Avian Biology Research

Print ISSN: 1758-1559
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On the Dalmatian Islands native large bodied ground-nesting bird species are rare, while the introduced Ring-necked Pheasant (Phasianus colchicus) is currently very common and often breed in abandoned farmlands. The survival chance of its nests in two different habitats was surveyed by using artificial ground nests on Solta Island in May 2008. Within a week, predators found and damaged all (100%) of the nests in the abandoned vineyards and 88% of those located in abandoned fields. The daily survival rate of artificial nests in the abandoned vineyard (41.86%) was significantly lower than that in the abandoned fields (79.82%). Predation patterns of chicken eggs versus plasticine eggs were similar in the two habitats. Predators removed 72% of chicken eggs and 72% of plasticine eggs from nests in the abandoned vineyard, and 64% of chicken eggs and 44% of plasticine eggs from nests in the abandoned fields. The primary predators to nests of ground-nesting birds on Solta Island are Hooded Crows (Corvus cornix). Damage to nests caused by small bodied birds, small mammals and snakes was quite insignificant. Wild boars (Sus scrofa) that colonised the island about a decade ago did not damage the experimental nests.
 
This review discusses the development of ostrich farming in Poland, emphasising the key success factors that led Poland to become one of the leaders of ostrich farming in Europe. The paper presents three stages of development of this new poultry sector in Poland, discusses adaptation of ostrich to climate conditions in Central Europe, provides information on the national and international market for ostrich products, as well as infrastructure and organisation of ostrich farming in Poland. It also summarises the main effects observed after Polish accession to the EU with respect to ostrich farming development and finally give prospects for the future.
 
Probing undiscovered hypothalamic neuropeptides that play important roles in the regulation of pituitary function in birds is essential for the progress of avian neuroendocrinology. The decapeptide gonadotropin-releasing hormone (GnRH) is the primary factor responsible for the hypothalamic control of gonadotropin secretion. Gonadal sex steroids and inhibin inhibit gonadotropin secretion via feedback from the gonads, but a neuropeptide inhibitor of gonadotropin secretion was, until recently, unknown in birds as well as other vertebrates. In 2000, Tsutsui and co-workers discovered a novel hypothalamic dodecapeptide that inhibits gonadotropin release in quail and termed it gonadotropin-inhibitory hormone (GnIH). This was the first demonstration of a hypothalamic neuropeptide inhibiting gonadotropin release in any vertebrate. From the past 8 years of research, we now know that GnIH exists in several avian species and acts as a new key neurohormone for the regulation of avian reproduction. GnIH acts on the pituitary and GnRH neurons in the hypothalamus via a novel G protein-coupled receptor for GnIH to inhibit gonadal development and maintenance by decreasing gonadotropin release and synthesis. GnIH neurons express melatonin receptor and melatonin stimulates the expression of GnIH. Thus, GnIH is capable of transducing photoperiodic information via changes in the melatonin signal, thereby influencing the reproductive axis. This review summarises the advances made in our understanding of the biosynthesis, mode of action and functional significance of GnIH in birds.
 
The aim of the present study was to investigate the effects of systemic administration of amylin on the avian tibia using histological, histomorphometrical and biochemical methods. Forty “Super Nick” laying hens 10 weeks of age were used. The experimental groups were injected subcutaneously in the loose skin at the nape of neck every other day with 75 μg kg-1 doses of rat amylin. The morphology of the cells and organic components of bone were studied in standard decalcified preparations at 14, 16, 18 and 20 weeks of age. Cortical bone and tibial growth plate widths were measured from the histological sections. Serum calcium, plasma amylin, parathyroid hormone related peptide (PTHrP) and calcitonin levels were determined at the same ages. Our results suggest that, when administered systemically to laying hens, amylin stimulates the proliferation of chondrocytes and osteoblasts and increases tibial growth plate thickness.
 
Comparison of the survival of ‘hard released’ Tawny Owls from this study and ‘soft released’ juvenile Tawny Owls (Bennett and Routh, 2000; Leighton et al ., 2008). Dashed lines are 95% confidence intervals. 
We investigated the survival of 57 rehabilitated juvenile Tawny Owls (Strix aluco) that were 'hard released' (without the provision of a release aviary or support food) by means of radio tracking. The birds were released in the month of August in three consecutive years: 2005, 2006 and 2007, in the counties of Somerset and Hampshire, United Kingdom. Tracking of the owls was successfully carried out for between three and 160 days. Mortality was recorded for 16 birds (28%). The transmitter was shed by 24 (42%) owls, the signal was lost for 12 (21%) and tracking was ceased for five (9%) owls. Survival of the owls was compared with results from previous studies on wild Tawny Owls and also rehabilitated 'soft released' Tawny Owls (released with provision of food and shelter after release) and found to be similar. This study suggests that employing costly and time-consuming soft release techniques may be unnecessary for juvenile Tawny Owls as their survival is not significantly reduced using hard-release methods. Measuring post-release success of rehabilitated birds of prey is discussed in relation to benchmarks used in previous studies.
 
Four separate nitrogen balance experiments with fast and slow growing genotypes of growing chicken were conducted to yield basic data for modelling of lysine and threonine requirements dependent on genotype, age, protein deposition and dietary amino acid efficiency. A total of 1008 individual nitrogen balance data in up to four age periods (I: 10-25 days; II: 30-45 days; III: 50-65 days; IV: 70-85 days) was utilised. According to principles of the diet dilution technique, experimental diets provided graded protein supply (60-360 g˙kg-1 crude protein) with lysine or threonine as the first limiting amino acid. The modelling procedure utilised currently observed model parameters for the theoretical potential of nitrogen retention (NRmaxT) and nitrogen maintenance requirement (NMR), respectively. The selected results of the applied modelling procedure are discussed in comparison with current recommendations for growing chickens and aspects of different procedures utilised for assessing quantitative amino acid requirements, respectively. The amino acid requirement data yielded by modelling were in line with current recommendations, but are not directly comparable due to discrepancies in the applied procedures. However, the concluded requirements for lysine and threonine are useful to improve actual predictions for “ideal amino acid ratio” in growing chickens which are in focus of on-going studies.
 
Ammonia emissions from poultry farms currently contribute to air pollution and acid rain. There are no regulations in North America regarding emissions of ammonia although regulations are being drawn up in the USA and there is concern about the impacts of animal agricultural on the environment. Low crude protein (CP) diets can be an effective contributor to strategies of ammonia mitigation. Since virtually all ammonia originates from nitrogenous compounds in feed, then any attempt at ammonia mitigation must involve scrutiny of the levels of nitrogen, protein and amino acids (AA). Reducing dietary nitrogen/CP leads to reduced nitrogen in the excreta with less potential for microbial conversion to ammonia. Using low CP diets may be an economical strategy for ammonia emissions since the concept involves no special feed additives other than replacement AAs. Although AA requirements for layer hens are well known, the minimal amount of CP required is less clearly defined. AA requirements should be independent of diet CP, assuming there is adequate nitrogen for protein synthesis. However, the birds' response in terms of reduced egg numbers and growth or change in egg composition, suggest that our estimates of amino acid supply are incorrect under these dietary regimes. Independent of bird age and AA supply, more problems are recorded when CP levels are < 14-15%. It is timely to redefine the maintenance AA requirements of layers. Since the composition of eggs should give us direct estimates of needs for production, the only other unknown in formulating low CP diets is the efficiency of utilisation of free amino acids versus intact proteins.
 
