Double-yolked Eggs Research Articles

Triple-yolked eggs in domestic ducks: a rare occurrence

Multiple-yolked avian eggs, and especially triple-yolked (TY) eggs, are rare. Over two years, 48,224 duck eggs (Anas platyrhynchos domesticus) were individually candled and seven (0.0145%) TY eggs were identified in a commercial breeding and incubation environment. When compared with double-yolked eggs (Salamon and Kent, 2016) their mean weight, length, width and shape index did not differ, but their dimensions were greater than for single-yolked duck eggs. Yolk fertility in the TY eggs was low (33.33%), and this was attributed to smaller yolk size and early ovulation and/or follicle immaturity. By day 8 of incubation, fertile yolks were positioned next to the airspace. Egg 5 contained one fertile yolk, and the embryo developed to enter the airspace, was consuming all three yolks, but failed to hatch.

Modelling the egg components and laying patterns of broiler breeder hens

There is scant information about the reproductive process in broiler breeders, with which to develop a feeding strategy that will be economically optimal for these birds. This study aimed to model the egg production of a flock of broiler breeder hens, using non-isometric equations. The number of eggs produced by 60 broiler breeder hens aged 24–60 weeks was monitored, as was the weight of these eggs and the weights of the components, yolk, albumen and shell. Oviposition sequences and the number and length of pauses between sequences were analysed. Non-isometric functions were applied to predict the weight of the egg; yolk weight was predicted from the age of the hen, while albumen and shell weights were predicted from yolk weight; and egg weight was obtained by summing the component weights. The incidence of soft-shelled and double-yolk eggs was also determined. Yolk weight (YW, g) can be described as YW = 18.03 × (1 – e–0.015 × (t – 103.4)) × e(0.001 × t), where t is the age of the bird (days). The weights of albumen (AW) and shell (SW) were based on YW predictions as follows: AW = 14.38 × YW0.375 and SW = 0.358 × (YW + AW)0.687. The rate of double-yolk egg (DY) production is described by DY = 2.28 × e(0.209 × TFE), and the rate of soft-shelled egg (SS) production by SS = 1.126 + 0.148/(1 – 0.024 × TFE) – 0.056 × TFE, as a function of time from first egg (TFE). On the basis of the results obtained, the model developed here is an accurate reflection of the changes that occur in the number of eggs produced by broiler breeders, as well as in the egg itself and in its components over the entire laying period. This model can thus be used in predicting the nutrient requirements of individual broiler breeder hens, which, when combined with simulated data from a large number of individuals, will accurately describe the laying performance of a flock of broiler breeders.

Occurrence of twin embryos in the eastern bluebird

We report the first record of presumed twinning in eastern bluebird (Sialia sialis) and provide a review of previously reported twinning events in wild birds. A nest containing twin eastern bluebird nestlings was monitored in 2013 in central Pennsylvania and reported to the Cornell Lab of Ornithology’s NestWatch program, a national program where volunteers submit data on wild nesting birds. A presumed double-yolked egg of a free-living eastern bluebird pair hatched successfully, and twin nestlings lived for 11 days in a nest box shared by three siblings. Due to the rarity of twinning in wild birds, engaging the public to monitor large numbers of nests is the most likely approach to documenting twinning in wild populations, and citizen science provides the infrastructure for individuals to share observations.

The History of Twins, As A Criterion Of The Relative Powers of Nature And Nurture1,,2

The History of Twins, As A Criterion Of The Relative Powers of Nature And Nurture1,,2

ZnO Hollow Spheres with Double‐Yolk Egg Structure for High‐Performance Photocatalysts and Photodetectors

Inspired by opening soft drink cans, a one-pot method to prepare ZnO hollow spheres with double-yolk egg (DEH) architectures is developed. The bubble-assisted Ostwald ripening is proposed for the formation of these novel structures. Uniqueness of DEHs morphology led to greatly enhanced photocatalytic activity and photodetector performance. The newly developed synthetic concept and the obtained novel morphologies should pave the way towards the design and fabrication of other similar materials with enhanced properties for microelectronics, optoelectronics, and other applications.

