Fe. The results obtained in this species, expressed per 100 ml-1 blood. day-1 and Kg-1 body weight. day-1, were compared with those of turkeys, ducks and chickens calculated from earlier papers. The highest values versus body weight were observed in pigeons. Organ (liver, spleen, tibia, heart, leg muscle, ribs, sternal keel, gonads and blood) distribution of 59Fe intravenous injection was analyzed during a period from 5 min up to 120 days (19 different times) in groups of 4 pigeons. At the 6 h period, the organs retained the highest dose (20% of total Fe injected), but by the 2nd day period, the radioiron in the blood represented about 98% of the total injected. A fast iron uptake by the circulatory blood was checked and compared with that of other species (domestic fowl, ducks and turkeys). The reticulocyte count in pigeons normally ranged from 4 to 12%, which was consistent with these results. A linear decreasing radioactivity in blood, with an inflexion point on the 40th day was observed. An inverse correspondence between blood and liver was found. Content in other organs decreased uniformly with time, except the heart where the iron content was practically constant during the whole time. Ribs and sternal keel are erythropoietic organs in young pigeons.

Animals↗
PubMed1970

The effect of progressive hypoxia on the respiratory and cardiovascular systems of the pigeon and duck.

1. During the initial stages of progressive hypoxia in ducks and pigeons (P(a, O2) 100 --> 60 mm Hg) there were no significant changes in heart rate, blood pressure or oxygen uptake, but respiratory frequency increased.2. As hypoxia became more profound (P(a, O2) 60 --> 30 mm Hg), there was a significant tachycardia, and blood pressure fell slightly in both animals. Respiratory frequency continued to increase in both species, and ducks were able to maintain their oxygen uptake at control levels at a lower P(a, O2) than pigeons.3. The response to progressive hypoxia of pigeons and ducks was compared with that of the domestic fowl. The former two birds could maintain control of their cardiovascular system at a lower environmental oxygen concentration than the latter. Arterial P(O2) followed a similar course in all three birds in relation to environmental oxygen content. Pigeons and ducks were therefore able to endure a lower arterial P(O2) than chickens.

Animals↗
PubMed1967

Calcitonin from ultimobranchial glands of dogfish and chickens.

Acid extracts of thyroid glands from a small shark Squalus suckleyi and domestic fowl Gallus domestica contained no detectable calcitonin activity, while very potent hypocalcemic responses were obtained in rats with similar extracts from the ultimobranchial glands of these two species. The calcitonin concentration was 4 to 40 times that present in hog thyroid, which, as in most other mammals, contains ultimobranchial tissue. The evidence suggests that calcitonin is a fundamental calcium-regulating hormone present in all higher vertebrates and that it is an ultimobranchial rather than a thyroid hormone. It also indicates an important and hitherto unrecognized function for the ultimobranchial glands.

Animals↗
PubMed2000

Genetic relatedness of Salmonella isolates from nondomestic birds in Southeastern United States.

Salmonella infections have been implicated in large-scale die-offs of wild birds in the United States. Although we know quite a bit about the epidemiology of Salmonella infection among domestic fowl, we know little about the incidence, epidemiology, and genetic relatedness of salmonellae in nondomestic birds. To gain further insight into salmonellae in these hosts, 22 Salmonella isolates from diseased nondomestic birds were screened for the presence of virulence and antibiotic resistance-associated genes and compared genetically using pulsed-field gel electrophoresis (PFGE) and random amplified polymorphic DNA analysis. Of the 22 Salmonella isolates examined, 15 were positive for the invasion gene invA and the virulence plasmid-associated genes spvC and pef. Most (15 of 22) were generally sensitive to antibiotics. However, two Salmonella isolates from pet birds were identified as Salmonella enterica serovar Typhimurium DT104. Despite the general susceptibility of these Salmonella isolates to most antimicrobial agents, antibiotic resistance-associated genes intI1, merA, and aadA1 were identified in a number of these isolates. Five distinct XbaI and nine distinct BlnI DNA patterns were observed for the 22 Salmonella isolates typed by PFGE. PFGE analysis determined that Salmonella isolates from passerines in Georgia and Wyoming were genetically related.

