Avian and Poultry Biology Reviews 15 (3/4), 2004

Subscribers can access full papers here

FUNDAMENTAL PHYSIOLOGY AND PERINATAL DEVELOPMENT IN POULTRY. ADAPTION IN POULTRY: THE IMPACT OF ENVIRONMENT

Institute of Biology, Humboldt-University of Berlin, Philippstraûe 13, 10115 Berlin, Germany

9-11 October 2003 

Preface

Barbara Tzschentke and Oliver Janke   

Possible Role of Nitric Oxide Emission from Bird Embryos

A. Ar*, O. Ifergan, A. Feldman, L. Zelik and A. Reizis
Department of Zoology, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel 

Keywords: NO, allometry, bird embryo, brood patch, Chorioallantois, oxygen consumption, incubation temperature   

Characteristics of Early Development of Body Functions and Epigenetic Adaptation to the Environment in Poultry: Focused on Development of Central Nervous Mechanisms

B. Tzschentkea*, D. Bastab, O. Jankea and I. Maierc
aWG Perinatal Adaptation, Institute of Biology, Humboldt-University of Berlin, Invalidenstr. 43, 10115 Berlin, Germany
 b Present address: Department of ORL at UKB, Free University Berlin, Warener Str. 7, 12683 Berlin
 c Present address: Institut fuÈr Hirnforschung, UniversitaÈt ZuÈrich, Winterthurerstrasse 190, CH-8057 ZuÈrich 

ABSTRACT

Embryos and ducklings of the Muscovy duck were incubated at 34.5, 37.5 (control) and 38.5_C during the last week of embryonic development. Neuronal hypothalamic thermosensitivity was investigated in brain slices using extra-cellular recordings. On day 28 of incubation the proportion of cold sensitive (CS), warm sensitive (WS) and temperature insensitive (TI) neurones in relation to all neurones investigated is not significantly different from that in hatchlings. Already on day 22y23 of incubation CS and WS neurones with same properties as observed in the aged embryos or post-hatched birds were found. On the first day after hatching, acute (Bombesin application) and chronic (changes in incubation temperature) thermal influences induce clear, but non-specific alterations in neuronal hypothalamic thermosensitivity. On day 1 and day 5 prenatal temperature experiences induced a clear alteration of hypothalamic thermosensitivity, but this alteration was not dependent on the changes in incubation temperature if increased or decreased from the normal level. On day 10 post-hatching prenatal cold load elevated the neuronal hypothalamic warm sensitivity by an increased proportion of WS and a reduced proportion of CS neurones in comparison with the control. Prenatal warm load induced the opposite effect. Prenatal cold load induces postnatal cold adaptation and prenatal heat load induces postnatal heat adaptation. On day 10 post-hatching changes in neuronal hypothalamic thermosensitivity reflect adaptive alterations observed in the periphery. These changes are signs for an epigenetic temperature adaptation. In addition, prenatal temperature experiences seem to stimulate an earlier maturity of the thermoregulatory system.   

Keywords: neuronal thermosensitivity, hypothalamus, epigenetic temperature adaptation, bird embryo, bombesin, incubation temperature    

Prenatal Development of Epigenetic Adaptation Processes in Poultry: Changes in Metabolic and Neuronal Thermoregulatory Mechanisms

B. Loha, I. Maierb, A. Winara, O. Jankea and B. Tzschentkea*
aWG Perinatal Adaptation, Institute of Biology, Humboldt-University of Berlin, Invalidenstrasse. 43, 10115 Berlin, Germany
bPresent address: Institut fuÈr Hirnforschung, Universitat ZuÈrich, Winterthurerstrasse 190, CH-8057 ZuÈrich, Switzerland

ABSTRACT

Adaptation can be divided into genotypic and phenotypic types. A special kind of phenotypic adaptation is epigenetic adaptation. Epigenetic adaptation processes obviously occur in order to adapt the organism to the expected postnatal environmental conditions during early preor postnatal ontogeny in short term windows when a functional system, such as temperature regulation, develops from a regulation system without negative feedback into a closed control system with feedback mechanism. Within the course of this process the actual controlled level of the regulated parameter, i.e. a high or low body temperature, might determine the set point of the respective control system during later life. Investigations were carried out to understand the effect of prenatal chronic warm or cold load on thermoregulatory heat production (HP), embryonic temperature (Taf) and neuronal hypothalamic thermosensitivity in precocial bird embryos at the end of incubation. During the course of present research in chicken and Muscovy duck embryos, incubated at 34.5, 37.5 (control) and 38.5_C during their last days of incubation, HP and Taf were determined at different ambient temperatures (Ta). In Muscovy ducks the proportion of warm sensitive, cold sensitive and temperature insensitive neurons in the preoptical area of the anterior hypothalamus (POyAH) was determined in relation to all neurons investigated. Chronic warm or cold incubated embryos showed a trend towards a higher HP. An important observation was that Taf strongly depended on incubation temperature. Interestingly prenatal temperature load leads to an increase within the proportion of thermosensitive neurons in both temperature groups.

