Effect of incubation temperature on sex-dependent embryo mortality and morphological traits in Mallard.

Although birds have genetically determined sex, the sex ratio has been reported to deviate from parity in several studies. Temperature-dependent sex determination, which is common in reptiles, is absent in birds. However, females are able to adjust their investment into eggs according to the sex of the embryo, which may cause sex-specific embryonic mortality. Incubation temperature may also cause sex-biased embryonic mortality, and it may differentially affect the phenotype of male and female hatchlings. We aimed to investigate differences between male and female Mallard embryos regarding their egg size, mortality during incubation and hatchling phenotype in relation to incubation temperature. Mallard eggs were incubated under six constant incubation temperatures (ranging from 35.0 to 38.0 °C). Hatchlings were weighed, and their morphological traits were measured. We determined the sex of hatchlings and unhatched embryos by genetic analysis and found higher male embryonic mortality at 35.5 °C (44 males vs. 28 females) and a higher proportion of female hatchlings at 38 °C (24 males vs. 38 females); however, these results were not statistically significant. Our results suggest that Mallard females do not differentiate quantitatively between sexes during egg production. Male hatchlings were significantly larger but not heavier than females. The size difference between sexes was most pronounced at temperatures around 36 °C, which is the mean temperature of naturally incubated Mallard eggs.

Efeito do período e temperatura de armazenamento de ovos férteis sobre o rendimento de incubação e características de qualidade de codornas neonatas / Effect of period and storage temperature of hatching eggs from breeder quails on hatching results and quality characteristics of neonate quails

Foram estudados parâmetros de incubação e de qualidade física de codornas japonesas neonatas oriundas de ovos submetidos a diferentes condições de armazenamento. Os tratamentos constituíram-se de combinações entre temperaturas e períodos de armazenamento dos ovos férteis. O delineamento foi em blocos casualizados em arranjo fatorial 2x5, temperaturas (ambiente (28±1,5ºC) e refrigerada (14ºC)) x períodos de armazenamento (um, três, seis, nove ou doze dias), totalizando 10 tratamentos com 105 repetições, sendo cada ovo uma unidade experimental. Os ovos foram incubados nas condições de 37,9ºC e 60% de umidade relativa (UR). Houve aumento de perda de peso do ovo com o período de armazenamento, com efeito linear positivo. Observou-se maior taxa de eclosão/ovos férteis para os ovos armazenados sob refrigeração. Houve efeito linear negativo para o período de armazenamento sobre a taxa de eclosão somente para os ovos armazenados em 28ºC. Para o peso da codorna neonata, houve efeito linear negativo, independentemente da temperatura de armazenamento. O comprimento do intestino delgado em temperatura ambiente sofreu influência do período de armazenamento, sendo que o período de 12 dias apresentou pior resultado. O pior escore de qualidade física foi encontrado em codornas neonatas oriundas de ovos armazenados em temperatura ambiente por 12 dias. Pode-se concluir que, para melhorar a eclosão e a qualidade física da progênie, ovos de codorna devem ser armazenados por até nove dias e em temperatura de 14ºC.

Incubation parameters and physical quality of neonate Japanese quails hatched from eggs that were subject to different storage conditions were evaluated. The treatments consisted of a combination of temperatures and storage periods of hatching eggs from breeder quails. The experiments were conducted in a randomized block design in a factorial arrangement 2x5, with two storage temperatures (ambient temperature ± 28°C and refrigerated temperature 14°C) and five storage periods (one, three, six, nine and twelve days), totaling 10 treatments with 105 repetitions, each egg considered to be an experimental unit. The eggs were incubated at 37.9°C with 60% of relative humidity (RH). There was a positive linear effect between egg weight loss and storage period. Higher rates of hatching/fertile eggs were observed for eggs stored in refrigerated conditions. A negative linear effect was observed between storage period and hatching rate when the eggs where stored at a temperature of 28ºC. There was a negative effect for neonate quail weight, independent of storage temperatures. The intestine length was influenced by storage period and 12 days of storage showed the shortest intestine length. Lower scores of physical quality were observed in quails that hatched from eggs stored in ambient temperatures during 12 days. In this context, to improve hatching rates and physical quality of neonate quails the eggs should be stored up to nine days at a temperature of 14°C.

