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PubMed1999

Three enzymes newly identified from the genus Eimeria and two more newly identified from E. maxima, leading to the discovery of some aliphatic acids with activity against coccidia of the domesticated fowl.

Nine enzymes were detected in sporulated oocysts of Eimeria tenella and E. maxima, parasites of the domesticated fowl (Gallus gallus). Three enzymes, hydroxybutyrate dehydrogenase, alanine aminotransferase and gamma-glutamyltransferase, all identified for the first time in Eimeria of fowl, occurred both in E. tenella and in E. maxima. The remaining enzymes assayed had previously been found in various Eimeria species of fowl, although creatine kinase and glutamate dehydrogenase were hitherto unknown from E. maxima. The three enzymes newly recorded from Eimeria of fowl are of interest as potential genetic markers, and also as potential chemotherapeutic targets. The discovery of hydroxybutyrate dehydrogenase led to the demonstration of anticoccidial activity by some aliphatic acids. The paper also includes a list of the enzymes detected in Eimeria of fowl in previous studies.

5'-Nucleotidase↗

PubMed1990

Comparison of haematological values in restricted- and ad libitum-fed domestic fowls: white blood cells and thrombocytes.

1. White blood cells and thrombocyte values were examined in normal domestic fowls of layer and broiler strains fed restricted or ad libitum diets. 2. Basophils were the only white blood cells to increase significantly in number after the period of food restriction. It is suggested that the increase may have been associated with stress. 3. There were more basophils in broilers than layers, in males than females and in younger than older birds. 4. In contrast, a decrease in the total number of white blood cells was seen in birds maintained on a restricted diet compared with those fed ad libitum. 5. Stress may also have been responsible for an increased thrombocyte count in the restricted birds as well as a slightly lowered eosinophil count. 6. Heterophil/lymphocyte ratios were not significantly altered by the restriction of food.

Age Factors↗

PubMed1981

Estimation of thyroidal radioiodide clearance in the domestic fowl (Gallus domesticus).

A method for estimating thyroidal clearance of radioiodide from the blood plasma of the domestic fowl is described. It differed from published methods in a number of ways. (1) It utilized total thyroid radioiodide concentration (IT) and did not require the use of goitrogens or the separation of free and protein-bound components. (2) Radioiodide was injected intravenously rather than by other routes. (3) Plasma radioiodide concentration (IB) was determined from several serial samples from each bird rather than once only. (4) The method allowed the clearance constant (kappa; microliter/min per mg) to be estimated for individual birds, rather than from groups, thereby enabling effective replication for comparative experiments. The constant was estimated from the model dIT/dt = kappaIB, measurements being made within 120 min after injection to ensure that exit of radioiodide from the thyroid was negligible. The improved method resulted in estimates of clearance constants which agreed well with published findings.

Animals↗

PubMed1981

Effect of gonadectomy on the concentrations of catecholamines in discrete areas of the diencephalon of the domestic fowl.

Concentrations of dopamine, noradrenaline and adrenaline in discrete areas of the diencephalon in male and female domestic fowl were correlated with changes in the plasma concentrations of LH induced by gonadectomy. Gonadectomized birds of both sexes exhibited raised plasma concentrations of LH and in castrated cockerels the daily administration of testosterone propionate was completely effective in preventing the postcastration rise in LH. Although no significant alterations in the brain concentrations of noradrenaline or adrenaline were observed in cockerels, the concentration of dopamine in the paraventricular nucleus (PVM), dorsomedial thalamic nucleus and mediobasal hypothalamus (MBH) were significantly raised in castrated compared with sham-operated birds by 136, 182 and 52% respectively. In each case the increase was partially suppressed by testosterone replacement therapy. In pullets, ovariectomy resulted in significant increases in the concentrations of dopamine (83%) and noradrenaline (78%) in the MBH and noradrenaline (35%) and adrenaline (34%) in the PVM. These findings suggest that in the fowl at least part of the negative feedback effect of gonadal steroids on LH secretion may be mediated by catecholaminergic mechanisms at the level of the hypothalamus.

Animals↗

PubMed1990

Participation of tri-iodothyronine and metabolic clearance rate in the inhibition of growth hormone secretion in thyroxine-treated domestic fowl.

