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PubMed1990

Effects of thyroid hormones on humoral and cell-mediated immune responses in the domestic fowl (Gallus domesticus).

We investigated the effect of raising and lowering circulating thyroid hormones in young domestic fowl on antibody production and the responses of peripheral blood lymphocytes (PBL) to the mitogens concanavalin A (con A) and phytohaemagglutinin (PHA). Circulating thyroid hormones were reduced by treatment with the goitrogen, methimazole, and raised by giving implants containing thyroxine (T4) and/or triiodothyronine (T3). Raising or lowering circulating thyroid hormones had no significant effect on peak antibody titers, though the decline in titer was slower in goitrogen-treated birds. Lowering circulating thyroid hormones caused a significant increase in the response to con A that was prevented by hormone replacement. There was no effect on the response to PHA and raising circulating hormones had no effect on the responses to con A or PHA. It is suggested that stress-induced changes in thyroid hormones could modulate cell-mediated immune responses.

Animals↗

PubMed1980

Cellular changes in the granulosa layer of the maturing ovarian follicle of the domestic fowl.

1. The relationships between length, width and height of the maturing ovarian follicle of the domestic fowl (Gallus domesticus) are shown. 2. During the rapid-growth phase (yolk deposition) of the oocyte, i.e. an increase in size from about 9 mm diameter to 35 mm diameter, there is about a 15-fold increase in its surface area. During this time the number of granulosa cells adjacent to the oocyte increases by about 5-fold. 3. The granulosa cells become flatter during the growth period of the follicle, consequently increasing their surface area adjacent to the oocyte by about 3-fold. 4. Together the change in shape of the granulosa cells and the increase in their number account for the increase in area of the granulosa layer during follicular growth. 5. Measurement of the DNA content of the granulosa layer indicated a progressive decrease in the cellular content of DNA as the follicle matures.

Animals↗

PubMed1990

Comparison of haematological values in restricted- and ad libitum-fed domestic fowls: red blood cell characteristics.

1. A haematological study of the red blood cell characteristics in domestic fowls fed restricted and ad libitum diets was examined. The characteristics included Hb (haemoglobin), PCV (Packed Cell Volume), Rbc (Red blood cell count), MCH (Mean Cell Haemoglobin), MCV (Mean Cell Volume), MCHC (Mean Cell Haemoglobin Concentration) and reticulocytes. 2. The investigation showed that Hb, PCV, MCH and MCV were all reduced when broilers were fed a restricted diet. The number of Rbc's in these birds also increased significantly compared with control ad libitum-fed broilers. MCHC and reticulocyte numbers did not alter significantly. 3. It is proposed that some of the red cell characteristics may be restored to within "normal" ranges by food restriction. However, the results did show that there was a tendency to induce a microcytic normochromic anaemia in these restricted-fed birds.

Animal Feed↗

PubMed1999

Sperm mobility determines the outcome of sperm competition in the domestic fowl.

The aim of this study was to establish whether the mobility of sperm of the domestic fowl, as measured by an in vitro assay, predicted the outcome of sperm competition. Thirteen pairs of New Hampshire roosters, comprising one male categorized as having high-mobility sperm and the other as having average-mobility sperm, were used. Each male provided 25 x 10(6) sperm, which were mixed and artificially inseminated into between four and seven New Hampshire hens, each of which produced 2-11 offspring. The experiment was conducted twice, such that the same pair of males inseminated the same females. Paternity was assigned by using microsatellite markers. There was a clear effect of sperm-mobility phenotype on the outcome of sperm competition: in all 13 pairs the high-mobility male fathered the majority of offspring (75.3% overall; p < 0.0001). The proportion of offspring fathered by the high-mobility male within pairs varied significantly between male pairs (p < 0.0005). This effect was associated with the difference in sperm-mobility scores between males within pairs; there was a significant positive relationship between the proportion of offspring fathered by the high-mobility male and the ratio of mobility scores between males (p < 0.05). In addition, compared with their success predicted from the non-competitive situation, in the competitive situation high-mobility males were disproportionately successful in fertilizing eggs compared with average-mobility males. This may occur because female sperm storage is limited in some way and a greater proportion of high-mobility sperm gain access to the female's sperm storage tubules. There was no evidence that female effects accounted for any of the variation in paternity.

Animals↗

PubMed1993

Regularities and irregularities in the structure of the seminiferous epithelium in the domestic fowl (Gallus domesticus). II. Co-ordination between germ cell associations.

