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At least 343 records · Page 19Linked to original sources
PubMed2003

Excess nuclear DNA in spermatozoa of guinea fowl.

The proportion of spermatozoa with elongated nuclei in ejaculates from a strain of guinea fowl was estimated, subjectively, to range from approximately 1 to 6%. It was confirmed by image analysis that in an ejaculate from one male, the distribution of nuclear lengths was bimodal, with a distinct population comprising 10% of spermatozoa having a mean nuclear length that was 52% greater than that of the remaining 90%. Furthermore, the mean DNA content of the 'large-nuclei' population was 1.85 times (not significantly different from twice) that of the main sperm population. The proportion of large-nuclei spermatozoa that was motile was less than that of normal sperm (31% versus 59%) and the velocity of motile spermatozoa was also less (24 microm/s versus 72 microm/s). The poor motility of the large-nuclei spermatozoa in vitro was reflected in their limited performance in vivo, since only 1.1% were found associated with the egg outer perivitelline layer. This is the first report to quantify the occurrence of, presumed, polyploid spermatozoa in a domestic bird. The incidence of such spermatozoa in commercial guinea fowl and other domestic poultry and the genesis and effects on fertility of such spermatozoa may be significant.

Acrosome↗
PubMed1998

Comparison of assessment of fowl sperm viability by eosin-nigrosin and dual fluorescence (SYBR-14/PI).

The kinetics of fowl sperm viability/mortality following short-term and long-term in vitro storage were studied using 2 different staining methods: eosin/nigrosin (observed under light microscopy) and SYBR-14/PI (dual fluorescence). Based on data obtained at 0, 30 min and at 2, 4 and 24 h (T0, T30, T2, T4, and T24) after in vitro storage (4 degrees C, agitated) of fresh or frozen-thawed semen, the dual association SYBR-14/PI was more effective than eosin/nigrosin (P < 0.05) staining for the detection of sperm viability/mortality at early stages (30 min) in nonfrozen ejaculates stored above 0 degree C. In cryopreserved preparations, the 2 techniques were comparable for assessing viable spermatozoa immediately after thawing, but higher percentages (P < 0.05) of nonviable spermatozoa were detected by the SYBR-14/PI procedure for up to 4 h of in vitro storage post thawing (4 degrees C, agitated). Finally, comparable results were observed between the 2 techniques 24 h after beginning in vitro storage post thawing. It is concluded that the dual association SYBR-14/PI procedure is more effective (or, at least, more rapid) than eosin/nigrosin staining for the assessment of sperm viability/mortality in both fresh and cryopreserved samples of fowl semen. However, in the latter case, the thawing stage needs to be followed by a period of in vitro storage lasting at least 4 h to allow for easier discrimination between viable and nonviable populations of spermatozoa.

Aniline Compounds↗
PubMed2002

Diverse expression of the K-1 antigen by cortico-medullary and reticular epithelial cells of the bursa of Fabricius in chicken and guinea fowl.

The immunocytochemical study of the K-1 monoclonal antibody indicates that the epithelial components of the bursa of Fabricius of the chicken and guinea fowl express the K-1 positive molecule. During embryogenesis, the K-1 antigen expression appears together with the bud-formation. As the number of B cells increases in the developing follicle, the K-1 expression gradually diminishes in the medullary reticular epithelial cells and completely ceases by hatching, which suggests that the molecule is developmentally regulated. After hatching, the expression of the molecule is restricted to the sealing off zone of the lymphoepithelial or medullary region of the follicle: i.e. to the cortico-medullary (CM) epithelial cells and the follicle associated epithelium (FAE) supporting cells in guinea fowl and to the latter ones in the chicken. The expression of the K-1 antigen by these epithelial components may support their structural identity. After hatching, the K-1 molecule is restricted to the CM epithelial cells and/or FAE supporting cells, which suggests that the function of the embryonic epithelial bud is taken over by the CM epithelial cells. The K-1 positive CM epithelial cells form arches, which encompass blast-like cells. The possible relationship of the CM epithelial cells and blast-like cells, which may represent the precursors of bursal secretory dendritic cells is discussed.

Animals↗
PubMed1987

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

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

Animals↗
PubMed1998

Inhibition of flagellar motility of demembranated fowl spermatozoa by protease substrates.