Surgical thyroidectomy increases basal and TRH-induced GH concentrations in the peripheral plasma of immature domestic fowl. Replacement therapy with thyroxine (T4; 100 micrograms/kg per day for 7 days, i.m.) suppressed the GH responses to thyroidectomy. Bolus administration of T4 (10 micrograms/kg, i.m.) to thyroidectomized birds promptly lowered the circulating GH concentrations, which remained suppressed for at least 4 h. Chronic (daily injections for 7 days) or acute (one injection) pretreatment of thyroidectomized birds with iopanoic acid (IOP; 40 mg/bird, i.m.) before the bolus administration of T4 attenuated, but did not prevent, inhibition of circulating GH levels by T4. Administration of IOP (40 mg/bird i.m.) 24 h and immediately before the administration of tri-iodothyronine (T3; 3 micrograms/kg, i.m.) or T4 (10 micrograms/kg, i.m.) also failed to suppress thyroidal inhibition of circulating GH concentrations in thyroidectomized birds. Administration of IOP alone had no effect on GH concentrations. Circulating T3 concentrations were not enhanced following the administration of T4 to IOP-treated birds, indicating its inhibition of hepatic monodeiodinase activity. The metabolic clearance rate (MCR) of 125I-labelled chicken GH in the plasma of thyroidectomized fowl was less than that in sham-thyroidectomized birds. Following pretreatment with T4 (100 micrograms/kg per day for 7 days) sham-thyroidectomized and thyroidectomized birds did not differ significantly in their MCR. The GH secretion rate in thyroidectomized birds was similar to that in sham-thyroidectomized birds and in both groups was markedly reduced following pretreatment with T4. These results demonstrate thyroidal inhibition of circulating GH concentrations in fowl.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Age related modulation of circadian time structure of blood, plasma and tissue variables in male domestic fowls.

To study modulation of circadian time structure of 11 blood, plasma and tissue variables in male domestic fowls, as a function of age, three experiments were made in one-day-old fowls (72) standardized by 12L:12D. In the first experiment, at 6 week age, 24 birds were killed by decapitation, four each at six different circadian stages (2, 6, 10, 14, 18 and 22 hr after light onset, HALO). Equal number of birds were killed at similar circadian stages at the age of 12 and 18 week in the second and the third experiments, respectively. Age affected both, the circadian patterns and the mesors (24 hr mean values). The circadian pattern included amplitude (half of the total extent of variation) and acrophase (estimated time of peak) for each variable. The results clearly suggest that the pattern of circadian rhythm may vary as a function of age of the bird.

Aging↗

PubMed1991

Influence of method of model fitting and gender on estimated parameters for the relationship between starvation heat production and body size in the domestic fowl.

The relationship between starvation heat production (SHP) in kJ/d and body weight (W) in kg for domestic fowl was examined with compiled calorimetric data for 294 fowls (Johnson and Farrell, 1985). Linear regression analyses using ordinary least squares methods were performed before and after transformation of the data to a logarithmic scale (base = 10). Coefficients of determination (R2) were similar for untransformed and log-transformed data (R2's = .56 and .53, respectively). The slopes for untransformed data of males and females were different (P less than 0.033). When the model parameters for: SHP = b0 Wb1 were derived from log-transformed data, there were no significant differences in exponents for males vs. females (P greater than .95). However, when the coefficients were estimated using non-linear regression techniques, a difference was detected at the level of P = 0.072. It was determined that there is no advantage in describing the relationship of SHP as a non-linear function of W, nor is it appropriate to express physiological variables as a ratio of weight raised to some mass exponent without statistical justification. Using W or W2 as a covariable for the statistical analysis of physiological data would produce equally acceptable determinations of significance.

Animals↗

PubMed1978

The topographical anatomy and blood supply of the carotid body region of the domestic fowl.

