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J D Wetherall - One of the best experts on this subject based on the ideXlab platform.
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microsatellite analysis of genetic diversity in wild and farmed emus Dromaius novaehollandiae
Journal of Heredity, 2002Co-Authors: E Hammond, A J Lymbery, Graeme Martin, David Groth, J D WetherallAbstract:The emu (Dromaius novaehollandiae) occupies most regions of the Australian continent and in recent times has been farmed for meat, oil, and leather. Very little is known about the genetic structure of natural or farmed populations of these birds. We report a preliminary study of genetic variation in emus undertaken by typing birds from five farms and two natural populations at five polymorphic microsatellite loci. Genetic diversity was high for all populations and there was little evidence of inbreeding, with most populations conforming to Hardy-Weinberg equilibrium for most loci. Significant heterozygote deficiencies at one locus in a number of populations were detected and may indicate the presence of null alleles. Comparisons of allele frequencies showed little evidence of genetic differentiation either among farmed populations or between farmed and natural populations.
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genetic evidence for mixed parentage in nests of the emu Dromaius novaehollandiae
Behavioral Ecology and Sociobiology, 2000Co-Authors: Emma L Taylor, J D Wetherall, David Groth, Dominique Blache, Graeme MartinAbstract:Parentage in emus (Dromaius novaehollandiae) was examined by microsatellite analysis using four independent loci. Of 106 chicks sampled in one breeding season from 18 nests, 54 (51%) were not fathered by the nesting male, 12 (11%) were not from the observed mate of the sitting male, and 9 (8%) represented intra-specific brood parasitism, having no alleles in common with either nest parent. Some males (11%) fathered all chicks in their nests, but the majority showed high levels of cuckoldry. Those males commencing incubation earliest in the season tended to have the highest levels of paternity in their own nests. These results reveal a high frequency of extra-pair fertilisations and resultant cuckoldry in a predominantly socially monogamous bird and support recent reports which have described the emu mating system as a complexity of polyandrous, promiscuous and monogamous behaviour. Parentage assignment of chicks resulting from extra-pair fertilisations revealed an evenly scattered pattern of paternity that did not show any particular male dominance in reproductive success. These results lead to a reassessment of behavioural observations of emus, the consequences of parentage distribution, and theories about mating systems and sexual selection. The frequency of extra-pair copulations and intra-specific brood parasitism suggests patterns of descent that differ greatly from those implied by social monogamy.
C Touraille - One of the best experts on this subject based on the ideXlab platform.
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meat quality traits in the emu Dromaius novaehollandiae as affected by muscle type and animal age
Meat Science, 1997Co-Authors: P Berge, Jacques Lepetit, M Renerre, C TourailleAbstract:Meat quality traits were determined in the major muscles of the emu (Dromaius novaehollandiae) at different slaughter ages (6, 10, 14, 17 or ≥20 months). A mean ultimate pH value of 5.5 was reached within around 3 h post mortem, but this value was 6.1 in animals that had suffered a preslaughter stress (transportation and fasting). The collagen and pigment contents varied widely among the muscles. The protein and pigment contents increased with animal age, but this effect was perceptible only between 6 and 14 months. The other chemical constituents were little affected by muscle type or animal age. The intense red colour of emu meat, due to a high pigment content, was very sensitive to oxidation, thus limiting the storage of fresh meat under aerobic conditions to short periods of time. Despite a rapid post-mortem tenderization (≤24 h), the residual myofibrillar strength obtained after extended ageing remained intermediate between those reported for chicken and beef. The tenderness of meat, cooked to 60 °C, differed between muscles and decreased with increasing age, thus reflecting the changes occuring in the concentration and in the heat stability of the intramuscular connective tissue.
Graeme Martin - One of the best experts on this subject based on the ideXlab platform.