Influência do aquecimento artificial de ovos de matrizes pesadas sobre o rendimento de incubação / Influence of artificial heating on hatchability of broiler breeder eggs

O desenvolvimento embrionário nas aves tem início antes mesmo da postura. A variabilidade do estágio de desenvolvimento embrionário no momento da oviposição é conhecida e influencia a taxa de eclosão, uma vez que estágios muito avançados ou muito precoces são prejudiciais por tornarem os embriões mais sensíveis ao estresse do armazenamento. O aquecimento de ovos férteis no período entre a postura e o armazenamento vem sendo estudado como forma de reduzir os efeitos negativos do armazenamento sobre o rendimento de incubação por permitir que os embriões progridam até um estágio em que são mais aptos a suportar o estresse do armazenamento. Este experimento teve como objetivo avaliar os efeitos do aquecimento artificial de ovos de matrizes pesadas no período entre a coleta e o armazenamento sobre o rendimento de incubação e o peso do pinto ao nascimento. Foram utilizados 5.760 ovos de matrizes pesadas Cobb(r) com 57 semanas de idade. O delineamento experimental foi inteiramente ao acaso, constituído por quatro tratamentos definidos com base no tempo de aquecimento dos ovos (zero, três, seis e nove horas). O aquecimento foi feito em câmara de fumigação a 30°C, e os ovos foram armazenados por três dias. O aquecimento artificial no período entre a coleta e o armazenamento não influenciou a eclodibilidade, a mortalidade embrionária e o peso do pinto ao nascimento, tendo sido, nessas circunstâncias, uma prática injustificada...

In birds, embryonic development begins before laying. The embryonic development variability at the time of egg laying is known and influences hatching rate, since very early or advanced stages are detrimental for embryos because they become more sensitive to stress storage. The heating of fertile eggs in the period between posture and storage has been studied as a way to reduce the negative effects of storage on hatchability since it allows embryos to progress to a stage where they are more able to survive during storage. This experiment aimed to evaluate the effects of artificial heating of fertile broiler breeder eggs in the period between the collection and storage on hatchability and chick weight at birth. For this, 5760 eggs from Cobb(r) broiler breeders, 57 weeks old, were used. The experimental design was completely randomized. It consisted of four defined treatments based on the heating time of eggs (zero, three, six and nine hours). Heating was done in a fumigation chamber at 30°C, and eggs were stored for three days. The artificial heating in the period between collection and storage didn't affect hatchability, embryo mortality and chick weight at birth, being, in this case, an unjustified practice...

Double-yolked pheasant eggs provide an insight into the control of albumen secretion in bird eggs.

1. The possible role of the presence of the yolk in stimulating secretion of albumen was investigated. 2. Double-yolked and single-yolked pheasant (Phasianus colchinus) eggs were opened to determine the masses of the shell, albumen and yolk(s). 3. In double-yolked eggs, the two yolk masses were not significantly different. Albumen mass was increased above that expected from an egg with a single-yolk of comparable size but below that expected from an egg having a mass of the combined yolks. The mass of shell per unit area reflected the mass of the initial mass of the egg irrespective of the number of yolks. 4. The additional mass of albumen is unrelated to yolk or initial egg mass. It is postulated that in double-yolked eggs the oviduct is mechanically stimulated by the presence of both yolks, which empties the stores of water-soluble albumen proteins in the magnum wall. Such stores are insufficient to provide the same amount of protein for the two yolks.

The eggshell: strength, structure and function.

In making a journey through the literature of the last 50 years one can easily highlight a sequence of seminal works-but the route has not been direct and to avoid the many profitable diversions and detours that have enriched and deepened our collective understanding of the subject of eggshell structure and function is to do the subject a serious disservice. This is a route march of science enabled by advances in technology.

The effect of gaseous ozone treatment on egg components.

BACKGROUND: Because of the salmonella problem in poultry, disinfection technologies are necessary. Ozone is a strong oxidant used for the disinfection of surfaces, drinking water and foods. However, since ozone not only destroys bacteria but may also damage eggs, it is necessary to clarify the effects of ozone treatment on hatching egg components. In this study, doses of gaseous ozone ranging from 10 to 50 mL L(-1) were tested. The vitamin A and E contents and fatty acid composition of the egg yolk were determined. To detect possible damage to the DNA of the germ disc, single-cell gel electrophoresis was used. Moreover, free SH groups were measured in the egg white. The soluble cuticula proteins were analysed by polyacrylamide gel electrophoresis. RESULTS: The yolk was not significantly affected by ozone treatment. However, the DNA of the germ disc was attacked and a significant decrease in free SH groups in the egg white was recorded at 50 mL L(-1) ozone. Even at low ozone doses the soluble cuticula proteins were completely destroyed. CONCLUSION: Significant alterations of egg components were caused by 50 mL L(-1) ozone. At lower ozone doses the oxidative processes occurred mainly at the egg surface and are therefore probably harmless to the developing embryo.