Two years after the first description of the heron species Intermediate Egret, in Manuel d'ornithologie (1840), the physician and natural historian Francesco Lanza observed several specimens of this species (under the name of Ardea egrettoides) in the valley of Neretva, just off the southern East Adriatic (Croatian) coast. Yet Lanza's observation remained unnoticed by the ornithological audience until the present day. An analysis of Lanza's description of the species, historical circumstances of this first record, as well as recent data on the appearance of this species outside its typical area of distribution speak in favour of the correct determination of specimens of this species in the valley of Neretva. Therefore, Lanza's description of Intermediate Egret in the valley of Neretva is the first record of this species in Europe. Sightings of this species outside its area of distribution confirm the existence of two distinct directions of movement: West African and Mediterranean.
 
Attempts to artificially incubate the eggs of wild birds have failed in many respects in duplicating the success of natural incubation. As part of a larger study we had the opportunity to artificially incubate the eggs of 22 species of birds (three domestic and 19 wild species). We report the successes and failures associated with artificial incubation of these eggs. Moisture loss varied widely, not only for Orders of birds but for similar species within an Order. Overall hatching success and success through to 90% of incubation varied for different Orders and for similar species. Humidity and temperature are critical elements in the artificial incubation of wild bird eggs and must be closely monitored throughout incubation to ensure the best possible chance of hatching. Even when these elements are addressed, artificial incubation still can not duplicate the success of incubation by the parent.
 
Based on experimental evidence obtained in Japanese quail (Coturnix coturnix japonica), concurrent determination of eggshell breaking strength in avian reproduction studies in addition to the routine parameter eggshell thickness is recommended. After transformation of breaking strength data, a regression analysis was performed on a large sample of eggs (n = 815) from untreated hens. A need for concurrent assessment of both endpoints was substantiated by their poor correlation that became apparent by a rather low coefficient of determination (r2) of less than 15%. It was further supported by strongly diverging results when sub-sets of eggs from smaller and more homogenous groups of quail in a number of one-generation studies were analysed for correlation of the two parameters.
 
Seventeen potentially Bridge Species in Croatia
The lack of epidemiological knowledge when planning the approach to preventing possible future outbreaks of avian influenza may lead to uncontrolled spreading of HPAI H5N1 virus and, consequently, danger to the poultry industry and human health and threats to the survival of endangered wild birds. The implementation of a model developed for the rapid assessment of ornithological data relevant to the spreading of avian influenza in the EU countries resulted in the identification of 23 Higher Risk Species and 17 Bridge Species for the territory of Croatia. It also identified a number of wetland areas, where Higher Risk Species come together during migration and wintering, as potential AI introduction and outbreak sites. The EU model was adapted to suit the Croatian circumstances. The migratory flyways of Higher Risk Species were analysed using data on birds ringed outside Croatia and found on the territory of Croatia between 1910 and 1992. These results form the ornithological part for the risk assessment of possible future outbreaks both at the national level and internationally, in neighbouring countries. It may also be used for AI research under the global European model. Data on poultry density, type of poultry husbandry, poultry trade and movement are needed. We propose the establishment of a database on the commercial movements of poultry and poultry products under the Early Warning System.
 
Between 2003 and 2005, we released 12 red kites (Milvus milvus) to the wild in Hampshire, England. Four kites were captive-bred and released as fledglings in artificial nests ('hacking'). The remaining birds were mature and released from a large aviary. Interaction with electricity power-lines killed two of the captive-bred birds three weeks post-release and a third captive-bred kite died as a result of head injuries six months post-release. One mature kite died 10 days post-release. We suggest that the different release methods of the two groups amplified the behavioural variation between individuals and exposed them to different risk factors. We concluded that releasing mature flight-fit kites from aviaries is likely to be a superior method to hacking pre-fledged kites in artificial nests. The flight skills of the mature kites, developed prior to release, enabled them to avoid potentially lethal interactions with power-lines and aggressive inter-specific encounters. Modifying or adapting release methods to incorporate behavioural variation between individuals within a release population should be a consideration for reintroduction practitioners, particularly where release numbers are small.
 
Graphical presentation of factorial correspondence analysis (FCA) showing the distribution of individual birds per breed (VB 1⁄4 white, GC 1⁄4 grey and LB 1⁄4 black). Per cent value in each axes indicates contribution to the total genetic variation (Axe 1 1⁄4 64,41%; Axe 2 1⁄4 35.59%; Axe 3 1⁄4 0.00%). 
Dendrogram constructed using D DAS genetic distances among individual genotypes and Neighbor-Joining algorithm by POPULATION software (VB 1⁄4 white circle; LB 1⁄4 black triangle; GC 1⁄4 grey square). 
Three fowl breeds, Valdarnese Bianca, a traditional white feathered breed from Tuscany, Golden Comet® a commercial hybrid and Livornese Bianca, a white leghorn type, were genotyped at eight microsatellite loci. A total of 74 alleles were detected with locus ADL181 recorded the lowest (six alleles) and locus ADL136 the highest (15 alleles) allele frequencies respectively. Heterozygosity values ranged from 0.210 (locus ADL210) to 0.742 (locus ADL176). The Wright's fixation index values were 0.089 (FST), 0.300 (FIS) and 0.363 (FIT). Factorial correspondence analysis and a dendrogram individual tree constructed using individual genetic distances showed genetic differentiation of the three breeds.
 
The emergence of highly pathogenic avian influenza (HPAI) viruses has raised concerns about the role of wild birds in the spread and persistence of the disease. In 2005, an outbreak of the highly pathogenic subtype H5N1 killed more than 6,000 wild waterbirds at Qinghai Lake, China. Outbreaks have continued to periodically occur in wild birds at Qinghai Lake and elsewhere in Central China and Mongolia. This region has few poultry but is a major migration and breeding area for waterbirds in the Central Asian Flyway, although relatively little is known about migratory movements of different species and connectivity of their wetland habitats. The scientific debate has focused on the role of waterbirds in the epidemiology, maintenance and spread of HPAI H5N1: to what extent are they victims affected by the disease, or vectors that have a role in disease transmission? In this review, we summarise the current knowledge of wild bird involvement in the ecology of HPAI H5N1. Specifically, we present details on: (1) origin of HPAI H5N1; (2) waterbirds as LPAI reservoirs and evolution into HPAI; (3) the role of waterbirds in virus spread and persistence; (4) key biogeographic regions of outbreak; and (5) applying an ecological research perspective to studying AIVs in wild waterbirds and their ecosystems.
 
Semen cryopreservation is an important tool for the storage of reproductive cells used for the ex situ management of genetic diversity in birds. Recent advances in poultry semen cryopreservation technology have resulted in the emergence of cryobanking, which is now being developed in an increasing number of countries. In addition, semen freezing methods are now effective for various domestic and wild bird species, although species such as guinea fowls are still highly affected by the process. The methods of freezing avian semen now use a small number of cryoprotectants, (mainly glycerol, dimethyl or N-methylacetamide) and cell packaging (such as straws or pellets). Temperature curves of freezing and thawing remain the most variable points as very slow or very rapid curves are sometimes used in the same species. Specific features of bird reproductive physiology are very important for sperm cryopreservation and application. The characteristics of initial semen quality, including cell membrane properties, mobility capacity and ability to undergo the acrosome reaction are critical points. The specific features of the oviparity system of reproduction and the internal fertilization process affect the conditions of semen use. The in vivo storage of spermatozoa in the sperm storage tubules of the female genital tract, and the conditions of the drastic selection of sperm in the highly specialized female oviduct constitute major factors that are highly species-specific. These constraints involve adaptations of the semen media used for freezing and of the zootechnical parameters of semen use. This review highlights the main factors that are critical for the success of semen cryopreservation in bird species.
 
