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At least 1,207 records · Page 67Linked to original sources
PubMed2005

Morphology of chimpanzee pinworms, Enterobius (Enterobius) anthropopitheci (Gedoelst, 1916) (Nematoda: Oxyuridae), collected from chimpanzees, Pan troglodytes, on Rubondo Island, Tanzania.

The chimpanzee pinworm, Enterobius (Enterobius) anthropopitheci (Gedoelst, 1916) (Nematoda: Oxyuridae), is redescribed based on light and scanning electron microscopy of both sexes collected from the feces of chimpanzees, Pan troglodytes, of an introduced population on Rubondo Island, Tanzania. Enterobius (E.) anthropopitheci is characterized by having a small body (males 1.13-1.83 mm long, females 3.33-4.73 mm long), a rather straight spicule with a ventral membranous formation in males, double-crested lateral alae in females, small eggs (53-58 by 24-28 microm), and a smooth eggshell with 3 longitudinal thickenings. Morphological comparison is made between the present and previous descriptions.

Animals↗
PubMed1980

Role of calcitonin in calcium homoeostasis in the chick embryo.

A radioimmunoassay for chicken calcitonin (CT) was used to study changes in the normal levels of CT in the circulation of chick embryos during incubation and in hatched chicks. The hormone was detectable in embryos whenever the plasma concentration of calcium was greater than 2.5 mmol/l. The level of CT at the time of 'pipping' was exceptionally high but when pipping was artificially advanced or retarded the peak of CT was dissociated from the physiological event of pipping. When embryos were injected with calcium, CT secretion was stimulated but the maximum level induced was substantially less than the normal peak level observed at pipping although an extreme degree of hypercalcaemia developed. When CT was removed from the embryonic circulation by injecting anti-CT plasma, a mild but statistically significant hypercalcaemia developed and in another experiment exogenous CT significantly decreased an artificially induced hypercalcaemia. The beta-antagonist, propranolol, decreased and the beta-agonist, isoprenaline, increased concentrations of CT in the circulation. We suggest that the role of CT in the chick embryo may be to restrict the hypercalcaemia resulting from the large movement of calcium from the eggshell to the developing embryo and its yolk-sac and that one of the natural stimuli for the release of CT in the late stages of incubation could be beta-adrenergic.

Animals↗
PubMed1998

Oogenesis in Atlantic salmon (Salmo salar L.) occurs by zonagenesis preceding vitellogenesis in vivo and in vitro.

Fish oogenesis represents pleiotropic cytodifferentiative programs including hepatic synthesis of the molecular components for both the eggshell and the oocytic energy deposits. Both hepatic processes are directly controlled by plasma levels of estradiol (E2), and injected E2 induces both biogenetic processes in prepubertal fish of both sexes. This work compares the temporal pattern of E2-induced biosynthesis of zona radiata proteins (zr-proteins) and vitellogenin in Atlantic salmon (Salmo salar L.) in vivo and in vitro. We monitored the presence of plasma zr-proteins and vitellogenin, using homologous polyclonal antiserum to zr-proteins and a monoclonal antibody to vitellogenin. Zr-proteins were induced by all E2 concentrations (0.001-1.1 mg/kg body weight (bw)) within one week of exposure while vitellogenin was not induced until two weeks post-injection and then only in plasma from fish injected with high E2 concentrations (0.4 mg or 1.1 mg/kg bw). After E2 treatment, hepatocytes isolated from male fish synthesized zr-proteins and vitellogenin in vitro. However, zr-proteins were secreted into the medium two days before vitellogenin, as measured by ELISA. The data indicate a preferential induction of zr-proteins compared with vitellogenin, both with regard to E2 sensitivity and response time to E2 treatment. These findings suggest an obligate sequence in salmon oogenesis. During sexual maturation low E2 levels at first induce only zonagenesis, while increasing levels of E2 subsequently induce both zonagenesis and vitellogenesis. In nature, the interval between zonagenesis and vitellogenesis may, therefore, be considerable. The data suggest new control mechanisms in fish oogenesis.

Animals↗
PubMed2005

Mercury patterns in wood duck eggs from a contaminated reservoir in South Carolina, USA.