It was investigated in the domestic fowl, whether a mechanism for a synchronous start of the proliferation of the differentiating spermatogonia in a transversely cut seminiferous tubule (called the "co-ordination" between germ cell association) operates effectively in this species. A trapezoid-shaped cellular association demarcated by two perpendiculars from the tubular lumen to the basement membrane was the unit of observation (provisionally called a "column" Each column is composed of a bundle of elongate spermatids and the neighbouring, various types of germ cells). The extent of closeness of the co-ordination was examined in a total of 2,650 columns, based on the continuity of the spermiogenic step-number of the youngest generation of spermatids within adjacent columns. In no case did all columns in a tubular cross section show the same-step spermatids. In most cases (50.2% of 2,650 columns), the same number was kept in only 2 to 6 adjacent columns. The arrangement of different but consecutive numbers (e.g., 1-2-3 or 1-2-1) was observed in a total of 882 columns. The co-ordination mechanism, therefore, is considered to work, albeit incomplete, among a limited number of adjacent columns in this species.

Animals↗

PubMed1969

Spontaneous and evoked release of neurotransmitter substances in the longitudinal muscle of the anterior mesenteric artery of the domestic fowl.

1. Changes in length of the longitudinal muscle of the anterior mesenteric artery of the domestic fowl (LMAMA) were recorded isotonically.2. The actions of physostigmine and hyoscine suggest that the tone of the LMAMA is dependent on a resting release of acetylcholine within the tissue.3. Catecholamines inhibited the contractions obtained in response to stimulation of cholinergic nerves; this was a beta-receptor effect. After beta-receptor blockade, noradrenaline, but not isoprenaline, weakly facilitated the effects of stimulating cholinergic nerves.4. In the presence of hyoscine, nicotine relaxed preparations of the LMAMA in which the tone had been raised with barium chloride. These relaxations were considered to be due to a release of catecholamine probably from sympathetic nerves.

Acetylcholine↗

PubMed1983

Ventilation, gaseous exchange and air sac gases during moderate thermal panting in domestic fowl.

Gaseous exchange, ventilatory pattern and gas levels within the interclavicular and abdominal air sacs of domestic fowl were monitored before, during and after periods of moderate hyperthermic panting. O2 consumption (VO2) remained virtually unaltered and CO2 production (VCO2) increased slightly during panting as compared to normal respiration. Resting VO2 was 12.2 ml X kg-1 X min-1. Resting (eupneic) PO2 and PCO2 of the interclavicular and abdominal air sacs were 100.1 and 38.5 torr, and 125.2 and 16.4 torr respectively. During panting the partial pressure of the abdominal air sac Pabs, O2 and Pabs, CO2 fell and rose to extreme values of 109 and 29.8 torr respectively. Simultaneously the partial pressure of the interclavicular air sac Pics, O2 and Pics, CO2 changed by smaller amounts to 107.5 and 32.3 torr respectively. Ventilatory pattern during thermal panting was characterized by rapid, shallow movements which were interrupted at regular intervals by short sequences of slower, deeper breaths. During these intermittent periods of eupneic breathing gas levels returned towards normal and these alterations were reflected in transient variations in VO2 and VCO2 about their mean values. Changes in gas levels within the lung-air sac system are discussed in connexion with the peripheral control of ventilation during panting.

Acid-Base Equilibrium↗

PubMed1988

Protein malnutrition in the domestic fowl induces alterations in adrenocortical function.

Adrenocortical function was investigated in immature, dietary protein-restricted domestic fowl (Gallus gallus domesticus). White Leghorn cockerels (2 weeks old) were fed isocaloric semipurified diets containing either 8% [low (L)] or 20% [normal (N)] soy protein for 4 weeks ad libitum. Cockerels were quickly killed by decapitation and exsanguination. Trunk plasma corticosterone (B) and ACTH levels were measured by RIA. Maximal B-binding capacity (CBC) of plasma was also measured. In addition, in randomly selected cockerels, a rough index of the B clearance rate was determined. Finally, to determine the influence of protein malnutrition on adrenocortical cell function per se, we measured the acute (2-h) B responses of highly enriched adrenocortical cell populations to various ACTH analogs, 8-bromo-cAMP (8-Br-cAMP), and cellular B production maximally supported with 25-hydroxycholesterol. Plasma B and ACTH concentrations of L cockerels were, respectively, 160% greater and 32% less than those of N cockerels. In addition, plasma B clearance rate of L birds was 85% greater than that of N birds, thus suggesting a greater B secretion rate in L birds. However, maximal plasma CBC of L cockerels was 59% less than that of N cockerels. Thus, the free plasma B concentration of L birds was greater than that of N birds. The increase in the plasma B concentration of L cockerels is explained in part by the relative adrenal weight of these birds which was 88% greater than that of N cockerels. In addition, there were differences at the adrenocortical cell level. On an equal cell concentration basis, basal and maximal B production values (stimulated by ACTH analogs and 8-Br-cAMP, and supported by 25-hydroxycholesterol) of L cockerel adrenocortical cells were, respectively, 73% and 139% greater than those of N cockerel adrenocortical cells. In addition, maximal ACTH-induced aldosterone production of L bird cells was 104% greater than that of N bird cells, such that the ratio of aldosterone production to B production was not altered by protein deprivation. The data suggest that the greater steroidogenic capacity of L cockerel cells was due to an increase in intracellular steroidogenic enzyme content and/or activity and not to an alteration in the composition of adrenocortical cell types within the populations of isolated cells. Furthermore, ACTH analog ED50 values for B, aldosterone, and cAMP production by L bird cells were about one third to one fifth the values for N bird cells, thus indicating that L bird cells were about 3-5 times more sensitive to ACTH than were N bird cells.(ABSTRACT TRUNCATED AT 400 WORDS)