Keywords: epigenetic adaptation, heat production, body temperature, neuron, thermoregulation, thermosensitivity, hypothalamus, incubation temperature, chicken, Muscovy duck, embryo    

c-Fos Induction in the Brain of Precocial Bird Embryos by Thermal Stimuli

O. Janke*, Y. Teklu and B. Tzschentke
Humboldt-University of Berlin, Institute of Biology, WG Perinatal Adaptation, Philippstraûe 13, Haus 2, 10115 Berlin, Germany

Keywords: c-Fos gene, thermal stimuli   

Red Blood Cells of the Chicken Embryo During Hypoxia: Hormonal Regulation of Function and Differentiation

S. Dragon* and R. Baumann
Institut fuÈr Physiologie, UniversitaÈt Regensburg, UniversitaÈtsstr. 31, 93040 Regensburg, Germany

Keywords: red blood cells, hypoxia, hormonal regulation   

Oxygen De®ciency and Blood-Gas-State in the Chorio-Allantoic Vein in the Chicken Embryo

A. HuÈhnke and H. ToÈnhardt*
Institute of Veterinary-Physiology, Free University Berlin, Oertzenweg 19b, 10589 Berlin, Germany

ABSTRACT

Influence of a reduced oxygen content in the incubation air (15% O2) on arterial blood pO2, pCO2, pH and oxygen-saturation (sO2) in the chorio-allantoic vein in chicken embryos were investigated. Also the body masses of embryos were obtained. The first experimental group was incubated with 15% O2 from day 6 to day 12 of incubation. This period has been extensively investigated and was described as a sensible phase in view to adaptation. The second experimental group was incubated with 15% O2 from D12 until sampling on days 14, 16 and 18 of incubation. pCO2 and the body masses of embryos increased with incubation time, while pO2 and pH decreased. Oxygen saturation decreased in the experimental group which was incubated with 15% O2 from day 12 until sampling. It is suggested that the reaction of the embryo changes during development. The moment of influence of oxygen deficiency decides if there is an adaptation or another try to equalise a spread of oxygen amount and oxygen supply.

Keywords: chicken embryo, chronic oxygen de®ciency, chorio-allantoic vein, blood-gas-state, body mass

Effects of Some Environmental Factors on the Amnion Rhythmic Contractions in Chick Embryogenesis

M.V. Nechaevaa*, H. ToÈhardtb, A. HuÈhnkeb, I.G. Makarenkoa and T.M. Turpaeva
aLaboratory of General Physiology, Institute of Developmental Biology RAS, Vavilov St. 26, Moscow 119334, Russia
 bFree University, Institute of Veterinary Physiology, Oertzenweg 19 b, 14163 Berlin, Germany

ABSTRACT

We studied the rhythmic contractions of the chick amnion in the egg at different developmental stages, performing continuous recording using a force transducer under normal conditions and under short-term changes of environmental factors (lowered temperature, acute hypoxia, hyperoxia, and hypercapnia). Acute hypoxia (10 and 15% O2) for periods of 10 ^ 20 minutes inhibited or arrested contractions of the amnion. During a 10 minute application of gas, 2% CO2 inhibited and 100% O2 accelerated the amniotic contractions. Lowering of temperature slowly decreased the frequency of the amnion contractions, and they stopped at 32 ^ 29_C. These changes of the amnion rhythmic contractions were reversible and the frequency of the amnion contractions restored after the returning to the normal conditions. The data on the isolated rostral part of amnion on day 8 of incubation demonstrated that the effect of temperature on the amnion contractions in egg is mainly a result of its direct influence. The morphological study of the smooth muscles described their distribution in this part of amnion, as the background for the contractile activity. Thus, the amnion rhythmic contractions are involved in short-term response of the embryo to the environmental factors that suggests their participation in the environmental adaptation during embryogenesis. As the amnion contractions produce mixing of the amniotic fluid, we propose that in combination with the other factors the changes in the amnion contractile activity could influence the level of the metabolic processes in the developing egg.

