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PubMed1998

Nutritional and developmental roles of insulin-like growth factors in poultry.

Insulin-like growth factor-I and -II are important multifunctional polypeptides that interact with membrane-bound receptors as well as soluble binding proteins. The biological actions of these hormones are multifaceted and dependent to a large extent on binding protein interactions. Some unique differences in insulin-like growth factor physiology and biochemistry are evident between mammalian and avian species. These include amino acid compositional and significant receptor differences as well as binding protein status. The biological response to both growth factors is different in birds. A greater proportion of the insulin-like growth factors exists in plasma as free peptide compared with the situation in mammals. This review is a brief summary of our knowledge of insulin-like growth factor physiology in domestic fowl.

Animal Nutritional Physiological Phenomena↗
PubMedDate not supplied

Pop-eye: an inherited Z-linked keratoglobus in the chicken.

A Z-linked recessive mutation in the domestic fowl is reported that results in a keratoglobus of both eyes. It does not appear to have any effect on the vision of affected individuals. The keratoglobus is not noticeable at hatching, but becomes obvious by 5-6 weeks of age. The mutant has been designated pop-eye, gene symbol pop. Initial studies suggest linkage with the late feathering (K) locus, and with the NM 7092 t (Z;1) translocation, which had previously been shown to be closely linked with Z-linked silver (S). There appear to be no other detrimental effects associated with this mutant. Preliminary analysis of T3 and T4 thyroid hormone levels do not indicate any thyroid malfunction.

Animals↗
PubMed1997

Associated effects of divergent selection for residual feed consumption on reproduction, sperm characteristics, and mitochondria of spermatozoa.

Eighteen generations of divergent selection for residual feed intake have been completed in two Rhode Island Red lines of domestic fowl. The high intake R+ line and the low intake R- line cocks used to sire Generation 19 of the selection experiment have been compared for associated responses on fertility, hatching, and sperm quality. Evaluations of sperm samples were based on volume, cell concentration, biochemical parameters (pH, uric acid and protein concentrations), and motility and morphology of spermatozoa. Finally, individual spermatozoa were analyzed by flow-cytometry (FCM) using Rhodamine 123 (Rh123) and nonyl-acrydine-orange (NAO) specific fluorochromes to assess, respectively, overall mitochondrial activity and overall mitochondrial content. Hatchability of incubated eggs was 20 points higher for the R- line, mainly because unfertilized eggs were only 6 vs 30% in the R+ line. Early embryo mortality was also twice as high in the R+ line (21%). The ratio of Rh123 to NAO fluorescence was identical for both lines. This result suggests that there was no difference in the energy producing potential of the individual mitochondria. Therefore, the difference seen for both dyes between the two lines might be attributed to a difference in the quantity of mitochondrial inner membranes present in the cell (with 17% less for the R+ line). In the R+ line, the poor performance at fertilization and during early embryonic development was associated with lower production of motile spermatozoa, possibly in relation to a lower quantity of mitochondria in spermatozoa from R+ cocks. Although the female contribution to the differences between lines was not explored separately, results suggest that selection for residual feed intake may have altered some cellular function related to the production of energy in the R+ line.

Analysis of Variance↗
PubMed1999

Thromboxane mimics the pulmonary but not systemic vascular responses to bolus HCl injections in broiler chickens.