Mercury contamination of wildlife populations has been documented widely in recent years as biomonitoring has become an important tool for assessing environmental contamination. Avian eggs provide an ideal assay material for Hg biomonitoring, particularly when the collection of eggs is simplified by using cavity-nesting species that nest in easily monitored nest boxes. However, studies are needed that address the dynamics of how Hg is distributed within eggs, and how Hg is deposited naturally within clutches laid by a single female and among clutches laid by different females occupying the same contaminated environment. We collected 138 eggs from 13 complete clutches of box-nesting wood ducks (Aix sponsa) during 1991 and 1992 at a contaminated reservoir of the U.S. Department of Energy's Savannah River Site in South Carolina, USA. Total Hg residues in egg components and clutches were determined, partitioning of Hg among egg components was examined, and effects of egg-laying sequence on egg component Hg levels were determined. Mean albumen Hg was 0.22 ppm wet mass, mean yolk Hg was 0.04 ppm, and mean shell Hg was 0.03 ppm. On average, 86.1% of total egg Hg was concentrated in the albumen, 11.2% in the yolk, and 2.7% in the shell. Mercury concentrations in all egg components varied significantly among clutches and between successive clutches laid by the same female in the same year. Laying sequence significantly affected Hg concentrations in the albumen and shell, but not in the yolk. Declines of albumen Hg due to laying sequence were more pronounced for clutches that contained higher average Hg levels. Our results suggest that collection of first-laid eggs may be preferable for assessing maximal Hg exposure to developing embryos, and that monitoring Hg levels through the use of empty eggshells following brood departure from nests may be valid only if the laying sequence is known.

Animals↗
PubMed2005

Vitellogenin detection and chick pathology are useful endpoints to evaluate endocrine-disrupting effects in avian one-generation reproduction study.

To investigate additional endpoints for screening of endocrine disruptors in birds, effects of 17beta-estradiol (E2) on one-generation reproduction in the Japanese quail (Coturnix japonica) were assessed. Pairs of the 10-week-old Japanese quail were fed a low-phytoestrogen diet containing E2 at 0 (control), 10, 100, and 1,000 ppm for six weeks. In the E2 100- and 1,000-ppm groups, the parental quail represented marked toxic changes including high mortality, decreased food consumption, decreased gonad weights, gross and histologic toxic changes in the reproductive and other organs, and inhibition of the reproduction. However, no adverse effects were observed in the parental quail from the E2 10-ppm group. In the parental males, serum vitellogenin (VTG) concentrations were increased significantly in the E2 10-ppm group, disclosing that serum VTG concentration is one of the highly sensitive endpoints for evaluating estrogenic endocrine activities. In the E2 10-ppm group, number of eggs laid, number of eggs with abnormalities, eggshell strength and thickness, fertility, early and late viabilities of embryos, normal hatchling rate, and clinical signs, mortality, viability, and body weight of chicks at 14 d of age were not affected. However, histopathology of the chicks in the E2 10-ppm group revealed meaningful morphological changes in the reproductive organs, such as cystic dilatation of seminiferous tubules, increased interstitial cells in the testis, and decreased theca cells in the ovary. The present study suggests that serum VTG concentration in the parental quail and histopathology of reproductive organs in the offspring are sensitive endpoints and are useful as additional endpoints in the avian one-generation reproduction test using the Japanese quail for evaluating estrogenic endocrine-disrupting effects.

Animals↗
PubMed1994

Use of live and inactivated Salmonella enteritidis phage type 4 vaccines to immunise laying hens against experimental infection.

Four groups of Dekalb Delta commercial layer hens (8 hens per group) were reared individually in cages in an isolation unit. At the age of 8 weeks, groups 1 and 2 were vaccinated with 9R Salmonella gallinarum live (9R live) vaccine. At the age of 18 weeks, group 1 was re-vaccinated with 9R live S. enteritidis vaccine, while groups 2 and 3 were vaccinated with S. enteritidis bacterin. At the age of 22 weeks, groups 2 and 3 were re-vaccinated with S. enteritidis bacterin. Group 4 was not vaccinated and was kept as a control group. At 24, 27 and 30 weeks of age, the four groups were challenged using various concentrations of S. enteritidis phage type 4 and various routes of inoculation. Eggs, cloacal swabs and blood were collected weekly for bacteriological and serological examination. Isolation of the challenge organism from the eggshells and egg contents of the vaccinated groups was significantly lower than with the control group. There was no correlation between humoral antibodies and the shedding of the challenge organism in eggs or cloacal swabs. A combined vaccination programme of 9R live S. enteritidis vaccine and S. enteritidis bacterin provided better protection to laying hens than either vaccine administered alone. Vaccination should never be performed alone but in conjunction with other measures related to veterinary hygiene and good management.

Agglutination Tests↗
PubMed1998

A major protein precursor of zebra mussel (Dreissena polymorpha) byssus: deduced sequence and significance.