Keywords: amnion, chick, hypercapnia, hyperoxia, hypoxia, rhythmic contractions, smooth muscles, temperature  

Electrophysiological Characterisation of the Amnion of the Domestic Fowl (Gallus gallus f. domestica)

H. Blasius*, H. ToÈnhardt and H. Martens
Institut fuÈr VeterinaÈr-Physiologie, Freie Universitat Berlin, Oertzenweg 19b - 14163 Berlin, Germany

ABSTRACT

For a better understanding of the protective and metabolic functions of the amnion, characterisation of the electrophysiological properties of this epithelium is necessary. Hence, the preparation of the epithelium for an in vitro study has been developed and corresponding buffer solutions have been tested for the in vitro incubation with the conventional Ussing chamber technique. Data are presented on the transepithelial potential difference, short circuit current, and the tissue conductance of the amnion.

Keywords: chicken embryo, amnion, preparation, Ussing camber, buffer, osmolarity, amniotic liquid, short circuit current, tissue conductance   

Non-destructive Measurements on Eggs During Incubation

F. Bamelis*, B. Kemps, K. Mertens, K. Tona, B. De Ketelaere, E. Decuypere and J. De Baerdemaeker
Katholieke Universiteit Leuven, Faculty of Agricultural Sciences, Egg Quality and Incubation Research Group, Kasteelpark Arenberg 30, B-3001 Heverlee, Belgium

ABSTRACT

In this review, different techniques are presented that measure non-destructively physiological aspects of incubation eggs during the incubation. Mainly, they can be categorised in four groups. Firstly, there are techniques that detect fertility of egg early in the incubation. These techniques are detecting the presence of a living embryo indirectly, i.e. by detecting events that are going on outside the embryo. Three different techniques were found in literature: an imaging technique, the calculation of blood values and an Acoustic Resonance Technique. There is discussion about the mechanisms that form the basis of these detection methods. Secondly, non-destructive techniques that measure heart rate of embryos are discussed. In general, two different approaches can be seen: the measurement of the ballistic displacement of the eggshell with a Ballistocardiogram (BCG) and the detection of pressure waves originating from the egg and caused by the arterial pulsation in the chorio-allantois membrane or Acoustocardiogram (ACG). In the peri-natal period, the ACG technique has also been able to measure respiratory movements. Thirdly, a technique is presented that detects the viability of the embryo itself by detecting its movements by measuring light transmission levels. Contrary to the techniques used to check for fertility early in the incubation, this technique is detecting the embryo itself. Finally, an approach was found to measure the progress of hatching in an incubator without opening. Therefore, the energy level in the noise signal is calculated.

Keywords: non-destructive, heart rate, monitoring embryonic growth, acoustic resonance analysis, monitoring hatching progress    

Pattern of Trypan Blue Storage in the Chick Embryonic Kidney Rejects Development of Absorptive Capacity of the Proximal Tubules

Z. Zemanova*
Institute of Physiology, Academy of Sciences of the Czech Republic, VõÂdenÏska 1083, 14220 Prague, Czech Republic

ABSTRACT

It is demonstrated that the mesonephroi of 5 ^ 7-day chick embryo absorb trypan blue (1.5% in a Ringer solution) in an age-dependent and predictable pattern. On day 5, the dye is absorbed and stored maximally in the cranial portion of the kidney and in the neighbouring section of the kidney. On day 6, maximum staining is shifted to the middle portion of the kidney, whereas on day 7 no discernable differences in trypan blue storage are apparent. This observation of a predictable pattern of trypan blue absorption, which mirrors the progress of the proximal tubule maturation, suggests an important tool for the evaluation of possible developmental delay in mesonephroi experimentally exposed to adverse factors (drugs, etc.). In order to standardize our methods, data were collected to develop a table of trypan blue optimum doses for ages ranging from 5 to 7 day, and for 5-hour and 24-hour exposure. The dye was administered either intra-amniotically or by dropping it on the chorio-allantoic membrane. The optimum doses of the trypan blue were selected to be ideally lower than LD50 of the dye (especially in the 24-hour exposed embryos), but high enough to colour distinctly the proximal tubules.

Keywords: mesonephros, chick embryo, tubule differentiation, trypan blue absorption, test of nephron maturity    

Early Development of Thermoregulatory Competence in Chickens: Responses of Heart Rate and Oxygen Uptake to Altered Ambient Temperatures

H. Tazawaa*, Y. Chibaa, A.H. Khandokera, E.M. Dzialowskib and W.W. Burggrenb
aDepartment of Electrical and Electronic Engineering, Muroran Institute of Technology, Muroran 050-8585, Japan
bDepartment of Biological Sciences, College of Arts and Sciences, University of North Texas, P.O. Box 305189, Denton, Texas 76203, USA