Feather pecking, the pecking at or removal of feathers from one bird by another, is a problem in the poultry industry. Elimination of damaging feather pecking from flocks is made especially difficult by the numerous factors that appear to influence its prevalence. This review outlines the various contributors to feather pecking organised around Tinbergen's four questions on causation, ontogeny, phylogeny and function. There is growing evidence that feather pecking (especially severe feather pecking) is related to foraging motivation and gut function. However, other factors, such as improper early experiences, strain and individual differences and perseveration of the behaviour help explain its continued occurrence, even if the birds are kept in enriched environments. To date, methods of dealing with feather pecking are inadequate and involve welfare concerns of their own and alternate solutions, such as provision of forages, are not usually successful in abolishing feather pecking behaviour. The problems of excessive pelage/plummage removal or redirected oral/foraging related behaviour are not unique to poultry and seem to occur in other species in which foraging and forage intake is important. Between species comparisons of related behaviour patterns may improve our understanding of feather pecking and help to design effective solutions. In order to solve the problem of feather pecking, the factors discussed in this review need to be accounted for or we risk applying 'band-aid' solutions, which may appear outwardly to be solving the problem. However, the underlying cause(s) may still be present and the animal's welfare may still be compromised.
 
A heavily speckled clutch of Great Tit, Parus major , Wytham Woods, Oxfordshire, showing concentration of pigment to form a corona ring around the crown. Photo by A. Gosler. 
Results of General Linear Mixed Model to predict the standardised fracture toughness of Great Tit eggshells measured as Jym 2
Photomicrograph of transverse section of Great Tit eggshell through pigment spot in shoulder region of the eggshell taken with bright field epi-illuminated lighting with a 6 200 magnification, and polarising filters. A scale bar of 0.1 mm is shown bottom right. The shell section is indicated by the bracket, and shows three distinct layers of protoporphyrin pigment within the shell section, giving the appearance of a laminate structure. The external egg surface is uppermost; the apparent structure external to the lower surface is deformation of the plastic in which the shell was mounted for sectioning. Preparation in resin and photo by Dr L. Marsh. 
A typical output from the strain gauges of the Instron (from egg 7) showing load in N for cuts made through Great Tit eggshells. The eggs were collected in Wytham Woods UK between 2004 and 2007. The yellow line shows the load required to cut pigmented eggshell over each mm of scissor extension through the sample. The blue line is an equivalent trace for unpigmented shell. 
Diagram showing the translation of vertical movement (closure of scissors) into horizontal movement (travel of cutting point E away from the hinge D). This was calculated according to the equation DE 1⁄4 4 y cos (180 – asin (AB y AD) þ ADC), where DE 1⁄4 the distance between the hinge and the point of cutting; AB 1⁄4 0.5 6 (distance between the handles); AD 1⁄4 distance from the centre of the handle to the hinge; ADC 1⁄4 the angle subtended at the hinge between the handle and the line AE (joining the centre of the handles and the cutting point, Vincent, 1992). 
Protoporphyrin pigmentation is a common feature of passerine eggshells worldwide, typically giving red to brown coloration. Although these may form a background colour to the egg, protoporphyrin more commonly forms speckles, blotches or patches of colour (maculation) against a white (unpigmented) or blue y green (biliverdin-pigmented) background. Conventional explanations for the presence of such pigmentation have focused on the eggs' appearance, and include crypsis and strategies to deter brood parasites, such as cuckoos (Cuculidae). More recently, evidence has emerged that there may also be a sexually-selected visual function. However, the pattern of occurrence across taxa and upon and within the eggshell, suggest that non-visual functions may be at least as important, or even the principal function of some pigmentation. In particular, correlations between protoporphyrin maculation, eggshell thickness, rates of water-loss and local calcium availability in the Great Tit (Parus major), suggest that the pigment could serve a structural function. Despite strong circumstantial evidence, however, a direct relationship between eggshell strength and protoporphyrin pigmentation has not previously been available. Here, we present preliminary findings from a comparison of fracture toughness (resistance to fracture) and brittleness of pigmented and unpigmented shell from the same Great Tit eggshells. These suggest that while pigmented shell is as brittle as unpigmented shell, the fracture toughness is significantly greater and more than compensates for the reduced shell thickness observed at a pigment spot. The data also suggest that although the first two principal components of pigmentation influence fracture toughness, neither influences how the material responded to the propagation of a crack through its surface. We suggest that pigmentation provides structural overcompensation for shell thinning caused, for example, by a deficit of dietary calcium, and the reasons for this are discussed.
 
A diagrammatic representation of the humidity conditions in and around the nest when the bird is incubating (adapted from Walsberg, 1980). P E is the water vapour pressure inside the egg, P N is the water vapour pressure in the air inside 
Relationship between water vapour pressures measured in bird nests and in the ambient environment surrounding the nest. Line indicates quadratic relationship fitted through the data points (see text for details). Diagonal line indicates the relationship with a slope of one and passing through the origin. 
Relationship between water vapour pressures measured in bird nests and in the ambient environment surrounding the nest for different types of nests. Solid and dashed lines indicate linear relationships fitted through the data points for scrape and cup nests respectively (see text and Table 2 for details). Diagonal line indicates the relationship with a slope of one and passing through the origin. 
Water vapour pressure gradient from the nest to the ambient air (P N – P A ), expressed as a proportion of the total 
Relationship between mass specific water vapour conductance of the eggshell and water vapour pressures measured in the ambient environment surrounding the nest. Solid and dashed lines indicate linear relationships fitted through the data points for scrape and cup nests respectively (see text and Table 4 for details). 
Nest humidity is a function of how water vapour is retained within the nest. Previous analysis suggested that in general, nest humidity was largely unaffected by ambient humidity but there was no consideration of the type of nest involved. This study examined data collected from the literature to test the hypothesis that the relationship between nest and ambient humidity is a function of the type of nest. Data for water vapour pressure for the egg (PE), nest (PN) and ambient air (PA) were collected for 48 examples of nests from 44 species of bird from a range of Orders. Initial egg mass and water vapour conductance of the eggshell was also recorded for each species. Analysis showed that birds on scrape nests are able to raise PN above PA by on average 5 Torr irrespective of PA. By contrast, PN in cup nests was unaffected by PA, such that at low values nests are well insulated against water vapour loss. The balance between the proportion of water vapour lost from the egg to the ambient air that is controlled by the nest varied with the type of nest and PA. For eggs in scrape nests mass specific water vapour conductance showed a positive relationship with PA. By contrast, for eggs in cup nests the relationship was negative and under conditions of low PA the high PN means that mass specific shell conductance values have to be high so as to ensure the appropriate rate of weight loss from the egg. Whilst birds do not control nest humidity directly the inter-relationship between weight loss from an egg, its initial mass, its shell conductance, and the incubation period can now be extended to include the water vapour conductance of the nest wall.
 
