Examining the effects of prestorage incubation of turkey breeder eggs on embryonic development and hatchability of eggs stored for four or fourteen days

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.

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.

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.

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.

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 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.

Pre-Incubation and Turning During Long Storage as a Method of Improving Hatchability and Chick Quality of Japanese Quail Eggs

In this study, we investigated the effect of modification of 12 d storage conditions of quail eggs from two flocks: at 17–20 weeks of life (A) and 36–39 weeks of life (B) on the incubation time, hatch window (HW), hatching results and chicks quality. The eggs were divided into experimental groups: COI = no pre-incubation (PI); SPIDES = were treated with 4 h PI, delivered at 4, 6, 8 and 10 d of storage; EG SPIDES = were treated with variable time of PI according to the scheme 5 d – 2 h, 7 d – 3 h, 9 d – 5 h and 11 d – 6 h. In addition, in each group, half of the eggs were turned (T) every 12 h, which is indicated as COI T, SPIDES T and EG SPIDES T. Pre-incubation was conducted at 37.8°C and 50–55% RH. It has been demonstrated that both storage profiles contribute to shortened incubation time, yet the HW is deteriorated if T is not applied. The benefits resulting from the EG SPIDES profile is an increase of 2.3 points in the “average score of all chicks” index compared to the COI group. In summary, the use of PI and T, and in particular the EG SPIDES profile with the concomitant use of T during long storage of quail eggs is recommended to obtain a considerable improvement of hatching results and chick quality.

Interactions between Egg Storage Duration and Breeder Age on Selected Egg Quality, Hatching Results, and Chicken Quality

Simple Summary

Egg storage duration and breeder age are two important factors influencing productivity and profitability of hatcheries. These factors probably interact with each other to influence egg quality, apparent fertility, hatchability, and hatchling quality. The aim of this study was to investigate interactions between egg storage duration and broiler breeder age on these parameters. It was demonstrated that eggs from young breeders were the most resistant to storage duration increase in relationship to early and middle embryonic mortality than eggs from older breeders. However, the opposite was found for hatchling quality, where yolk free body mass, which increased from young to old breeders after five days of storage, increased only from middle to old breeders after prolonged storage (19 days). The intestine percentage decreased also after long storage in younger breeders, but in older breeders no significant effect of egg storage duration was found.

Abstract

Egg storage duration and breeder age are probably interacting to influence egg quality, hatchability, and hatchling quality. To evaluate this interaction, the impact of breeder age (31, 42, 66 weeks) and storage duration (2, 5, 12, 19 days) was investigated on broiler breeder eggs (Arbor Acres). Thick albumen diameter and pH increased, and yolk dry matter decreased between 2 and 19 days of storage. With the increase of breeder age from 31 to 66 weeks, albumen height, percentage and dry matter and shell percentage decreased and the egg weight and yolk percentage, dry matter and diameter increased. Prolonged egg storage increased the yolk pH in all breeder ages, but earlier and steeper in the oldest breeders. Prolonged egg storage resulted in a lower hatchability of set and fertile eggs due to a higher percentage of embryonic mortality. Early mortality increased earlier and steeper with prolonged egg storage in the oldest compared to younger breeders. Between 5 and 19 days of storage, yolk free body mass, liver and proventriculus + gizzard percentages decreased, as well as hatchling length and yolk efficiency (yolk absorption per initial yolk weight). The latter effects were most pronounced in the younger than in the older breeders. Therefore, eggs are preferably stored shorter than 7 d, but if long storage (≥12 days) cannot be avoided, we recommend to store eggs of older breeders when egg quality and hatchability are most important. In case hatchling quality is most important, it would be better to store eggs of younger breeders (31 weeks) for a prolonged period.

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.