Bolus i.v. injections of 1.2 N HCl elicit a rapid but transient pulmonary vasoconstriction in broiler chickens. In mammals, the pulmonary vasoconstrictive response to bolus acid injection depends on increased synthesis of thromboxane A2; however, the vascular responsiveness of domestic fowl to thromboxane previously had not been evaluated. In the present study, we tested the hypothesis that, if HCl triggers pulmonary vasoconstriction by stimulating thromboxane A2 synthesis in broilers, then bolus i.v. injections of the potent thromboxane A2 mimetic U44069 (9,11-dideoxy-9alpha,11alpha-epoxy-methanoprostaglandin++ + F2alpha; 1 micromol/mL; 0.5 mL injected volume) should trigger hemodynamic responses similar to those elicited by HCl (1.2 N; 1.5 mL injected volume). Both HCl and the thromboxane mimetic elicited twofold or greater increases in pulmonary vascular resistance, which in turn increased pulmonary arterial pressure by 50% despite concurrent reductions in cardiac output. The reductions in cardiac output were associated with reductions in stroke volume but not heart rate. The thromboxane mimetic also increased the total peripheral resistance, which minimized the reduction in mean systemic arterial pressure associated with the decrease in cardiac output. In contrast, HCl injections did not increase total peripheral resistance; consequently, the reduction in cardiac output caused the mean systemic arterial pressure to decrease by 30 mm Hg. Mannitol (2.5%; 1.5 mL) was injected i.v. as a volume control, and had no influence on any of the variables. This study provides the first direct evidence that thromboxane is a potent pulmonary vasoconstrictor in broilers, and provides support for the hypothesis that thromboxane mediates the pulmonary vasoconstrictive response to bolus i.v. injections of HCl. The differential response of the systemic vasculature to the thromboxane mimetic and HCl may indicate that cardiopulmonary responses to HCl injections are not mediated solely via thromboxane production. Alternatively, a direct dilatory effect of elevated hydrogen ion concentrations on the systemic vasculature may have counteracted any tendency for simultaneously evolved endogenous thromboxane to elicit systemic vasoconstriction.

Animals↗
PubMed1999

Effects of transient treatment with 6-N-propyl-2-thiouracil on testis development and function in breeder turkeys.

Experiments were conducted to address recent reports of precocial testis development or testicular hypertrophy induced by the anti-thyroid agent 6-N-propyl-2-thiouracil (PTU) in domestic fowl and rodents. In three experiments, PTU was administered to male turkeys during different stages of development. The PTU was given in the feed at a concentration of either 0.1 or 0.5% and effects on thyroid hormones were measured. Periods of PTU treatment were 8 to 16 or 10 to 18 wk of age (Experiment 1); 0 to 8, 0 to 16, and 8 to 16 wk of age (Experiment 2); and 8 to 16 and 20 to 35 wk of age (Experiment 3). Data were collected to determine the effect of PTU treatment on testicular growth (weight), sexual maturation (semen onset and plasma testosterone concentrations), and early adult testicular function in terms of semen quantity (semen volume and sperm concentration) and quality (sperm viability and fertilizing ability). The 0.1% PTU treatment at 8 to 16 wk of age in Experiment 1 resulted in greater testis weights and sperm production than those of untreated controls at 24 wk of age. The difference was absent by 36 wk of age. Likewise, in Experiment 2, onset of semen production was advanced by about 2 wk by the 8 to 16 wk treatment as compared to untreated controls (23.3 vs 25.9 wk), although, at 32 and 36 wk of age neither the quantity nor quality of semen were significantly affected. Also in Experiment 2, 0.1% PTU treatment from 0 to 8 or 0 to 16 wk of age delayed the onset of semen production and depressed semen volumes at 32 and 36 wk of age without affecting semen quality. In Experiment 3, the mean age at the onset of semen was not significantly affected by 0.5% PTU treatment from 8 to 16 or 20 to 35 wk of age. In addition, semen volume and quality at 32 and 36 wk of age was similar to controls. It was concluded that antithyroid treatment with PTU was dependent on dose and time of treatment for effects on both sexual development and early reproductive performance. Precocial development and associated hypertrophy of the testes occurred but was transient. Thereafter, during initial reproductive function, semen quantity and quality were normal.

Aging↗
PubMed2006

Identification of a novel pituitary-specific chicken gonadotropin-releasing hormone receptor and its splice variants.