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in vitro initiation of the acrosome reaction in the emu Dromaius novaehollandiae
British Poultry Science, 2013Co-Authors: Ruhani Singh, Irek Malecki, P K Rybniktrzaskowska, Umar Farooq, K V H Sastry, Graeme MartinAbstract:Abstract 1. An assessment of the efficiency of the acrosome reaction (AR) provides an important predictor of the fertilizing potential of semen and for diagnosis of the causes of infertility. A standardized protocol was therefore developed for initiation of the acrosome reaction in emu spermatozoa in vitro, and the role of CaCl2 or perivitelline membrane (PVM) proteins in determining the outcome of the reaction was investigated. 2. The acrosome reaction (assessed by FITC-PNA) was successfully induced in live spermatozoa by incubation for 2 min in NaCl-TES medium supplemented with 5 mM CaCl2. The maximum response was 32% live acrosome-reacted spermatozoa (LAR) achieved after 10 min incubation. 3. Compared to the outcome with 5 mM CaCl2 or PVM protein alone, the response was significantly better with a combination of PVM protein and CaCl2. 4. A significant variation in the percentage of LAR spermatozoa among individual males was observed. No treatment affected the percentage of dead acrosome-reacted spermat...
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microsatellite analysis of genetic diversity in wild and farmed emus Dromaius novaehollandiae
Journal of Heredity, 2002Co-Authors: E Hammond, A J Lymbery, Graeme Martin, David Groth, J D WetherallAbstract:The emu (Dromaius novaehollandiae) occupies most regions of the Australian continent and in recent times has been farmed for meat, oil, and leather. Very little is known about the genetic structure of natural or farmed populations of these birds. We report a preliminary study of genetic variation in emus undertaken by typing birds from five farms and two natural populations at five polymorphic microsatellite loci. Genetic diversity was high for all populations and there was little evidence of inbreeding, with most populations conforming to Hardy-Weinberg equilibrium for most loci. Significant heterozygote deficiencies at one locus in a number of populations were detected and may indicate the presence of null alleles. Comparisons of allele frequencies showed little evidence of genetic differentiation either among farmed populations or between farmed and natural populations.
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fertile period and clutch size in the emu Dromaius novaehollandiae
Emu, 2002Co-Authors: Irek Malecki, Graeme MartinAbstract:We tested whether female Emus lay fertilised eggs for a prolonged period, defined as the 'fertile period', following artificial insemination (AI) and natural mating (NM), and if so, whether the duration for which fertilised eggs are laid corresponds with the length of the period over which a clutch is laid. To determine the clutch duration, we studied the egg-laying pattern of AI females by recording oviposition and estimating oviposition interval. To determine the fertile period in NM females, we removed their male partners for 15 days and placed them in adjacent pens. The NM females laid fertilised eggs for a median duration of 11 days (range 7-14) after removal of males. For the fertile period after AI, the experiment was replicated 3 times. The mean fertile period of AI females was 16.2 ± 1.3 days, but maximum fertility was guaranteed for only 9 days. The AI females laid 6.7 ± 1.6 eggs per clutch and the oviposition interval within the clutch was 3.0 ± 0.1 days. The fertile period, estimated from the clutch size and egg interval, was 20.1 days. In conclusion, female Emus lay fertilised eggs for a prolonged time following an insemination, but their fertile period appears to be shorter than the period over which the clutch is laid.