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1986

Liver- and muscle amino-acid concentrations during the development of domestic fowl.

The concentrations of free amino acids in liver, leg muscle and wing muscle of developing domestic fowl chicks were measured and compared with those of adults. Leg and breast muscles showed a remarkably parallel pattern of change in free-amino-acid concentrations during development up to day 5 after hatching, in agreement with their lack of differentiation up to day 5. Liver free-amino-acid concentration pattern with the development were very similar to those of the muscles, in significant difference with Mammals. Adult free tissue amino acids were lower than those of developing chicks. Most changes in amino-acid concentration in chick tissues were observed around hatching, and have been tentatively attributed to changes in diet. Combined amino acids changed very little during the period studied in muscles and liver. Taurine constituted a very big share of total amino acids.

Age Factors↗

PubMed1986

Genetic-dependent alterations in adrenal stress response and adrenocortical cell function of the domestic fowl (Gallus domesticus).

Strain-dependent differences in adrenocortical function were investigated in male White Leghorn domestic fowl. Adrenocortical function of Cornell K strain (K) (genetic control), autosomal dwarf strain (ADW), and sex-linked recessive dwarf strain (SLD) was evaluated in vivo by measuring plasma corticosterone and in vitro by measuring acute (2 hr) corticosterone production by enriched adrenocortical cell populations. Regardless of strain, there was an age-dependent decrease (27-57%) in plasma corticosterone from 1 to 12 weeks of age. However, there was a tendency for plasma corticosterone values of ADW and SLD to be, respectively, greater and less than that of K. In addition, at 12 weeks of age, plasma corticosterone responses of ADW and SLD to transient heat stress (50 degrees C, 30 min) were, respectively, 22.8% greater and 15.9% less than that of K. Strain differences in adrenal weight and relative adrenal weight (mg% body wt) were also apparent. At 12 weeks of age, adrenal weights of ADW and SLD were, respectively, 33 and 42% less than that of K, whereas relative adrenal weights were, respectively, 27.6% greater and 22.4% less than that of K. In addition there were strain-dependent differences in adrenocortical function at the cellular level. Although there were no consistent strain differences in basal and maximal corticosterone production by cells, there were strain differences in cellular sensitivity to ACTH and pregnenolone. On an equal cell concentration basis, the half-maximal steroidogenic concentrations (ED50 values or effective doses for 50% maximal effect) of ACTH for ADW and SLD adrenocortical cells were, respectively, 0.23 and 2.07 times the ED50 value for K cells. In addition, the ED50 value of pregnenolone for ADW cells was 0.46 times that for K and SLD cells. Since ED50 values are a measure of cellular sensitivity (the greater the ED50 value the lesser the cellular sensitivity), the order of sensitivity to ACTH was ADW greater than K greater than SLD and the order of sensitivity to pregnenolone was ADW greater than K = SLD. However, there were no strain differences in ED50 values of 8-bromo-cyclic AMP. These data suggest that strain differences in plasma corticosterone response to stress are, in part, due to differences in relative adrenal weight and differences in adrenocortical cell function.

Adrenal Cortex↗

PubMed1975

The effects of environmental temperature on fertility of the domestic fowl.

Three experiments were conducted to determine the influence of environmental temperature upon the fertility of domestic fowl. It was found that a cold environmental temperature depressed testes growth and delayed spermatogenesis in maturing cockerels. There was also a highly significant difference in the fertility of mature males kept at different environmental temperatures. Males kept at 19 degrees C. had higher fertility than males kept in either 30 degrees or 8 degrees C. The effects of environmental temperature on female fertility was also studied. Fertility was significantly lower in the hens kept at 30 degrees C. than that of similar groups held at an environment of 8 degrees C.