The topographical anatomy of the carotid body region was investigated on both sides in 30 adult domestic fowls (Gallus gallus domesticus). On each side of the body the two parathyroid glands always adhered to each other, the caudal gland being the smaller. The right cranial parathyroid usually touched the thyroid gland, but on the left side the two glands were nearly always separate. The ultimobranchial gland was usually attached to the parathyroid glands on the left side, but was always well separated on the right side. The carotid body, the identity of which was checked by light and electron microscopy, was ovoid in shape, whitish in colour, and about 0.8 x 0.6 x 0.5 mm in size. It was almost always in direct contact with the medial surface of one or both parathyroid glands have commonly been portrayed astopographically separate from each other. The oesophagotracheobronchial artery, the artery to the carotid body, and the caudal thyroid artery arose close together, though in variable positions, from the lateral aspect of the common carotid artery. The artery to the carotid body was always the middle of the three. The venous drainage of the carotid body was associated with the veins of the parathyroid and ultimobranchial glands. The carotid body was innervated by a filament from the distal vagal ganglion. The topographical observations on the carotid body region have been compared with those of other authors. The cranial and caudal parathyroid glands have commonly been portrayed as topographically separate from each other. The carotid body has seldom been depicted in direct contact with the parathyroid glands. The size of the carotid body has invariably been shown far too large. These discrepancies are discussed and are attributed largely to the reliance by other authors on serial reconstruction rather than microdissection.

Animals↗

PubMed2001

Eimeria parasites of domestic fowl: genetic relationships of different isolates estimated from random amplified polymorphic DNA.

Genetic relationships between Eimeria parasites of domestic fowl, including three isolates of E. acervulina, one of E. maxima, four of E. mitis, six of E. praecox, one of E. tenella, and two of uncertain identity, were analyzed by random amplified polymorphic DNA (RAPD) and the unweighted pair-group method with arithmetic mean, using 12 primers. Each primer amplified 4-34 DNA fragments/isolate. The similarity coefficients and phenograms were calculated from RAPD products with 230-2,000 bp in silver-stained polyacrylamide gels. Some primers generated RAPD markers which were species-specific for E. acervulina, E. mitis, and E. praecox. The phenograms revealed six clusters, each corresponding to an individual Eimeria species. The pBP and pBP2 isolates, of uncertain identity, clustered with the E. acervulina isolates (100% bootstrap). The intraspecific relationships showed certain degree of genetic isolation of the Eimeria populations, and it was associated with broiler house and with geographic separation.

Animals↗

PubMed1997

Isoenzymes of Eimeria from the domestic fowl: electrophoretic variants among species, strains and clones.

Electrophoretic variation of enzymes in five Eimeria spp. of the domestic fowl, including nine strains, ten single-sporocyst clones and two single-sporozoite clones of E. acervulina, three strains each of E. maxima and E. tenella, two strains of E. praecox and one strain of E. necatrix, were assayed using cellulose acetate electrophoresis. Ten enzymes [aldehyde oxidase (AO), alkaline phosphatase (ALP), amylase (AMY), fumarate hydratase (FUM), glucose-6-phosphate dehydrogenase (G6PDH), glucose phosphate isomerase (GPI), glutamate-oxaloacetate transferase (GOT), isocitrate dehydrogenase (IDH), malate dehydrogenase (MDH) and phosphoglucomutase (PGM)] were analyzed for their ability to distinguish between these species and strains. Enzymatic activity of G6PDH, GPI, IDH, MDH and PGM was detected in all the Eimeria spp. examined. Strains within each species were characterized by the same electrophoretic variant of G6PDH. Electrophoretic variants of GPI and PGM were the most valuable in the identification of inter- and intra-specific variation, particularly in the field strains of E. acervulina and E. tenella. These two enzymes were used to examine single-sporocyst and single-sporozoite clones derived from two strains of E. acervulina. The enzymes in E. maxima appeared to be conserved, showing no variation among strains with the five enzymes detected. Relative mobilities, calculated as described in this paper, were found to be consistent between different electrophoresis runs and may serve as a reference when this medium is used.

Animals↗

PubMed1987

Plasma immunoreactive-growth hormone in domestic fowl: measurement by homologous and heterologous radioimmunoassays.

