Egg storage and the embryo

The effect of methionine and folic acid administered in ovo on the blood biochemical parameters of chickens (Gallus gallus domesticus)

Methionine is one of the most frequently supplemented amino acids in raising of poultry. However, an overdose of methionine can cause hyperhomocysteinemia. Folic acid, taking part in the process of homocysteine remethylation, is a factor affecting the reduction of the concentration of this amino acid. The study was carried out in 2 stages. The experiment of step I was to investigate the effect of methionine and/or folic acid administration in ovo in the early stage of embryogenesis (E4), and the experiment of the second stage - in the late stage of embryogenesis (E17) on the following biochemical parameters of chicken blood: glucose concentration in whole blood and concentration of homocysteine and uric acid in plasma of domestic chickens (Gallus gallus domesticus). Our results confirm that methionine supplementation may increase the concentration of uric acid and homocysteine. Moreover, we demonstrated that folic acid administered during embryogenesis decreased homocysteine concentration, also in groups simultaneously supplemented with methionine, especially in the initial stage of postnatal life of the bird.

Breeder age and hatching egg storage duration: effects on post-hatch performance of FUNAAB- α broiler chickens

This trial was designed to evaluate the influence of hatching egg storage length and broiler breeder hens' age on post-hatch growth performance and physiological responses of FUNAAB-α chickens. Five hundred fertile eggs from each of 60 and 32-wk-old FUNAAB-α breeder hens were collected and assigned to five storage durations (0, 3, 7, 11, and 15 d). The hatching eggs were incubated using the conventional protocol. Data were collected on the growth performance and physiological responses. A 2 × 5 factorial design was used for the experiment. The results revealed that there was a decline in the final body weight in chickens from eggs of 15 and 11 d storage compared to the chickens from 7, 3, and 0 egg storage days. Chickens of 32-week-old breeder hens had higher (P < 0.05) mean corpuscular volume, white blood cell, heterophil, and pack cell volume values compared to 60-week-old breeder hens. Hatchlings from 60-week-old breeders had a higher liver percentage (3.0% yolk-free body weight [YFBW]) than those from 32-week-old breeders (2.8% YFBW). It was concluded that an extended storage duration of 15 d adversely affected the carcass traits and growth performance of chickens from egg storage above seven days.

Embryonic methionine triggers post-natal developmental programming in Japanese quail

Embryonic development is one of the most sensitive and critical stages when maternal effects may influence the offspring's phenotype. In birds and other oviparous species, embryonic development is confined to the eggs, therefore females must deposit resources into the eggs to prepare the offspring for the prevailing post-natal conditions. However, the mechanisms of such phenotypic adjustments remain poorly understood. We simulated a maternal nutritional transfer by injecting 1 mg of L-methionine solution into Japanese quail eggs before the onset of incubation. The increase in early methionine concentration in eggs activated the insulin/insulin-like signalling and mechanistic target of rapamycin (IIS/mTOR) signalling pathways and affected post-natal developmental trajectories. Chicks from methionine-supplemented eggs had higher expression of liver IGF1 and mTOR genes at hatching but were similar in size, and the phenotypic effects of increased growth became apparent only a week later and remained up to three weeks. Circulating levels of insulin-like growth factor-1 (IGF-1) and expression of ribosomal protein serine 6 kinase 1 (RPS6K1), the mTOR downstream effector, were elevated only three weeks after hatching. These results show that specific nutritional cues may have phenotypic programming effects by sequentially activating specific nutrient-sensing pathways and achieving transgenerational phenotypic plasticity.

Impact of broiler breeder hens' age and egg storage on egg quality, embryonic development, and hatching traits of FUNAAB-alpha chickens

This study aimed to determine the impact of the age of breeder hens and egg storage on egg quality, embryonic development, hatching events and chick quality in FUNAAB-alpha chickens. The study involved the use of 500 hatching eggs each collected from 32-wk and 60-wk-old of FUNAAB-alpha broiler breeder hens at the Animal Breeding and Genetic Unit of the Federal University of Agriculture, Abeokuta, Nigeria and subjected to 5 storage periods (0, 3, 7, 11, and 15 d). The quality traits of the eggs were recorded and incubated using the conventional protocol. Data were collected on the internal and external egg characteristics, embryonic development, hatching events, and chick quality. The data collected were laid out in 2 by 5 factorial design. The results showed that eggs from 32-wk-old breeder hens had higher albumen height and Haugh unit (HU) value than those from 60-wk-old breeders. The albumen height and HU decreased progressively with storage length in the 2 age groups. Extended storage duration linearly increased (P < 0.01) egg weight loss and decreased (P < 0.01) yolk height. The eggs from both breeder ages had increasing blastodermal diameters at oviposition up until d 11 of storage but decreased on d 15 of storage in eggs from 32 wk breeders. Eggs of 32-wk-old FUNAAB-alpha breeder hens had larger diameters at oviposition compared with 60-wk-old breeders. The chicks from 60-wk breeder had late internal pipping (469.06 h), early external pipping (474.46 h) and a shorter time lag between both pips (9.00 h) compared to chicks from 32 wk breeder. The highest fertility was recorded in eggs stored for 3 d (80.7% and 79.6%), while the lowest fertility was in eggs stored for 15 d (53.4% and 47.7%) in both 32-wk and 60-wk-old breeders, respectively. Chicks from young breeder hens stored for 3 d had better quality scores (100%) compared to 0, 7, 11, and 15-d storage duration and in 60-wk-old breeders across all storage duration. It was concluded that both egg storage duration and age of breeder affected egg quality, hatching events and hatchling quality of FUNAAB-alpha chickens and the interaction effects of both factors was recorded for some of these traits. However, extended storage beyond 7 d had a larger negative impact on egg quality and hatchability of eggs from an old breeder (60 wk) than on eggs of a young breeder (32 wk).

Rapid egg cooling rate after oviposition influences the embryonic development, hatchability, and hatch time of young and old broiler hatching eggs

This study investigated the effect of the egg cooling profile after oviposition on blastoderm development, embryonic mortality, hatchability, and hatch time of broiler hatching eggs from young and old breeder flocks. Hatching eggs were obtained from commercial Ross 308 broiler breeders at 28 wk (young) and 64 wk (old) of age. A total of 3,150 eggs laid within a 15-min period were collected and randomly assigned to 2 temperature-controlled chambers in both flocks. The eggshell temperature (EST) was cooled to 24°C either within 6 h (control) or 45 min (rapid). After the EST reached 16°C in the chambers in all groups, eggs were transported to the commercial hatchery. Eggs were stored for 6 d at 16°C and 75% relative humidity. The development of the blastoderm in sampled eggs (25 embryos in each batch) was determined immediately after egg collection and before transport to the hatchery (after cooling) on a farm in each flock. At each flock age, there were 5 replicate trays of 150 eggs per egg cooling treatment set in a single commercial incubator. The results showed that the embryonic developmental stage was retarded by rapid cooling and by the younger flock. A flock age × cooling rate interaction was observed for fertile hatchability and early and late embryonic mortality (P < 0.001). In the young flock eggs, the fertile hatchability was significantly lower in the rapid than in the control cooling treatment (88.7 vs. 92.8%) due to higher early and late embryonic mortality, whereas rapid cooling reduced early embryonic mortality (P < 0.01) and numerically increased the fertile hatchability (88.7 vs. 87.2%) in the old flock eggs. Hatch time was affected by the cooling treatment. The average hatch time was delayed by 3 h by rapid cooling (486.2 vs. 489.2 h) after oviposition compared with the control. This study showed that cooling the EST to 24°C within 45 min (rapid cooling) compared to 6 h (control) after laying retarded the blastoderm developmental stage and hatch time of eggs from both young and old broiler breeder flocks. This was apparently detrimental for the young flock as indicated by the higher early and late embryonic mortality but beneficial for the old flock due to the lower early embryonic mortality. The differences in hatchability between young and old flock eggs resulting from a rapid cooling rate might depend on the differences in embryonic development at oviposition.

Impact of storage duration and short periods of incubation during egg storage on embryonic development and hatching traits of hybrid chicken strain

The study assessed chicken egg storage duration and short periods of incubation during egg storage (SPIDES) on embryo development. Eggs samples from 310 eggs from 72-week-old hybrid layer breeder flocks were divided and stored at 16 °C and 75% RH for 1, 4, 7, 10, 14, 17, and 21 days (D). Some eggs were also divided between 14D and 21D alone and stored. One subgroup received heat application for 6 h during storage resulting in 0-h × 14D (control); 0-h × 21D (control); 6-h × 14D (SPIDES) and 6-h × 21D (SPIDES). Storage durations between 1D and 21D did not influence most egg quality parameters. The interaction of storage duration and SPIDES affected initial, final egg weights and egg weight loss. SPIDES eggs recorded heavier wet embryos than non-SPIDES eggs at embryonic days (ED) 4, ED7, ED11, and dry embryo weight at ED11. SPIDES resulted in longer embryos at ED4 and ED11. In 21D stored eggs hatchability was higher in SPIDES compared to non-SPIDES treatments (66.7 vs. 48.3%). The reverse effect of SPIDES occurred in 14D stored eggs. In conclusion, the study shows positive effect of SPIDES in longer stored eggs and could be due to a positive impact on embryo.