The histology of the oesophagus and crop was studied in six species of birds: Rock Dove, Collared Dove, Rose-ringed Parakeet, Kestrel, House Sparrow and Linnet. In species, the epithelium of oesophagus and crop was a keratinised stratified squamous. The lamina propria was a loose connective tissue containing glands. Glands were either purely mucous or seromucous (mixed). In the rock dove, rose-ringed parakeet and collared dove, there were no glands either in the cervical part of oesophagus or in the crop. There were differences in the histochemistry of glands' secretions. The muscularis mucosa was present as a thick layer of smooth muscle fibres. The tunica submucosa was a loose connective tissue containing vessels and nerves. The tunica muscularis consisted of smooth muscle and was surrounded by the tunica adventitia at the cervical part of the oesophagus and crop, and by the tunica serosa at the thoracic part of the oesophagus.
 
Three issues concerning avian peripheral blood glucose concentrations that require more investigation are: (a) whether they are as variable and high in free-living as in captive and domesticated adults, (b) the sources of variation in adult concentrations and (c) if and how they change during nestling development. Whole blood glucose concentrations (BGlu) of wild adults of four native passerine and one exotic dove species varying in mass and diet were measured in south-east Australia. There was significant inter-specific variation in BGlu, but the range in mean values (11.1 to 17.0 mmol L−1) conformed with that published for many adult captive and domestic birds of similar size and was well above that for adult mammals of comparable mass. BGlu also varied markedly intra-specifically in four species (coefficients of variation 17.5-32%). Trapping procedure and timing of sampling did not explain this variation, but adult body mass was associated with BGlu in two species. If whole blood haemoglobin concentrations (Hb) reliably reflect body condition, most of the adults sampled were in good condition. Wild nestling Welcome swallows (Hirundo neoxena) and Spotted doves (Streptopelia chinensis), respectively, underwent 20% and 40% continuous, linear, developmental increases in BGlu. Swallows fledged with a mean BGlu 23% greater than, and doves with a mean similar to, that of adults. The developmental increase probably reflected an increase in metabolic rate as nestlings gained mass and became more active.
 
This review details the six lineages of large flightless birds that evolved in the Late Cretaceous, Tertiary and Quaternary periods of geological time. Estimates of mass for each type of bird suggest that maximal mass is no greater than 500kg with most species attaining only 250-300 kg or less. By contrast, non-avian Archosaurs of the Mesozoic, and many mammal species of the Tertiary, attained great size with many species reaching several tonnes. Size has been limited in flightless birds because of the strength of the eggshell and in the largest species reproduction was only possible if the smaller males incubated. That reproductive characteristics limit mass in flightless birds suggests that truly gigantic non-avian theropods could not contact incubate their eggs and had to rely on environmental sources of heat energy to drive embryonic development. If fossil evidence ever arises to support proper contact incubation in a non-avian theropod then it is predicted that it will only be from a small (<250 kg) species.
 
In recent years, increasing evidence suggests that sex differences in the phenotype of all tissues are influenced by the inequality of effects of sex chromosome genes in the two sexes. In birds, genes on the Z chromosome are not well dosage compensated, so that most Z genes are expressed higher in ZZ male cells than in ZW female cells. The sex difference in expression of Z and W genes is likely to cause sex differences within cells, in addition to the sex differences caused by different levels of testicular and ovarian hormones. The sexual imbalance in cell physiology has implications for aviculture and novel developments in the poultry industry.
 
Specific essential oil (EO) blends and probiotics used as feed additives have been shown to promote healthy digestive microbials resulting in improved poultry production. Two consecutive experiments were conducted with broilers fed corn-soybean meal diets to determine comparative effects of feed additives on ileal and caecal microbial populations (MP). Ross 708 broilers were placed in 84 pens with previously used litter and treatments maintained in the same pens for both experiments. Eight treatment groups were fed diets containing: Bacitracin methylene disalicylate (BMD) as positive control (PC); no additives as negative control (NC); three probiotics: BC-30; BioPlus 2B (B2B); and Calsporin; and the essential oil blends Crina Poultry Plus (CPP) at 300 or 150 ppm in the first experiment; and CPP at 300 ppm and Crina Poultry AF at 100 ppm in experiment 2. Starter and grower diets contained the ionophore (Coban). Ileal and caecal samples were collected at 43 days of age from male broilers. The DNA of microbial populations was isolated from digesta samples and analysed by denaturing gradient gel electrophoresis to generate percentage similarity coefficients (%SC) from band pattern dendrograms. Differences were observed in ileal and caecal populations depending on treatment, respectively, and especially between experiments. Broilers fed diets with probiotics had very similar MP. The EO CPP at 300 ppm resulted in ileal MP similar to those observed in chickens fed probiotics. We concluded that antibiotic treatment affected ileal, but no caecal MP. More pronounced changes in ileal and caecal MP were seen in broilers at 43 days of age following probiotic and essential oil treatments.
 
Map showing the topographic relief and the geographical regions of Turkey. The shaded areas were visited during our 2007 breeding survey. 
Frequency of historical records of Saker breeding attempts or breeding-season sightings in each of the seven geographic regions of Turkey during five time periods: the 19th century, the first half of the 20th century, 1960 -79, 1980 -99 and since 2000
Map showing known current breeding distribution of the Saker Falcon outside Turkey (data from www.mefrg.org). This disjunct distribution is characterised by spatially discreet populations in central Europe, eastern Europe and central Asia (shaded grey), whilst Sakers are absent or breed at low density in intervening areas (hatched grey). 
Breeding season diet of Saker Falcons in Central and Eastern Anatolia assessed from pellets and prey remains collected at three nest sites in 2007
Distribution of 20 Saker breeding localities in Turkey over three different time periods; 1960 – 79 (circles), 1980 – 99 (triangles) and 2000 – 08 (squares). 
The Saker Falcon Falco cherrug breeds in Turkey and also occurs in the country during passage and in winter. Turkey represents the southwestern range limit of the global breeding distribution of the species and is relatively isolated from the neighbouring population centres in Europe and Central Asia. A review of literature and other record sources indicated that the 19th century breeding population in Thrace had disappeared by the 1950s, in line with dramatic declines in the Southern Balkans. We could find no data on the Saker Falcon population elsewhere in Turkey prior to the 1960s. In the 1960s, the Saker Falcon was a rare breeding species found mainly in steppe habitats of Central and Eastern Anatolia. Despite increased ornithological recording activity in the country, the number of Saker Falcon records declined in the 1980s and 1990s, probably because of habitat loss, a reduction in the Anatolian Souslik (Spermophilus xanthoprymnus) population and the activities of falcon trappers. A recent resurgence in records since 2000 probably reflects an increase in ornithological recording by resident and visiting ornithologists. Our survey in 2007 confirmed that the Saker is a rare breeding species in Central and Eastern Anatolia despite there being much apparently suitable habitat and prey available in these regions. It is not clear whether or not the Saker population in Turkey is currently held at a low level by anthropogenic factors or whether the low population size is a characteristic of an isolated population of a species occurring at the edge its global distribution range.
 