Incubation and Fertility Research Group {WPSA Working Group 6 (Reproduction)} 2011 Meeting - Ede, the Netherlands, 30th-31st August 2011

The 2011 Incubation and Fertility Research Group {WPSA Working Group 6 (Reproduction)} conference took place on 30-31 August 2011 in Ede, The Netherlands. Speakers from all over the world took part and considered all aspects of incubation and fertility in a variety of avian species. We are delighted to present abstracts from 27 of the presentations given at the meeting. The topics include: improving the fertility of cryopreserved poultry semen; sexing of day zero unincubated chicken eggs; hypoxia effects on embryonic development; the effects of thermal manipulation during early embryogenesis; antimicrobial activity of egg white; egg size variation in double yolked duck eggs; treatments to preserve hatchability during storage; and the question of how to engineer the heart of broiler chickens during incubation.

Analysis of Fitness Predominance for Gaoyou Duck’s Double Yolk Egg

Analysis of Fitness Predominance for Gaoyou Duck’s Double Yolk Egg

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.

Multishell nanoparticles: Atomic‐Scale Characterization of Aluminum‐Based Multishell Nanoparticles Created by Solid‐State Synthesis (Small 16/2010)

Core/double-shell nanoparticles are produced by solid-state precipitation in an aluminum matrix and characterized by atom-probe tomography (APT). By choosing three solute elements (Yb, Sc, Li) with substantially disparate diffusivities and by judiciously selecting aging temperatures to precipitate each element sequentially, nanoparticles are formed with three chemically distinct, concentric Al3(Yb,Sc,Li) regions with diameters of ∼3, 7, and 27 nm, respectively. An even more complex structure can be created when two such particles coalesce. The cover image shows an APT reconstruction of such a coalesced nanoparticle, reminiscent of a double-yolk egg. This novel structure consists of i) two Yb-rich Al3(Li,Yb,Sc) cores (“yolks,” rich in red Yb atoms) with 4--5 nm diameter, ii) two Sc-rich Al3(Li,Sc,Yb) inner shells (blue) surrounding their respective cores and iii) one Li-rich Al3Li outer shell (orange) enfolding the previous regions and contained within an Al matrix (black). For clarity, only the minority Yb atoms are shown. For more information, please read the Communication “Atomic-Scale Characterization of Aluminum-Based Multishell Nanoparticles Created by Solid-State Synthesis” by D. N. Seidman and co-workers, beginning on page 1728.

Modelling egg production and nutrient responses in broiler breeder hens

SUMMARYThe model described simulates the response of a population of broiler breeders to a daily allowance of a feed of specified composition for up to 280 days from sexual maturity. The population is generated using normally distributed values for initial bodyweight, initial body lipid and protein weight, age at first egg, yolk weight constant and ‘aggressiveness’, the latter producing different feed intakes around the controlled mean. Age at sexual maturity for each bird is predicted from bodyweight and from information about rearing lighting programmes. Egg production, clutch patterns, yolk weights, egg component weights, double-yolked eggs, internal laying and soft-shelled eggs are predicted. Body protein growth, including feathers, is assumed to cease at sexual maturity, thus bodyweight changes after maturity are due entirely to accumulation or utilization of lipid.Energy transactions are expressed in units of effective energy. Protein required for egg production is calculated from the composition of the next egg to be laid and an assumed fixed chemical composition. Assumptions for protein partition rules are that maintenance has highest priority, yolk protein deposition second and albumen protein third. Provided that sufficient energy and nutrients are available, yolk protein deposition is assumed to occur continuously to meet the predicted growth rate, unless inter-clutch intervals exceed 2 days (user defined), when yolk growth ceases. Energy and nutrients (amino acids) for albumen production accumulate in a pool which has some controlling influence over ovulation. If the energy and nutrients in the albumen pool will support the predicted development of the next egg then ovulation will occur, otherwise ovulation is delayed until sufficient energy and nutrients are available. All events are timed within a 24 h day assuming that feeding is at one time in the morning.The desired feed intake is calculated each day according to the supply of the first limiting energy or nutrient (invariably an amino acid) in relation to potential need. Actual feed intake is either the desired intake or the feed allowance, whichever is the lower. The additional energy required for thermogenesis is taken into account, but not the constraining effects of high temperature or the bulkiness of the food as a constraint to voluntary food intake.Some shortcomings of the current model are discussed, these being areas suitable for further research on broiler breeder nutrition.