The zebra mussel is a nonindigenous invader of North American lakes and rivers and one of the few freshwater bivalve molluscs having a byssus--a sclerotized organ used by the mussel for opportunistic attachment to hard surfaces. We have sequenced a foot-specific cDNA whose composite protein sequence was deduced from a series of overlapping but occasionally nonidentical cDNA fragments. The overall deduced sequence matches tryptic peptides from a major byssal precursor protein--Dreissena polymorpha foot protein 1 (Dpfp1). The calculated mass of Dpfp1 is 49 kDa; but this is known to be extensively hydroxylated and O-glycosylated during maturation. Purified native Dpfp1 analyzed using matrix-assisted laser-desorption ionization mass spectrometry with time-of-flight indicates that the protein occurs as at least two size variants with masses of 48.6 and 54.5 kDa. In all probability, the sequence variants reported in this study are related to the larger mass variant. Dpfp1 has a block copolymer-like structure defined by two consensus motifs that are sharply segregated into domains. The N-terminal side of Dpfp1 has 22 tandem repeats of a heptapeptide consensus (P-[V/E]-Y-P-[T/S/delta]-[K/Q]-X); the C-terminal side has 16 repeats of a tridecapeptide motif (K-P-G-P-Y-D-Y-D-G-P-Y-D-K). Both consensus repeats are unique, with some limited homology to other proteins functioning in tension: marine mussel adhesives, plant extensins, titin, and trematode eggshell precursors.

Amino Acid Sequence↗
PubMed1979

The rate of absorption into the embryonic chicken (Gallus domesticus) of 3H-testosterone.

The maximum absorption of tritiated testosterone by 5-day old embryos occurred one hour after its application to the eggshell. This decreased to relatively low levels during a 77 hour period. When the hormone was applied at the eleventh day of incubation there was a relatively large initial uptake by the bursa, spleen and thymus in that order and a subsequent diminution. Activity absorbed by the spleen remained essentially unchanged throughout the experimental period. The bursa appeared to have the greatest affinity for the hormone.

Absorption↗
PubMed1996

Experimentally induced Chiari-like malformation with myeloschisis in chick embryos.

Though several pathogenetic theories concerning the frequent association of Chiari malformation and hydrocephalus with myeloschisis have been suggested, none of them explains all the aspects of the disorder. To investigate whether myeloschisis is the direct cause of Chiari malformation and hydrocephalus or these conditions are the results of another basic event, we observed the morphological changes of the posterior cranial fossa and its components in the chick embryos with surgically induced myeloschisis. To make myeloschistic lesions, we opened the neural tube for a length of 9-11 somites in Hamburger and Hamilton stage 16-19 chick embryos. They were divided into cervicothoracic (C-T) and lumbosacral(L-S) groups according to the area of incision. The embryos were re-incubated until postoperative day 11. In the control group, embryos were incubated with the eggshell window open as their experimental counterparts. The survival rates of each group were as follows; 11% (9 survivors/85 operated embryos), 8% (7/83), and 17% (10/60) in the C-T, L-S and control groups, respectively. Myeloschisis positive rates were 100% in the operated groups and 0% in the control group. The heads of embryos were sectioned along the sagittal plane to observe the morphological changes in the posterior cranial fossa and its components. Of the survivors, five in the C-T group, two in the L-S group and six in the control group were available for light microscopic inspection. In the majority of embryos with myeloschisis, without difference between the C-T and L-S groups, the fourth ventricles were smaller than those of the control group and the subarachnoid spaces in the posterior cranial fossa were also narrower. In embryos with severe changes, the cerebellum displaced downward comparing with that of the control embryos. No evidence of hydrocephalus was present Though not always typical, morphological changes similar to Chiari malformation were observed in chick embryos with surgically induced myeloschisis. It suggests a strong direct causal relationship between the two conditions and supports the theories of derangements in cerebrospinal fluid dynamics rather than those of primary mesenchymal or neural origin as a pathogenetic mechanism of Chiari malformation.

Animals↗
PubMed2002

[Influence of the conditions of storage and cooking on growth, invasion and survival of Salmonella enteritidis in eggs].