Posture in ovo as a precursor of footedness in ostriches (Struthio camelus).

Two categories of behaviour involving lateralized posture were observed in semi-natural conditions in ostriches (Struthio camelus). Observing preferences for left or right foot, both in the forward foot posture (the foot standing in front at rest) and the starting foot used to initiate locomotion, a population-level right-foot preference was shown for the whole group and for each of the three age ranges considered (chick, young and adult). Ostriches are known to rely upon a lateralized behaviour during hatching (using their right foot to break the egg shell) suggesting the hypothesis that the precocious motor laterality observed at hatching might stand as a precursor of limb preference later in development, as already observed in other avian species.

An appraisal of nuclear organisation in interphase embryonic fibroblasts of chicken, turkey and duck.

Determining the nuclear 'addresses' of chromosome territories is a well-documented means of assaying for nuclear organisation in many cell types and species. Data in avian species are however limited at best, despite the pivotal role played by birds (particularly chickens) in agriculture, and as model organisms in developmental biology. That is, studies have hitherto focussed mostly on mammals (especially humans) and have demonstrated the importance of chromosome territory positioning in embryology, disease and evolution. Thus a detailed study of nuclear organisation in many species, many cell types and many developmental stages in birds is warranted, however, before this is achieved, 'baseline' needs to be established to determine precisely the relative locations of chromosome territories in at least 1 cell type of at least 1 bird. With this in mind we hybridised FISH probes from chicken chromosomes 1-28 to embryonic fibroblast nuclei, determining nuclear addresses using a newly developed plug-in to the image analysis package ImageJ. In our experience, evenly spaced representative BAC clones yielded more consistent results than hybridisation of chromosome paints. Results suggested that chromosome territory distribution best fitted a chromosome size-based (rather than gene density-based) pattern. Identical BAC clones were then hybridised to turkey and duck in a comparative genomic strategy. Observations were consistent with those seen in chicken (although, less well-defined in duck), providing preliminary evidence of conservation throughout evolution.

The guinea fowl spleen at embryonic and post-hatch periods.

The spleen of the guinea fowl was bean-shaped but without a dented hilus. It is supplied by three short arteries that came from the ventral surface, two on the cranial end and one at the caudal end of the organ. The whole organ had a thin but tough capsule covering the outer surface except at the point of entry of the blood vessels. By day 18 of incubation, the spleen had a thin but well-defined capsule and internal to this been complete network of sinusoids filled with erythrocytes, lymphocytes and granulocytes. By day 19, dark and light staining zones, which could be termed red and white pulps, had appeared. By day 20, the granulocytes with a lot of granules within their cytoplasm, had become the biggest-sized cells in the spleen. At day 21, arteries and veins were noticed clearly in the spleen and many lymphocytes, few granulocytes and reticular cells surrounded these. Red pulp with its sinusoids was now distinct. A giant cell containing three nuclei was seen within the red pulp. At day 1 post-hatch, the capsule was at its greatest thickness so far and muscle cells were seen at the inner most part of the capsule. Granulocytes that had been a constant feature suddenly disappeared. At day 5, the small lymphocytes had dominated the large and medium-sized ones. By 2 weeks, the red and white pulps were virtually equal in distribution but by 3 weeks, the red pulp was convincingly greater. By 7 weeks, plasma cells had appeared in the peripheral splenic cords. Monocytes were observed in the sinusoids. Two germinal centres were identified for the first time in week 13 post-hatch.

Effects of egg mass and percentage mass loss during incubation on hatchability of eggs of the rock partridge (Alectoris graeca).

1. The effects of initial egg mass (IEM) and percentage mass loss during incubation (%ML) on hatchability of rock partridge eggs were investigated. 2. Eggs at the extremes of IEM had lower fertility and embryonic mortality. 3. Eggs at the extremes of %ML also had low fertility and hatchability was disproportionately reduced in eggs that had lost less mass during incubation. 4. Chick mass was a function of both IEM and mass lost during incubation. 5. In these respects rock partridge eggs are similar to that of other domesticated species of poultry.