ABSTRACT

Avian embryos need a heat supply from the external environment to develop, because heat loss from an egg overwhelms heat production of an embryo and accordingly they cannot maintain body temperature constant during incubation. In the domestic fowl, a minute homeothermic competence appears during the end of incubation with subsequent large augmentation soon after hatching. However, hatchling's metabolic rate still produces less heat than that required to offset heat loss. This stage prior to reaching ``full-blown'' homeothermy is designated as ``power-limited''. In this power-limited stage of thermoregulation, development of thermoregulatory competence in response to altered ambient temperature (Ta) involves the rapid maturation of heart rate (HR) regulation. The first part of this report reviews briefly: (1) early development of homeothermic thermal and metabolic responses to altered Ta in chick embryos and hatchlings, and (2) HR responses to altered Ta in newly hatched chicks during the power-limited stage of thermoregulation, which depend on the state of development of thermoregulatory competence. The last part concerns our recent preliminary experiment and hypothesis with regard to the early development of thermoregulatory competence in hatchlings developing in the powerlimited stage. The preliminary experiment shows possible influence of brooding temperatures (i.e. preferred brooding Ta of 35_C and low brooding Ta of 24 ± 27_C) to the development of thermoregulatory competence in terms of HR responses to altered Ta. We hypothesise that homeothermic-metabolic response to altered Ta develops in parallel with the homeothermic HR response and additionally the brooding temperature will influence the maturation of homeothermic-metabolic response so that hatchlings maintained at low Ta will develop the homeothermic-metabolic response earlier than those at the preferred brooding Ta. The result shows that homeothemic-metabolic response obtained in the white leghorn chickens does not develop in parallel with the homeothermic HR response obtained previously in the broiler chickens. In addition, maturation of homeothermic-metabolic response is observed on just hatched chicks maintained at both the preferred brooding Ta and low Ta. The failure of proving the hypothesis suggests other possibilities of which investigation will improve our knowledge of thermoregulation in avian embryos and hatchlings.    

Cardiac Rhythms and Their Responses to Cooling in Newly Hatched Ducks

S. Fukuoka*, T. Sakata, S. Hasegawa, Y. Chiba, R. Akiyama and H.Tazawa
Department of Electrical and Electronic Engineering, Muroran Institute of Technology, Muroran 050-8585, Japan

Keywords: instantaneous heart rate, ducklings, thermoregulation, cardiac rhythms    

Relationship Between Heart Rate Fluctuation and Shivering in Chick Hatchlings

H. Yoneta*, W. Nakata, K. Moriya, R. Akiyama and H. Tazawa
Department of Electrical and Electronic Engineering, Muroran Institute of Technology, Muroran 050-8585, Japan

Keywords: heart rate fluctuation, shivering    

Ontogeny of Respiratory Sinus Arrhythmia in the Domestic Fowl

Y. Chiba, H. Yoneta, S. Fukuoka, R. Akiyama and H. Tazawa*
Department of Electrical and Electronic Engineering, Muroran Institute of Technology, Muroran 050-8585, Japan

ABSTRACT

Instantaneous heart rate (IHR) of avian embryos fluctuates distinctively towards hatching and after hatching HR fluctuations augment further. In the domestic fowl, HR fluctuations of hatchlings are categorised mainly into three types. Among them, Type I HR fluctuation is HR oscillation of which frequency has been proved to be identical with respiratory frequency by means of simultaneous measurements of IHR and breathing activity; that is, respiratory sinus arrhythmia (RSA) of hatchlings. RSA is recorded as a distinctive wide range for the HR baseline when the recording of IHR is made for a prolonged period. Such a wide range for the HR baseline has been observed in externally pipped (EP) embryos and termed empirically RSA of embryos. However, it remains to be proved by simultaneous measurements of IHR and breathing signal of embryos as did in the hatchlings. Breathing activity of EP embryos can be detected by a condenser microphone, which has been originally used to measure cardiogenic signal of late embryos. The present report reviews at first measurement of cardiogenic signals (ballistocardiogram and acoustocardiogram) of late embryos inside an eggshell, finding of breathing signal (acoustorespirogram) by the condenser microphone and HR fluctuations and oscillation during the pipping period. After additional review of RSA in hatchlings, original data on the simultaneous measurements of IHR and breathing signal in EP embryos are presented to ascertain and refer to RSA of EP embryos.