Concentrations of immunoreactive (IR) growth hormone (GH) in the plasma of domestic fowl have been measured by homologous and heterologous radioimmunoassays and the estimates compared. Both assays detected an age-related decline in the circulating IR-GH concentration, an increase in IR-GH secretion following TRH-stimulation or fasting, and a fall in the IR-GH concentration following adrenocorticotropin administration. However, while the overall estimates of IR-GH concentration were significantly correlated, the magnitude of the changes in IR-GH concentration determined by the homologous assay were far greater than those detected by the heterologous system, which failed to show any inhibitory effect of anesthesia or exogenous thyroid hormones on basal or stimulated IR-GH release. These results suggest that the heterologous GH radioimmunoassay lacks the sensitivity of the homologous chicken GH assay and that circulating GH in birds is probably composed of heterogeneous moieties with differing immunoreactivities with rat GH antibodies.

Adrenocorticotropic Hormone↗

PubMed1991

Eimeria tenella: localization of the sporozoites in the caecum of the domestic fowl.

When sporozoites of Eimeria tenella were inoculated into an isolated horn of the bicornuate caecum of the domestic fowl, replicating infections, culminating in the production of oocysts, were found, almost exclusively, in the inoculated horn. In contrast, sporozoites of E. tenella introduced into the bloodstream via a superficial vein induced infections of equivalent intensity in both horns of the caecum. These findings are discussed with reference to (1) the detection (by tissue transfer) of infective sporozoites in samples of cardiac blood and vascular tissues taken within 3 to 18 h of the oral inoculation of oocysts, and (2) the (previously published) observation that the sporozoites of E. tenella are transported from the superficial epithelium of the caecum (site of invasion) to the crypts (site of initial development) within host intra-epithelial lymphocytes. We suggest that a local inflammatory response to the invasion of sporozoites may be responsible for their re-location in proximity to the site of entry. This could act by directing the homing (or retention) of the parasite-bearing lymphocytes, and/or by providing a stimulus for the sporozoite to leave its transporting cell.

Animals↗

PubMed1985

Relationship between starvation heat production and body size in the domestic fowl.

The relationship between starvation heat production (SHP) in kJ/d and body weight (W) in kg for the domestic fowl was examined by compiling calorimetric data on 78 immature and 222 mature fowls. Linear regression analyses were performed after transformation of the data to a logarithmic scale (base = 10). The derived relationship (re-transformed) for mature birds was found to be: SHP = 406 W0.602 The weight exponent (b) was significantly (P less than 0.01) different to the value of 0.75 normally used for mature birds.

Age Factors↗

PubMed1980

Specialized cell contacts and the blood-testis barrier in the seminiferous tubules of the domestic fowl (Gallus domesticus).

The ultrastructure of Sertoli-Sertoli and Sertoli-germ cell surface specializations in the domestic fowl was studied in material fixed by vascular perfusion through the thoracic aorta. Three main types of surface specializations were found between adjacent Sertoli cells. These are focal tight junctions, desmosome-like devices, and a specialization characterized by the presence of long and dilated subsurface cisternae of rough endoplasmic reticulum. Typical inter-Sertoli cell junctions similar to those of mammals were absent. Germ cells were attached to Sertoli cells mainly by desmosome-like devices of varying appearance. The junctions between Sertoli cells and elongating or elongated spermatids, "the mantle", consisted of only slight condensations of filamentous material in the Sertoli cell. The tight junctions between adjacent Sertoli cells were efficient in preventing lanthanum from passing towards the lumen beyond the level of the spermatogonia.

Animals↗

PubMed1993

Ultrastructural changes in nervous elements associated with the granular cells of the common carotid artery of the domestic fowl after distal vagal ganglionectomy.

Intramural granular cells of the left and right common carotid artery of the domestic fowl were examined with the electron microscope after left distal vagal ganglionectomy. The vast majority of the nerve fibers and endings associated with the granular cells of the left common carotid artery degenerated rapidly after ipsilateral ganglionectomy, indicating that they are derived from the left vagus. On the other hand, left distal vagal ganglionectomy resulted in transformation of the intramural granular cells of the right common carotid artery and the few nervous elements associated with them, into a typical chemoreceptor tissue. This tissue was made up of small granule (60-120 nm) containing cells associated with many nerve fibers, nerve endings and fenestrated capillaries. The nerve endings were of two types; presumptive afferent endings and adrenergic efferent endings. Both types of endings made synaptic junctions with the granular cells.