Animals↗
PubMed1986

Semen collection and spermatozoa characteristics in budgerigars (Melopsittacus undulatus).

Semen samples were obtained from budgerigars by applying gentle pressure to both sides of the cloaca. The semen appeared to be stored in the seminal glomera, two structures on either side of the proctodeum. These structures have been described before in Passeriformes. The spermatozoon in budgerigars is similar to the spermatozoon of the domestic fowl, but differs from the spermatozoon of Passeriformes.

Animals↗
PubMed1997

Studies on the development and use of a monoclonal sandwich ELISA for the detection of verotoxic Escherichia coli in animal faeces.

A sandwich ELISA using monoclonal antibodies to Escherichia coli verocytotoxins 1 and 2 for capture and detection was developed for detection of verocytotoxin-producing Escherichia coli (VTEC) in animal faeces. For optimal toxin detection, the faeces were cultured in MacConkey broth before subculture on to trypticase soy agar containing mitomycin C. It was possible to detect between 10 and 10(3) VTI-producing and 1 to 10 VT2-producing E coli/g faeces, and overall the sensitivity and specificity of the ELISA for VTEC in faeces were 80.5 per cent and 91.2 per cent, respectively, when compared with a verocell assay. A limited survey of faeces from healthy animals (89 cattle, 16 sheep, 22 pigs, 11 goats and six domestic fowl) and faeces from 144 cattle with enteric disease detected VTEC in 64 per cent, 63 per cent, 5 per cent, 45 per cent, none and 16 per cent of the samples, respectively.

Animals↗
PubMed1999

Salmonella pullorum in the common pheasant (Phasianus colchicus).

In 1996, pullorum disease due to Salmonella enterica serovar Gallinarum biovar pullorum (Salmonella pullorum) was diagnosed in pheasants on a gamebird rearing enterprise in south-west Scotland. The gross pathology and bacteriological findings are described, as are the results of screening for S pullorum on the site in 1997. The causal organism was readily isolated from the lung, liver, yolk sac and heart blood on direct culture, but less readily from the digestive tract or by the use of selective media. The bacteria recovered from the pheasants were identified as S pullorum phage type 7, a phage type previously associated with pheasants rather than domestic fowl, and the organisms were most probably introduced to the site by the movement of carrier pheasants.

Animals↗
PubMed2002

Infectious agents associated with respiratory disease in pheasants.

In a case-control study of the infectious agents associated with natural outbreaks of respiratory disease in pheasants, 28 batches of birds from sites affected by disease and eight batches of birds from unaffected sites were examined by six veterinary laboratories in England, Wales and Scotland, and tested for mycoplasmas, other bacteria and viruses. Sinusitis was the commonest sign of disease and was associated with Mycoplasma gallisepticum as detected by PCR in the trachea (P < 0.05) and conjunctiva (P < 0.01). Sinusitis was also associated with pasteurella cultured from the sinus (P < 0.05), antibody to avian pneumovirus (APV) (P < 0.01) and avian coronaviruses as detected by reverse-transcriptase PCR (P < 0.05); there was no association between disease and APV as detected by PCR. Avian coronaviruses were the most common infectious agents detected. They were genetically close to infectious bronchitis virus (IBV) but differed in their gene sequence from all the serotypes of IBV previously identified in domestic fowl, and serological tests with six known IBV types showed little cross reactivity. Mycoplasma species other than M gallisepticum were cultured in 18 batches of pheasants but, with the exception of Mycoplasma gallinaceum, were not associated with disease.

Animals↗
PubMed1975

Metabolic adaptation of the chick embryo to chronic hypoxia.