We investigated the effects of various protease substrates on the motility of demembranated fowl spermatozoa. In the presence of ATP, the motility of demembranated spermatozoa was vigorous at 30 degrees C, but decreased markedly following the addition of protease substrates, such as N alpha-carbobenzoxy-L-lys-thiobenzyl ester (BLT), N-benzoyl-phe-val-arg p-nitroanilide or N alpha-benzoyl-D,L-arg p-nitroanilide (BAPNA) in a dose-dependent manner, within the range 0-1 mM. The subsequent addition of 100 ng/ml trypsin released the inhibitory effect of protease substrates within 10 s. Phosphorylation or dephosphorylation of several proteins of demembranated spermatozoa was observed following the addition of protease substrates, however, no consistent patterns of protein phosphorylation or dephosphorylation were associated with the inhibition of motility. These results suggest that endogenous protease activity is instrumental in the maintenance of fowl sperm motility and that the site of action of this protease is in the axoneme and/or accessory cytoskeletal components. This enzyme may not act directly on the phosphorylation of sperm proteins involved in the regulation of motility.

Animals↗
PubMed2001

Development of a raceway method to assess aversion of domestic fowl to concurrent stressors.

The requirement for assessing the effects of stressor combinations in improving the welfare of animals has not been widely recognised. Knowledge of the effects of concurrent stressors is needed to improve environments such as transport, where animals are presented with many simultaneous challenges. However, no method for measuring the effects of different stressors with a common unit is currently available. A locomotor passive avoidance method was developed as a common currency measure of the aversion of domestic fowl to concurrent stressors, using vibrational and thermal stressors as an exemplar. Juvenile fowl, fasted overnight, were trained to run a raceway into a goal-box for small food rewards (FR1). When running consistently, the reinforcement schedule was superimposed with a FR5 treatment schedule (60 min confinement in the goal-box with either a control of no other stressors [N] or concurrent vibration and thermal stressors [VT]). Subsequent latency to return to the goal-box was recorded as a measure of aversion. The factors affecting bird response were addressed in a series of experiments to optimise the method and clarify interpretation of results. Pre-feeding (20% ration 2 h prior to testing) did not affect response, but increasing the number of treatment presentations facilitated learning and increased method sensitivity. Treatment responses were consistent across experiments; overall VT was avoided (P<0.001), but N was not. However, there was large individual variation in response to VT. A final experiment indicated that, given a visual discriminatory cue, birds were capable of learning the required association between entering the goal-box and receiving the treatment, suggesting that the delay responses were due to aversion rather than the immediate impact of treatment on ability to respond. Further work is required to test the singular stressors, but the method retains common currency potential for assessing aversion to multiple stressors.

Journal Article↗
PubMed2000

The possible role of protein-carboxyl methylation in the regulation of flagellar movement of fowl spermatozoa.

Both intact and demembranated fowl spermatozoa were incubated at 30 degrees C and 40 degrees C with adenosine, 3-deazaadenosine and homocysteine thiolactone. This combination of products is known to block intracellular protein-carboxyl methylation reaction. The motility of intact spermatozoa incubated at 30 degrees C was vigorous but decreased markedly after the addition of 100 microM adenosine+100 microM 3-deazaadenosine+100 microM homocysteine thiolactone. During this incubation period, the intracellular ATP concentrations of spermatozoa were maintained at approximately 40 nmol ATP/10(9) cells, in spite of the inhibition of motility. The motility of demembranated spermatozoa at 30 degrees C was not inhibited by the same concentrations of blocker. At 40 degrees C, the motility of intact spermatozoa without any effectors was almost negligible. The addition of blocker did not appreciably affect the motility of spermatozoa, which remained almost negligible. In contrast, motility became vigorous even at 40 degrees C when intact spermatozoa were suspended in fluid to which had been added 1 mM CaCl(2) or 100 nM calyculin A, a specific inhibitor of protein phosphatase-type 1 and -type 2. Stimulation of motility by Ca(2+) or calyculin A was inhibited by the presence of a blocker. Contrary to that of intact spermatozoa, the motility of demembranated spermatozoa stimulated by protein phosphatase inhibitor at 40 degrees C was not inhibited by the presence of a blocker. These results suggest that protein-carboxyl methylation may be involved in the regulation of fowl sperm motility. Furthermore, it appears that the methylating enzyme may be present in the cytoplasmic matrix and/or the plasma membrane but not retained in the axoneme and/or accessory cytoskeletal components.