Ingredient and nutrient composition of experimental diets with different levels of CP
Whole body composition and protein utilisation of broilers as influenced by different dietary CP levels from 1 to 26 days of age a
Economic evaluation of different dietary CP levels fed to broilers from 1 to 26 days of age
protein intake, protein efficiency ratio and mortality of broilers as influenced by different dietary CP levels from 1 to 26 days of age a
A trial was conducted to study the effect of lowering dietary crude protein (CP) with optimal amino acids profile on growth and whole body composition of broilers from 1 to 26 days of age. Four isocaloric (Metabolisable energy - 2925 kcal y kg) experimental broiler diets with CP levels of 23 (control), 22, 21 and 20% were formulated. Digestible lysine was maintained at 1.1% of the diet. A total of 1,760 dayold, Hubbard broiler chicks were randomly divided into 16 experimental units of 110 chicks and each diet was offered to 4 experimental units at random. Weight gain, feed intake and feed conversion ratio were not significantly affected by any of the treatment groups during the experimental period. Whole body composition and protein utilisation of broilers were also unaffected by the reduction in dietary CP content. However, total protein intake was decreased (P < 001) and protein efficiency ratio was increased (P < 001) linearly with low CP diets. Economics of different experimental diets fed to birds revealed that maximum economic returns were observed in 20% CP diet. The results suggested that dietary CP level could be reduced to 20% during starter period without any harmful effect on broiler performance when supplemented with critical amino acids.
 
Effect of zinc supplementation on carcass yields of broilers a 
Effect of zinc supplementation on immunity of broilers* 
Zinc is an essential trace mineral for birds, functioning elaborately in enzyme systems and being involved in protein synthesis, carbohydrate metabolism, and many other biochemical reactions. Zinc is required for normal growth, reproduction, and glandular development of birds. A severe zinc deficiency causes numerous physical and pathological changes including skin lesions, decreased growth, general disability of bones and joints, very poor feathering, reproductive failure, and reduced immunity to infection of several diseases. In skin, it is five to six times more concentrated in the epidermis than the dermis. In addition, zinc is associated with wound healing because of its role in collagen and keratin syntheses. All proliferating cells, including inflammatory cells, epithelial cells, and fibroblast, require zinc. Furthermore, zinc is an essential element of more than 200 metalloenzymes and affects their conformity, stability, and activity. The superoxide dismutase, one of the zinc-containing antioxidant enzyme, has a critical role in keeping broiler skin healthy and increasing the shelf-life of broiler meat. However, a clear appreciation of the role of this element in broiler production is still limited. This article provides an overview on the role of zinc in broiler feeding and nutrition, immunity, reproduction, and meat quality in particular.
 
Coccidiosis is an infectious disease that causes the most widespread health problems in the broiler industry. This study indicated that chickens fed with the probiotic Lactobacillus plantalum CMU- FP002 exhibited an 85.63% reduction in the number of oocysts of Eimeria tenella shed in the faeces compared with the control group. The average number of oocysts shed by the group fed the probiotic and a group fed an antibiotic were both significantly (P<0.05) less than the average number of oocysts shed by the control group. Coccidiosis is an infectious disease caused by a protozoan parasite of the genus Eimeria and is the most consistently reported health problem in poultry (Biggs, 19–82; Rose et al, 1987; Williams, 1999). Generally, the number of oocysts shed in the faeces is dependent on the number of sporozoites and merozoites that penetrate the enterocytes for a given inoculum dose, and so represents the infection-resistant ability of broilers. Susceptibility to Eimeria can also be assessed on the basis of the number of oocysts obtained from droppings collected for four days starting on day 6 post-inoculation (Dalloul et al., 2005).
 
A study was conducted to determine the effect of sources and levels of zinc on tissue zinc concentration and the carcass quality of broilers. A total of 6,000 1-day-old unsexed broiler chicks were allotted randomly to four floor pens with 1,500 birds per pen. A corn-wheat-soybean meal basal diet (Control) was formulated, and 40 ppm inorganic zinc (40 IZ), 40 ppm organic zinc (40 OZ), and 80 ppm organic zinc (80 OZ) were added to the basal diet to form four dietary treatments. During the 4-wk experimental period, feed and water were provided ad libitum. At the end of the feeding trial, five birds from each pen were randomly selected as five replicates, slaughtered and carcass evaluation was performed. Results showed that zinc supplementations have no effect on zinc content in thigh muscle but a significant increase was found in skins from broilers in 80 OZ (P<0.05). The epidermis thickness of tibia and back skin were not affected by the zinc supplementations. However, significant increases of tibia and back skin dermis thickness were found (P<0.05) by zinc supplementation and organic zinc was more effective than inorganic zinc in this respect (P<0.05). The collagen contents of breast and thigh muscle were not affected by dietary zinc supplementation, but organic zinc increased the collagen contents in the back skin of broilers (P<0.05). Shear force values of back skin and breast muscle were not affected by zinc supplementation. It is concluded that dietary organic zinc is more effective in increasing the skin zinc concentration, and improving skin quality of broilers than inorganic zinc.
 
Regular, non-aversive interaction with humans can reduce domestic and captive animals' fear of them. This has management implications because it can sometimes beneficially affect the animals' condition, reproduction and productivity, probably as a result of a reduction in chronic stress. We determined for domesticated budgerigars living in flocks whether regular visual contact with humans for six weeks affected body mass, condition and peripheral blood parameters that are thought to indicate chronic stress levels. Contact comprised 300 - 360 min of visual exposure weekly to an experimenter pacing slowly in front of the aviary; control flocks had no exposure, except briefly during husbandry. Body mass and condition and the blood parameters were measured at the start (Sampling time 1, ST1) and end (ST2) of the treatment period and again after a further six weeks in which all birds were isolated from humans (ST3). Mass, residual mass (i.e. condition) and blood haemoglobin concentration were greater at ST3 than at ST1 or ST2, the heterophil/lymphocyte ratio increased from 0.35 to 0.67 between ST1 and ST2 and haematocrit decreased from 59 to 54% during the experiment. Improved nutrition and adjustment to the new environment were possible factors influencing these temporal trends. The changes were similar in visually exposed and control birds, so regular visual contact with a human of the specific type and extent imposed had no effect on body mass, condition or the blood parameters. Possible reasons for the lack of an effect are discussed.
 
The first-reported incidence of a hard, massive fibroma on the leg of an ostrich is described. It consists of numerous fibres and originates from the skin. The fibroma apparently develops as a consequence of the bumping and abrasive action of the limbs with paddock surfaces and the ground during movement. We deduce that the fibroma growth impaired movement, although the combination with tibio-tarsal rotation was clearly a contributing factor.
 
The objective of this study was to find the specific expressed genes in chicken sperm storage tubules. One hundred and fifty dual-purpose hens at 30 weeks of age were inseminated with 1 × 108 spermatozoa on two consecutive days. Eggs were collected and set daily during the 24 days following the latter of two inseminations. Five hens with fertility below 60% were inseminated with fresh semen. Fifteen hens with fertility above 80% were divided into three groups. Fresh semen, frozen dead semen and 0.9% NaCl, respectively, were injected into the vagina of five hens in each group. RNA from the utero-vaginal junction (UVJ) of the hens was reverse transcribed and differentially displayed. Four bands of interest which were expressed in UVJ from hens inseminated with fresh semen or frozen semen but not from hens inseminated with saline were selected, re-amplified, cloned and sequenced. BLAST search showed that band A is similar to part of chromosome 3 (the homology is 98%) and the nearest gene to the fragment is 1,722 base pairs up-stream whose product is mitogen-activated kinase. Band B is similar to phosphatidylinositol glycan anchor biosynthesis gene (PIGK) and the homology is 98%. PIGK is a subunit of glycosylphosphatidylinositol transamidase (GPI8). GPI-linked proteins participate in the release of membrane proteins. Band F is similar to a hypothetical protein gene and the homology is 97%. This hypothetical protein belongs to chicken neurexophilin. Band G is similar to fat3 and the homology is 97%. Neurexophilin and fat3 are proteins that function in the nervous system. Taken together these data indicate that hens may regulate sperm storage in UVJ through the nervous system and may release sperm from the UVJ through GPI8.
 