Basal studies for the confirmation of sanitary rules in the kitchen were performed, focusing on preventing an outbreak of food poisoning due to eggs contaminated with Salmonella Enteritidis (SE), using hen and quail eggs. SE did not grow at 5 degrees C but grew markedly at 25 degrees C in eggs. The invasion and growth of SE were marked under very humid conditions regardless of whether the eggshell was damaged. The invasion of SE into egg also occurred when eggs were taken in and out of the refrigerator. Moreover, SE was spread immediately to all non-contaminated eggs when SE-contaminated eggs were cracked into a bowl with non-contaminated eggs. In homemade mayonnaise containing 15% vinegar, sterilization took several hours to occur. On a stainless-steel bowl, SE survived for 2 weeks or more. These findings suggest that it is necessary to pay attention to secondary contamination.

Animals↗
PubMed1976

Sexual maturation and productivity of Japanese quail fed graded concentrations of mercuric chloride.

Japanese quail (Coturnix c. japonica) were fed 0, 2, 4, 8, 16, and 32 p.p.m. Hg as mercuric chloride (HgCl2) from the time of hatching up to the age of 1 year. None of the birds manifested any gross signs of mercury poisioning. Food consumption, growth rate, and weight maintenance were unaffected. Initial oviposition tended to occur at a younger age as dietary mercuric chloride increased, e.g., the median age at which egg laying began among hens fed 32 p.p.m. Hg was 6 days younger than for controls. The average rate of egg production was positively related to the concentration of mercuric chloride with the most pronounced differences between treatments occurring among young (less than 9-week-old) hens. Beyond 9 weeks of age production was more uniform among the treatments, but even after 1 year hens on 32 p.p.m. Hg were laying an average of 13.5% more eggs than controls. Rate of egg fertilization was generally depressed for all Hg-treatments above 4 p.p.m. Hatchability of fertilized eggs and eggshell thickness appeared unaffected by mercuric chloride.

Animals↗
PubMed1981

The relationship of serum calcium to shell weight and other criteria in hens laying a low or high incidence of shell-less eggs.

Experiments were conducted to determine the relationship of serum calcium to shell weight and other criteria. Blood samples for calcium analysis were taken at oviposition in Experiments 1 and 2 from hens fed a 3.5% calcium diet. In Experiment 3, blood was taken at various intervals from hens laying a high or low incidence of shell-less eggs. These hens were fed a control diet or various calcium-deficient diets throughout a 45-day period. No relationship was found between serum calcium and shell weight, or egg weight. Hens laying a high incidence of shell-less eggs showed no decrease in serum calcium or egg production when fed a .58, .25, or .07% calcium diet. However, these criteria were reduced in hens laying a low incidence of shell-less eggs. It was concluded that the normal variation in serum calcium is not related to the hen's ability to produce eggshell. The mechanism of action responsible for cessation of lay when control hens were fed a calcium-deficient diet appeared not to function as it does in hens laying a high incidence of shell-less eggs.

Animals↗
PubMed1982

The influence of diflubenzuron on several reproductive characteristics in male and female-layer-breed chickens.

The possibility exists for the accidental contamination of feedstuffs used in poultry and livestock feeds with diflubenzuron (Dimilin, TH 6040; N-[[(4-chlorophenyl)amino]-carbonyl]-2, 6-difluorobenzamide), an insect growth regulator. The effect of this insecticide on reproduction in chickens was tested by feeding diflubenzuron at levels of 1, 2.5, 25, and 250 ppm to male and female layer-breed chickens from 1 day of age through a laying cycle. Characteristics measured were egg production, egg weight, eggshell weight, fertility, hatchability, and effects on the progeny. Feeding diflubenzuron at levels up to 250 ppm did not affect the characteristics measured. These results will be useful in evaluating the use of diflubenzuron in the field.

Animals↗
PubMed1982

Long-term shell-less culture of turkey embryos.

A technique is described for the long-term shell-less culture of turkey embryos. Cultured embryos demonstrated a similar rate of growth through 17 days of total incubation (4 days in ovo plus 13 days in culture) compared to embryos incubated in ovo. Thereafter, the cultured embryos grew at a reduced rate compared to their in ovo counterparts. Cultured embryos also exhibited elevated hematocrit values but reduced serum protein levels compared to the embryos incubated in ovo. Serum zinc, copper, and iron concentrations were similar for both groups of embryos, although each element reached a maximum concentration at a different point during incubation. Embryos incubated in ovo demonstrated a sustained elevation of serum calcium concentration from day 16 of incubation that was absent in the cultured embryos. The significance of eggshell calcium stores to embryo growth is discussed. Shell-less avian embryo culture represents a potentially useful technique for the study of trace element metabolism during avian embryonic growth and development.

Animals↗
PubMed1983

Toxicity of a vitamin D steroid to laying hens.