In all vertebrates, GnRH regulates gonadotropin secretion through binding to a specific receptor on the surface of pituitary gonadotropes. At least two forms of GnRH exist within a single species, and several corresponding GnRH receptors (GNRHRs) have been isolated with one form being pituitary specific. In chickens, only one type of widely expressed GNRHR has previously been identified. The objectives of this study were to isolate a chicken pituitary-specific GNRHR and to determine its expression pattern during a reproductive cycle. Using a combined strategy of PCR and rapid amplification of cDNA ends (RACE), a new GNRHR (chicken GNRHR2) and two splice variants were isolated in domestic fowl (Gallus gallus domesticus). Full-length GNRHR2 and one of its splice variant mRNAs were expressed exclusively in the pituitary, whereas mRNA of the other splice variant was expressed in most brain tissues examined. The deduced amino acid sequence of full-length chicken GNRHR2 reveals a seven transmembrane domain protein with 57%-65% homology to nonmammalian GNRHRs. Semiquantitative real-time PCR revealed that mRNA levels of full-length chicken GNRHR2 in the pituitary correlate with the reproductive status of birds, with maximum levels observed during the peak of lay and 4 wk postphotostimulation in females and males, respectively. Furthermore, GnRH stimulation of GH3 cells that were transiently transfected with cDNA that encodes chicken GNRHR2 resulted in a significant increase in inositol phosphate accumulation. In conclusion, we isolated a novel GNRHR and its splice variants in chickens, and spatial and temporal gene expression patterns suggest that this receptor plays an important role in the regulation of reproduction.

Amino Acid Sequence↗
PubMed1989

Radioiodination of chicken luteinizing hormone without affecting receptor binding potency.

By improving the currently used lactoperoxidase method, we were able to obtain radioiodinated chicken luteinizing hormone (LH) that shows high specific binding and low nonspecific binding to a crude plasma membrane fraction of testicular cells of the domestic fowl and the Japanese quail, and to the ovarian granulosa cells of the Japanese quail. The change we made from the original method consisted of 1) using chicken LH for radioiodination that was not only highly purified but also retained a high receptor binding potency; 2) controlling the level of incorporation of radioiodine into chicken LH molecules by employing a short reaction time and low temperature; and 3) fractionating radioiodinated chicken LH further by gel filtration using high-performance liquid chromatography. Specific radioactivity of the final 125I-labeled chicken LH preparation was 14 microCi/micrograms. When specific binding was 12-16%, nonspecific binding was as low as 2-4% in the gonadal receptors. 125I-Labeled chicken LH was displaced by chicken LH and ovine LH but not by chicken follicle-stimulating hormone. The equilibrium association constant of quail testicular receptor was 3.6 x 10(9) M-1. We concluded that chicken LH radioiodinated by the present method is useful for studies of avian LH receptors.

Animals↗
PubMed1993

Modulation of the fertilizing ability of spermatozoa from roosters carrying the Sd (sperm degeneration) allele.

Roosters carrying the Sd (sperm degeneration) allele produce spermatozoa that die prematurely in vivo. Consequently, these mutants are subfertile. The objective of the present study was to determine whether or not subfertility could be modulated. A previous study found that the proximal efferent ducts of mutants were characterized by a reduced surface-to-volume ratio. We hypothesized that if subfertility was exacerbated by hemicastration of chicks, which increases daily sperm production in adults, then a relationship between efferent duct function and sperm longevity would be likely. In experiment 1, hemicastration of chicks exacerbated the subfertility of adults (p < 0.001). As inferred from SDS-PAGE in previous research, mutants lack at least one non-albumin seminal plasma protein. Therefore, it was hypothesized that protein supplementation would ameliorate subfertility. In experiment 2, fertility increased (p < 0.001) when spermatozoa from mutants were mixed with albumin-depleted seminal plasma protein from fertile roosters before insemination. In contrast, supplementation with BSA had no effect (p > 0.05). In summary, the subfertile status of Sd roosters was dynamic and appeared to depend upon the interaction of testicular output, efferent duct structure, and seminal plasma protein. Thus the study of this dysfunction may help to identify factors responsible for sperm maturation in the domestic fowl.

Animals↗
PubMed2000

Sperm mobility: phenotype in roosters (Gallus domesticus) determinedby concentration of motile sperm and straight line velocity.