Effect of storage periods and conditions on embryonic mortalities and hatchability of artificially incubated ostrich eggs

1. Despite substantial research, the hatching failure of ostrich eggs remains a key concern for many commercial breeding farms.2. This source of reproductive failure needs to be addressed for ostrich farming to become more profitable.3. Information from 2212 eggs were obtained from the ostrich resource flock at the Oudtshoorn Research Farm (2013-2014). Egg data were divided on a daily basis into two groups: Group 1 included eggs stored from 1 to 13 d in cold storage (CS) at a controlled temperature of 17°C and a relative humidity (RH) of 90%. Group 2 was stored for the same time interval as Group 1, but in a cool room (CR) at ambient temperature to simulate the uncontrolled storage conditions prevalent on most breeding farms.4. Overall embryonic mortalities (OEM) were significantly higher for eggs stored for 1 d (0.38 ± 0.04) and for 8 d or more (between 0.31 ± 0.04 and 0.43 ± 0.04) compared to eggs stored for between 2 and 7 d (between 0.20 ± 0.03 and 0.26 ± 0.04).5. The moisture loss during storage (ML) for eggs stored for 13 d in CS during spring was on average slightly higher (1.28%) than that during summer (0.95%). In contrast, the ML of eggs stored in the CR for 13 d was significantly higher, at 1.59% in spring and 2.08% in summer.6. A general reduction in chick weight occurred for all the seasons (winter, spring and summer) as the number of storage days increased. Ostrich eggs should be stored for between 2 and 8 d under controlled storage conditions for improved hatchability.

Effects of age and eggshell thickness on the hatching results of stored broiler breeder eggs

The present study was conducted to determine the effects of breeder age and eggshell thickness on the hatching results of broiler breeders. A total of 3000 eggs were collected from three flocks at different ages, viz., 27 (young), 48 (middle-aged) and 65 (old) weeks. Eggs were individually weighed and eggshell thicknesses were determined using an ultrasound gauge. The eggs of each age group were classified as thin-, medium- or thick-shelled and stored for 7 days at 18°C and 60% relative humidity prior to incubation. Total egg weight loss during storage and incubation was higher in middle-aged (48 weeks old) flock eggs (11.46%) than in young (10.14%) and old (10.37%) flock eggs. Hatchability was significantly lower in the eggs of the old flock than of the other flocks. The highest hatchability (70.6%) was observed in the young flock. Eggs with thick shells better tolerated the detrimental effects of storage and more eggs remained fertile than amongst the medium- and thin-shelled eggs. The overall hatchability of the old flock was 38.0%, whilst hatchability of set eggs in the thick-shelled group of old flock eggs was 58.3%.

Effects of Long-Term Storage on Hatchability and Incubation Length of Game Farmed Quail Eggs

The long-term storage of eggs before incubation is a common practice in some alternative poultry systems but needs to be performed under conditions that preserve egg viability. The effects of the long-term storage of game farmed quail (Coturnix coturnix) eggs on weight loss during the storage and incubation periods, chick weight at hatch, hatchability, and incubation length were investigated. The eggs were arranged in six treatments submitted to 0-, 7-, 14-, 21-, 28-, and 35-day storage periods at 15.8 °C and 80% relative humidity. The storage length reduced the hatchability of eggs (p < 0.05) when the storage was extended to 35 days, decreasing by more than half compared to eggs stored up to 28 days. Egg weight loss during storage progressively increased with the storage length (p < 0.05). Chick weight at hatching was reduced in eggs stored for more than 14 days (p < 0.05), and relative chick weight decreased significantly in eggs stored for 35 days (p < 0.05). Incubation length progressively increased with the storage length (p < 0.05), achieving less hatching synchrony in eggs stored for a longer time (p < 0.05). In conclusion, game quail eggs store well with little deterioration up to 28 days at 15.8 °C and 80% relative humidity, allowing for extended storage when shipping long-shelf-life eggs or assembling batches large enough to fully set an incubator in farms with small breeding flocks.

Molecular mechanisms underlying adverse effects of dexamethasone and betamethasone in the developing cardiovascular system

Antenatal glucocorticoids accelerate fetal lung maturation and reduce mortality in preterm babies but can trigger adverse effects on the cardiovascular system. The mechanisms underlying off-target effects of the synthetic glucocorticoids mostly used, Dexamethasone (Dex) and Betamethasone (Beta), are unknown. We investigated effects of Dex and Beta on cardiovascular structure and function, and underlying molecular mechanism using the chicken embryo, an established model system to isolate effects of therapy on the developing heart and vasculature, independent of effects on the mother or placenta. Fertilized eggs were treated with Dex (0.1 mg kg-1 ), Beta (0.1 mg kg-1 ), or water vehicle (Control) on embryonic day 14 (E14, term = 21 days). At E19, biometry, cardiovascular function, stereological, and molecular analyses were determined. Both glucocorticoids promoted growth restriction, with Beta being more severe. Beta compared with Dex induced greater cardiac diastolic dysfunction and also impaired systolic function. While Dex triggered cardiomyocyte hypertrophy, Beta promoted a decrease in cardiomyocyte number. Molecular changes of Dex on the developing heart included oxidative stress, activation of p38, and cleaved caspase 3. In contrast, impaired GR downregulation, activation of p53, p16, and MKK3 coupled with CDK2 transcriptional repression linked the effects of Beta on cardiomyocyte senescence. Beta but not Dex impaired NO-dependent relaxation of peripheral resistance arteries. Beta diminished contractile responses to potassium and phenylephrine, but Dex enhanced peripheral constrictor reactivity to endothelin-1. We conclude that Dex and Beta have direct differential detrimental effects on the developing cardiovascular system.

The effect of storage periods and SPIDES on embryonic mortality, hatching characteristics, and quality of newly hatched chicks in broiler eggs

Egg storage duration can affect embryo mortality, hatching characteristics, hatching time, and post-hatch chick quality. In order to assess these effects, the impact of storage duration (5 days, 10 days, 15 days) and short incubation period during egg storage (SPIDES) investigated further 18, 900 eggs of broiler breeder (ROSS 308) in 3 × 2 factorial arrangement design. In the SPIDES treatment, the egg shell temperature was raised from its storage temperature (18 °C) and held at 100 °F for 3.5 h. Storage periods could significantly (P < 0.05) influence on embryo mortality (total, early, middle, and late), hatchability of both the total eggs and fertile eggs. The SPIDES treatment had a significant (P < 0.05) impact on a lower embryonic death rate and improved egg hatchability. Eggs stored for 5 days and eggs treated with SPIDES significantly (P < 0.001) shorten hatching time, batch’s 90% hatching time (T 90% H), mean hatching time (MHT), maximal hatching period (MHP), and hatching window (HW). Chick quality was also determined, whereas storing eggs for 5 days and using the SPIDES treatment resulted in enhanced (P < 0.001) chick weight relative to egg weight (CW/EW), activity (AC), and chick quality score (CQS). The residual yolk sac weight (RYSW), unhealed navel (UHN %), and dirty feather (DF%) recorded the lowest (P < 0.001) values compared to long storage periods and control group. Finally, stored for 5 days treated by SPIDES positively affected the hatchability characteristics, the shortening hatching time, and the quality of chicks. Regarding the results, it was confirmed that using the SPIDES treatment to prevent the harmful effects of broiler eggs being stored for an extended period of time is a viable option.

Temperature-induced embryonic diapause in chickens is mediated by PKC-NF-κB-IRF1 signaling

BACKGROUND

Embryonic diapause (dormancy) is a state of temporary arrest of embryonic development that is triggered by unfavorable conditions and serves as an evolutionary strategy to ensure reproductive survival. Unlike maternally-controlled embryonic diapause in mammals, chicken embryonic diapause is critically dependent on the environmental temperature. However, the molecular control of diapause in avian species remains largely uncharacterized. In this study, we evaluated the dynamic transcriptomic and phosphoproteomic profiles of chicken embryos in pre-diapause, diapause, and reactivated states.

RESULTS

Our data demonstrated a characteristic gene expression pattern in effects on cell survival-associated and stress response signaling pathways. Unlike mammalian diapause, mTOR signaling is not responsible for chicken diapause. However, cold stress responsive genes, such as IRF1, were identified as key regulators of diapause. Further in vitro investigation showed that cold stress-induced transcription of IRF1 was dependent on the PKC-NF-κB signaling pathway, providing a mechanism for proliferation arrest during diapause. Consistently, in vivo overexpression of IRF1 in diapause embryos blocked reactivation after restoration of developmental temperatures.