Polymorphism in NPY and IGF-I genes associate with reproductive traits in Wenchang chicken.

Alleles of physiological candidate genes for reproductive traits, insulin-like growth factor-I (IGF-I) and neuropeptide Y (NPY) were assessed to determine the association with total egg production (NE), average days of continual egg-laying (ADCE) and number of double-yolked eggs (DYE) in Wenchang chicken (Chinese indigenous breed). PCR-RFLP method was used for genotypes identification. The frequency of restriction enzyme A/a alleles in the population was 0.46 (A) and 0.54 (a) for NPY. The frequency of restriction enzyme B/b alleles in the population was 0.53 (B) and 0.47 (b) for IGF-I, respectively. Four significant associations were found (P < 0.05): between NPY and NE (300 d) and between IGF-I polymorphism and NE (300 d), NE (400 d) and ADCE. Two significant effects were observed: for NPY and NE (300 d) and for IGF-I and NE (300 d). The current research supports the effects of NPY and IGF-I genes on reproductive traits of chickens. Key words: Chicken, NPY, IGF-I, reproduction, SNP.

Association of polymorphisms in the intron 1 of duck prolactin with egg performance

Gaoyou duck (Chinese indigenous breed) is famous for double-yolked egg. In the present study, SNP of prolactin (PRL) gene intron 1 of Gaoyou duck was detected by PCR-RFLP and DNA sequencing. The results indicated that there were 2 Dra I recognition sites in intron 1 of the PRL gene, but only 1 was of polymorphism. A T/C mutation at the position of the 1326 bp of the PRL gene was found by DNA sequencing, and resulted in 3 genotypes AA, AB, and BB. The frequencies of genotype BB and allele B were the highest. The association analysis between the polymorphism PRL gene intron 1 and egg performance was carried out. The least square analysis showed that the BB ducks had significant egg weight at the age of 30 weeks than AB ducks (P < 0.01), the double-yolk percentage of the AB ducks was much higher than that of BB ducks (P < 0.05) in double-yolk ducks, but there was not significant difference in egg number, longest clutch days, and the body weight at first egg among the three genotypes.

Effects of Nutrient Density and Age at Photostimulation on Carcass Traits and Reproductive Efficiency in Fast- and Slow-Feathering Turkey Hens

This study was conducted to compare BW gain, carcass composition, and reproductive fitness in fast- and slow-feathering turkey females between 29 and 56 wk of age. A total of 452 Hybrid standard fast-feathering (FF) and experimental slow-feathering (SF) hens (226/group) were fed either a control or a high-energy, high-protein diet. Birds were photostimulated at 29 or 31 wk. Data on BW and carcass characteristics (keel and shank, keel, breast muscle, fatpad, liver, ovary, and oviduct weight) and egg production were assessed. At photostimulation, FF birds had an increased shank length (2.6%) compared with SF birds. After photostimulation, FF birds were heavier than SF birds by 7.8%. Fast-feathering hens had greater ovary weight (49%), oviduct weight (52%), keel length (2.8%), and had one more large yellow follicle at the end of lay. The number of large yellow follicles was greater in birds photostimulated at 31 wk (8.3) compared with birds photostimulated 2 wk earlier (7.8). Absolute ovary weight and oviduct weight were increased by 21 and 18%, respectively, in birds photostimulated at 31 wk compared with 29 wk. These effects of delayed photo-stimulation were greater in SF birds. Ultimately, FF hens had a greater total hen-housed egg production (55 vs. 33%), peak egg production (76 vs. 68%), and laying sequence length (5.7 vs. 3.3 d). Although delaying photostimulation did not affect total egg production, it did reduce the number of double-yolked eggs. Nutrient density had minimal effects on production in this trial. These data indicate that despite having similar BW, fleshing, and conformation traits to FF birds, the SF strain had inferior reproductive efficiency traits. This problem will need to be remedied before an SF turkey strain can become commercially viable.