Adenosine↗
PubMed1998

Randomly amplified polymorphic DNA (RAPD) for evaluating genetic relationships among varieties of guinea fowl.

The present study investigated the use of randomly amplified polymorphic DNA (RAPD) in estimating the intra and inter varietal genetic variation in three varieties of guinea fowl (Lavender, Pearl and White). The estimates, measured as band sharing were high for within population (0.946-0.971) and between population (0.990-0.999) genetic similarity. The respective estimates were 0.898-0.929 and 0.923-0.928 when estimated as frequency of occurrence of bands. The results indicated a very low level of intra and inter varietal genetic variation in these guinea fowl varieties, which in turn suggested the low level of genetic variation in these populations. The possible reasons for this high genetic similarity has been discussed.

Animals↗
PubMed2001

Maturation-dependent neointima formation in fowl aorta.

Fowl show spontaneous elevation of blood pressure (BP) and neointimal plaque formation in the abdominal aorta at young ages. Maturation/age-dependent modulation of vascular lesions and a causal relationship between elevated BP and neointima formation, however, have not been clarified. We therefore intended to characterize, first, maturation/age-dependent neointimal plaque formation and vascular lesions and, second, their relationship to BP elevation. The BP measured in conscious domestic fowl, Gallus gallus, White Leghorn breed, DeKalb strain, via an indwelling catheter inserted into the ischiadic artery, increased with maturation in males; and at plateau level, BP (mmHg) was significantly (P<0.01) higher in males (194.0+/-4.6, n=11) than in females (169.3+/-3.1, n=10). Neointimal plaques consisting of neointimal cells and abundant extracellular matrix appeared initially in the distal segment of the abdominal aorta (lesion-prone area) of chicks as early as 6 weeks old. The area (size) of neointimal plaques right above the ischiadic bifurcation increased with maturation, whereas the plaque area became smaller with some degenerative changes in adult birds. In some birds, diffuse subendothelial hyperplasia and more extensive plaque formation at the branching points of the aorta were observed. The plaque area appears to be larger in birds, particularly in males that have higher BP (r=0.68). The width of aortic smooth muscle (SM) layers, measured in regions with no plaque, increased with age, whereas the number of cells per unit of area decreased, suggesting that hypertrophy of vascular SM occurs in response to exposure of the vascular wall to high BP. The number of cells was significantly (P<0.01) higher in the plaque than in underlying aortic SM layers or in layers with no plaque formation. Both neointimal plaques and underlying SM layers are immunohistochemically positive for alpha SM actin, suggesting that neointimal cells are modulated SM cells, whereas the staining with SM myosin heavy chain antibody is low in neointimal plaques. Furthermore, plasma arginine levels dropped in accordance with the time of neointimal plaque formation, whereas plasma cholesterol levels showed an age-dependent increase. The results suggest that spontaneous development of neointimal plaques may be a consequence of exposure to high BP and associated local hemodynamic changes.

Actins↗
PubMed1998

Temperature-dependent flagellar motility of demembranated, cytosol-free fowl spermatozoa.

A rapid and gentle procedure for preparing demembranated, cytosol-free sperm models was applied to fowl spermatozoa. Intact spermatozoa were introduced to a Triton X-100-containing extraction medium layered on top of a discontinuous Percoll gradient in a 1.5 ml microfuge tube. After brief exposure to the extraction medium, spermatozoa were separated from the plasma membrane and detergent-soluble components by centrifugation through a 55% Percoll layer, finally collecting on top of a 90% Percoll cushion from where they were recovered. Optimum conditions consisted of a Triton X-100 concentration in the extraction medium of 0.15%, duration of demembranation time of 1.5 min and ATP concentration in the reactivation medium of 0.5 mM. Demembranated sperm models obtained by this procedure could be reactivated, and the motility at 30 degrees C was more than 60%, but negligible at 40 degrees C. These values were similar to those obtained from the conventional method, in which centrifugation is not carried out, and which results in some of the cytosolic components being transferred to the reactivation medium along with the spermatozoa. Inhibition of motility was observed following the addition of EGTA or myosin light chain kinase (MLCK) substrate peptide at 30 degrees C, whilst the presence of protein phosphatase inhibitors, such as calyculin A or okadaic acid, permitted the restoration of motility at 40 degrees C. These results demonstrate that the axoneme and/or accessory cytoskeletal components are directly involved in the temperature-dependent regulatory system of fowl sperm motility in the absence of plasma membrane and/or soluble components of cytoplasm.