Keywords: respiratory sinus arrhythmia, instantaneous heart rate, heart rate oscillation, acoustorespirogram, respiratory signal, embryo, hatchling, chick    

Prenatal Development of Rhythmic Blood Pressure and Heart Rate Fluctuations in Chick (Gallus gallus var. domesticus) Embryos ± A Chance to Compensate Environmental Stress

M.A. Goldhammera*, H. Tonhardta, R Akiyamab, J.T. Pearsonb, H. Tazawab, M. Nichelmannc and J. Hocheld
aInstitut fur Veterinar-Physiologie, Freie Universitat Berlin
bDepartment of Electrical and Electronic Engineering, Muroran Institute of Technology, Muroran 50, Japan
cInstitut fuÈr Biologie, AG Perinatale Anpassung, Humboldt-Universitat zu Berlin
djetzt Schering AG, Berlin, Germany

Keywords: prenatal, rhythmic blood pressure, heart rate, chick embryo, environmental stress    

Variation in Area Fraction of Blood Vessels and Tissue Thickness between the Area Under the Air Cell and the Rest of the Chorio-Allantoic Membrane of the Chick Embryo

A. Reizisa, I. Hammelb and A. Ara*
Departments of Zoologya and Pathologyb, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel

Keywords: air-cell, blood vessels density, chick embryo, chorioallantois, incubation    

Comparative Investigations of Heat Production and Body Temperature in Embryos of Modern Chicken Breeds

O. Jankea*, B. Tzschentkea and M. Boerjanb
aHumboldt-University of Berlin, Institute of Biology, WG Perinatal Adaptation, Philippstr. 13, Haus 2, 10115 Berlin, Germany
 bPasReform Hatchery Technologies, R&D embryology, P.O. Box 2, NL-7038 ZG Zeddam, The Netherlands

ABSTRACT

Genetic progress has made giant strides in chicken breeds, which have led to important gains in performance. The time to achieve the standard processing weight of 2 kg has been shortened by 10 days as assessed in the period from 1988 to 1998 for Ross broilers. Furthermore, the gap between layer and broiler breeds became larger in both adults as well as in embryos. Most data on chick embryonic oxygen consumption and heat production (HP) were obtained before 1970 and used as basis for incubation programs till now. Due to lack of actual data on modern breeds and the demand in poultry industry to optimise incubation conditions, it was felt necessary to investigate embryos of actual high yield breeds. In two broiler chicken lines (Ross 308 and 508) and a layer line (Lohmann white leghorn) oxygen consumption for calculation of HP and body temperature (Tb) were measured during the second half of incubation period. HP as well as Tb did not differ significantly among the broiler lines tested. But there were significantly higher values in both parameters in the broiler breeds compared to the layers from day 12 of incubation until hatching except on days 16, 17 and 18, probably due to differences in embryonic growth rate and composition of tissues. Broiler chicks of both lines hatched a day ahead of the layers. Hence, it would be appropriate to adapt incubation parameters to each poultry breed for optimum results of incubation. In continuation of genetic progress, it is suggested that regular determination of embryonic physiological parameters are performed.

Keywords: chicken embryos, broiler, layer, heat production, body temperature    

Entrainment of Rhythmic Melatonin Production by Light and Temperature in the Chick Embryo

M. Zemana,b*, P. Pavlika, D. LamosÏovaÂb, I. HerichovaÂa and E. Gwinnerc
a Department of Animal Physiology and Ethology, Comenius University Bratislava, Mlynska dolina B-2, 842 15 Bratislava, Slovak Republic
b Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, 900 28 Ivanka pri Dunaji, Slovak Republic
cMax Planck Institute for Ornithology, 823 46 Andechs, Germany

ABSTRACT

In addition to a light-dark cycle, temperature cycles are also capable of synchronising the circadian rhythm of melatonin production in the chick embryo. Exposure of 19-day chick embryos to a low temperature of 4_C for 60min during the dark-time increased a pineal melatonin content. By contrast, exposure of eggs to a high temperature of 41_C did not evoke changes in pineal melatonin concentrations. Embryos exposed to either a high or a low temperature during periods of light did not show an increased melatonin production. The rhythm in the pineal melatonin concentrations was synchronised by the 4.5_C amplitude temperature rhythm (33y37.5_C) and high melatonin levels were found during the low temperature phase. The rhythm persisted under constant environmental conditions, suggesting that it is driven by an endogenous circadian rhythmicity. Periodic exposure to a low temperature for 6 hours failed to increase melatonin concentrations in the pineal gland when it occurred during the light time. The present study demonstrated temperature entrainment of the circadian rhythms controlling melatonin production in the pineal gland of an endothermic vertebrate. The data suggest that rhythms in ambient light and temperature interact with the circadian system in shaping the rhythm in pineal melatonin production in the chick embryo.