CONCLUSIONS

We concluded that embryonic diapause in chicken is characterized by proliferation arrest, which is the same with other spices. However, chicken embryonic diapause is strictly correlated with the cold stress signal and mediated by PKC-NF-κB-IRF1 signaling, which distinguish chicken diapause from the mTOR based diapause in mammals.

Embryonic development of quail eggs (Coturnix coturnix japonica) in a homemade incubator

Knowledge of the embryonic development of species such as quail is important for our understanding of its production and reproduction. Quail provides a practical solution to the animal protein shortage problem in developing countries and is an excellent alternative to chicken (Shanaway, 1994). This study evaluated quail embryonic viability by comparing the main morphological changes that occur over the development in a homemade incubator with previous data; the incubator was built using easily accessible and low-cost materials, which allows small producers and communities to develop quail farms as an activity to increase income or even produce a source of animal protein for the community in the Brazilian Amazon region. The homemade incubator measured 40 cm × 42 cm × 32 cm and was constructed with wooden boards, a digital thermostat, and an incandescent lamp. A total of 24 fertile eggs were incubated at a temperature of 37.5 °C and 60% relative humidity; age "0" was set at the start of incubation. Two eggs were opened on each day of development, starting from day 5 to day 16 of incubation. After gently opening the eggs, the embryos were removed, separated from the placenta and amniotic fluid, washed with running water, and weighed on a digital scale (SHIMADZU AUY 220 brand and UNI BLOC model). Crown-rump length and other measurements were performed with a digital caliper and the morphological structures were observed using a stereomicroscope (NOVA brand and NOVA ZTX-E model). All eggs opened contained live embryos, indicating that the homemade incubator temperature, relative humidity, and manual turning were adequate to maintain the quail's viability. The morphometric data of the embryos at different developmental time points were similar to those described in the literature. Embryos weighed 0.0069 g at day 5 and 4.7863 g at day 16, and the crown-rump length (CRL) means were 0.368 cm and 3.657 cm, respectively. Weight and CRL increased by 0.434 g and 2.593 cm per day of incubation, respectively. In conclusion, after 16 days of incubation in a homemade incubator, the embryos presented all phases of the development cycle, with appropriate development of weight and height based on the days of incubation without anomaly or external interference. These findings demonstrate that the homemade incubator does not alter the embryonic development of quail embryos in the Brazilian Amazon region.

Storage temperature dictates the ability of chicken embryos to successfully resume development by regulating expression of blastulation and gastrulation genes

The avian embryo has a remarkable ability that allows it to suspend its development during blastulation for a long time at low temperatures, and to resume normal development when incubated. This ability is used by poultry hatcheries to store eggs prior to incubation. We have previously found that this ability correlates with the temperature during storage; embryos recover much better following prolonged storage at 12°C rather than at 18°C. However, the molecular and cellular mechanisms underlying these differences are poorly understood. To successfully resume development following storage, the embryo has to shift from the blastulation phase to gastrulation. Several genes are known to partake in the blastulation-to-gastrulation transition under normal conditions, such as the pluripotency-related genes Inhibitor of DNA Binding 2 (ID2) and NANOG that are expressed during blastulation, and the gastrulation-regulating genes NODAL and Brachyury (TBXT). However, their expression and activity following storage is unknown. To elucidate the molecular mechanisms that initiate the ability to successfully transit from blastulation to gastrulation following storage, embryos were stored for 28 days at 12°C or 18°C, and were assessed either prior to incubation, 12, or 18 h of incubation at 37.8°C. Immediately following storage at 18°C group showed remarkable impaired morphology compared to the blastoderm of the 12°C group and of non-stored control embryos. Concurrently with these, expression of ID2 and NANOG was maintained following storage at 12°C similar to the control group, but was significantly reduced upon storage at 18°C. Nevertheless, when the 18°C-stored embryos were incubated, the morphology and the reduced genes were reverted to resemble those of the 12°C group. At variance, key gastrulation genes, NODAL and its downstream effector Brachyury (TBXT), which were similarly expressed in the control and the 12°C group, were not restored in the 18°C embryos following incubation. Notably, ectopic administration of Activin rescued NODAL and TBXT expression in the 18°C group, indicating that these embryos maintain the potential to initiate. Collectively, this study suggests a temperature-dependent mechanisms that direct the transition from blastulation to gastrulation. These mechanisms promote a successful developmental resumption following prolonged storage at low temperatures.

The effects of hen's age and egg storage duration on selected growth parameters of turkey embryos

The aim of this study was to determine the effects of hen's age (A) and egg storage duration (T) on selected growth parameters of turkey embryos. At 32, 38, 46, and 51 wk of hen's age, 1,512 eggs laid on one or 2 consecutive days were collected randomly and marked. At each sampling date, the eggs were randomly divided into 4 groups and were stored for various periods of time, that is, 7, 10, 13, and 17 d. All eggs were stored at a temperature of 15°C and relative air humidity of 76%. On d 9, 15, 21, and 24 of incubation, 5 eggs containing live embryos were randomly selected from each group for analysis of the following parameters: relative body weight (RBW) of embryos, relative weight of the yolk sac (RWY), relative weight of unused albumen (RWA). The effects of hen's age and egg storage duration on the RBW of embryos were observed on d 15, 21, and 24 of incubation (P < 0.05). The effects of hen's age and egg storage duration on RWY were noted on all analyzed days of incubation (P < 0.05). Embryos in eggs laid by younger hens (aged 32 and 38 wk) and stored for a shorter period were characterized by a faster rate of albumen utilization than embryos in eggs laid by older hens (aged 46 and 51 wk). The largest amount of unused albumen was found in eggs laid by hens in wk 51 of the laying season (P < 0.05), and stored for 17 d (P < 0.05). In conclusion, numerous interactions (AxT) between selected growth parameters of turkey embryos indicate that the quality of hatching eggs changes with hen's age, affecting their suitability for long-term storage under standard conditions. Therefore, eggs laid by younger breeders should not be stored for longer periods due to undesirable changes in RWY and RWA.

How Egg Storage Duration Prior to Incubation Impairs Egg Quality and Chicken Embryonic Development: Contribution of Imaging Technologies

Storing fertilised eggs prior to incubation is a frequent practice in commercial hatcheries to coordinate activities and synchronise hatchings. However, the conditions used to store eggs can have major impacts on egg quality and the subsequent viability of chicken embryos. While storage temperatures of 16-18°C are classically used in hatcheries, the duration of storage varies from three to more than 10 days. We explored the effect of storage duration (zero, three or 10 days; D0, D3 and D10, respectively) at 16°C, 80% relative humidity (RH) on egg quality (Broiler, Ross 308), using computed tomography (CT) and classical measurements (egg weight, eggshell strength, egg white pH, Haugh units, yolk index and colour). The results revealed that a storage duration of up to 10 days negatively affected some egg quality traits (yolk index and volume, air chamber volume and egg white pH). Eggs stored for three or 10 days were further incubated for 11, 13 or 15 days (37.8°C, 55% RH). Eggs were analysed by magnetic resonance imaging (MRI) and CT to assess the development of the embryo and internal egg changes occurring during incubation. First, data showed that the fertility and sex ratio of eggs were not affected by storage duration. However, the mortality of viable eggs was increased in the D10 group compared to the D3 group. Results of non-invasive imaging technologies revealed that the storage of eggs for 10 days impaired embryo growth as early as 11 days of incubation (decrease in brain and embryo volumes). Collectively, these data provide new evidence that the duration of egg storage negatively affects embryonic growth. They further corroborate that this parameter is likely to be crucial to synchronising embryonic stages and maybe reducing the hatching window, hence limiting the time spent by newborn chicks in hatchers. In addition, our results highlight that CT and MRI imaging technologies are useful non-invasive tools to evaluate egg quality prior to incubation and the impact of storage (or incubation) practices on developmental growth of the embryo.

The Role of Incubation Conditions on the Regulation of Muscle Development and Meat Quality in Poultry

Muscle is the most abundant edible tissue in table poultry, which serves as an important source of high protein for humans. Poultry myofiber originates in the early embryogenic stage, and the overall muscle fiber number is almost determined before hatching. Muscle development in the embryonic stage is critical to the posthatch muscle growth and final meat yield and quality. Incubation conditions including temperature, humidity, oxygen density, ventilation and lighting may substantially affect the number, shape and structure of the muscle fiber, which may produce long-lasting effect on the postnatal muscle growth and meat quality. Suboptimal incubation conditions can induce the onset of myopathies. Early exposure to suitable hatching conditions may modify the muscle histomorphology posthatch and the final muscle mass of the birds by regulating embryonic hormone levels and benefit the muscle cell activity. The elucidation of the muscle development at the embryonic stage would facilitate the modulation of poultry muscle quantity and meat quality. This review starts from the physical and biochemical characteristics of poultry myofiber formation, and brings together recent advances of incubation conditions on satellite cell migration, fiber development and transformation, and subsequent muscle myopathies and other meat quality defects. The underlying molecular and cellular mechanisms for the induced muscle growth and meat quality traits are also discussed. The future studies on the effects of external incubation conditions on the regulation of muscle cell proliferation and meat quality are suggested. This review may broaden our knowledge on the regulation of incubation conditions on poultry muscle development, and provide more informative decisions for hatchery in the selection of hatching parameter for pursuit of more large muscle size and superior meat quality.