Animals↗

PubMed1986

Characterization and composition of uroliths from domestic fowl.

Urolithiasis (kidney stone formation) is an acquired degenerative kidney lesion affecting sexually mature and immature domestic fowl. For the present study, uroliths were collected from three commercial flocks during outbreaks of urolithiasis. Uroliths also were collected from a research flock in which urolithiasis was induced by feeding immature chickens a diet formulated to contain excess calcium (3.25% Ca) and .4% available phosphorus. All uroliths were tested by x-ray diffractometry, infrared spectrophotometry, and emission spectrography. With one exception, the stones were composed of compact masses of microcrystalline to fine pleomorphic crystals of calcium sodium urate, with random substitution of magnesium for calcium, and potassium for sodium. No initiating nidus was evident. One of four stones from one laying hen flock was positively identified as an ammonium acid (hydrogen) urate. The unique calcium-sodium-urate stone composition in all but one of the stones tested suggests that similar processes were involved in stone formation in the four different flocks.

Animals↗

PubMed1982

Ossification of the laryngeal, tracheal and syringeal cartilages in the domestic fowl.

The process of ossification in the cartilages of the larynx, trachea and syrinx of the domestic fowl has been studied in growing and in adult Golden Comet birds. In the laryngeal cartilages, mineralisation occurred consistently in the body and wings of the cricoid cartilage, in the procricoid cartilage and in the bodies of the arytenoid cartilages. In 7 out of 12 adult birds there were small additional centres in the tips of the rostral processes of the arytenoid cartilages and in one adult bird there were small centres in the caudal processes also. When present, these additional centres were always found bilaterally. Mineralisation in the laryngeal cartilages developed from 105 days post-hatching onwards and was first seen in the bodies of the arytenoid cartilages. Some evidence of a segmental pattern was noted, both in the earliest centres and in the final stage in the caudal region of the body of the tcricoid cartilage. Mineralisation in the trachea developed from 98 days post-hatching onwards. It was first found in the caudal region and spread craniad. The rings at the caudal end of the trachea and the cranial end of the tympanum (but not the last two rings of he tympanum) were always fully involved. Rings in the cranial part of the trachea remained more lightly mineralised. In the syrinx, mineralisation regularly occurred only in the pessulus and in the base of the first bronchial syringeal cartilages. In some birds, it was also encountered more caudally in the cartilages of the primary bronchi. Histological examination showed that, in the early stages, the alizarin staining was due to the presence of mineralised cartilage. At 182 days post-hatching and in the adults, actual bony tissue was observed. The possible significance of the occurrence of ossification in these cartilages of birds in briefly considered.

Animals↗

PubMed1994

Vasotocin fibers and neurons in the brain of the domestic fowl (Gallus gallus domesticus).

Vasotocin fibers (VIFs) and neurons (VINs) in the brain stem of the domestic fowl (Gallus gallus domesticus) were described using an immunohistochemical technique. Attention was especially focused on the VIF network. VIFs were seen in the preoptic area around the septomesecephalic tract, periventricular nuclei of the hypothalamus, the lateral geniculate nucleus, the superficial synencephalic nucleus, the triangular nucleus, the ovoidal nucleus, the ectomammillary nucleus, the superficial layer (IIa-d) of the tectum, the locus ceruleus, the caudal lineal nucleus, the descending nucleus of the trigeminal nerve and the nucleus of raphe. VIFs in the retinorecipient nuclei such as the lateral geniculate nucleus and tectum indicated the possibility of interplay between the visual and the vasotocinergic nervous systems. Moreover, VIFs in the non-retinorecipient nuclei mentioned above suggested that the vasotocinergic nervous system was related not only to the visual but also to other functions, such as the autonomic and sensory nervous systems. VINs were found in the preoptic area, the lateral and the medial hypothalamus, including the nucleus periventricularis magnocelullaris, and the dorsolateral thalamus. The dorsolateral thalamic VINs were found lateral and dorsal to the lateral forebrain bundle, lateral to the nucleus periventricularis magnocellullaris, and around the nucleus rotundus.

Animals↗

PubMed1990

Morphometry of the galliform cecum: a comparison between Gambel's quail and the domestic fowl.