Keywords: ontogeny, pineal gland, circadian rhythm, embryo, avian    

Daily Rhythms of Melatonin and Selected Biochemical Parameters in Plasma of Japanese Quail

I. HerichovaÂa*, M. Zemana,b, M. JuraÂnib and D. LamosÏovaÂb
aDepartment of Animal Physiology and Ethology, Comenius University, Mlynska dolina B-2, Bratislava, Slovakia
bInstitute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Ivanka pri Dunaji, Slovakia

ABSTRACT

Endogenous circadian rhythms govern cycles in rest-activity, food intake and metabolism, and profoundly affect performance of animals. Daily rhythms are mediated and imposed on the organism through the circadian system consisting from the hypothalamus, pineal gland and retina that contain multiple self-sustained circadian oscillators. The main signal from this complex is hormone melatonin. Oscillators were also discovered recently in peripheral organs and it is not known how peripheral and central oscillators are coupled. The role of diffusible signals, such as hormones and small molecular weight food metabolites, in this process was suggested. In our experiment we measured a daily pattern of melatonin levels in plasma and the pineal gland and the profile of selected parameters of saccharide, lipid and protein metabolism in Japanese quail kept in light:dark cycle 16 : 8 h. Significant daily patterns in concentrations of glucose, triacylglycerols, creatinine and uric acid were recorded. Cholesterol, albumin and total proteins did not express daily variations.We suggest that in addition to melatonin, there are also rhythmic changes in plasma concentrations of other small compounds that reflect intermediary metabolism, and these may contribute to communication between central and peripheral oscillators. All these components contribute to formation of the multiple redundant temporal organisation that is flexible and capable to anticipate rhythmic changes in the environment and to respond to them adequately at every level of the organism.

Keywords: glucose, cholesterol, triacylglycerols, lipids, creatinine, uric acid, albumin    

Development of Heart Rate Circadian Rhythm in Chickens

K. Moriyaa*, R. Akiyamab, E.M. Dzialowskic, W.W. Burggrenc and H. Tazawab
a Department of Electrical and Electronics Engineering, Hakodate National College of Technology, Hakodate 042-8501, Japan
bDepartment of Electrical and Electronics Engineering, Muroran Institute of Technology, Muroran 050-8585, Japan
c Department of Biological Sciences, University of North Texas, Denton, Texas, USA

ABSTRACT

In chick embryos, various instantaneous heart rate (IHR) fluctuations (e.g. HR variability, HR irregularities) have been found and developmental patterns of mean heart rate (MHR) have been elucidated. IHR changes have also measured in newly hatched and young chickens in order to investigate the developmental patterns of MHR and any potential diurnal HR rhythmicity such as a circadian rhythm. The present report reviews measurements of embryonic and hatchling HR fluctuations and examine development of HR circadian rhythms during the late stages of incubation and after hatching. Embryonic HR was continuously measured during the last half period of incubation. After hatching, continuous measurements of HR were made for two weeks at the longest in eight chickens ranging in age from 0 to 47 days. During the embryonic development, circadian rhythm of HR was found to be absent until hatching. After hatching, distinct circadian rhythm of HR appeared with increasing daily MHR from day 0 to day 7. During the second week of post-hatch life, the daily scope of MHR (diurnal maximum-nocturnal minimum) reached a maximum level ranging from 200 to 300 bpm with constant baseline of nocturnal MHR. In young chicks, the nocturnal HR baseline was the same as that during the fortnight of posthatch life and daily scope of MHR decreased to 100 ^ 150 bpm.

Keywords: circadian rhythm, developmental pattern, chick hatchlings, mean heart rate, heart rate fluctuation, continuous measurement    

Gender-Speci®c Expression of Arginine-Vasotocin in the Chicken Brain

R. Grossmanna*, A. Jurkevichb and S. Kleina
a Department of Functional Genomics and Bioregulation, Institute of Animal Science Mariensee, Federal Agricultural Research Centre, 31535 Neustadt, Germany
bPermanent address: Institute of Ecology, Vilnius University, Vilnius LT 2600, Lithuania

ABSTRACT

The avian neuropeptide arginine vasotocin (AVT), originally characterised as the antiduretic hormone, is produced by neurosecretory cells within the brain. Major locations are the preoptic area including supraoptic nucleus, the hypothalamic paraventicular nucleus and the limbic bed nucleus of the stria terminalis (BnST). Magnocellular AVT neurons of the hypothalamic locations project to the neurohypophysis and make a major contribution to the peptide content in the circulation. Major physiological functions of circulating AVT are regulation of hydromineral balance as well as its contribution to reproductive events like oviposition. Parvocellular AVT neurons located in the limbic BnST are quite different in their properties and, most likely, functions. In these neurons the AVT gene is expressed in a sexually dimorphic manner and are found solely in males. During embryogenesis these neurons occur in both sexes and are subjected to sexual differentiation during perinatal stages of ontogeny. Embryonic oestrogen may exert organisational effects on specific sex dimorphic peptidergic circuits in the chicken brain. AVT is involved in the modulation of different aspects of reproductive behaviour. Moreover, evidence coming from ethological, physiological and anatomical studies strongly suggests a role for the vasotocinergic system in various forms of adaptive responses.