Effect of heat treatment on pre-stocking of Turkey eggs and its impact on incubation and hatching

Egg stocking is used to meet housing demands in the hatchery industry. Stocking periods longer than 10 days of occur commonly, despite the fact that this practice causes productive losses during the incubation process. To minimize these losses, eggs are heated before incubation to stimulate the embryo, thereby reducing the range of birth intervals. The objective of this study was to determine whether heat treatment (37.5 °C) prior to incubation would improve hatching rates. We also determined the heat-exposure time necessary to improve productivity. We stored 5376 Nicholas pedigree eggs, aged between 40 and 51 weeks, for seven days. These eggs were distributed in three groups: groups 1 and 2 received 4 and 6 h of heat treatment, respectively; group 3 was used as control (no heat treatment, remaining at 17 °C). After heat treatment, the eggs were stored for 7 days at 17 °C, together with eggs from the control group. We found significant variation in the cumulative dispersion of birds born during the hatch window; greater numbers of birds were born in group 1 that underwent the 4-h heat treatment with a 24-h hatch window and in group 3 that underwent the 6-h heat treatment with a 12-h hatch window. Hatch rate, yolk retention and the relationship between average chick weight/average egg weight did not differ between treatments. These data suggest that heat treatment modulates the hatch window; nevertheless, the treatment did not influence the average weight the chicks, the number of chicks born, the percentage of hatching or yolk retention.

Impacts of various storage periods on egg quality, hatchability, post-hatching performance, and economic benefit analysis of two breeds of quail

The effect of storage period on hatching and post-hatching performance of two quail breeds (brown Japanese quail (BJQ) and French white quail (FWQ)) was investigated using 940 eggs from each breed. Eggs were divided into four equal groups (235 eggs each), in each group. A total number of 210 eggs were used for incubation (with three replicates, 70 eggs each) and additional 25 eggs served as samples for egg quality parameters, each group was kept for special storage period. The first group was incubated on the same day of collection (zero day storage). Whereas the second, third, and fourth groups were stored for 4, 7, and 10 d, respectively. Increasing the storage period more than 4 d significantly decreased the relative albumen weight, yolk index, total hatchability, and fertile eggs but significantly increased the relative yolk/albumen ratio, absolute and relative egg weight loss. Moreover, FWQ eggs exhibited higher (P < 0.05) hatchability compared to BJQ eggs after 10 d of storage and yielded heavier chicks (P < 0.05) after all storage periods. The economic analysis indicated that the storage costs for FWQ eggs were significantly greater than those of BJQ at a 0 d of storage (2.42 vs. 4.81 US cent (¢); P < 0.05). Furthermore, the total costs for BJQ eggs were significantly lower than the total costs for FWQ eggs (3.0 vs. 7.0 ¢; P < 0.05). With respect to profitability, the total return represented by selling the chicks was calculated at 5.43 ¢ for BJQ and 9.01 ¢ for FWQ. The net return estimated for FWQ was significantly greater than that of BJQ (3.0 vs. 2.0 ¢; P < 0.05). However, the hatchability loss for FWQ was significantly greater than that of BJQ over different storage periods.

Effect of warming profile at the onset of incubation on early embryonic mortality in long stored broiler eggs

In 6 experiments, it was investigated whether the pattern of warming from storage temperature to incubation temperature affects early embryonic mortality in broiler eggs. The warming profile (WP) from 21°C to the final incubation temperature of 37.8°C was divided into 2 equal parts (above and below 29.4°C) and the duration of warming in both parts was varied (3 to 17 h). In all experiments, eggs were stored for 13 to 16 d at a storage temperature of 18±2°C. In experiment 1, embryo morphology was evaluated at several time points during a linear warming curve of 24 h from 21°C to an eggshell temperature (EST) of 37.8°C. Results from experiment 1 showed that during the 24 h of warming, embryos did not advance in morphological stage (P = 0.74).Results of experiment 2 and 3 showed that the duration of the WP below 29.4°C (3 to 17 h) had no effect on early embryonic mortality (P ≥ 0.77). Experiment 4 and 6 showed that in eggs from prime breeders, a slow WP (>12 h) above 29.4°C resulted in lower embryonic mortality during the first 2 d of incubation (on average 5.0%) compared to a fast WP of 3 to 6 h (on average 11.3%). In experiment 6, an interaction was found between WP and breeder flock age for embryonic mortality till day 7 of incubation (P = 0.002). Warming profile did not affect embryonic mortality during the first 7 d of incubation in eggs from the young breeder flock. However, in eggs from the prime breeder flock, a WP of 12 h in the first part of warming, followed by 17 h in the second part of warming (WP12-17) had 6.2% lower embryonic mortality in the first 7 d of incubation compared to WP12-3. It can be concluded that a slower WP above 29.4°C reduces early embryonic mortality in long stored eggs, especially those of prime breeder flocks. At this moment, it remains unclear which mechanisms are involved in this phenomenon.