Previous research demonstrated that sperm mobility, i.e., the net movement of a sperm population, is a quantitative trait of the domestic fowl. However, the cellular basis for this trait was unknown. In the present work, individual motile sperm were evaluated with a Hobson SpermTracker in order to identify one or more properties of motile sperm that could account for variation in sperm mobility observed among males. A method was validated for assessing sperm motion over an erythrocyte monolayer at body temperature. A small-scale experiment with roosters from the tails and center of a normal distribution of sperm mobility phenotypes (n = 33 roosters) demonstrated that straight line velocity (VSL) and motile concentration were critical to expression of phenotype. The importance of these variables was confirmed with a large-scale experiment using a representative subpopulation (n = 100 roosters). VSL of individual sperm at 41 degrees C ranged between 5 and 100 microm/sec. VSL averaged 32, 39, and 40 microm/sec for low, average, and high sperm mobility phenotypes. Sperm were diluted to 1.2 x 10(6)/ml for motion analysis. Mean motile concentrations were 0.52, 0.84, and 0.95 x 10(6)/ml for low, average, and high sperm mobility phenotypes. Motile concentration was correlated with sperm mobility (r = 0.71). VSL appeared to have an additive effect as it was correlated with straightness of sperm cell trajectory (r = 0.79).

Animals↗
PubMed1989

An allometric study of pulmonary morphometric parameters in birds, with mammalian comparisons.

Comprehensive pulmonary morphometric data from 42 species of birds representing ten orders were compared with those of other vertebrates, especially mammals, relating the comparisons to the varying biological needs of these avian taxa. The total lung volume was strongly correlated with body mass. The volume density of the exchange tissue was lowest in the charadriiform and anseriform species and highest in the piciform, cuculiform and passeriform species. The surface area of the blood-gas (tissue) barrier, the volume of the pulmonary capillary blood and the total morphometric pulmonary diffusing capacity were all strongly correlated with body mass. The harmonic mean thickness of both the blood-gas (tissue) barrier and the plasma layer were weakly correlated with body mass. The mass-specific surface area of the blood-gas (tissue) barrier (surface area per gram body mass) and the surface density of the blood-gas (tissue) barrier (i.e. its surface area per unit volume of exchange tissue) were inversely correlated (though weakly) with body mass. The passeriform species exhibited outstanding pulmonary morphometric adaptations leading to a high specific total diffusing capacity per gram body mass, consistent with the comparatively small size and energetic mode of life which typify passeriform birds. The relatively inactive, ground-dwelling domestic fowl (Gallus gallus) had the lowest pulmonary diffusing capacity per gram body mass. The specific total lung volume is about 27% smaller in birds than in mammals but the specific surface area of the blood-gas (tissue) barrier is about 15% greater in birds. The ratio of the surface area of the tissue barrier to the volume of the exchange tissue was also much greater in the birds (170-305%). The harmonic mean thickness of the tissue barrier was 56-67% less in the birds, but that of the plasma layer was about 66% greater in the birds. The pulmonary capillary blood volume was also greater (22%) in the birds. Except for the thickness of the plasma layer, these morphometric parameters all favour the gas exchange capacity of birds. Consequently, the total specific mean morphometric pulmonary diffusing capacity for oxygen was estimated to be about 22% greater in birds than in mammals of similar body mass. This estimate was obtained by employing oxygen permeation constants for mammalian tissue, plasma and erythrocytes, as avian constants were not then available.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1999

Brevibacterium avium sp. nov., isolated from poultry.

Two strains of a Brevibacterium-like bacterium originating from bumble-foot lesions of domestic fowls were subjected to a polyphasic taxonomic study. The phenotypic characteristics of the bacterium were consistent with its assignment to the genus Brevibacterium although comparative 16S rRNA gene sequencing showed that the organism represents a distinct subline within the genus. Chromosomal DNA-DNA pairing studies confirmed that the unidentified bacterium was genomically distinct and worthy of separate species status. Based on the phenotypic and genotypic distinctiveness of the bacterium from poultry, a new species, Brevibacterium avium, is proposed. The type strain of Brevibacterium avium is NCIMB 703055T.

Animals↗
PubMed1992

Host range of Rous sarcoma virus pseudotype RSV(HPRS-103) in 12 avian species: support for a new avian retrovirus envelope subgroup, designated J.