Avian Reproduction

There are about 10,400 living avian species belonging to the class Aves, characterized by feathers which no other animal classes possess and are warm-blooded vertebrates with four-chamber heart. They have excellent vision, and their forelimbs are modified into wings for flight or swimming, though not all can fly or swim. They lay hard-shelled eggs which are a secretory product of the reproductive system that vary greatly in colour, shape and size, and the bigger the bird, the bigger the egg. Since domestication, avian species have been basically reared for eggs, meat, pleasure and research. They reproduce sexually with the spermatozoa being homogametic and carry Z-bearing chromosomes, and the blastodisk carries either Z-bearing or W-bearing chromosomes, hence, the female is heterogametic, and thus, determines the sex of the offspring. The paired testes produce spermatozoa, sex hormones and the single ovary (with a few exceptions) produces yolk bearing the blastodisk and sex hormones. Both testis and ovary are the primary sex organs involved in sexual characteristics development in avian. In avian reproduction, there must be mating for fertile egg that must be incubated to produce the young ones. At hatch, hatchling sex is identified and reared to meet the aim of the farmer.

Review: Implication of redox imbalance in animal health and performance at critical periods, insights from different farm species

The process of oxidative stress occurs all over the production chain of animals and food products. This review summarises insights obtained in different farm species (pigs, ruminants, poultry, and fishes) to underpin the most critical periods for the venue of oxidative stress, namely birth/hatching and weaning/start-feeding phase. Common responses between species are also unravelled in periods of high physiological demands when animals are facing dietary deficiencies in specific nutrients, suggesting that nutritional recommendations must consider the modulation of responses to oxidative stress for optimising production performance and quality of food products. These conditions concern challenges such as heat stress, social stress, and inflammation. The magnitude of the responses is partly dependent on the prior experience of the animals before the challenge, reinforcing the importance of nutrition and other management practices during early periods to promote the development of antioxidant reserves in the animal. When these practices also improved the performance and health of the animal, this further confirms the central role played by oxidative stress in physiologically and environmentally induced perturbations. Difficulties in interpreting responses to oxidative stress arise from the fact that the indicators are only partly shared between studies, and their modulations may also be challenge-specific. A consensus about the best indicators to assess pro-oxidative and antioxidant pathways is of huge demand to propose a synthetic index measurable in a non-invasive way and interpretable along the productive life of the animals.

Synergy Between Dietary Quercetin and Vitamin E Supplementation in Aged Hen’s Diet Improves Hatching Traits, Embryo Quality, and Antioxidant Capacity of Chicks Hatched From Eggs Subjected to Prolonged Storage

The current study aims to investigate the effects of the synergy between quercetin and vitamin E in aged hen’s diet on hatchability and antioxidant levels of the embryo and newly hatched chicks from prolonged storage eggs. A total of 400 breeder laying hens of 65 weeks of age were selected and randomly divided into 4 groups. Birds were fed a basal diet alone (Control), and basal diets supplemented with quercetin (Q) (0.4 g/kg) and vitamin E (VE) (0.2 g/kg) alone and their combination (0.4 g/kg Q + 0.2 g/kg VE) for 14 weeks, respectively, to determine their effects on yolk antioxidant status, fertility, embryonic mortality, hatchability, antioxidant status of embryonic tissues, as well as the antioxidant status of the newly hatched chicks. The results showed that the hen’s dietary Q + VE increased the yolk weight, as well as increased the antioxidant status of the egg yolk (p < 0.05). Compared with the control group, the supplementation of Q + VE significantly increased the hatchability of set-fertile eggs and decreased early embryonic mortality in eggs stored for 7 and 14 days, respectively (p < 0.05), and also improved the antioxidant capacity of the embryos obtained from eggs stored for 14 days (before incubation) (p < 0.05). Moreover, Q + VE increased the levels of SOD, GSH-Px, T-AOC, T-SOD, and CAT in the liver, heart, and pectoral muscle of the embryo, 1-day-old and 14-day-old chicks (p < 0.05), as well as upregulated the antioxidant related genes (GPx-1, GPx-2, GPx-4, DIO-1, and SOD-1) in the liver of the embryo, 1-day-old and 14-day-old chicks hatched from 14-days storage eggs (p < 0.05). Meanwhile, the MDA levels were decreased by the Q + VE in the embryo and post-hatched chicks (p < 0.05). In conclusion, these findings suggested that maternal dietary Q + VE exerts beneficial synergistic effects on the antioxidant capacity of the egg yolk, embryo, and chicks during prolong egg storage, therefore, Q + VE could be used as a dietary measure to enhance hatchability and chick quality in poultry production.

Transcriptome analysis of blastoderms exposed to prolonged egg storage and short periods of incubation during egg storage

BACKGROUND

Cool temperature egg storage prior to incubation is a common practice in the broiler industry; however, prolonged egg storage causes increased embryonic mortality and decreased hatchability and growth in surviving chicks. Exposing eggs to short periods of incubation during egg storage (SPIDES) reduces the adverse consequences of prolonged storage. SPIDES increases blastodermal cell viability by reducing apoptosis, though the counteracting mechanisms are unclear. To define the impact of prolonged storage and SPIDES, transcriptome analysis compared gene expression from blastoderms isolated from eggs exposed to the following treatments: control (CR, stored at 17 °C for 4 days), prolonged storage (NSR, stored at 17 °C for 21 days), SPIDES (SR, stored at 17 °C for 21 days with SPIDES), and incubated control (C2, stored at 17 °C for 4 days followed by incubation to HH (Hamburger-Hamilton) stage 2, used as the ideal standard development) (n = 3/group). Data analysis was performed using the CLC Genomics Workbench platform. Functional annotation was performed using DAVID and QIAGEN Ingenuity Pathway Analysis.

RESULTS

In total, 4726 DEGs (differentially expressed genes) were identified across all experimental group comparisons (q < 0.05, FPKM> 20, |fold change| > 1.5). DEGs common across experimental comparisons were involved in cellular homeostasis and cytoskeletal protein binding. The NSR group exhibited activation of ubiquitination, apoptotic, and cell senescence processes. The SR group showed activation of cell viability, division, and metabolic processes. Through comparison analysis, cellular respiration, tRNA charging, cell cycle control, and HMBG1 signaling pathways were significantly impacted by treatment and potential regulatory roles for ribosomal protein L23a (RPL23A) and MYC proto-oncogene, BHLH transcription factor (MYC) were identified.

CONCLUSIONS

Prolonged egg storage (NSR) resulted in enriched cell stress and death pathways; while SPIDES (SR) resulted in enriched basic cell and anti-apoptotic pathways. New insights into DNA repair mechanisms, RNA processing, shifts in metabolism, and chromatin dynamics in relation to egg storage treatment were obtained through this study. Although egg storage protocols have been examined through targeted gene expression approaches, this study provided a global view of the extensive molecular networks affected by prolonged storage and SPIDES and helped to identify potential upstream regulators for future experiments to optimize egg storage parameters.

HREM, RNAseq and Cell Cycle Analyses Reveal the Role of the G2/M-Regulatory Protein, WEE1, on the Survivability of Chicken Embryos during Diapause

Avian blastoderm can enter into diapause when kept at low temperatures and successfully resume development (SRD) when re-incubated in body temperature. These abilities, which are largely affected by the temperature and duration of the diapause, are poorly understood at the cellular and molecular level. To determine how temperature affects embryonic morphology during diapause, high-resolution episcopic microscopy (HREM) analysis was utilized. While blastoderms diapausing at 12 °C for 28 days presented typical cytoarchitecture, similar to non-diapaused embryos, at 18 °C, much thicker blastoderms with higher cell number were observed. RNAseq was conducted to discover the genes underlying these phenotypes, revealing differentially expressed cell cycle regulatory genes. Among them, WEE1, a negative regulator of G2/M transition, was highly expressed at 12 °C compared to 18 °C. This finding suggested that cells at 12 °C are arrested at the G2/M phase, as supported by bromodeoxyuridine incorporation (BrdU) assay and phospho-histone H3 (pH 3) immunostaining. Inhibition of WEE1 during diapause at 12 °C resulted in cell cycle progression beyond the G2/M and augmented tissue volume, resembling the morphology of 18 °C-diapaused embryos. These findings suggest that diapause at low temperatures leads to WEE1 upregulation, which arrests the cell cycle at the G2/M phase, promoting the perseverance of embryonic cytoarchitecture and future SRD. In contrast, WEE1 is not upregulated during diapause at higher temperature, leading to continuous proliferation and maladaptive morphology associated with poor survivability. Combining HREM-based analysis with RNAseq and molecular manipulations, we present a novel mechanism that regulates the ability of diapaused avian embryos to maintain their cytoarchitecture via cell cycle arrest, which enables their SRD.