Eggs contain complete protein and can supply essential amino acids. Eggs also contain nine non-essential amino acids, vitamins, minerals, antioxidants, saturated, monounsaturated and polyunsaturated fatty acids, cephalin, lecithin, and cholesterol. The content of low-calorie eggs benefits populations throughout the world at every stage of the human life cycle. As a designer food, eggs can be packaged with more nutrients needed to prevent diseases. Moreover, this food has new uses as bioreactors for several pharmaceuticals produced in egg albumen or yolk. While eggs have been employed to produce influenza vaccines for more than 50 years, newer techniques will most likely reduce their use in this important arena. Due to high quality protein, a plethora of required nutrients, low calories and excellent functional properties, once again, egg consumption is rising. This increase in consumption along with evolving use as a designer food and a bioreactor in the pharmaceutical industry may help to maintain or boost notoriety of eggs as "nature's most perfect food".
 
Codon usage in mitochondrial genes of 11 Gallus gallus and two Anatidae species was analysed to determine the general patterns in codon choice of Gallus gallus species. C3 contents were higher in Gallus gallus than in mammalian mitochondrial genomes that encode protein codon positions. The high C3 contents of Gallus gallus might be the result of relatively strong mutational bias that occurred in the lineage of the Gallus gallus species. A and C ending codons were detected as the "preferred" codons in Gallus gallus and Anatidae. The NNR codon families are dominated by the A-ending codons, the NNY codon families are dominated by the C-ending codons and the NNN codon families are dominated by the A-ending or the C-ending codons. A comparison of the relative synonymous codon usage (RSCU) and synonymous codon families (SCF) of tRNA and proteins was made, and two groups can be classified by SCF. The codon usage in Gallus gallus species indicates that codons containing A or C at the third position are used preferentially, regardless of whether corresponding tRNAs are encoded in the mtDNA. In both Gallus gallus and Anatidae species mtDNA, codon usage biases are highly related to CC-ending binucleotide condons.
 
Nest predation experiment to survey survival probabilities of larger bodied ground-nesting birds (ducks) was carried out on Lake Kuti in May 2006. From 25 artificial ground nests on the floating reedbed islands and 25 nests on the grazed islands, 8 and 1, respectively, were depredated. On the contrary to our expectations, the daily survival rate of artificial nest on the reedbed islands i.e. closed habitats was significantly lower (95.06%) than in the open habitat islands being grazed by sheep and cattle (99.43%). Broken chicken eggs and the marks left behind on plasticine eggs suggested that the predators were probably small mammals and birds. Such predators do not pose serious threat to real nests and clutches, thus they are unlikely to have had significant influence on the dramatic decrease of nesting bird populations in the area.
 
Origin of the Hippolais warbler blood samples used for this study 
Microsatellites are a valuable tool in the analysis of population genetic structure. Utilising microsatellite markers that were originally isolated from other species (cross-species amplification) can prove an efficient way, in terms of time and cost, to obtain markers for genetic studies. Here, 55 avian microsatellite primer pairs were tested for the cross-amplification in the Melodious Warbler (Hippolais polyglotta). Thirty-five markers amplified, of which 22 were polymorphic, displaying two to nine alleles in the 15 individuals genotyped. The 35 markers which amplified in the Melodious Warbler were tested in its sister species the Icterine Warbler (H. icterina). Twenty-four markers were amplified, 14 of which were polymorphic in the five H. icterina individuals genotyped. Thirteen loci were polymorphic in both species. The polymorphic loci identified are suitable for analysing the genetic population structure and assigning parentage.
 
Ross 708 broiler chickens were fed one of three levels of crude protein (12, 21 or 30%) from 7 to 28 days of age. Birds were then switched to either a higher (30%) or lower level of crude protein (12% and sampled three days following the switch. The purpose of these treatments was to test effects of changes in protein level at a representative time during the finisher phase (days 28 to 31) of broiler growth and to relate changes to metabolic plasma hormone levels (IGF-I, IGF-II, insulin, leptin, T3, T4, glucagons, Ghrelin) and regulatory enzymes [malic enzyme (ME), aspartate aminotransferase (AAT), and NADP-isocitrate dehydrogenase (ICD)] and their respective mRNAs The data from this experiment show that a priority of hormones can be established with respect to correlations between circulating values and representative metabolic enzymes and their mRNAs. It is suggested from these data that both IGF-I and T4 are equal in a metabolic priority scheme and are superior to glucagon and Ghrelin which are still significantly related to certain enzymes and their mRNAs. It is entirely possible that mRNA levels do not correlate or totally regulate enzyme protein (as evidenced by activities of regulatory enzymes) although the relationships for ME (R=0.69; P<0.001), ICD (R=0.64; P<0.001) and AAT (R=0.47, P<0.001) does lend some credence that transcriptional events regulate these two enzymes.
 
A total of 364 Turtle Dove (Streptopelia turtur) nests were found in the Tadla irrigated area during the 2006–2009 breeding seasons. Of these, 135 were located in orange orchards, 178 in olive orchards and 51 in olive hedgerows. Gaussian generalised linear modelling was used to model the nest height and the nest–trunk distance according to the characteristics of olive and orange trees in the orchards and hedgerows. Tree height and type of plantings had the strongest effects on both nest height (R 2 = 0.67) and nest–trunk distance (R 2 = 0.48). Overall, the same pattern of Turtle Dove nest height was recorded in the three types of plantings, whereas different patterns were noted for the nest–trunk distance. The results provide evidence of non-random patterns of nest placement in olive and orange agro-ecosystems. This game species exhibits adaptive behavioural plasticity in nest placement and appears to be well-adapted to the olive and orange grove conditions in this region. This high adaptability is beneficial to maintaining the species in these artificial habitats. Additional quantitative studies are needed to improve our understanding on the mechanisms driving the choice of nest placement by Turtle Doves in this agricultural man-made environment.
 
Since the introduction of Alectoris chukar in Spain, hybridisation has occurred in the wild and on farms with the native A. rufa but the native species is phenotypically indistinguishable from the hybrid partridges. In order to provide tools for the identification of the native and hybrid birds a partridge genomic library was constructed using the plasmid pSMART-HCKan and Escherichia cloni 10G bacterial cells. DNA from bacteria containing recombinant plasmids was transferred onto nylon hybridisation membranes in order to screen for plasmids containing (AC)13 and (AG)13 which are the most common dinucleotide repeats in the avian genome. DNA hybridisation was performed using (AC)13 and (AG)13 probes labelled with the TexasRed and fluorescein fluorochromes and hybridisation was detected using a fluorescence microscope. Two microsatellites were identified in non-coding regions of the partridge genome and these have been used to characterise a number of A. rufa individuals from different parts of Europe.
 
The binding modes of the influenza A(H7N9) neuraminidase in complexes with avian-type (3′-SLN) and humantype (6′-SLN) receptor analogues are investigated by combined homology modelling, molecular docking and quantum mechanical/molecular mechanical (QM/MM) methods. The results reveal that these two analogues could be docked into the active site surrounding by residues of R118, T148, R152, E227, R276 and R371, and bind well in the receptor binding site. Comparing with the docking results, we find that the stabilities of the binding modes are all strengthened after optimisation. However, human-type 6′-SLN might be a preferable receptor analogue as it generates more HB interactions. Whether in the docking results or in the optimised structures, both of analogues (3′-SLN and 6′-SLN) bind in the receptor binding site mainly using their sialic acid groups of the analogues. This conclusion is consistent with most experimental results obtained from crystal structures. Our results give a good understanding on how the N9 interacts with host receptors from a structural perspective. They support the conclusion that the receptor binding mode might be changed from a avian-type to human-type receptor binding. This result might provide a theoretical guide for the study of the influenza A (H7N9) in the future.
 