Animals↗
PubMed1975

The fowl (Gallus domesticus) and a lepidopteran (Setomorpha rutella) as experimental hosts for Tetrameres mohtedai (Nematoda).

The life-cycle of Tetrameres mohtedai in the fowl involving a hitherto unknown intermediate host, Setomorpha rutella, is described and methods for laboratory demonstration are given. Development to infectivity in the intermediate host took less than 2 weeks under laboratory conditions. Infections could be established using infective larvae dissected from the intermediate host. The pre-patent period in the fowl averaged 36 days. Experimental evidence is given for infection of the final host by ingestion of either infected adult or infected larval Setomorpha. Development of the parasite to the infective stage does not depend on metamorphosis of the intermediate host.

Animals↗
PubMed2003

A multiplex PCR assay for the simultaneous detection and discrimination of the seven Eimeria species that infect domestic fowl.

This study reports the development of a novel multiplex PCR assay based on SCAR (Sequence-Characterised Amplified Region) markers for the simultaneous diagnosis of the 7 Eimeria species that infect domestic fowl. Primer pairs specific for each species were designed in order to generate a ladder of amplification products ranging from 200 to 811 bp. Sensitivity tests for each species were carried out, showing a detection threshold of 1-5 pg, which corresponds approximately to 2-8 sporulated oocysts. Distinct isolates of the 7 Eimeria species from different geographical sources were tested and successfully detected by the assay. All the species were amplified homogeneously, whether or not one of them was present in a high quantity, indicating that there was no cross-interference. The assay was also tested with different sources of Taq DNA polymerase and thermocycler models, confirming the high reproducibility of the reaction. The economy of consumables and labour represented by a single-tube reaction greatly facilitates the molecular diagnosis of a large number of samples, making it appropriate for field epizootiological surveys. We propose the use of this multiplex PCR assay as a rapid and cost-effective diagnostic method for the detection and discrimination of the 7 Eimeria species that infect domestic fowl.

Animals↗
PubMed1976

Developing visual function in the red jungle fowl embryo.

The onset of visual system function in the wild red jungle fowl embryo was measured by the pupillary reflex technique and compared with its domesticated descendant, the domestic chick. The first neurally mediated pupillary reflex in the jungle fowl embryos was found at Day 15 of incubation after 77% of incubation was completed. This point did not differ significantly from the onset of this reflex in the domestic chick embryo (after approximately 83% of incubation). Thus, it was concluded that the relatively late onset of overt visual system function in the chick, as compared with several other precocial avian species, was not a result of its history of intense domestication but rather was most likely a normal characteristic of this and other closely related species.

Age Factors↗
PubMed1976

Murray Valley encephalitis virus infection in mosquitoes and domestic fowls in Queensland, 1974.

Field studies during an epidemic of Murray Valley encephalitis (MVE) led to the isolation of MVE virus from a pool of mosquitoes (Culex annulirostris) and a sentinel chicken from Charleville, south-west Queensland. A high proportion of domestic fowls at Charleville had antibody to MVE virus at the beginning of February 1974, in advance of the first case recognized in Queensland and allowing early warning from health authorities. A survey of antibody in domestic fowls in mid-1974 suggested widespread activity of MVE virus in western and east-central Queensland. Virus isolation and serological studies showed activity in south-west Queensland of three other viruses known to infect man, Ross River, Sindbis and Kunjin viruses.

Animals↗
PubMed2002

Pre- and post-insemination episodes of sexual selection in the fowl, Gallus g. domesticus.

Although much attention has been recently directed to sexual selection arising after insemination from sexual promiscuity, little is known about the mechanisms determining reproductive success after insemination, and the way these mechanisms interact with each other and with selective mechanisms occurring before insemination: mate choice and mate acquisition. Here, we briefly review the findings of an on-going study investigating the mechanisms generating variation in reproductive success at both a pre- and a post-insemination stage in the domestic fowl. Female preference consistently favours socially dominant males before and after insemination. However, although social status mediates the number of sperm that a male inseminates into a female, dominant males may inseminate sperm of lower fertilising quality than their subordinates. We argue that mitochondrial genes may contribute to determine sperm quality, and speculate that the maternal control of mitochondrial genes may prevent sexual selection from operating on males, thus explaining both the lack of a positive correlation between social dominance and sperm quality and the maintenance of variation in male quality in the fowl.