Simulated natural lighting and constant 14-hour photoperiods for broiler breeders during the rearing period, and interactions of lighting with body weight

Spring-hatched broiler breeders housed in non-lightproof facilities are frequently maintained on long daylengths to prevent precocity, but controlled-feeding and delayed dissipation of photorefractoriness retard sexual maturation. Trials were conducted to determine the appropriate growth for birds maintained on 14-h photoperiods, and to compare responses with naturally increasing and decreasing daylengths. Birds maintained on 14-h photoperiods matured about 5 d earlier and produced 2 more eggs to 60 weeks for each 10-d advance in age at 2.1 kg. However, despite requiring 0.2 kg less feed to reach 2.1 kg, accelerating growth resulted in 0.5 kg more feed being consumed to sexual maturity. The accelerated-growth birds produced more eggs that were too small for hatching and more double-yolked eggs during the early weeks of production. The data suggest that profitability is maximised when constant-14-h birds reach 2.1 kg at about 18-19 weeks. There were no significant differences in maturity between conventionally-grown birds given increasing or decreasing daylengths or those held on 14-h photoperiods, though there was a tendency for the constant 14-h birds to have later maturity, to produce 6-7 fewer eggs to 60 weeks, and to consume more feed per egg, resulting in a lower economic margin than naturally lighted birds. The wisdom of rearing Springhatched broiler breeders on long photoperiods to avoid precocity is therefore questionable. Birds allowed faster growth, generally matured about three weeks earlier than conventionally-grown birds, but matured five weeks earlier when given an increasing lighting regimen that started from 10 h rather than 11 h.

Extent of variation within a laying flock: attainment of sexual maturity, double-yolked and soft-shelled eggs, sequence lengths and consistency of lay

1. An experiment was conducted to determine the amount of variation that exists within a population of laying hens in age at first egg, the number of birds that did not come into lay, the prevalence of soft-shelled and double-yolked eggs, sequence characteristics and consistency of lay. 2. Oviducal problems accounted for most of the poor laying performance. About a third of the flock produced double-yolked or soft-shelled eggs at the onset of lay, the proportion being influenced by the age at photostimulation. In some instances these aberrations interrupted sequences. Differences in laying performance were particularly evident in mean sequence length, mean prime sequence length and mean pause length both within and between individuals. Furthermore, sequence length did not always decline in a regular fashion with advancing age. 3. The information gathered here has been used to develop a mechanistic, stochastic population model for laying hens.

Associations of Gonadotropin-Releasing Hormone Receptor (GnRHR) and Neuropeptide Y (NPY) Genes' Polymorphisms with Egg-Laying Traits in Wenchang Chicken

Single nucleotide polymorphisms (SNP) of chicken gonadotropin-releasing hormone receptor (GnRHR) and neuropeptide Y (NPY) were selected to identify the genotypes of Wenchang (Chinese indigenous breed) chicken with restricton fragment length polymorphisms. The associations of the SNPs with the total egg production (NE), average days of continual laying (ADCL), and number of double-yolked eggs (DYE) traits were analyzed. The frequency of restriction enzyme A/a alleles in the population was for GnRHR 0.69 ( Bpul102 I A) and 0.31 ( Bpul102 I a) and for NPY 0.46 ( Dra I B) and 0.54 ( Dra I b). Trait data from a total of 120 hens, which were purebred introduced from Hainan Province, China from one generation were recorded. Two significant effects of genes' marker were found: for GnRHR and number of eggs (dominant; t=2.67, df= 116) and NPY and number of eggs (additive; t= 1.97, df= 116). The current research supports the effects of GnRHR and NPY genes on egg-laying traits of chickens.