SYBR Green I based real-time RT-PCR assay was developed for the detection and quantification of duck reovirus (DRV) using ABI PRISM 7500 sequence detection system. The assay was carried out using a set of primer designed to amplify highly conserved sequences of S2 gene of DRV. A 10-fold dilution series assay using a plasmid containing the cDNA of DRV S2 gene demonstrated the high sensitivity of the assay with a lowest detection limit of ≤1.48 copies/μL. Standard deviation and coefficient of variation were low for both intra-assay and inter-assay variability. The assay performance was evaluated on 80 samples obtained from artificially infected Cherry Valley ducklings and 10 field specimens compared with the conventional RT-PCR assay. It was shown that 10 artificially infected samples tested negative in gel-based assay were positive for the real-time RT-PCR. DRV could be detected in all eight different tissues collected from the ducklings infected artificially. In contrast, the higher detection rate was obtained in the bursa of fabricius (90%), lung (90%), spleen (80%), and thymus (70%) than that in the liver (30%) as well as in the pancreas (10%). This method was rapid, specific, and sensitive for the detection of DRV and will be useful in veterinary diagnostic applications.
 
Nucleotide sequence of RSIL-2 DNA. The predicated coding region of 434 bp and resulting amino acid sequence of 140 aa of RSIL-2, the nucleotide sequences of primers used in the PCR are underlined. The Genbank accession number of this DNA sequence is JX239767.  
Phylogenetic tree of IL-2 nucleotide sequences of several mammalian and bird species. The numbers of the staff gauge indicate the evolution distance of different species. GenBank accession numbers of the compared sequences are as follows: rabbit IL-2 (DQ852342); human IL-2 (NM000586); horse IL-2 (X69393); cat IL-2 (L19402); dog IL-2 (D30710); goat IL-2 (AF307018); cattle IL-2 (M12791); pig IL-2 (AY294018); chicken IL-2 (AF502412); turkey IL-2 (AJ007463); Japanese quail IL-2 (AY386204); swan goose IL-2 (AY392557); muscovy duck IL-2 (AY193713); ruddy shelduck IL-2 (JX239767); mallard IL-2 (JX239765) ; spot-billed duck IL-2 (JX239768).  
Analysis of rRSIL-2 protein expressed in E. coli. A. SDS-PAGE analysis. Lanes 1–3,total protein of RSIL-2 mature protein after IPTG induced for 2, 3, 4 h. Lane 4, total protein of RSIL-2 mature protein before IPTG induction. Lane 5, pET32a vector alone. Lane 6, protein molecular weight markers; B. Western blot analysis. Lane 1 represent the rRSIL-2 protein recognised by antihis tag mouse mAb. Lanes 2 and 3 reveal that pET32a vector alone and the protein before IPTG induced does not recognise the anti-his tag mouse mAb.  
In vitro lymphocyte proliferation assay of the rRSIL-2. Cells containing RPMI1640-FCS only were used as a negative control, and RPMI1640-FCS only was used as blank. Values are expressed as mean counts ±SE.  
Identification of the biological activity of fusion rRSIL-2. The stimulation index (SI) of lymphocytes = (ODrRSIL-2 – ODblank)/(ODnegative – ODblank).  
Interleukin-2 (IL-2) is one of the most actively studied interleukins. It is a powerful growth factor for a variety of cell types, plays a central role in the cell differentiation and stimulates the activity of many kinds of killer cells. However, little information is available on the IL-2 genes in migratory waterfowl, ecologically important species potentially involved in virus transmission. In this study, the cDNA of wild ruddy shelduck IL-2 was cloned by RT-PCR from peripheral blood lymphocytes stimulated with Concanavalin A (ConA), and the recombinant ruddy shelduck IL-2 (rRSIL-2) mature protein was expressed in Escherichia coli. In vitro bioactivity of rRSIL-2 was demonstrated in a lymphocyte proliferation assay. The results showed that RSIL-2 cDNA contained an open reading frame (ORF) of 423 bp encoding a protein of 140 amino acids (aa) with a putative signal peptide of 21 aa. Phylogenetic analysis based on nucleotide sequences showed that RSIL-2 was most closely related to IL-2s of the muscovy duck and mallard (homology of 97.4% and 96.2%), and to a lesser extent to spot-billed duck and swan goose sequences (homology of 95.8% and 93.6%). The RSIL-2 showed genetic diversity compared with other birds of anseriformes. Fusion protein expressed in E. coli had the molecular weight of around 31.7 kDa, as shown by SDS-PAGE and western blotting. The rRSIL-2 affected the duck, chicken, and goose lymphocyte proliferation in the same concentration, although the effect on goose and chicken lymphocytes was relatively weak. Our study reported the molecular signatures and bioactivity of IL-2 in a migratory waterfowl species.
 
The major aim of this study was to examine the influence of the European Pine Marten (Martes martes) predation on the heights of nests of Blue Tits (Cyanistes caeruleus) and Great Tits (Parus major) in nestboxes of different security levels. To this end we performed a comparison of nest heights before and after introducing an anti-predator device to two size-types of wooden nestboxes set up in a deciduous forest. Blue Tit and Great Tit nest sizes were influenced by the application of plastic entrance tubes as anti-predator devices that elongated a distance between the entrance and the interior of the nestbox. Nests were taller in nestboxes equipped with anti-predator devices regardless of nestbox size. Nests located in smaller nestboxes were destroyed by Martens more frequently than nests built in bigger nest boxes. Most nest functions in cavity-nesting birds, such as filling the excessive cavity space, maintenance of proper humidity, thermal, light and sanitary conditions for eggs and nestlings, improve with nest sizes. Because, in contrast, the risk of nest predation by martens increases with nest size (height within the nestbox), the nest predation constitute a major factor that constrains cavity-nesting birds in constructing tall nests.
 
Gennfibrozil and L-carnitine are involved in fatty acid metabolism. We assessed the impact of administering gemfibrozil together with L-carnitine on the performance, lipid redistribution, intramuscular fat, and carcass quality in broiler chickens. Day-old male Ross 308 chicks were randomly divided among nine treatments, with three replicates per treatment. There were of 10 chicks in each replicate. The experiment involved a 3x3 factorial arrangement of treatments, with three levels of L-carnitine, in combination with three levels of gemfibrozil. Body weight, feed intake and feed conversion ratio (FCR) were obtained weekly from 3 to 6 weeks of age. At the end of the experimental period, the chicks were sacrificed and carcass and blood samples were obtained for various measures. There were interactions between L-carnitine and gemfibrozil on weight gain, feed intake, FCR, full and empty abdominal carcass weights, breast and wing weights, abdominal fat weight, heart weight and triglyceride concentration (P<0.05). The presence of dietary L-carnitine and gemfibrozil together reduced the weight gain, feed intake, abdominal fat weight and triglyceride concentration. Conversely, combinations of L-carnitine and gemfibrozil significantly increased the heart weight. There were no effects of L-carnitine and gemfibrozil on eviscerated carcass weight nor on liver weight. Dietary L-carnitine and gemfibrozil together influence measures of performance, fat distribution and carcass quality in broiler chickens.
 