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social mating system and sexual behaviour in captive emus Dromaius novaehollandiae
Emu, 2000Co-Authors: Dominique Blache, Carl D Barrett, Graeme MartinAbstract:Summary: Previous studies based on field observations have described the sexual behaviour of emus, but the social mating system of the species remains uncertain because of the lack of quantitative and detailed data. We therefore placed individually identified birds, 33 females and 27 males, in a large free-range pen (2.5 km 2 ) and recorded their behaviour twice weekly for 11 weeks, from the beginning of the laying period until all the males had begun incubating. The behaviour of both birds involved in a stable pair relationship was recorded in detail during 16 sets of onehour observations. Over 70% of males and females were classified as ‘socially monogamous’, but 7% of males and 3% of females were classified as ‘socially polygamous’. Also, 15% of the females were engaged in sequential polyandry. Within the pair, the females were the most active in pair formation and maintenance, directed their behaviour primarily towards their mate, and also protected access to their mate. Conversely, before they began incubating, the males were prompt to court females other than their mates and often walked away from their mates. Factor analysis reinforced these observations showing that female behaviour is mainly directed towards the mate whereas male behaviour has a major promiscuous component. We concluded that the social mating system of the emu is of a monogamous type but a few individuals are promiscuous — the males before they start incubating, and the females after their mate has started incubating. In addition, there are significant numbers of extra-pair copulations. The potential contribution of this relatively small proportion of promiscuous behaviours to the reproductive success of individuals cannot be assessed from behavioural studies and remains to be established by techniques that permit determination of chick parentage.
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genetic evidence for mixed parentage in nests of the emu Dromaius novaehollandiae
Behavioral Ecology and Sociobiology, 2000Co-Authors: Emma L Taylor, J D Wetherall, David Groth, Dominique Blache, Graeme MartinAbstract:Parentage in emus (Dromaius novaehollandiae) was examined by microsatellite analysis using four independent loci. Of 106 chicks sampled in one breeding season from 18 nests, 54 (51%) were not fathered by the nesting male, 12 (11%) were not from the observed mate of the sitting male, and 9 (8%) represented intra-specific brood parasitism, having no alleles in common with either nest parent. Some males (11%) fathered all chicks in their nests, but the majority showed high levels of cuckoldry. Those males commencing incubation earliest in the season tended to have the highest levels of paternity in their own nests. These results reveal a high frequency of extra-pair fertilisations and resultant cuckoldry in a predominantly socially monogamous bird and support recent reports which have described the emu mating system as a complexity of polyandrous, promiscuous and monogamous behaviour. Parentage assignment of chicks resulting from extra-pair fertilisations revealed an evenly scattered pattern of paternity that did not show any particular male dominance in reproductive success. These results lead to a reassessment of behavioural observations of emus, the consequences of parentage distribution, and theories about mating systems and sexual selection. The frequency of extra-pair copulations and intra-specific brood parasitism suggests patterns of descent that differ greatly from those implied by social monogamy.
John Thomson Soley - One of the best experts on this subject based on the ideXlab platform.
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a re evaluation of sperm ultrastructure in the emu Dromaius novaehollandiae
Theriogenology, 2014Co-Authors: Lizette Du Plessis, John Thomson SoleyAbstract:Abstract Existing reports on sperm structure in the emu do not adequately illustrate or describe all the salient ultrastructural features necessary for a meaningful comparison of normal and abnormal sperm in this species. As sperm morphology forms an important parameter in determining semen quality, and in view of the proposed role of artificial insemination in the farming of ratites, this article re-evaluates and complements the existing data on the topic, provides a fully illustrated description of emu sperm ultrastructure, and documents some unreported morphologic features. Conventional transmission and scanning electron microscopy and high resolution scanning electron microscopy were used to describe the ultrastructure of sperm harvested from the distal deferent duct of sexually mature birds slaughtered during the breeding season. In addition to broadly confirming the basic ultrastructural characteristics previously described for emu sperm, this study revealed a number of unreported morphologic features. These included distinct differences in surface properties between the acrosome and nucleus, the presence of a thread-like appendage near the base of the nucleus, variable positioning of the annulus relative to structures located at the midpiece–principal piece junction and regional differentiation of the principal piece. Although the emu displayed similar basic morphologic features to sperm of other ratites and the tinamou, marked structural peculiarities were obvious, notably the lack of an endonuclear canal and a perforatorium and the presence of significantly more mitochondria in the midpiece coupled with an absence of intermitochondrial cement. Although the broad morphologic features of emu sperm would appear to add credence to the general view that the ratites, together with the tinamous, form a monophyletic group at the base of the avian phylogenetic tree, it is also clear that emu sperm are distinctly different from those of the ostrich, rhea, and tinamou which together share morphologic affinities. This observation may lend some support to the alternate view that the Australasian ratites represent a separate clade that developed independently from flightless ancestors.