The host ranges of the Rous sarcoma virus (RSV) pseudotype RSV(HPRS-103) of a novel avian leukosis virus (ALV), strain HPRS-103, and representative RSV pseudotypes of subgroups A to F, have been determined in embryo fibroblasts from 12 avian species. Domestic fowl, red jungle fowl, Sonnerat's jungle fowl and turkey were susceptible to infection by RSV(HPRS-103); ring-necked pheasant, Japanese green pheasant, golden pheasant, Japanese quail, guinea-fowl, Peking duck, Muscovy duck and goose were resistant. The host range pattern of RSV(HPRS-103) differs from those of viruses of subgroups A to G and I, and provides support for placing the HPRS-103 strain of ALV in a new envelope subgroup, designated J.

Animals↗
PubMed1990

[The growth of the skeleton, body mass and muscle fiber diameter of the turkey (Meleagris gallopavo) from hatching to the 224th day].

Growth of body mass, femur, tibiotarsus, and tarsometatarsus length as well as the diameter of muscle fibers in the M. pectoralis were measured in (Large White) female turkeys between birth and day 224. Growth-specific approximations were established with the Janoschek function as modified by Sager (1978) and with the Logistic function. While the Janoschek function fairly described the growth of the turkey, the Logistic function throughout gave beginning values that were too high and theoretical end values that were too low. Of the five growth parameters that were measured, the diameter of the muscle fibers showed its maximal rate of growth first on day 21. The following decrease in growth rate took the following sequence: length of tarsometatarsus, femur, and tibiotarsus, diameter of muscle fibers, body mass. 99% of growth had occurred in the tarsometatarsus length on day 109, femur length on day 117, tibiotarsus length on day 138, diameter of muscle fibers on day 166, and the body mass on day 231. A comparison of this growth with that of other domestic fowl showed close relationships between the way turkeys and chickens grow.

Animals↗
PubMed1963

THE ACTION OF HISTAMINE ON THE ISOLATED HEART.

A method is described for recording the coronary flow and the rate and the amplitude of contraction of an isolated heart maintained at constant temperature. Both histamine and noradrenaline increased the contractility of the guinea-pig heart. Pronethalol antagonized noradrenaline but not histamine. Mepyramine, 10-(2-pyrrolidin-1'-ylethyl)phenothiazine hydrochloride (pyrathiazine) and diphenhydramine reduced the contractility of the guinea-pig heart but did not antagonize the action of histamine. The influence of histamine and noradrenaline on coronary flow was variable but when the contractility of the heart increased there was a concomitant increase in coronary flow. Histamine decreased the contractility of the rat heart and the domestic fowl heart.

Animals↗
PubMed1976

The pharmacology of anaphylaxis in the chicken intestine.

1 The Schultz-Dale phenomenon has been demonstrated in several circular smooth muscle strips of oesophagus, crop, duodenum, jejunum and ileum taken from young and adult domestic fowl sensitized actively to crystalline bovine albumin or horse plasma. 2 The ileal strips contract to acetylcholine, histamine, 5-hydroxytryptamine (5-HT), prostaglandins E1, E2, F2alpha, bradykinin and bovine slow reacting substance of anaphylaxis (SRS-A). Marked seasonal and individual variations in the responsiveness of gut tissues to these exogenous agonists were noted. 3 Antagonism of contractions to histamine by mepyramine suggests the existence of H1-histamine receptors in chicken ileum. Blockade of 5-HT-induced contractions by methysergide shows the preponderance of 'D'-musculotropic tryptamine receptors. 4 Failure of selective receptor antagonists of acetylcholine, histamine and 5-HT to modify the Schultz-Dale reaction suggests the nonparticipation of aminergic mechanisms in this reaction. 5 Partial to complete blockade of the Schultz-Dale reaction by a prostaglandin receptor antagonist (polyphloretin phosphate, PPP); prostaglandin synthetase inhibitors (sodium meclofenamate and phenylbutazone); inhibitors of synthesis and release of histamine and SRS-A (PR-D-92-EA, M & B 22948, diethylcarbamazine citrate, and PPP) and an inhibitor of proteinases (aprotinin) strongly suggests the involvement of vasoactive lipids and polypeptides in the anaphylactic response of chicken ileum to specific antigen.