Animals↗
PubMed1986

Frequency and structure of macrophages and abnormal sperm cells in guinea fowl semen.

Semen from young and old guinea fowl was examined for macrophages and abnormal sperm cells. Large numbers of macrophages were found in the semen from both groups. However, there were significantly more abnormal sperm cells in the semen of the young males. The abnormal cells consisted of large coiled cells, bent spermatozoa, and round-headed cells. The predominant abnormality in the young males was bent sperm, although their semen also contained large round cells. The large round cells were identified as abnormal spermatids by electron microscopy and were more prominent in the older males. The abnormal spermatids were pleomorphic and exhibited various stages of intermediate and late spermatid development. The macrophages were activated cells that exhibited phagocytosis of large number of normal spermatozoa but were never observed to engulf abnormal cells. Their ultrastructure consisted of numerous lipid droplets, vesicles of ingested spermatozoa, lysosomal structures, residual bodies, and undigested remnants of spermatozoa. The presence of macrophages and abnormal spermatids in semen has been associated with lowered fertility in other species; thus, semen with exorbitant numbers of these cells should not be used for artificial insemination of the guinea fowl.

Acrosome↗
PubMed1991

Differential effects of T4 and T3 on TRH- and GRF-induced GH secretion in the domestic fowl.

The in vivo growth hormone (GH) response of immature domestic fowl to thyrotrophin-releasing hormone (TRH) and GH-releasing factor (GRF) was suppressed in birds fed diets supplemented (1 ppm) with triiodothyronine (T3) or given bolus intraperitoneal (ip) injections (100 micrograms/kg for 10 d) of T3. Supplementation (ppm) of the diet with T4 had no effect on secretagogue- induced GH release. Exogenous T3 or T4 suppressed basal, TRH- and GRF-induced GH release 2 h after daily ip administration (100 micrograms/kg for 10 d). 24 h after the last injection, only T3 was effective in inhibiting basal and stimulated GH secretion in vivo. The systemic administration of T3 was followed 2 h and 24 h later by a downregulation of pituitary TRH binding sites. T4 administration had no effect on pituitary TRH binding. When chicken pituitary glands were incubated in vitro, basal GH release was unaffected by the addition of 10(-9)-10(-5) M T3 or T4 to the incubation media. The in vitro GH response to TRH (10(-6) M) or GRF (10(-6) M) challenge was, however, suppressed in a dose-related manner by T3 but was unaffected by the coincubation of T4. These results demonstrate inhibitory effects of T3 and T4 on basal and secretagogue-induced GH secretion in fowl. T4 is less active than T3 and probably exerts some of its effects via T3-independent mechanisms.

Administration, Oral↗
PubMed1996

Monophyletic origin and unique dispersal patterns of domestic fowls.

With the aim of elucidating in greater detail the genealogical origin of the present domestic fowls of the world, we have determined mtDNA sequences of the D-loop regions for a total of 21 birds, of which 12 samples belong to red junglefowl (Gallus gallus) comprising three subspecies (six Gallus gallus gallus, three Gallus gallus spadiceus, and three Gallus gallus bankiva) and nine represent diverse domestic breeds (Gallus gallus domesticus). We also sequenced four green junglefowl (Gallus varius), two Lafayette's junglefowl (Gallus lafayettei), and one grey junglefowl (Gallus sonneratii). We then constructed a phylogenetic tree for these birds by the use of nucleotide sequences, choosing the Japanese quail (Coturnix coturnix japonica) as an outgroup. We found that a continental population of G. g. gallus was the real matriarchic origin of all the domestic poultries examined in this study. It is also of particular interest that there were no discernible differences among G. gallus subspecies; G. g. bankiva was a notable exception. This was because G. g. spadiceus and a continental population of G. g. gallus formed a single cluster in the phylogenetic tree. G. g. bankiva, on the other hand, was a distinct entity, thus deserving its subspecies status. It implies that a continental population of G. g. gallus sufficed as the monophyletic ancestor of all domestic breeds. We also discussed a possible significance of the initial dispersal pattern of the present domestic fowls, using the phylogenetic tree.

Animals↗