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light microscopic features and morphometry of sperm in the emu Dromaius novaehollandiae
Theriogenology, 2014Co-Authors: Lizette Du Plessis, John Thomson SoleyAbstract:Abstract A comprehensive morphologic description of emu sperm at the light microscopy level, an essential prerequisite for the routine evaluation of semen quality in this species, is not currently available. In this study, sperm morphology and morphometry were evaluated using conventionally prepared Romanowsky-stained semen smears of samples collected from the distal ductus deferens from 15 adult birds and fixed in 2.5% glutaraldehyde. Examination of the smears using phase contrast under 100× magnification readily resolved the various components of the cell, namely, the acrosome, nucleus, midpiece, principal piece, and endpiece. This technique was simple to use and produced consistently reproducible results. Normal emu sperm were typically filiform in appearance and closely resembled sperm of the ostrich and other non-passerine species, particularly poultry. A previously undescribed cytoplasmic appendage, associated with the base of the head, was a novel morphologic feature. The acrosome was short (1.84 ± 0.31 μm; mean ± standard deviation), whereas the nucleus measured 11.77 ± 0.93 μm in length. The length of the segments of the flagellum were 2.91 ± 0.4 μm for the midpiece, 47.45 ± 2.8 μm for the principal piece, and 3.69 ± 0.82 μm for the endpiece. The total sperm length was 67.64 ± 3.13 μm (range, 60.14–79.49) and the head:tail ratio was 1:4. Sperm dimensions in the emu were similar to those of other ratites.
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structural peculiarities associated with multiflagellate sperm in the emu Dromaius novaehollandiae
Theriogenology, 2012Co-Authors: Lizette Du Plessis, John Thomson SoleyAbstract:Multiflagellate sperm represent a rare defect in mammals and also in the emu where an incidence of only 1% multiflagellate sperm was recorded in semen samples from 15 birds. Biflagellate sperm were the most frequent form of the defect observed, but 3- to 5-tailed sperm were also noted. An association was apparent between multiple tails and macrocephalic sperm, which accounted for 0.6% of multiflagellate sperm. Structural features of the defect were generally similar to those seen in mammals. The duplicated tails shared a single midpiece, which housed supernumerary centriolar complexes, each surrounded by a mitochondrial sheath. A single row of mitochondria separated adjacent centriolar complexes. Elements of the connecting piece (segmented columns, capitellum) appeared normal. The nuclear base appeared flat, staggered, or scalloped depending on the number and depth of additional implantation fossae. Multiflagellate emu sperm of normal head dimensions displayed a widened nuclear base (in the form of an attenuated peripheral nuclear extension) to accommodate the attachment of the additional centriolar complexes. Defective mammalian sperm do not show this modification of the nuclear base as the inherently wider sperm head is able to accommodate the supernumerary centrioles. Although often spiraled around each other, the duplicated principal pieces of the tail were generally separated and free. However, in some cells the proximal parts were collectively bound within the plasmalemma. Multiflagellate sperm appear to have a dual origin with some defective cells originating from incomplete cytokinesis and others as a result of abnormal centriolar duplication.