Two experiments were conducted with 56-week-old or 104-week-old Leghorn hens to determine if feeding vitamin D steroids in excess of requirement levels caused any marked affects on eggshell quality. In the first experiment caged hens had reduced feed consumption, egg shell quality, and egg production as early as 6 weeks after initially consuming a basal diet supplemented with 6.8 micrograms 1 alpha-hydroxycholecalciferol (1 alpha-OH-D3)/kg. The second experiment confirmed the previous results and showed that extensive weight loss occurred with continued feeding of 10 or 15 micrograms 1 alpha-OH-D3/kg diet. No adverse affects were observed in either experiment when the level of 1 alpha-OH-D3 supplementation was 5.0 micrograms/kg diet or less. No toxic effects were observed when the hormone precursor 25-OH-D3 was supplemented to diets at 6 or 12 micrograms/kg. It is suggested that the pathological effects observed are related to the potent calcium homeostatic properties of 1 alpha-OH-D3 that at elevated levels may cause aberrations in circulating calcium.

Animals↗
PubMed1984

Blood ionic calcium responses of hens from thick-shell and thin-shell lines to ethyleneglycol-bis-(B-aminoethylether)-N,N'-tetraacetic acid injections.

Experiments were conducted on laying and nonlaying hens from genetically selected lines that produce thick (TK) or thin (TN) eggshells. At 44 weeks of age, TK layers exhibited significantly higher total plasma calcium concentrations than TN layers. Total plasma calcium concentrations were not significantly different between TK and TN layers at 80 weeks of age, reflecting an effect of aging on total plasma calcium. Intravenous injections of ethyleneglycol-bis-(B-aminoethylether-N,N'-tetraacetic acid (EGTA) were administered to TK and TN layers at 44 weeks of age and to TK and TN layers and nonlayers at 80 weeks of age. EGTA is a calcium chelating agent that creates hypocalcemia when injected intravenously. Laying hens of both lines and at both ages exhibited a similar degree of hypocalcemia during EGTA injections, and a similar rate of recovery to normocalcemia was noted after cessation of EGTA administration. Nonlayers were unable to recover from the EGTA-induced hypocalcemia. Because the pattern of calcium depression and recovery during and after the EGTA challenge has been shown to be associated with the capacity of parathyroid hormone-sensitive target tissues to buffer blood ionized calcium, it was concluded that the capacity to buffer ionized calcium by these target tissues is similar in TK and TN layers. However, nonlayers have a restricted capacity to buffer blood ionic calcium.

Animals↗
PubMed1984

In vitro prostaglandin E2 stimulation of 45Ca mobilization from chick bone.

The ability of prostaglandin E2 (PGE2) to mobilize 45Ca from chick embryo long bones was assayed in an in vitro bone culture system. Concentrations of PGE2 tested ranged from 10(-9) to 10(-5) M. The PGE2 was effective in stimulating release of 45Ca from prelabelled bones at all concentrations tested except at 10(-9) M. In addition, stimulation of 45Ca release could be produced daily for 4 consecutive days of PGE2 culture-pulsing at what appeared to be the optimal PGE2 concentration, 10(-7) M. We conclude, as in mammals, PGE2 is a potent stimulator of calcium mobilization from avian bone. The potential involvement of prostaglandins in eggshell formation is discussed.

Animals↗
PubMed1984

Increasing hatchability of turkey eggs by matching incubator humidity to shell conductance of individual eggs.

One of the most important factors determining hatchability of avian eggs is the proper water balance of the eggs during incubation. In turkey eggs, a total diffusive water loss (F) of 12 +/- 1% SD initial egg mass in 28 days, yielded maximal hatchability irrespective of the combination of eggshell water vapor conductance (G) and incubator humidity (PI), which brought about this water loss. A good correlation was found between G as obtained at the beginning of incubation and the final F in a given PI. The G in a random sample of 1256 fresh turkey eggs was normally distributed around the mean of 18.70 +/- 2.87 SD milligrams (100 g X day X torr)-1 (Coefficient of variation = 15.3%). The distribution of G in eggs with dead in the shell embryos had, in addition, two more peaks of G values [around 22.5 and 13.0 mg (100 g X day X torr)-1]. When eggs were sorted into low (less than 17), medium (17 to 20), and high (greater than 20) G categories, and incubated at low (19.4), medium (26.6), and high (33.9) torr PI, respectively, hatchability increased by a factor of 1.08. Poor hatchabilities were obtained in mismatching humidities and conductances. It seems that hatchability success may be experimentally improved if a correct rate of water loss is fitted to sorted eggs during incubation.

Animals↗