A practical approach to the post-mortem examination of eggs, embryos and chicks

The failure of eggs to hatch, or of young chicks to survive, is a frequent and important problem when birds are bred in captivity. Under such circumstances, the examination of eggs, embryos and 'neonates' can provide useful information. Investigative techniques that work well for poultry can be adapted to the study of samples from non-domestic birds. Meticulous dissection of specimens and cautious interpretation are essential (AU)

Ontogeny of the dendritic, and follicle-associated epithelial cells in the bursa of Fabricius of guinea fowl (Numida meleagris).

A panel of monoclonal antibodies was produced to study the mesenchymal stromal elements of the bursa of Fabricius in guinea hen. The intracellular antigens recognized by GIIF3 and NIC2 monoclonal antibodies are of 50 and 30 kD, respectively. The cells identified by these antibodies emerge in the mesenchyme around day 12 of incubation, and immigrate into the surface epithelium of the bursal folds, which precedes the follicle formation. The GIIF3 cells move up to the luminal surface of the follicle and differentiate to follicle-associated epithelial cells. The NIC2 cells remain in the medulla, produce and secrete large amount NIC2 positive substance, when the bursal function starts up. The presence of double positive (GIIF3 and NIC2) cells in the medulla around hatching, seems to indicate, that the two cells might have a common origin. The NIC2 positive product of the bursal secretory dendritic cells contributes to the microenvironment, and possibly necessary for the B cell clonal expansion and establisment of the immune repertoire in the guinea hen.

Efeitos da suplementação dietética com quelatos de zinco e de manganês na produção, qualidade de ovos e morfologia intestinal de galinhas poedeiras / Effects of chelated and inorganic zinc and manganese supplementation on egg production, egg quality and intestinal morphology for laying hens

Um experimento foi conduzido para estudar o efeito de fontes quelatadas de zinco e manganês em comparação à suplementação com óxido de zinco e sulfato de manganês em dietas para poedeiras. Uma dieta controle à base de milho-soja (17 porcento PB, 3,80 porcento Ca, 0,36 Pd, 50 mg Zn, 70 mg Mn) foi suplementada com 0 ou 40 ppm de Zn adicional, provindo do óxido de Zn ou quelato de Zn, e 0 ou 40 ppm de Mn adicional, provindo do sulfato de Mn ou quelato de Mn, em um arranjo fatorial de tratamentos 3x3. A unidade experimental foi representada por 8 aves alojadas em 4 gaiolas adjacentes. O experimento obedeceu um delineamento tipo blocos ao acaso, com 9 tratamentos e 8 repetições. Um total de 640 galinhas...

Cambios en el contenido de tocoferoles de la yema de huevo en función del tiempo y del tipo de almacenamiento / Changes in the content of tocopherols in yolk acoording to time and type of storage

En este estudio se ha determinado como cambia el contenido de vitamina E (a-tocoferol, b-tocoferol, c-tocoferol. d-tocoferol) y acetato de a-tocoferol de la yema de huevo durante su almacenamiento. Éste se realizó bajo dos formas distintas de conservación (temperatura ambiente a 18-23ºC y refrigeración a 4ºC). Los resultados obtenidos muestran que el contenido de acetato de a-tocoferol disminuye significativamente en ambos tipos de conservación (F = 7,33; P<= 0,001) durante el alamcenamiento. Sin embargo, el contenido de a, b+c y d-tocoferoles no cambia significativamente. Los niveles de a-tocoferol, b-tocoferol y acetato de a-tocoferol fueron significativamente mayores en las yemas de los huevos refrigerados que en las de los huevos almacenados a temperatura ambiente (F = 21,70 y P<=0,001; F =7,27 y P<=0,01; F =7,90 y P<=0,01, respectivamente). Por el contrario, el nivel de b+c-tocoferoles no presenta diferencias significativas en función del tipo de conservación. (AU)

O desenvolvimento do corpo vertebral em aves é modulado pela matriz extracelular / Vertebral body developmente