In a colony of white leghorn chickens maintained at 3,800 m successive generations exhibited an increasing hatchability of fertile eggs incubated at elevation of 3,100m. Embryonated eggs produced by the high-altitude-adapted line (WM) and by genetically similar but unselected stocks at sea level (D) were incubated at 3,100 m and at sea level, and the oxygen consumption was measured on individual eggs after the 17th day of incubation. At sea level, oxygen consumption rates of WM strain were less than that of SL stocks during late embryonic development. At 3,100 m, embryonic respriation of all strains was reduced, but to a much lesser degree in the high-altitude strain. It appears that a decreased metabolic activity of the late embryo coupled with a slower rate of embryonic developement is an important factor in the adaptation of the domestic fowl to high altitude.

Acclimatization↗
PubMed1988

Model for evaluating avian renal hemodynamics and glomerular filtration rate autoregulation.

Multiple vascular connections in normal avian kidneys make it difficult to experimentally manipulate renal blood flow patterns and perfusion pressures. In this study, hemostatic clips were used to obstruct the ureter of one kidney at the level of the ischiadic artery (IA) in anesthetized 3-wk-old chicks (Gallus domesticus). Kidney tissue upstream from the ureteral obstruction degenerated, leaving an intact caudal renal division with one route of arterial inflow branching from the IA. Renal function studies were conducted, using general anesthesia, when the birds reached 12-15 wk of age. A snare placed around the IA was used to unilaterally decrease renal arterial perfusion pressure (RAPP) for the experimental kidney. Under control conditions (snare loose), urine flow rates (UFR), glomerular filtration rates (GFR), clearance of p-aminohippuric acid, and fractional excretion of Na, K, Ca, and PO4 did not differ significantly, per gram of kidney weight, when experimental and intact contralateral kidneys were compared. Gradual tightening of the IA snare reduced RAPP stepwise. UFR decreased significantly from the initial control value when RAPP reached 40 mmHg, and urine flow ceased completely when RAPP reached 30-35 mmHg. In four of five birds, GFR did not decrease significantly between 110 and 60 mmHg but did decrease significantly below 60 mmHg. Urine osmolality was inversely correlated with UFR. Clearance of PAH did not decrease significantly from control values as RAPP ranged from 100 to 37 mmHg, possibly caused by increased renal portal blood flow. Overall, these results provide the first direct demonstration that in domestic fowl GFR is autoregulated at reduced RAPP.

Animals↗
PubMed1993

Response of the avian kidney to acute changes in arterial perfusion pressure and portal blood supply.

Domestic fowl kidneys autoregulate total renal blood flow and glomerular filtration rate (GFR) over a wide range of renal arterial perfusion pressure (RAPP). Sustained (approximately 2-4 h) restriction of renal portal blood flow attenuates the autoregulatory responses. The present study was designed to assess the effects of acute (approximately 10 min) alterations of renal portal blood flow on renal function, and to dissociate the renal responses to altered renal portal blood flow from the renal responses to reductions in RAPP. The thermal pulse decay (TPD) technique and p-aminohippuric acid clearance (CPAH) were used to measure blood flow. During acute increases and decreases in renal portal blood flow, regional renal blood flow as measured by the TPD system (RBFTPD) was significantly positively correlated with total kidney blood flow represented by CPAH (RBFPAH). These results indicate that changes in total kidney blood flow induced by alteration of portal perfusion were reflected in the regional measurement of renal blood flow. Changes in renal portal blood flow did not affect the urine flow rate (UFR), GFR, or fractional excretion of sodium (FENa). Reducing RAPP from 120 to 50 mmHg significantly reduced UFR, GFR, and FENa. Overall, these results indicate that large acute changes in renal portal blood flow can significantly alter total renal blood flow without significantly affecting parameters (UFR, GFR, and FENa) primarily influenced by the renal arterial vasculature.

Animals↗
PubMed1993

Characterization of organic osmolytes in avian renal medulla: a nonurea osmotic gradient system.