Albumins↗
PubMed1999

Perinatal development of circadian melatonin production in domestic chicks.

In contrast to the situation in mammals, in which circadian melatonin production by the pineal gland does not begin until some time after birth, the development of pineal gland rhythmicity is an embryonic event in the precocial domestic fowl. A distinct melatonin rhythm was found in 19-d-old chick embryos maintained under light:dark (LD) 16:8. No significant variation in melatonin levels was detected in embryos exposed to LD 8:16. The melatonin rhythm in the pineal gland and plasma of chick embryos incubated for 18 d in LD 12:12 persisted for 2 d in constant darkness indicating that melatonin production is under circadian control at least from the end of embryonic life. A 1-d exposure to a LD cycle during the first postembryonic day was sufficient to entrain the melatonin rhythm, and previous embryonic exposure to either LD or constant darkness (DD) neither modified this rapid synchronization nor did it affect the melatonin pattern during the two subsequent days in DD. It is suggested that, in contrast to the situation in mammals, the avian embryo has evolved its own early circadian melatonin-producing system because, as a consequence of its extrauterine development, it cannot use the system of its mother.

Animals↗
PubMed1977

Ultrastructural studies on the endogenous development of Eimeria brunetti. II. Microgametogony and the microgamete.

The ultrastructural changes of Eimeria brunetti which occur during microgametogony in the small intestine of the domestic fowl are described. The development of the trophozoite into the microgametocyte was accompanied by cytoplasmic growth and nuclear division. The developing microgametocytes could be differentiated from developing schizonts because of ultrastructural differences in both cytoplasm and nuclei. The surface area of the microgametocyte was increased by deep invaginations of the limiting membrane. At this developmental stage, the nuclei were situated adjacent to this membrane and protrusions which developed, initiated microgamete formation. Two centrioles were positioned between each nucleus and the limiting membrane and were transformed into the basal bodies of the flagella. The flagella grew out from the basal bodies which then entered the protrusions. A mitochondrion and the dense chromatin-containing portion of the nucleus also entered each protrusion. The microgametes matured while they were attached to the residual cytoplasm of the microgametocyte; they were finally budded off into the parasitophorous vacuole. The microgamete consists of an elongated nucleus which overlaps a mitochondrion towards the arterior of the cell. At this end, a dense plaque (perforatorium) is found together with the 2 basal bodies and their attached flagella. 5 microtubules were apparent and ran longitudinally from the basal body region. In cross section they were arranged in a row of 4 with 1 diagonally opposite; only 2 of these microtubules extended to the posterior tip of the microgamete.

Animals↗
PubMed1977

Ultrastructural studies on the endogenous development of eimeria brunetti. III. Macrogametogony and the macrogamete.

The ultrastructural changes occurring during macrogametogony in Eimeria brunetti were studied in tissue from the small intestine of infected young domestic fowls. As the macrogametocyte developed, an increase in the volume of the cytoplasm and the nucleus occurred. At this early stage of development the organism was limited by a single unit membrane which possessed a number of micropores. The organism was situated in a parasitophorous vacuole which contained intra-vacuolar folds and intra-vacuolar tubules. The wall forming bodies of type II (WFB II) started to appear before the wall forming bodies of Type I (WFB I). The WFB I developed in the cytoplasmic matric whereas the WFB II were formed within the cisternae of the rough endoplasmic reticulum apparently in association with Golgi bodies. The mature WFB I were homogeneous, limited by a unit membrane, and larger than WFB II which had no limiting membrane but remained surrounded by a membrane of the rough endoplasmic reticulum. Polysaccharide granules were formed in the cytoplasm between strands of the rough endoplasmic reticulum. During maturation the WFB I & II and the polysaccharide granules increased in size and number, and as this occurred a number of electron translucent vacuoles were ejected from the surface of the macrogametocyte. The mature macrogamete possessed a large nucleus with a nucleolus, a number of multi-membranous vacuoles, mitochondria, and canaliculi. The WFB I & II were located at the cell periphery and the polysaccharide granules further towards the interior of the organism. The organism was limited by a unit membrane but during macrogametogony a homogeneous layer had developed which extensively coated the macrog...

Animals↗