Storage Temperature or Thermal Treatments During Long Egg Storage Duration Influences Hatching Performance and Chick Quality

This study was designed to improve the hatching performance, chick robustness and poultry health in the event of long-term egg storage and suboptimal age of the reproductive flock. A total of 9,600 eggs from one young breeder flock (28 weeks of age, batch B) and 9,600 eggs from an older breeder flock (59 weeks of age, batch E) were used (ROSS 308). Each batch was separated into three sub-groups and stored for 14 days. The first sub-group of eggs (Cool, group C) was stored at 11.6°C. The second sub-group of eggs (Warm, group W) was stored at 18.3°C with two pre-incubation on days 6 and 10 of the storage period. The final sub-group of eggs (Control, group Ct) was stored at 18.3°C throughout the storage period. Eggs were similarly incubated and hatched birds were raised on the same experimental farm. In both batches, embryonic development was significantly more advanced in W eggs than in C and Ct eggs ( p < 0.01). In both batches, C and W treatments decreased early embryonic mortality by more than 10% compared with Ct, decreased the proportion of late-hatched chicks and improved the percentage of first grade chicks: in batch E, 42% of Ct eggs were first grade chicks vs. 57% in group W and 59% in group C. Benefits were even higher in batch B, where only 60% of Ct eggs gave first grade chicks vs. 83% in others groups. The hatching rate was thus higher in groups C and W regardless of flock age: for batch B eggs, 85% hatched in W and 84% in C vs. 62% in Ct, while for batch E eggs, 59% hatched in W and 61% in C vs. 45% in Ct. Day-old Ct chicks from batch E were heavier than W and C ones, and heavier than W chicks from batch B ( p < 0.05). Long-term parameters on farm were not significantly different between groups. Thermal treatments during the storage of eggs from both young and old breeder flocks counterbalance the negative effects of prolonged egg storage on hatching rate, without altering chicken performance during rearing.

Quality assessment of chukar partridge (A. chukar) eggs during different conditions (time, turning and position) of storage

The present study was conducted with the aim of investigating the effect of storage length, turning frequency and egg position on internal quality traits of chukar eggs obtained from 56-week-old chukar partridges under the same nutrition and management conditions. A total of 720 eggs were collected and assigned to 36 subgroups according to storage length (7, 14, 21, and 28 d), turning frequency (0, 1, and 24 per day) and egg position (pointed end up, blunt end up and horizontal). As a result of the study, almost all the internal quality traits of chukar eggs were negatively affected by lengthening of storage period especially 21 days and longer (p < 0.001). Internal egg quality traits weren't statistically affected by turning frequency except yolk index (p < 0.01). An improvement was observed in Haugh unit, albumen index and heigh of eggs stored with pointed end up (p < 0.001). Some significant interactions occurred among all internal egg quality traits which were mostly dependent on the eggs stored horizontally, extended storage time more than 21 days and egg turning during storage. The results and interactions showed that internal quality traits would be preserved well for the eggs stored less than 21 days with the position of pointed end up independent of turning. If the storage period was to exceed 21 days, the eggs should be positioned horizontally and turning should be applied to preserve the quality of chukar eggs.

Effects of egg storage duration on egg quality, metabolic rate, hematological parameters during embryonic and post-hatch development of guinea fowl broilers

Considering the value of guinea fowl keets, successful incubation of eggs is particularly desirable in this poultry species. This study evaluated the effect of egg storage duration on egg quality, heat production, hematological parameters during embryonic development and post hatch performance of guinea fowl broilers. A total of 800 hatching eggs of guinea fowl were used for this study. Before incubation, 12 eggs per treatment were used to analyse egg quality. Then, eggs were numbered, weighed, and assigned to 2 treatment groups of 400 eggs each according to storage duration of 5, and 10 d at a temperature of 18°C. The eggs were set for incubation at 37.7°C and 55% relative humidity for 28 d in a forced-draft incubator. To determine heat production as a measure of metabolism, 60 eggs in each replicate were transferred to respiratory cages post hatch two 12 wk old guinea fowl were also used to determine heat production. CO₂ and O₂ were recorded to calculate heat production at internal pipping, hatch and at 12 wk of age. The hatched keets were reared for 12 wk and data were collected on feed intake, body weight and feed conversion ratio. Blood samples were collected at hatch and at 12 wk of age from 24 guinea fowls per treatment to analyze haematological parameters. The results showed that embryos and guinea fowls at 12 wks of age from eggs stored for 5 d had higher (P ˂ 0.05) heat production and body weights. However, a significant higher (P ˂ 0.05) level of basophile, eosinophils, and lymphocytes was observed in guinea fowls from 10 d storage egg. It was concluded that extended duration of egg storage negatively influenced the metabolic rate of embryos. It also impacted hematological parameters which may suggest influence on immune response during embryonic and post-hatch growth.

Research Note: Effects of preincubation and higher initiating incubation temperature of long-term stored hatching eggs on hatchability and day-old chick and yolk sac weight

We studied the effect of increased initial incubation temperature and repeated preincubation of 35-d stored eggs from 46-week-old Ross 308 parental stock on the hatchability and day-old chick and yolk sac weight. Two different temperatures were applied during the first 36 h and they were combined with 4 preincubation treatments during storage. One half of the hatching eggs (2,400) were incubated for the first 36 h at an incubation temperature of 38.3°C, and the second half were incubated at a higher temperature of 39.2°C. Four different preincubations were applied; none, once at the 7th d of hatching egg storage, twice at the 7th and 12th d of storage and 3 times at the 7th, 12th and 19th d of storage. Both preincubation and increased temperature had negative effects on hatchability (P < 0.001). The interaction between these 2 factors was also significant (P < 0.05). These 2 factors also negatively affected early and late embryonic mortality (P < 0.001). However, middle embryonic mortality was not influenced. Live weight, weight of residual yolk sac, and yolk sac proportion were not affected by repeated preincubation nor by increased temperature over the first 36 h of incubation (P > 0.05). A higher initial temperature decreased chick yolk free body mass (P < 0.05). Although neither increased initial temperature in the setter nor repeated preincubation affected one-day-old chick weights, these treatments were not suitable for long-term stored eggs because of decreased hatchability and impairment of one day chick yolk free body mass.

The chick blastoderm during diapause, a landmark for optimization of preincubation storage conditions

At the time of oviposition, the chicken embryo is in its blastodermal stage. The blastoderm displays the unique ability to undergo developmental arrest at low temperatures in a process called “embryonic diapause.” In the wild, diapause occurs in freshly laid eggs until the last egg of the clutch has been laid, providing an evolutionary advantage to hens that can synchronously hatch their eggs. The poultry industry utilizes the diapause phenomenon to store eggs before incubation, thereby mitigating their logistic problems. The embryos can only be stored at particular embryonic stages—termed “diapause developmental window” (DW)—if they are to continue to develop normally thereafter. Both cellular and molecular mechanisms define the limits of this DW which broadly comply with onset of blastulation to early gastrulation. Storage conditions affect the cellular and molecular characteristics of the embryo during this window and their ability to successfully resume development (SRD). At storage temperatures of ~12°C to 18°C, embryos can undergo diapause for a short period (up to 7 days (d)) without affecting SRD. However, following longer period of diapause (up to 28 d), embryo stored at ~12°C, but not at ~18°C, can resume development normally. Moreover, eggs can be heated before or during the storage period which will lead to their commencing in development; however, unlike the non-heated embryos, the storage temperature for heated embryos, which are more advance in developing, is not clear. Thus, based on SRD, this review brings evidence supporting the notion that a lower storage temperature is beneficial for early-stage blastoderms whereas a higher storage temperature is favorable for later-stage/gastrulating embryos. Our understanding of the molecular mechanisms underlying the relationship between storage temperature and development stage within the DW is rather limited. However, it is expected to become relevant in light of the effect of selective breeding of modern avian birds on the advancement of embryonic development stage. Thus, this review discusses parameters that are regulated during the DW and affect SRD, and presents the need to adopt new storage techniques. The pre-managerial decision of required duration of storage with manipulation of storage temperature in the currently used storage techniques may improve SRD characteristics.

Effects of flock age, storage temperature, and short period of incubation during egg storage, on the albumen quality, embryonic development and hatchability of long stored eggs

1. The effect of breeder flock age, storage temperature and a short period of incubation during egg storage (SPIDES) on albumen quality, development of blastoderm, and hatchability of long-stored eggs was evaluated.2. Hatching eggs were collected from 28-week-old (young) and 40-week-old (prime) Ross female line grandparent flocks and were stored for 14 d at 12, 15 or 18°C. During storage, the eggs were either kept continuously in the storage room (control) or were subjected to SPIDES treatment.3. Embryonic development was more advanced in eggs from the prime flock, exposed to SPIDES and warmer (18°C) storage temperature (P ≤ 0.05). There was a difference in the albumen pH for flock ages (P < 0.05), but the SPIDES treatment did not affect albumen height and pH (P > 0.05). On d 14 of storage, albumen pH was positively (P < 0.05) correlated with storage temperature. Hatchability was higher in the prime flock (P < 0.05).4. At both flock ages, hatchability increased (P < 0.05) by storing the eggs at 15°C, compared to 18°C, with 12°C intermediate. The hatchability improvement was due to reduced early embryonic mortality.5. The SPIDES treatment decreased late embryonic mortality and the percentage of second-grade chicks (P < 0.05), which increased the hatchability of fertile eggs (P < 0.05). SPIDES only reduced (P < 0.05) early embryonic mortality in eggs stored at 18°C.6. The highest hatchability was observed in the eggs stored at 15°C and exposed to one SPIDES treatment during 14 d storage.