A mechanistic, stochastic, population model of egg production

1. A mechanistic, stochastic egg production model is presented. Mean age at first egg may be predicted from the lighting programme applied during rearing, using the Bristol–Reading model (Lewis et al., 2002). 2. Rate of ovulation is determined by an amended version of the mathematical model of the ovulatory cycle, originally proposed by Etches and Schoch (1984). 3. Oviposition times are estimated from ovulation times. 4. Yolk, albumen and shell weights are calculated using allometric functions. 5. The model predicts egg production of a theoretical flock of laying hens for a full laying year, including random occurrences of double-yolked and soft-shelled eggs and internal ovulations.

A comparison of the effects of feeding treatments and lighting on age at first egg and subsequent laying performance and carcase composition of broiler breeder hens

1. The effects of the growth curve from 15 to 20 weeks, age at photostimulation and pattern of photostimulus on sexual maturity, egg production and egg weight were evaluated in two trials with broiler breeder females to 56 and 34 weeks of age (housed in litter pens and individually caged, respectively). Carcase composition and reproductive morphology of hens varying in laying efficiency were measured in the second trial. 2.1. Trial 1: Four growth curves were applied from 15 to 20 weeks to pullets housed in litter pens. Birds were transferred from 8- to 10-h photoperiods at 20 or 24 weeks of age, followed by weekly increments of one hour to reach a 16-h final photoperiod. 2.2. Lower-than-recommended body weights at 20 weeks significantly delayed sexual maturity, reduced peak rate of lay, total eggs and mean egg weight. However, double-yolked egg production was lower, resulting in non-significant differences in settable egg numbers between body weight treatments. 2.3. Birds reared to the heaviest body weight exhibited a significantly advanced sexual maturity, but total egg numbers, peak rate of lay and mean egg weight were not significantly affected. However, the laying of more double-yolked eggs resulted in a decrease in the number of settable eggs. Delaying photostimulation to 24 weeks significantly retarded sexual maturity, reduced total and settable egg numbers, and increased mean egg weight. A tendency for fewer double-yolked eggs was observed. 3.1. Trial 2: At 19 weeks, birds were selected from the 4 body weight categories in Trial 1 and moved to individual cages in 8 rooms. Five lighting programmes were applied. 3.2. The pattern of photostimulation applied did not affect any of the production traits measured. 3.3. At 34 weeks, 24 birds were selected for the analysis of reproductive morphology, presence of internal or multiple ovulations, and carcase composition. Eight hens showing an early age at first egg and regular egg production records, 8 birds showing erratic laying performance and 8 non-layers were killed for this purpose. There were no differences in carcase composition or reproductive morphology between these groups. No internal ovulations or double or multiple ovarian hierarchies were observed. 4. The results presented confirm that broiler breeders do not require a lighting stimulus in order to initiate ovarian activity and that, where no lighting stimulus is given, body weight or feeding level plays a critical role in stimulating the birds to attain sexual maturity. However, when a lighting stimulus is given, factors such as body weight and body composition become relatively less important in regulating the age at sexual maturity.

Effects of body weight at, and lighting regimen and growth curve to, 20 weeks on laying performance in broiler breeders