An animal's antioxidant system is fundamentally complex aiming at finding a balance between pro-oxidative and anti-oxidative stressors in the body. To further unravel the animal's response to oxidative stressors we used free-range broilers combined with severe feed restriction as opposed to conventional broilers as a reference. At 21 days of age, 36 Ross 308 broilers were divided into three groups. The first group (I42) was raised indoors according to common practices and fed ad libitum. The second group (O42) was transferred to outdoors on a grass pasture and fed once daily 50% ad libitum. At 42 days of age, eight birds from each group were sampled. The third group (O70) was reared similar to O42 but was sampled at 70 days, having approximately the same final weight as birds I42. Compared to I42 birds, the O42 birds showed a higher and lower concentration of malondialdehyde and a-tocopherol in their plasma, respectively; indicating oxidative stress after 3 weeks of free-ranging and feed restriction. As a response, the glutathione synthesis was up-regulated as manifested by increased levels of glutathione in the liver in O42 compared with I42, and in the jejunal mucosa in O42 and O70 compared with I42, and by a three- to four-fold increase in erythrocytes in O70 compared with the other groups. Regarding meat quality, the outdoor birds showed a darker and yellower colour of breast meat as compared with those reared indoors. Muscle total fatty acid content was higher in O42 compared to I42 and O70, which was reflected in the content of individual fatty acids (mg/100g meat), whereas differences in fatty acid profile (% of total fatty acids) between groups were marginal. To conclude, free-ranging together with feed restriction elicited remarkable changes in the animal's antioxidant system, while changes in meat oxidative stability were less pronounced and more difficult to interpret.
 
A diagrammatic representation of the extra-embryonic membranes and fluid compartments for the chick embryo around a third of the way through incubation. Note that the sizes of these structures, and their development relative to each other, have been modified to clarify types of cells present in each of the membranes.  
The pattern of changes in the mass of the embryo, yolk and albumen, and in the volume of the fluid compartments, of the developing fowl egg. Data from Romanoff (1968). the area vasculosa just beneath the shell membranes (Babiker & Baggott, 1992). As the area vasculosa is also a respiratory organ (Lomholt, 1984), this process improves the access of the embryo to the air. In unturned eggs the yolk sac floats less and sits deeper in the albumen (Babiker & Baggott, 1992), an outcome that may contribute to the greater embryonic mortality of unturned eggs.  
An account of the development of extra-embryonic membranes in the embryo of poultry. The roles of these membranes in the transfer of water from albumen to yolk and to embryonic tissue is reviewed.
 
Developmental changes of the gizzard have rarely been studied in nestlings of non-domesticated birds or under natural conditions. Because nestlings would have variable amounts of stomach contents, we wanted to discover whether in natural conditions gizzard developmental changes are dependent on digesta mass. We examined the mass of gizzard and digesta in 56 nestling Rooks Corvus frugilegus aged between 1 and 13 days old. We found that gizzard mass increased nearly nine-fold, from an average of 1.25 g to 10.85 g. Gizzard mass expressed as a proportion of body weight significantly decreased with the age of nestlings. In hatchlings, the median ratio of gizzard mass to body weight was 18.4%; in 13-day old nestlings this value was only 5.8%. Tarsus length, a poor predictor of gizzard mass, explained 61% of its total variance. Nestlings (regardless of their age) without digesta or with small volumes of digesta had statistically significantly smaller gizzards (expressed as ratio of gizzard mass to body weight) than did nestlings with full gizzards, which suggest a rapid response of gizzard volume and musculature to variable food intake during post-hatch development.
 
The normal developmental sequence of the turkey embryo from the initial cleavage divisions through hypoblast formation has been described previously in 11 separate stages based on the progressive morphological differentiation of the embryo (Gupta and Bakst, Turkey embryo staging from cleavage through hypoblast formation. J. Morphol., 217, 313–325, 1993). However, in recent preliminary studies, our attempts to apply this stage table to describe the stages of embryo development were not successful. Therefore, we re-evaluated the development sequence of the turkey using eggs obtained from modern day commercial lines. Embryos from unincubated eggs and eggs incubated at different time intervals up to 25 hour were examined. In contrast to the observations by Gupta and Bakst, embryos from unincubated eggs lack an area pellucida (AP) but are characterised by dense clusters of cells that do not begin to dissipate and begin forming the AP until after 3–4 hours of incubation. Koller's sickle may or may not be present prior to and during hypoblast formation. Based on these new observations, a revised stage table including the above observations is presented to reflect more accurately the development of the modern commercial turkey embryo.
 
The present study was conducted on the tongues of six Punjab white quails. The tissues from the apex, body and root of the tongue were processed for paraffin sectioning and scanning electron microscopy studies. The tongue was triangular in shape having an apex, body and root. The dorsal surface of the apex and body was smooth whereas large lingual conical papillae were located symmetrically and converging in median line between the body and the root. There was an additional layer of conical papillae composed of two large papillae behind the main row of papillae. The tongue was lined by stratified squamous epithelium which was keratinised at the apex. The anterior lingual salivary glands were mainly serous type whereas the posterior salivary glands were mucous type. There were topographical differences in the size, shape and appearance of the exfoliated superficial cells of the dorsal surface epithelium in the apex and body of the tongue.
 
This study was carried out to examine histological and enzyme histochemical characteristics of the oesophageal tonsil in ducks (Anas platyrhynchos). Tissue samples were collected from distal parts of the mucosal folds at the oesophageal y proventricular junction. We applied alpha naphthyl acetate esterase and acid phosphatase to tissue sections for localisation of T or B lymphocytes. Trichrome staining, silver impregnation, methyl green-pyronin staining and PAS reaction were used for determination of light microscopic structure of the oesophageal tonsils. The oesophageal tonsils were located at the junction of the oesophagus and proventriculus. Interestingly, we detected the existence of high endothelial venules in the interfollicular area and of the accumulated positive cells in lymphoid nodules. It can be said that these tonsils have functions similar to the Harderian gland in avian species and Waldeyer's ring in mammalian species.
 
The viability and hatchability of Houbara bustard (Chlamydotis undulata) embryos were investigated in a surrogate (chicken) albumen and eggshell system. Egg yolk including embryos were separated from freshly laid Houbara bustard eggs, and cultured in albumen from chicken and Houbara, respectively. The viability of Houbara embryos after day 4 in the same sized chicken eggshell was 76.9% and 61.1% in chicken and Houbara albumen, respectively. The entire content (egg yolk with embryo and the surrogate albumen) were then transferred on day 4 into an eggshell of a larger double yolk chicken egg, and incubated for a further 19 days. On day 14, the viability of Houbara embryo in the surrogate Houbara and chicken albumen were 27.3%, and 57.1%, respectively. Two Houbara chicks hatched successfully from the chicken albumen (7.7%), while one hatched from the Houbara albumen (5.6%). The results showed that Houbara embryo could develop to hatching in chicken albumen and eggshell. This technology will provide a tool to hatch damaged eggs as well as soft-shelled egg of endangered wild birds.
 
Top-cited authors
Denis Charles Deeming
  • University of Lincoln
Mark Mainwaring
  • University of Montana
Silas James Reynolds
  • University of Birmingham
Hossan Md. Salim
Vito Laudadio
  • Università degli Studi di Bari Aldo Moro