Effects of coated hatching eggs obtained from old broiler breeders with chitosan on embryonic growth, hatching results and chick quality

The aim of this research was to determine the effects of coating broiler hatching eggs with chitosan on egg quality, embryonic growth, hatching results and chick quality. Eggs obtained from old broiler breeder, aged 59 weeks, were used. Eggs were divided into two groups (coated with chitosan and uncoated) groups. Each group was divided into three groups according to the storage period. Eggs were stored for periods of 1, 4 and 7 days at 15°C and 80% humidity. Then, they were incubated. Storage period of eggs up to 7 days did not affect the egg quality, egg weight loss, embryo growth, chick properties and hatchability of fertile eggs. However, embryo development, relative residual yolk sac weight and relative chick weight were affected by coating eggs with chitosan. Interaction was not found between storage lengths and coating of eggs with chitosan for all examined parameters. The results of the present study suggested that hatching eggs obtained from old broiler breeder flocks were immersed into chitosan solution once and quickly have negative effect on the embryo weight, yolk sac absorption and relative chick weight. It has been observed that covering the hatching eggs with chitosan is not suitable in this respect even if immersion takes place once and in a short time.

Research Note: Effects of turning and short period of incubation during long-term egg storage on embryonic development and hatchability of eggs from young and old broiler grandparent flocks

Longer egg storage times (>7 d) are common in broiler parent and grandparent hatcheries to obtain the requested flock size. However, prolonged storage is known to decrease hatchability. The aim of this study was to investigate the effects of turning and short period of incubation during egg storage (SPIDES) for 14 d on the stage of blastoderm development, embryonic mortality, and hatchability of eggs from young and old grandparent flocks. Hatching eggs were obtained from Ross female line grandparent flocks aged 29 wk (young) and 58 wk (old). Eggs were stored at 15°C, and turned 90° 0 or 4 times daily during storage. On day 5 after egg collection, the eggs were either held in the storage room (control) or subjected to SPIDES treatment. The development of the blastoderm in sample eggs was determined immediately after collection on a farm and again after the SPIDES treatment. Each of the 8 subtreatments was tested on 6 replicate trays of 150 eggs (900 eggs per subtreatment) with 7,200 hatching eggs set in a single-stage setter and hatcher for the trial. The stage of blastoderm development was advanced by the old flock, by SPIDES, and by turning 4 times daily during egg storage (P ≤ 0.05). There was a significant interaction effect of flock age × turning during storage on embryonic development, which suggested that turning advanced the stage of blastoderm development only in eggs from the old flock (P ≤ 0.05). Eggs from the young flock had a better hatchability than eggs from the old flock (P ≤ 0.05). Hatchability was increased by turning 4 times/day during the storage period compared with no turning because of a decrease in the percentage of late embryonic mortality (P ≤ 0.05). SPIDES decreased early and late embryonic mortality as well as the percentage of second-grade chicks (P ≤ 0.05), which increased the hatchability of fertile eggs at both flock ages (P ≤ 0.05). The results of this study showed that a combination of turning eggs 4 times daily along with one SPIDES treatment during 14 d of storage resulted in the highest hatchability in both young and old broiler grandparent flocks.

Incubation, hatchery practice and the welfare of layer hens

For modern layers to achieve optimum production performance and welfare state, the entire production process needs to be managed to achieve target bodyweight, body composition and flock uniformity. In addition to genetic improvements, flock health, environment, nutrition and on-farm husbandry practices, incubation and hatchery practices have become a focal point for producing optimum chick quality. Chick quality is a collective term involving chick size and anatomical features, physiology, robustness and liveability over the first week after placement. Chick quality is a key focus for hatcheries as this has been positively correlated with overall flock performance, especially egg production, shell quality, liveability and animal welfare. Recent advances in incubation have focussed on the benefits of all-in–all-out (single-stage) machines. Innovation in incubation systems is completely conducted today by international manufacturers, and is largely driven by the meat chicken industry. Disposal of male layer chicks has increased as a consumer welfare concern, and while investment in research and legislation changes are focussed towards providing or driving new solutions, there are currently no commercial options for industry to deal with this problem before incubation or hatch. Chick transport systems and equipment have also significantly improved in recent years, providing optimum conditions to ensure temperature uniformity and minimal moisture loss during transit before placement, thus optimising chick quality. Together, recent improvements in incubation equipment and hatchery practice can produce commercial layer chicks that are healthy, of high quality, and are then in an optimal physiological state and condition to achieve their genetic potential.

Effect of storage duration on egg quality, embryo mortality and hatchability in FUNAAB-ɑ chickens

Effect of extended storage on egg quality, embryo mortality and hatchability in FUNAAB-ɑ chickens was determined. Hatchable eggs (n = 288; weighing 53.2 ± 4.67 g) collected from a flock of FUNAAB-ɑ layer breeder hens aged 32 weeks were stored in egg tray with broad end up under 16 ± 1.5°C for either 0, 4, 8, 12, 16 or 20 d. Before incubation, eight eggs from each group were evaluated for internal and external quality traits. Remaining eggs were set in an incubator and transferred into hatcher on embryonic day 18. Data collected were subjected to one-way analysis of variance. Egg weight loss (EWL; p < .001), surface area (p < .001), yolk diameter (p < .001), inner and outer blastoderm diameters (p < .05) and dead in germ (DIG; p < .001) increased with storage duration while yolk height (p < .001), yolk index (p < .001), albumen weight (p < .05), albumen height (p < .05), albumen index (p < .01), Haugh's unit (HU; p < .05), fertility (p < .001), hatchability of set (HATCHS; p < .001) and fertile eggs (p < .05) decreased. Weight losses of 0, 1.2, 2.2, 3.4, 4.6 and 6.1% were recorded in egg stored for 0, 4, 8, 12, 16 and 20 days respectively. Eggs stored beyond 8 days exhibited higher DIG and lower HATCHS. Shell percentage in 4 days storage (11.4%) was lower (p < .05) than in 16 days storage (13.4%). Shell thickness was similar in eggs stored for 0 to 12 days, but 8 days storage (0.60 mm) had thinner (p < .01) shell than day 16 (0.71 mm) and day 20 (0.73 mm) storage. Internal quality unit (IQU) was higher (p < .05) in fresh eggs (180.4) than in 12 days (167.8) and 20 days (167.8) stored eggs. Extended storage of FUNAAB-ɑ eggs caused EWL, surface area shrinkage, lowered HU and IQU, loss of yolk and albumen quality, increased blastoderm diameters and DIG, and decreased egg fertility and HATCHS from day 8 forward. Storing FUNAAB-ɑ eggs beyond 8 days reduced quality parameters; therefore, other mitigating factors are recommended when storing beyond 8 days.

Research Note: Storage period and prewarming temperature effects on synchronous egg hatching from broiler breeder flocks during the early laying period

The effects of the storage period and prewarming temperature on embryonic mortality, hatchability, and synchronous hatching of broiler eggs were investigated. Eggs were obtained from commercial flocks of Ross 308 broiler breeders at 27 and 28 wk of age for trials 1 and 2, respectively. In both trials, 2,400 eggs were stored for 4 d (short) or 11 d (long) at 18°C (64.4°F) and 75% RH and were randomly assigned to 2 groups at either a prewarming temperature of 26.1°C (79°F, low) or 29.4°C (85°F, high) for 8 h before setting. The eggs were transferred from setters to hatching baskets at 444 h (18.5 d) of incubation. The hatched chicks were counted at 6-h intervals between 468 h and 516 h of incubation and categorized as early, middle, or late hatching. The eggs stored for 4 d hatched earlier than the eggs stored for 11 d (P < 0.05). An increased prewarming temperature (29.4°C) resulted in a 1.0-h shorter incubation duration, but this difference was not significant (P = 0.064). An interaction between the storage period and prewarming temperature was observed for middle- and late-hatched chicks (P < 0.05). No interactions between the storage period and prewarming temperature were observed for hatchability of fertile eggs or embryonic mortality; however, a significant interaction was found between the storage period and prewarming temperature on the second-quality chick percentage (P < 0.05). The eggs stored for 11 d had a significantly reduced hatchability of fertile eggs owing to increased embryonic mortality than short-stored eggs (P < 0.05). The interaction effect indicated that eggs held for 8 h with prewarming at 29.4°C after 11 d of storage had more middle- and fewer late-hatched chicks and improved chick quality than those that received the 26.1°C prewarming treatment (P < 0.05), but no significant difference was found among the prewarming treatments for eggs stored for 4 d. This study demonstrated that prolonged egg storage resulted in reduced hatchability, increased incubation duration, and an asynchronous hatching time. Moreover, increasing the prewarming temperature could be used to promote uniformity among embryos through synchronous hatching, thus improving broiler flock uniformity and performance of the prolonged stored eggs.