Keywords: vasotocin, reproduction, adaptation, chicken, development, osmoregulation, oviposition, gene expression    

Further Observations on the Roles of FOXL2 in Ovarian Differentiation and Function in the Chicken

M. Govorouna*, M. Pannetierb, E. Paillouxb, I. Coutya, J.-P. Brillarda, F. Batelliera and C. Cotinotb
 aStation de Recherches Avicoles, INRA, 37380 Nouzilly, France
bLaboratoire de Biologie du DeÂveloppement et Biotechnologies, INRA, Jouy-en-Josas, France  

High Concentration of Progesterone is Located in the Outer Layer of Japanese Quail Eggs (Coturnix Coturnix Japonica)

R. Hackla, V. Bromundtb, J. Daiselyb, K. Kotrschalb and E. MoÈstlc*
a Clinic of Poultry and Pet Birds, University of Veterinary Medicine Vienna
bKonrad Lorenz Research Station GruÈnau
c Institute for Biochemistry, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria

Keywords: progesterone, Japanese quail, yolk layer, eggs    

Embryo Development and Chick Temperature

A. Lourens*
Applied Research, Animal Sciences Group, PO Box 2176, 8203 AD Lelystad, The Netherlands

Keywords: embryo development, chick temperature    

Influence of Incubation Temperature on Muscle Development in the Turkey and Possible Consequences for Post-Hatch Growth

V. Maltby, A. Somaiya and N. Stickland*
The Royal Veterinary College, University of London, Royal College St, London, NW1 0TU, United Kingdom    

Egg Weight Loss during Incubation and Relative Hatching Chick Weight and their Relationships to Post-Hatch Blood Glucose Concentration, Body Temperature, Visceral Changes, and Liver Glycogen Concentrations in Nutrient Restricted Broilers

E.D. Peeblesa*, R.W. Keirsb, L.W. Bennettb, S.K. Whitmarsha and P.D. Gerardc
 a Poultry Science Department, Box 9665 b College of Veterinary Medicine, Box 9825, and
c Experimental Statistics Unit, Box 9653, Mississippi State University, Mississippi State, Mississippi 39762, USA

Keywords: broiler, chick, egg weight loss, incubation, liver glycogen, nutrient restriction, plasma glucose, viscera    

Impact of Egg Storage on Early Embryo Development in the Turkey

M.R. Bakst*
Biotechnology and Germplasm Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Beltsville Agricultural Research Center, Beltsville, Maryland, USA 20705

Keywords: egg storage, early embryo development     

Associations of Increased Late Embryo Loss with incidences of Anomalies and Head Disorientation toward the Small End in Broiler Hatching Eggs

R.W. Keirsa, E.D. Peeblesb*, S.K. Whitmarshb and P.D. Gerardc
a College of Veterinary Medicine, Box 9825, b Poultry Science Department, Box 9665, and
c Experimental Statistics Unit, Box 9653, Mississippi State University, Mississippi State, Mississippi 39762, USA

Keywords: late embryo loss, head disorientation, embryo anomalies     

Yolk Utilisation and Chick Length as Parameters for Embryo Development

N.J. Wolanskia*, E.J. Luitenb, R. Meijerhofb, and A.L.J. Vereijkenb
 a Department of Agriculture, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada, T6G 2P5
bHybro B.V., Veerstraat 38, 5831 JN Boxmeer, The Netherlands

Keywords: yolk utilisation, chick length     

Influence of Incubation Temperature on the Noradrenaline Concentration in Blood Plasma and cAMP Content in Heart Muscles Cells of Chicken Embryo

H. ToÈnhardt*, N. Brauch and D. von Plettenberg
Institute of Veterinary Physiology, Free University of Berlin, Oertzenweg 19b, 14163 Berlin, Germany

Keywords: noradrenaline concentration, blood plasma, cAMP contents     

The Role of Calcium and Feed Supplementation in Poultry Production

S.Y. Saleh*
Department of Physiology, Faculty of Veterinary Medicine, Cairo University, 12515 Giza, Egypt

ABSTRACT

Many trials using certain feed additives aimed to increase egg production andyor improve egg quality as well as meat production. The characteristics of calcium agonists and antagonists are reviewed first. Some untraditional feed additives, such as lasalocid and reserpine as well as calcium gluconate, were used in studies described. Modulation of blood calcium will be in consideration to clarify the relationships between the exogenously administrated calcium, rate of growth, the egg production and some reproductive hormones in both sexes. High calcium intake to broiler from one day caused delay in growth rate poor calcification of bones, decreased PTH secretion, and increased level of calcitonin. In cocks administration of calcium gluconate alone induced alteration in the stages of spermatogenesis, giant cells with multiple nuclei which showed heterolysis of interstitial cells of the testis, that mean the use of Ca gluconate should be taken with cautiousness. Calcium gluconate modulate Gn-RH in relation to gondotropins release, concluded that increasing the dietary calcium for layers ration in the second year of egg production, as it may simulate the action of Gn-RH moreover, reserpine plus calcium carbonate improve egg production rather than reserpine alone. So, calcium agonist supplementation could be considered as a good practical tool to retain good egg production level in second year layers.