Animals↗

PubMed1985

Adrenocortical cell function in the hypophysectomized domestic fowl: effects of growth hormone and 3,5,3'-triiodothyronine replacement.

The control of adrenocortical function in the domestic fowl (Gallus domesticus) was investigated using adrenocortical cells isolated from hypophysectomized (hypox) and intact cockerels and from hypox cockerels injected with T3, purified chicken GH (cGH), and T3 plus cGH. Corticosterone in plasma and cell incubations was measured by RIA. Cellular responses to varying concentrations of steroidogenic agents were fitted and statistically analyzed by computer. Hypophysectomy reduced the basal plasma corticosterone (B) concentration to 53% of the value in intact birds and eliminated a stress response. Although hypophysectomy reduced adrenal weight by 20%, it did not change relative adrenal weight (milligrams per 100 g BW). However, replacement with cGH increased relative adrenal weight by 24%, whereas replacement with T3 or T3 plus cGH reduced relative adrenal weight by 16%. In the absence of steroidogenic agents, there were no detectable differences in B production by adrenocortical cells isolated from various experimental groups. However, with a maximal steroidogenic concentration of ACTH, B production by isolated adrenocortical cells from hypox birds was 61% of that by cells from intact birds. The ED50 of ACTH for cells from hypox cockerels was 2.7 times greater than that of cells from intact cockerels, thus indicating a loss of cell sensitivity to ACTH after hypophysectomy (the greater the ED50, the lesser the cell sensitivity). Although cGH replacement increased maximal B production (Bmax) induced by ACTH to 329% that by cells from hypox cockerels, it increased the ACTH ED50 3.6 times, thus decreasing cell sensitivity more than hypophysectomy alone. In contrast to cGH, T3 replacement maintained the cell sensitivity to ACTH at the level of cells from intact birds, but lowered Bmax to 54% that of cells from hypox cockerels. The combination of cGH and T3 administered to hypox cockerels both maintained cell sensitivity to ACTH and raised the Bmax to 358% that of cells from hypox animals. These treatments also affected 8-bromo-cAMP-induced Bmax and pregnenolone-supported Bmax, but did not significantly alter the ED50 of these agents.(ABSTRACT TRUNCATED AT 400 WORDS)

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1988

Light and dark cells in the lumbar sensory ganglia of pre and post-hatching domestic fowl.

Clear and dark satellite cell classes were identified by electron microscopy in the lumbar sensory ganglia of domestic fowl in 8 pre and 4 post-hatching stages of development. Some cytologic differences found between the two classes relating to the rough-endoplasmic reticulum, ribosomes, Golgi apparatus and junctional complexes suggest the existence of distinct functional features for both types of satellite cells.

Animals↗

PubMed1985

Pleiotropisms associated with alleles of the C locus in the domestic fowl.

Pleiotropisms associated with the recessive white (c) and albino (ca) alleles at the C locus of the domestic fowl were investigated. Hatchability of fertile eggs was not significantly different for the colored (C+/c, C+/ca), recessive white (c/ca), and albino (ca/ca) chicks; however, late embryonic mortality was higher in ca/ca embryos P less than or equal to .005). Albinos exhibited shorter down lengths (P less than or equal to .01), higher incidences of subcutaneous hemorrhage and inflammation (P less than or equal to .01) and an increased incidence of yolk sac protrusions (P less than or equal to .01). Suppressed body weights (P less than or equal to .01) were evident at all times, except at hatching, in both male and female albinos reared in batteries. Recessive white females also exhibited smaller body weights than colored chicks at 7 and 8 weeks of age in battery trials (P less than or equal to .01). Significant suppression of body weights occurred in albinos only at 4 weeks of age in trials where floor rearing was used. Mortality in albinos was also significantly higher, particularly under floor rearing conditions (P less than or equal to .01). In addition, both feed consumption and feed utilization were reduced in albinos (P less than or equal to .01). These data suggest that melanin synthesis is an important component in the expression of a number of important physiological traits and that the C locus exerts a previously undefined regulatory influence on such traits.

Albinism↗