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distribution and structure of glandular tissue in the oropharynx and proximal esophagus of the emu Dromaius novaehollandiae
Acta Zoologica, 2011Co-Authors: Martina Rachel Crole, John Thomson SoleyAbstract:Crole, M.R., Soley, J.T. 2011. Distribution and structure of glandular tissue in the oropharynx and proximal esophagus of the emu (Dromaius novaehollandiae). —Acta Zoologica (Stockholm) 92: 206–215. The glandular regions of the upper digestive tract in the emu were non-pigmented (except for the tongue in most specimens) and invested by a non-keratinised stratified squamous epithelium. The glands found in these regions were exclusively simple in nature and composed of tubular secretory units lined by Periodic Acid Schiff Stain-positive mucus-secreting cells. The naming of the various glandular fields was based on previously identified anatomical features and on nomenclature modified from previous studies on birds. The glands were classified into two main types, namely, simple tubular and simple branched tubular mucus-secreting glands. Simple branched tubular glands were a feature of the regions exposed to the greatest amount of friction during feeding, whereas simple tubular glands were a feature of regions exposed to less friction. The saliva produced by the salivary glands in birds functions to moisturize and lubricate food boli. Mucins in saliva also protect mucosal surfaces from desiccation and mechanical damage, assist in maintaining cellular water balance, provide lubrication and have an antimicrobial action. This study suggests that, in addition to the role of specific gross anatomical features, the type and distribution of glandular tissue in the emu upper digestive tract supports the cranio-inertial feeding method employed by this species.
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incidence structure and morphological classification of abnormal sperm in the emu Dromaius novaehollandiae
Theriogenology, 2011Co-Authors: Lizette Du Plessis, John Thomson SoleyAbstract:Little detailed information is currently available on the incidence and morphological characteristics of abnormal sperm in the emu (Dromaius novaehollandiae) and of ratites in general. This situation is further compounded by the lack of a uniform system for the morphological classification of avian sperm defects. Considering the important role that sperm morphology plays in the assessment of semen quality, a detailed description of avian sperm defects is of paramount importance. Based on morphological data provided by light and electron microscopy, a mean of 17.3% abnormal sperm was recorded in semen samples collected from the distal deferent duct of four adult emus during the middle of the breeding season. Four categories of defects were identified. Head defects (57.2% of total defects) consisted of bent heads, macrocephalic heads, round heads and acephalic sperm. Zones of incomplete chromatin condensation and retained cytoplasmic droplets appeared to be implicated in head bending, while giant heads were often associated with multiple tails. Acephalic sperm revealed a complete tail devoid of a head which was replaced by a small spherical structure. Tail defects (22.6% of total defects) were subdivided into neck/midpiece defects and principal piece defects. In the neck/midpiece region disjointed sperm were the exclusive defect noted and were characterized by the complete separation of the head and midpiece in the neck region but within the confines of the plasmalemma. Defects observed in the principal piece were subdivided into short tails, coiled tails and multiple tails. No conclusive evidence was obtained that tail coiling represented the 'Dag' defect. Biflagellate sperm were the most common form of multiple tails, demonstrating two complete tails with all the normal structural elements. Cytoplasmic droplets (13.9% of total defects) were classified as a separate defect. The location and eccentric positioning of retained cytoplasmic droplets was similar to that described in ostrich sperm although the composition of the droplets differed markedly between the two species. A small percentage of sperm (6.3% of total sperm defects) displayed multiple abnormalities. Based on these findings we propose a morphological classification for abnormal ratite sperm identifying head and tail defects, with additional categories for cytoplasmic droplets and multiple defects. Each category is further subdivided to reflect a range of specific defects within the category. It is envisaged that additional defects will be added to each category or that new categories may be added as future studies on the detailed morphology of avian sperm defects are completed.
Marco Giaretti - One of the best experts on this subject based on the ideXlab platform.
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differentiation of the species ostrich struthio camelus and emu Dromaius novaehollandiae by polymerase chain reaction using an ostrich specific primer pair
Meat Science, 2000Co-Authors: Fabio Colombo, Raffaella Viacava, Marco GiarettiAbstract:Through polymerase chain reaction a zone of the gene for the cytochrome b of ostrich (Struthio camelus) mitochondrial DNA was amplified using a primer pair which permits to identify the ostrich and differentiate it from the emu (Dromaius novaehollandiae), thus giving different size fragment; in the ostrich of about 543 bp and in the emu of about 229 bp. This has been obtained without adopting other techniques such as, e.g., the fragment digestion by means of suitable restriction enzymes or single strand conformational polymorphism (SSCP).