Tissues from the proximal, middle, and distal regions of the ceca of Gambel's quail and domestic fowl were examined by scanning and transmission electron microscopy. Cellular and subcellular structures, including epithelial cell height, mitochondrial volume fraction, microvillous surface area, proportion of goblet cells, and junctional complex characteristics, were quantified by a variety of stereologic procedures and other measurement techniques. The mucosal surface of quail cecum shows a much more highly developed pattern of villous ridges and flat areas than that of fowl cecum. The fowl has significantly greater cell heights than the quail in all cecal regions. The mitochondrial volume fraction does not differ significantly with species or region, but mitochondria are concentrated on the apical side of the nucleus. In both species, the proximal cecal region has the greatest microvillous surface area. All 3 components of junctional complexes, including zonula occludens, zonula adhaerens, and macula adhaerens, are quantified. When all factors are considered, the quail cecum appears to have morphological characteristics consistent with a greater potential capacity for absorption than the fowl cecum.

Animals↗

PubMed1982

Effects of temperature on the ventilatory response to inspired CO2 in unanaesthetized domestic fowl.

The influence of raised environmental temperature on the respiratory response to CO2 in awake, spontaneously breathing domestic fowl was investigated. In terms of their effects on ventilation VE temperature and CO2 were additive and non-interactive, VE being approximately 1900 ml . min-1 greater at 33 +/- 1 degree C compared to 18 +/- 1 degree C, regardless of inspired CO2 partial pressure PICO2. Temperature had no effect on the slope of the relationship between VE and both arterial and clavicular air sac PCO2. Blood and clavicular sac PCO2 were regulated within 2-3 Torr of normal at PICO2 levels below approximately 20 Torr as a result of hyperventilation but PCO2 regulation began to fail at higher PICO2. Hypercapnia induced increases in respiratory frequency f at normal temperatures but decreases in f at 33 +/- 1 degree C. There was little change in f at 25 +/- 1 degree C. The ventilatory increase in response to CO2 at 18 +/- 1 degree C and 25 +/- 1 degree C could be described by a linear relationship between VE and tidal volume VT. However, respiration departed from this pattern at temperatures above the panting threshold (32-34 degrees C). These findings are discussed in the context of central and peripheral mechanisms which may be involved in the control of rate and depth of breathing.

Animals↗

PubMed1996

Myoelectric activity of the cecum in fed and fasted domestic fowl (Gallus sp.).

To study cecal motility and its relation to the fed and fasted condition in domestic fowl, we sutured 7 miniature electrodes onto the ceca and ileum of 4 roosters. After recovery from the surgery, the birds received recordings of myoelectric activity for a total of 169 h while fasted and for 28 h while in the fed state. We found that single or brief clusters of action potentials (APs) occurred in the cecal smooth muscle at mean frequencies of 10.8 to 25.0/h, with the fewest when the lumen contained little food (after fasting > 24 h). Virtually all APs propagated, whether orad (toward the ileocecocolic junction) or retrograde (toward the cecal tip), with retrograde activity significantly more frequent (P < 0.001). Propagation velocity was rapid, varying from 8 to 750 cm/min (mean = 106 cm/min), being slower when birds were in the fed state. Thus, fasting resulted in fewer and more rapid APs and more that propagated toward the cecal tip. Motor activity was well coordinated between ceca, both organs showing essentially simultaneous spike activity; 72% of APs occurred within 8.1 s of each other. No relationship between ileal and cecal activity was apparent. Prominent slow waves were recorded in the ceca (5 to 5.5/min), the same slow-wave frequency as in the ileum (small intestine). From the results obtained here and from earlier studies, we conclude that the single or brief clusters of APs represent contractions that produce mixing of the luminal contents; occasional periods of protracted APs represent evacuation of cecal contents.

Action Potentials↗

PubMed1994

Arginine vasotocin gene expression in neuroendocrine, reproductive and gastrointestinal tissues of the domestic fowl: detection by reverse transcriptase polymerase chain reaction.

Arginine vasotocin gene transcripts in various tissues of the domestic fowl were detected by reverse transcriptase polymerase chain reaction followed by Southern blot analysis using a 209 bp fragment from the 3'-region of a cDNA encoding chicken arginine vasotocin as the probe. Relatively strong signals were observed with hypothalamic, adenohypophysial and proventricular RNA as the starting material. Lesser signals were obtained from RNA isolated from shell gland, adrenal gland, post-ovulatory follicles and ovarian thecal cells. Arginine vasotocin gene transcripts were undetectable in the posterior pituitary gland, small intestine and large intestine. These results suggest that in addition to its well-known antidiuretic and oxytocic actions, arginine vasotocin may act as a local neuromodulator or mediator and have other important autocrine or paracrine actions in non-hypothalamic tissues.

Animals↗