Effects of broiler breeder strain, age, and eggs preheating profile in single-stage systems on the hatchability of eggs and quality of chicks

Preheating can increase the efficiency of commercial broiler breeding. A slow increase in temperature can counteract the negative effects of water condensation on the surface of the shell and reduces the thermal shock to the embryos. It is essential to design different preheating profiles because of the variances between breeds in terms of egg construction and the course of embryogenesis, along with the influence of the parental flocks' age on hatching rates. This study aimed to analyze six preheating profiles with different time and temperature patterns (A-F), which were immediately applied before the egg incubation began. These profiles were used for two broiler breeder strains - Hubbard Flex and Ross 308 - for the entire laying cycle divided into six age ranges: 25-30, 31-36, 37-42, 43-48, 49-54, and 55-60wk of life. A total of 7839250 Hubbard Flex and 57167060 Ross 308 eggs were used in the study. The eggs were stored for 4-7d before the preheating profile was applied. Mortality during incubation, hatchability, and the quality of chicks were analyzed. The most favorable results were obtained with profile B - 02 h (25.0 °C):02 h (29.4 °C):02 h (32.2 °C):02 h (35.0 °C):02 h (37.8 °C), while the worst results were obtained with profile C - 03 h (23.9 °C):03 h (25.0 °C):04 h (32.2 °C). These findings indicated that compared to a rapid temperature increase during incubation, multistage slow heating of eggs is more advantageous as it enables achieving better hatchability from apparent fertile eggs and obtaining more first-grade chicks. An analysis of the interaction of different preheating profiles with flock age and breed of parental flock revealed that profile C is not suitable for eggs from older flocks, in particular Ross 308. Deterioration of hatchability of chicks from apparent fertile eggs was also confirmed for flocks over 49wk of life after the application of profile E - 03 h (77 °C):02 h (29.4 °C):02 h (32.2 °C):01 h (35.0 °C):02 h (37.8 °C). Increased early and late mortality of embryos was observed in the case of Hubbard Flex after the use of profile D - 03 h (25.0 °C):02 h (29.4 °C):01 h (32.2 °C):02 h (35.05 °C):02 h (37.8 °C). Based on the obtained results, it can be recommended that profile B can be applied for the entire duration of Ross 308 and Hubbard Flex flock utilization to achieve high egg hatchability and obtain high-quality chicks.

The effect of methionine and folic acid administered in ovo on the hematological parameters of chickens (Gallus gallus domesticus)

Methionine (Met), an essential amino acid in poultry diets, when overdosed may cause hyperhomocysteinemia, which is mainly a trigger for cardiovascular diseases in humans. Homocysteine is neutralized (remethylated) in the presence of folic acid (FA), which also plays an important role in hematopoiesis and participates in the synthesis of DNA, and its deficiencies may result in the development of neural tube defects. One of the basic tools in studying the impact of both xenobiotics and nutrients on the animal organism is hematological analysis. Thus, the aim of this study was to determine the effect of in ovo supplementation with Met and FA on the hematological parameters of broiler chickens. On the 17th day of incubation, embryonated eggs (Ross 308) were injected with 5 or 25 mg of Met per egg (M5 and M25), 3 and 15 mg of FA per egg (F3 and F15), or a mixture of these 2 compounds (M5/F3 and M25/F15). The broilers were reared in accordance with welfare regulations and fed with commercial diets ad libitum. Blood samples were collected on the first, seventh, and 35th day of rearing (D1, D7, and D35), and complete hematological analysis was performed. The observed changes in red blood cell parameters probably result from physiological changes occurring during bird growth. Mean erythrocyte volume decreased with the age of chickens in the control, M5, and M25 groups, but not in those supplied with FA. Among supplemented groups, the number of white blood cells on D1 was lower only in group M5 than in the sham (C) group. The analysis of leukograms showed no significant differences between the groups. Comparing D1 with D7 in the group injected with a higher dose of Met and FA (MF25/15), a statistically significant increase in the percentage of lymphocytes and a significant decrease in the percentage of heterophils were observed. In addition, in the group injected with a higher FA dose (F15), there was statistically significant reduction in the percentage of eosinophils and a significant increase in the percentage of monocytes at day 7 compared with day 1. It seems that Met supplementation led to temporary immunosuppression in the animals.

The Effects of Broiler Breeder Dietary Vitamin E and Egg Storage Time on the Quality of Eggs and Newly Hatched Chicks

Simple Summary

Broiler breeder dietary vitamin E supplementation has been indicated to enhance the antioxidant status of egg yolks, embryos, and newly hatched chicks. However, knowledge of the relationships involving breeder dietary vitamin E, the egg storage time, and the quality of the eggs and newly hatched chicks in poultry, especially in broiler breeders, is still limited. Here, we aimed to provide important evidence regarding broiler breeder dietary vitamin E and egg storage time intervention in egg characteristics and hatchability and the antioxidant status of the egg yolks and newly hatched chicks. Our results showed that prolonged egg storage time (14 vs. 0 d) increased the embryonic mortality, decreased the hatchability, and impaired the antioxidant status of egg yolks and newly hatched chicks, while increasing the broiler breeder dietary vitamin E levels (100 vs. 6 mg/kg) improved the livability of embryos and the antioxidant status of newly hatched chicks in the case of long-term egg storage. These findings suggested that broiler breeder dietary vitamin E could be applied in extending the storage time of breeder eggs.

Abstract

This study was conducted to investigate the effects of broiler breeder dietary vitamin E and egg storage time on the egg characteristics, hatchability, and antioxidant status of the egg yolks and newly hatched chicks. A total of 512 71-week-old Ross 308 breeder hens were fed the same basic diets containing 6 or 100 mg/kg vitamin E for 12 weeks. During this time, a total of 1532, 1464, and 1316 eggs were independently collected at weeks 8, 10, and 12, respectively, and subsequently stored for 0 or 14 d before hatching. The outcomes from three trials showed that prolonged egg storage time (14 vs. 0 d) negatively affected (p < 0.05) the egg characteristics, hatchability traits, and the yolk total antioxidant capacity (T-AOC) (p < 0.05). Chicks derived from the stored eggs exhibited higher malonaldehyde (MDA) and T-AOC in the serum and yolk sac (p < 0.05). Broiler breeder dietary vitamin E (100 vs. 6 mg/kg) increased (p < 0.05) the hatchability and the antioxidant status of the yolks as indicated by a higher α-tocopherol content and T-AOC and lower MDA level (p < 0.05). The supplementation of vitamin E also remarkably increased (p < 0.05) the total superoxide dismutase (T-SOD) activity (yolk sac, weeks 8 and 12) and T-AOC (serum, weeks 8, 10, and 12; yolk sac, weeks 8 and 12) and decreased (p < 0.05) the MDA content of chicks (yolk sac, week 10; serum, week 12). Interactions (p < 0.05) were found between the broiler breeder dietary vitamin E and egg storage time on the hatchability and antioxidant status of chick tissues. Broiler breeder dietary vitamin E (100 vs. 6 mg/kg) increased (p < 0.05) the hatchability and the T-AOC in the serum and liver of chicks, and decreased (p < 0.05) the early embryonic mortality and the MDA content in the yolk sacs of chicks derived from eggs stored for 14 d but not for 0 d. In conclusion, prolonged egg storage time (14 vs. 0 d) increased the embryonic mortality, decreased the hatchability, and impaired the antioxidant status of egg yolks and newly hatched chicks, while the addition of broiler breeder dietary vitamin E (100 vs. 6 mg/kg) could partly relieve these adverse impacts induced by long-term egg storage.

Blastodermal development, hatchability and chick quality of Marshall® broiler breeders of different flock ages during egg storage

The blastoderm, which represents the fertilized germinal disc, undergoes cellular events of division, differentiation and organization to achieve embryonic development in chickens. In this study, blastodermal cell counts and hatching performance of Marshall^® broiler breeders as influenced by flock age and egg storage were investigated. A total of 1,520 eggs from the flock ages, 43 weeks (younger) and 65 weeks (older), under similar management and nutritional regime were incubated after storage at 16°C with 75% relative humidity for duration of 0 (fresh eggs), 4, 7 and 10 days. Results show that total blastodermal cell counts (BCC) for both ages declined with increasing storage duration, with a sharp regression at 4d storage from younger breeders. Higher percentages of fertility and hatchability were recorded for younger breeders compared to older breeders. Percentage hatchability was statistically similar (p > .05) for both 43 weeks and 65 weeks old broiler breeders under 0, 4 and 7d storage except at 10d storage which was lower for older breeders. Chick lengths were longer with younger breeders whereas older breeders had heavier chick weights. Also, significant associations were found between BCC and fertility, hatchability of fertile eggs and chick weights, respectively, under different conditions. These results indicate that fresh eggs (0d) and short-term stored eggs (4- and 7 d) from 43 weeks old breeders had higher total blastodermal cell counts, fertility, hatchability and increased chick lengths compared to 65 week old breeders which produced heavier chicks. Therefore, egg storage longer than 7 days especially from older breeders resulted in modifications to the blastoderm which subsequently affected fertility, hatchability, embryo liveability and hatched chick quality. Also, detection of BCC in fertile eggs can serve as a predictive tool in fertility and hatchability evaluations.