A distribuição dis colágenos tipos I e II foi estudada no desenvolvimento do corpo vertebral, ao nível dos membros superiores, de embriões de Gallus gallus domesticus, L no período de dois a 21 dias (estádio 14 a estádio 46 de Hamburger e Hamilton) de incubação e de animais pós-eclosão, utilizando o método avidina-biotina marcada com enzima peroxidase (método Lab)em espécimes fixados e inclídos em parafina. Inicialmente (estádios 17-22), as reações com os anticorpos anticolágeno tipo I e antifibronectina foram muito intensas na matriz extracelular do esclerotoma em migração, e fraca com anticorpo anticolágeno tipo II, a qual foi intensa na membrana basal do notocórdio e do tubo neural. Mais adiante (estádios 25-27) foram obtidas fortes reações com os anticorpos anticolágeno tipo I e antifibronectina bem como positividade muito intensa com o anticorpo anticolágeno tipo II. Pelo estádio 32, as reações com os anticorpos anticolágeno tipo I e antifibronectina diminuíram, excetuando-se no pericõndrio, onde o colágeno tipo II apresentou reação intensa, com o anticorpo específico, em áreas de condrificação. Ao final (estádios 40-46), foi observada positiviade muito intensa, para todos os anticorpos estudados, as áreas de hipertrofia dos condrócitos (começando pelo estádio 36). Nas trabéculas ósseas (começando polo estádio 41), a positividade restringiu-se aos anti-corpos anticolágeno tipo I e antibronectina. Este mesmo padrão foi observado nos espécimes pós-eclosão. Esses resultados sugerem um papel ativo para as macromeléculs da matriz extracelular nos processos de migração, condrogênese e osteogênese. As células notocordais e o epitélio do tubo neural induzem a migração das células mesenquimais, que sintetizamcolágeno tipo I e fibronectina durante os processos de migração e condogênese precose e colágeno tipo II na diferenciação ondrogênica. A particiapçaõ dos colágenos tipos I e II mais a fibronectina é essencial na etapa de condro-apoptose da osteogênese

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

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

25-hydroxycholecalciferol in poultry nutrition.

Vitamin D is a complex of secosteroids that must undergo metabolic alterations to reach optimal biological activity. The parent compounds 1) ergocalciferol (D2) and 2) cholecalciferol (D3) can be synthesized in the leaves of many plants or in the skin of most animals, respectively. Transport of vitamin D steroids after absorption is associated with vitamin D binding proteins (DBP). In general, the relative binding affinities of the vitamin D steroids are: 25-hydroxy vitamin D3 [25-(OH)D3] = 24,25-dihydroxy vitamin D3 [24,25-(OH)2D3] = 25,26-dihydroxy vitamin D3 [25,26-(OH)2D3] > 25-hydroxy vitamin D2 (25-(OH)D2) > 1,25-dihydroxy vitamin D3 [1,25-(OH)2D3] > vitamin D3. The DBP in poultry does not bind D2 forms effectively, and therefore poultry can not use this form of vitamin D adequately. The concentration of 25-(OH)D3 in blood seems to be well correlated with dietary vitamin D intake or exposure to ultraviolet light. The 1 alpha hydroxylase enzyme in the kidney is subject to negative feedback regulation and is critical for formation of the active metabolite 1,25-(OH)2D3. The intracellular vitamin D receptor (VDR) specifically binds 1,25-(OH)2D3 and is necessary for cellular action. Increased levels of two to three orders of magnitude are required for 25-(OH)D3 to compete with 1,25-(OH)2D3 for binding on VDR. Feeding studies with 25-(OH)D3 suggest it has nearly twice the activity of vitamin D3. Hatchability studies have shown that 25-(OH)D3 supports good fertility and hatchability, whereas hens fed only 1,25-(OH)2D3 did not have normal hatchability. Likewise, 1,25-(OH)2D3 seems to reach toxic levels at dietary concentrations only two to three times optimal dietary levels whereas feeding 25-(OH)D3 for extended periods at levels 8 to 10 times requirement seems to have no adverse effects. It seems that 25-(OH)D3 is the most active metabolite of vitamin D3, ultimately capable of supporting both cellular functions and embryonic development in chickens and turkeys when fed as the sole source of vitamin D3.

Factors affecting hatchability during commercial incubation of ostrich (Struthio camelus) eggs.

1. A batch of 320 ostrich eggs from 9 different farms in Zimbabwe were incubated in a single stage operation and the fate of each was recorded. 2. Hatchability was only 37.2% and the result of high rates of infertility and contamination (22.2% and 22.8% respectively); it varied between eggs from different farms. 3. Embryonic mortality was high at the start and end of incubation, a pattern similar to that of other domestic birds. 4. Mortality of late stage embryos was related to percentage water loss and mass specific water vapour conductance of the shell, with extremes of the ranges causing the highest mortality. 5. Microbial contamination of the eggs was a significant problem and varied in eggs from different farms indicating that more attention is needed in both breeder bird and nest management.