Keywords: calcium, feed additive, lasalocid, verapamil calcium agonist, calcium antagonist    

Expression of Genes of the Somatotropic Axis in the Chicken: Developmental Changes and Impact of Nutrition

R. Grossmanna*, R. Zhaob and E. MuÈhlbauerc
 a Department of Functional Genomics and Bioregulation, Institute of Animal Science, Mariensee, Federal Agricultural Research Centre, 31535 Neustadt, Germany
b Present address: Key Laboratory of Animal Physiology and Biochemistry, Nanjing Agricultural University, Nanjing, PR China
c Present address: Institute of Anatomy and Cell Biology, Martin-Luther-University, Halle, Germany

ABSTRACT

Growth is determined by genotype as well as by environmental factors including nutrition. The neuroendocrine system involved in the regulation of growth acts as an interface to integrate both internal and external inputs. Among all neuroendocrine factors involved the hypothalamo-pituitary somatotropic axis has been received greatest attention. In order to better understand the role of growth hormone (GH) on poultry (and avian) growth and development, we studied broilertype and laying-type chickens and compared expression levels of various genes during embryonic and post-hatch development. We found significant differences in the level of gene transcription between layer and broiler chickens. In the fastgrowing broiler chickens there were higher levels of hepatic GH receptor (GHR) mRNA but there was a lower steadystate GH mRNA level in the pituitary. The observed differences are contributed by both genetic and nutritional factors, since the birds were raised under their own standard diets with different nutritional levels. Therefore, we evaluated the effect of nutrition on the patterns of gene expression of GH and GHR in broiler and layer chickens.

Keywords: growth, gene expression, chicken, growth hormone, receptor expression, liver, pituitary, development, nutrition     

Effect of Feeding Bt176 Maize on Physiological and Performance Parameters in Broiler Chickens

M.A. Tonya*, A. Butschkea, J. Zagona, H. Brolla, M. Schauzua, I. Halleb, S. DaÈnickeb, G. Flachowskyb and H.M. Hafezc
a Federal Institute for Risk Assessment (BfR), Berlin, Germany
b Institute of Animal Nutrition, Federal Agriculture Research Centre (FAL), Braunschweig, Germany
c Institute of Poultry Diseases, Free University, Berlin, Germany

Keywords: transgenic maize, broiler performance, maize-DNA digestion and uptake    

Use of Physiological Indicators for Determinig Lysine Requirement of the Laying Hen

M.H. Shahira*, F. Shariatmadaria, S.A. Mirhadib, M.Zakeric and B.Vaziric
a Tarbiat Modarres University, Tehran, Islamic Republic of Iran
bAnimal Science Research Institute, Karaj, Islamic Republic of Iran
c Pastor Institute, Tehran, Islamic Republic of Iran

ABSTRACT

This study was conducted to determine the lysine requirement of laying hen during peak egg production (26 ^ 42 weeks of age) using different physiological indicators as response criteria. A basal diet based on corn-corn gluten meal-soybean meal was used, which contained 0.58% total lysine. Nine graded levels of lysine as L-Lysine. HCl were added to the basal diet. Each experimental diet was fed to 48 hens in a completely randomized design with 4 replicate for each treatment. At the end of the experiment blood samples were taken from wing vein for determining blood biochemical parameters. Broken-line analysis suggests that plasma free lysine, serum albumin, serum total calcium and serum uric acid concentrations are worthwhile physiological indicators of lysine requirement in laying hen. Based on the results of this experiment,daily total lysine requirement was estimated to 815mg henÿ1 dÿ1.

Keywords: lysine, laying hen, requirement, physiological indicators     

Observations on Gizzard Erosions in Hatching Chicks

G. Manarolla, C. Recordati, T. Rampin*, G. Sironi and C. Domeneghini
FacoltaÁ di Medicina Veterinaria, UniversitaÁ degli Studi di Milano ± Via Celoria 10, 20133 Milano, Italy

Keywords: gizzard, erosion, chick, gastrin    

Importance of Thermoregulatory Behaviour in Poultry during the first days after Hatching: Interaction between Temperature Preference and Thermoregulatory Heat Production

B. Tzschentke*
WG Perinatal Adaptation, Institute of Biology, Humboldt-University of Berlin, Invalidenstrasse 43, 10115 Berlin, Germany

Keywords: thermoregulatory behaviour