The effects of hen's age and egg storage time on the frequency of occurrence of physical defects in turkey poults

The aim of this study was to determine the effect of the interaction between hen's age and egg storage time on the frequency of occurrence and type of physical defects in turkey poults. The experimental materials comprised 6,048 eggs laid by BUT 6 turkey hens at 32, 38, 46, and 51 wk of age (1,512 eggs per week), which were randomly divided into 4 groups (378 eggs per group) and stored for different periods of time, i.e., 7, 10, 13, and 17 D. After incubation, poults were evaluated individually. Egg weight and the hatch-weight of poults increased with hen's age (P < 0.001). The relative body weight of poults, expressed as a percentage of egg weight, was highest in the group of the youngest hens (70.6%). Prolonged egg storage before incubation contributed to an increase in the percentage of poults with physical abnormalities (P < 0.001). Umbilical abnormalities were most common regardless of the week of the laying season and egg storage time.

Effects of maternal dietary vitamin E on the egg characteristics, hatchability and offspring quality of prolonged storage eggs of broiler breeder hens

This research aims to evaluate the effects of maternal vitamin E (VE) dietary supplementation on the egg characteristics, hatchability and antioxidant status of the embryo and newly hatched chicks of prolonged storage eggs. A total of 576 75-week-old Ross 308 breeder hens were randomly allocated into three dietary VE treatments (100, 200 and 400 mg/kg) with 6 replicates of 32 hens, for a 12-week feeding trial. At week 12, a total of 710 eggs were collected over a 5-day period, and eggs per treatment were attributed into 5 replicates and stored for 14 days until incubation. The egg yolk, trunk and head of 7-day-old embryo and the serum, liver, brain and yolk sac of newly hatched chicks were sampled for the evaluation of antioxidant status. Results showed that as maternal dietary VE levels increased, yolk α-tocopherol concentration increased (p < .05). Compared with 100 mg/kg VE, the use of 200 and 400 mg/kg VE increased the hatchability of set/fertile eggs and total antioxidant capacity (T-AOC) of liver and serum in chicks (p < .05), and decreased both the early embryonic mortality and the malondialdehyde (MDA) content of trunk and head in 7-day-old embryos (p < .05); moreover, 400 mg/kg VE increased the yolk T-AOC (p < .05) and decreased yolk and brain MDA content of chicks (p < .05). Brain T-AOC of chicks in 200 mg/kg VE group was improved compared to that of chicks in 100 mg/kg VE group (p < .05). In conclusion, maternal dietary VE at 200 or 400 mg/kg could increase hatchability by decreasing early embryonic mortality and increasing the antioxidant status of egg yolk, embryo and newly hatched chicks as breeder egg storage was prolonged to 14-18 days. The suitable VE level for the broiler breeder diet was 200 mg/kg as breeder egg storage was prolonged.

Preliminary evaluation of application of a 3-dimensional network structure of siloxanes Dergall preparation on chick embryo development and microbiological status of eggshells

The spatial network structure of Dergall is based on substances nontoxic to humans and the environment which, when applied on solid surfaces, creates a coating that reduces bacterial cell adhesion. The bacteriostatic properties of siloxanes are based on a purely physical action mechanism which excludes development of drug-resistant microorganisms. The aims of the present study were to 1) evaluate a Dergall layer formed on the eggshell surface regarding the potential harmful effects on the chick embryo; 2) evaluate antimicrobial activity and estimate the prolongation time of Dergall's potential antimicrobial activity. Dergall at a concentration of 0.6% formed a layer on the eggshell surface. In vitro testing of the potential harmful effects of Dergall by means of a hen embryo test of the chorioallantoic membrane showed no irritation reaction at a concentration of 3% and lower. The hatchability of the groups sprayed with a Dergall water solution with a concentration of 0 to 5% was 89.1 to 93.8% for fertilized eggs (P > 0.05) but decreased to 63.7% (P < 0.05) in the group sprayed with a 6% concentration of the solution. This phenomenon was caused by embryo mortality in the first week of incubation. At the concentration of 0.6%, Dergall exhibited strong antibacterial properties against bacteria such as Staphylococcus aureus, Escherichia coli, Shigella dysenteriae, Shigella flexneri, and Salmonella typhimurium. For Streptococcus pyogenes, the highest antibacterial activity of Dergall was reported in the concentrations of 100 and 50%. For Pseudomonas aeruginosa, no antibacterial activity of Dergall was generally observed, but in vivo testing showed a strong decrease of all gram-negative bacteria growth. Moreover, a prolonged antimicrobial effect lasting until 3 D after disinfection was observed, which makes Dergall a safe and efficient disinfectant.

Factors Associated with Cumulative First-Week Mortality in Broiler Chicks

First-week mortality is an important performance index as well as an important welfare indicator. The aim of the present study was to identify internal (individual-dependent) and external (management or environmental) factors that could influence the cumulative first-week mortality of broilers. To carry out this study, field data obtained from a hatchery company were used, in which 2267 flocks of broiler chicks (from 2015 to 2018), were analyzed. A generalized linear mixed model was used to analyze the data. Farm ID and house by farm were incorporated as random effects. The Odds Ratio was estimated for each factor, determining the effect of each explanatory variable. First-week mortality was significantly related to breeder age (p < 0.0001), chick gender (p < 0.0001) and breed (p < 0.0001) as internal factors, and type of broiler house (p = 0.0129), presence or absence of drip cup (p < 0.0001), egg storage (p < 0.0001), study year (p < 0.0001) and season (p < 0.0001) as external factors. Therefore, these factors should be considered in the decision making of poultry breeding companies, in order to reduce possible welfare problems and increase productive performance.

A review on yolk sac utilization in poultry

During incubation, embryonic growth and development are dependent on nutrients deposited in the egg. The content of the yolk can be transferred to the embryo in 2 ways: directly into the intestine via the yolk stalk or through the highly vascularized yolk sac membrane. It has been suggested that, as a result of genetic selection and improved management, the increase in posthatch growth rate and concurrently the increase in metabolic rate of broiler chickens during the last 50 yr has also increased embryonic metabolism. A higher metabolic rate during incubation would imply a lower residual yolk weight and possibly lower energy reserve for the hatchling. This might affect posthatch development and performance. This review examined scientific publications published between 1930 and 2018 to compare residual yolk weight at hatch, metabolic heat production, and yolk utilization throughout incubation. This review aimed to investigate 1) whether or not residual yolk weight and composition has been changed during the 88-yr period considered and 2) which abiotic and biotic factors affect yolk utilization in poultry during incubation and the early posthatch period. It can be concluded that 1) residual yolk weight and the total solid amount of the residual yolk at hatch seem to be decreased in the recent decades. It cannot be concluded whether the (lack of) differences between old and modern strains are due to genetic selection, changed management and incubation conditions, or moment of sampling (immediately after hatch or at pulling). It is remarkable that with the genetic progress and improved management and incubation conditions over the last 88 yr, effects on yolk utilization efficiency and embryonic metabolic heat production are limited; 2) factors specially affecting residual yolk weight at hatch include egg size and incubation temperature, whereas breeder age has more influence on nutrient composition of the residual yolk.

Indústria do Ovo: qual é o significado e uso dessa expressão?

Resumo No início dos anos 2000, ovos foram reabilitados como saudáveis, sendo alimento nutritivo e economicamente acessível, de uma rica fonte de proteína animal e uma alternativa à carne vermelha. O presente trabalho objetivou identificar se a expressão “Indústria do Ovo” é utilizada em publicações acadêmicas e, se confirmada sua utilização, a que produção se refere frequentemente, bem como em que contexto é utilizada quanto à temática dos artigos científicos. Para tanto, realizou-se uma revisão sistemática da literatura, considerando investigações publicadas nas bases de dados Scopus e Web of Science. Os resultados obtidos demonstraram que a utilização da expressão “Indústria do Ovo” em artigos científicos ocorre desde 1947, sendo empregada para designar, principalmente, a produção comercial de ovos de galinha, cujo uso apresenta linha de tendência crescente. Os artigos com foco em administração, economia, mercados e certificações foram predominantes no emprego da expressão “Indústria do Ovo” no decorrer do período analisado.