We measured the organic osmolytes present in the renal cortex and medullary cones of adult female domestic fowl before and after 48 h of water deprivation. Urine osmolality increased from 198 +/- 82 to 569 +/- 42 mosmol/kgH2O after water deprivation. In water-deprived birds, the major organic osmolytes, myoinositol, betaine, and taurine, in the medullary cones increased by 40, 100, and 24%, respectively, compared with control birds. No sorbitol was detected, and glycerophosphorylcholine (GPC) content was not affected by water deprivation. In the renal cortex, only betaine content increased significantly (4.8 +/- 0.6 vs. 3.1 +/- 0.3 mmol/kg wet wt) after water deprivation. In this study, we demonstrated that birds, like mammals, accumulate organic osmolytes in response to the increased interstitial osmolality that occurs during antidiuresis. Because urea is nearly absent in the avian medullary interstitium, our observation that GPC is not osmoregulated in the avian kidney supports the idea that GPC is the "counteracting osmolyte" for urea in the mammalian kidney. Furthermore, the organic osmolytes present in avian medullary cones are remarkably similar to those of the mammalian outer medulla. This similarity may be relevant to the morphological analogy of the two regions.

Animals↗
PubMed2001

Aldosterone suppresses expression of an avian colonic sodium-glucose cotransporter.

Transport in the colon of the domestic fowl switches from sodium-linked hexose and amino acid cotransport on high-salt intake to amiloride-sensitive sodium channel expression on low-salt (LS) diets. The present experiments were designed to investigate the role of aldosterone in suppression of the colonic sodium-glucose luminal cotransporter (SGLT). LS-adapted hens were resalinated with or without simultaneous aldosterone treatment. Changes in the electrophysiological responses and SGLT protein expression levels were examined at 1, 3, and 7 days of treatment. Serum aldosterone levels fell from approximately 400 pmol/l in LS-adapted hens to values below the detection limit (<44 pmol/l) after 1 day of resalination. At the same time, glucose-stimulated short circuit current (I(SC)) increased from 20.9 +/- 8.7 to 56.3 +/- 15.5 microA/cm(2), whereas amiloride-sensitive I(SC) decreased from -68.9 +/- 12.7 microA/cm(2) on LS to +0.6 +/- 12.0 microA/cm(2). Glucose-stimulated I(SC) increased further at 3 and 7 days of resalination, whereas amiloride-sensitive I(SC) remained suppressed. When resalinated birds were simultaneously treated with aldosterone, the LS pattern of high amiloride-sensitive I(SC) and low glucose-stimulated I(SC) was maintained. Immunoblotting results from the same tissues demonstrated that SGLT-like protein expression increased following resalination. Aldosterone treatment completely blocked this effect. These results demonstrate that aldosterone suppresses both activity and protein expression of hen colonic SGLT. Resalination either through decreased aldosterone or other factors may be able to activate SGLT activity independently of increases in protein expression.

Aldosterone↗
PubMed1981

Stimulation of avian renal phosphate secretion by parathyroid hormone.

Phosphate buffers (ammonium, sodium, potassium, and calcium phosphate, pH 5.5, 7.2, 8.5) and 32P were infused unilaterally into the renal portal systems of intact, parathyroidectomized (PTX), and parathyroid hormone-infused (PTH) domestic fowl to study the secretory flux for inorganic phosphate (Pi). Urine samples were collected simultaneously from both kidneys, with the uninfused kidney serving as a control for the portal-perfused kidney (modified Sperber technique). No consistent unilateral excess of Pi or 32P excretion occurred for any of the experimental groups. For intact birds, fractional 32P excretion by both kidneys (FE32p) was identical to fractional Pi excretion (FEpi) (determined by chemical analysis) and reflected net reabsorption (0.64). However, during PTH infusion, FE32p was 0.82 (net reabsorption) while FEPi was 1.21 (net secretion). These results indicate that a) the peritubular-to-lumen flux for Pi and 32P is a minor component of net tubular transport, regardless of the parathyroid status, counterion availability, or peritubular Pi concentration; b) plasma Pi and 32P enter the tubule lumen predominantly by filtration; c) PTH stimulates tubular Pi secretion; and d) the secreted Pi is derived from an organic or inorganic pool that does not readily equilibrate with infused 32P (or presumably peritubular Pi).

Animals↗

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