1. A total of 4000 Ross broiler breeders were reared to a 20-week target body weight of 1·55, 2·16 (standard), 2·50 or 2·84 kg, using either a convex or concave growth curve. Each treatment group was either exposed to a conventional broiler breeder lighting regimen, with a series of weekly one-hour increments in photoperiod from 8 h at 19 weeks to a 16-h maximum, or maintained from 4 d on a 17-h photoperiod. 2. Each 100 g increment in body weight at 20 weeks was associated with a significant increase of 0·55 kg in cumulative food intake, and a 1·5-d advance in sexual maturity. However, leaner body weights at 20 weeks resulted in smaller body weight gains between 20 and 60 weeks (− 2·4 g/d/kg body weight at 20 weeks), and an increased production of double-yolked eggs. Neither egg production nor mean egg weight was affected by 20-week body weight. 3. Birds fed to produce more rapid early growth had higher feed intakes to 20 weeks, but reached sexual maturity 7 d later than birds permitted accelerated growth from 15 weeks. Growth curve did not influence body weight gain in lay, egg production or mean egg weight. 4. Birds maintained on 17-h photoperiods reached sexual maturity 27 d later, produced 7 fewer eggs to 60 weeks, and had a mean egg weight 1·2 g heavier than birds photostimulated at 19 weeks. Lighting treatment did not affect food intake to 20 weeks, the proportion of double-yolked eggs or body weight gain between 20 and 60 weeks. 5. Birds fed to have a faster growth early in the rearing phase and maintained on 17-h photoperiods produced 11 fewer eggs than those fed to have accelerated growth at the end of the rearing phase, yet there was only one egg difference between the growth-curve groups for the conventionally lighted birds, which was not significant. 6. The earlier sexual maturity of the conventionally lighted birds compared with those maintained on 17-h photoperiods either indicates that broiler breeders require an increment in photoperiod to stimulate rapid gonadal development or that broiler breeders exhibit juvenile photorefractoriness that takes longer to be dissipated when birds are not given a period of short days. 7. The findings suggest that a nutritional stimulus late in rearing is only necessary for satisfactory egg production if birds have not received a concurrent increment in photoperiod.

Defective eggs and their relationship to egg yield, egg and body weight in hens of five original laying lines

We investigated 3 985 individually housed hens of five original laying lines of two breeds RIR and BPR. The proportion of abnormal eggs out of the eggs laid before the age of 240 days ranged between 7.0% and 9.7%, in dependence on the line. The average number of cracked eggs ranged between 2.5% and 4.4%, double-yolk eggs between 2.2% and 3.0% and shell-less eggs between 2.0% and 2.7%. The correlation between the number of eggs laid at the beginning of the laying period and during the period of observation, and the frequency of double-yolk eggs was positive (r&lt;sub&gt;P &lt;/sub&gt;= 0.00 to r&lt;sub&gt;P &lt;/sub&gt;= 0.21) and mostly statistically highly significant (P &amp;lt; 0.01). On the other hand, statistically highly significant negative correlations (P &amp;lt; 0.01) were found between the number of eggs laid during the period of observation and the frequency of cracked eggs, where the correlations in the individual lines ranged between r&lt;sub&gt;P &lt;/sub&gt;= &amp;ndash;0.04 and r&lt;sub&gt;P &lt;/sub&gt;= &amp;ndash;0.23. Positive correlations, mostly statistically highly significant (P &amp;lt; 0.01), were found between the number of eggs laid during the period of observation and the frequency of shell-less eggs (r&lt;sub&gt;P &lt;/sub&gt;= 0.00 to r&lt;sub&gt;P &lt;/sub&gt;= 0.15). With the increasing weight of eggs the frequency of abnormal eggs also increased, in particular of double-yolk eggs (r&lt;sub&gt;P &lt;/sub&gt;= 0.08 to r&lt;sub&gt;p&lt;/sub&gt;= 0.32), for the most part statistically highly significantly (P &amp;lt; 0.01). The correlations between the individual types of abnormal eggs were positive. Statistically highly significant correlations (P &amp;lt; 0.01) were discovered between the frequency of double-yolk eggs and cracked eggs (r&lt;sub&gt;P &lt;/sub&gt;= &amp;ndash;0.02 to r&lt;sub&gt;p&lt;/sub&gt;= 0.22) on the one hand and, between double-yolk eggs and shell-less eggs (r&lt;sub&gt;P &lt;/sub&gt;= 0.16 to r&lt;sub&gt;P &lt;/sub&gt;= 0.24) on the other. &amp;nbsp;