Efeito do período e temperatura de armazenamento de ovos férteis sobre o rendimento de incubação e características de qualidade de codornas neonatas

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

Effects of storage time on hatchability of artificially incubated Greater Rhea (Rhea americana) eggs

(1) A study was conducted to determine the effects of the length of the storage period on the hatchability of artificially incubated Greater Rhea eggs. Hatchability was evaluated in eggs gathered daily from a captive population and in eggs collected less frequently from a semi-captive population. (2) Eggs form both sites were either immediately incubated after being collected or were stored for 1 to 9 d prior to incubation. (3) The maximum number of days for which an egg could be stored without depressing hatchability (with respect to non-stored eggs) was longer in the eggs collected daily. (4) Eggs collected daily and stored for 4d or more showed total hatchability (28%) and fertile hatchability (43%) which was approximately 30% lower than non-stored eggs or eggs stored for 3 d or less. In the semi-captive population, the total and fertile hatchability of non-stored eggs and of eggs stored for one day were 40% greater than of eggs stored for 2 to 9 d (20 and 34%, respectively). (5) The period for which Greater Rhea eggs could be stored without depressing hatchability varied depending on the frequency of egg collection: non-daily egg collection reduces the possible period of storage.

Performance and bone mineralisation in broiler chicks fed on diets with different concentrations of cholecalciferol at a constant ratio of calcium to non-phytate phosphorus

1. An experiment was conducted with broiler female chicks (720) to study the effects of graded concentrations (75, 15, 225 or 30 microg/kg) of cholecalciferol (CC) in diets containing varying levels of calcium (Ca) and non-phytate phosphorus (NPP) at a 2:1 ratio (4:2, 5:25, 6:3 or 7:35 g/kg, respectively), on the performance (2-35 d of age), bone mineralisation and mineral (Ca, P, Mn, Fe, Cu) concentration in excreta. 2. Body weight gain, food intake, tibia density and tibia ash increased, and leg abnormality score decreased with dietary increase of CC from 75 to 30 microg at 4 g Ca and 2 g NPP. However, this improvement was not comparable with the birds receiving the highest concentrations of CC, Ca and NPP (30 microg, 7 g and 3.5 g, respectively/kg diet). 3. Significant improvements in the majority of parameters noted with increasing CC up to 225 microg at 5 g Ca and 25 g NPP/kg, which was comparable to those fed the highest levels of CC, Ca and NPP. 4. Concentrations of Ca, P, Mn, Fe and Cu in excreta decreased significantly with increasing CC at all Ca:NPP ratios tested. 5. The predicted requirement of CC for most of the parameters ranged between 1625 and 25 microg/kg diet at 5 g Ca and 25 g NPP. 6. Considering the performance, bone mineralisation, and mineral concentration in excreta, it can be concluded that Ca and NPP levels in broiler diet could be reduced to 5 and 25 g, respectively, while maintaining CC at 25 microg/kg.

Egg storage and the embryo

In domestic avian species, eggs are stored at cool temperatures until they can be placed into an incubator. The low temperature-induced diapause enables the embryo to survive until optimal temperature and humidity incubation conditions can be provided to support embryonic growth. Egg storage is a logistical necessity for the hatching egg industry both at the breeder farm and at the hatchery. However, it is well known that egg storage longer than 7 d negatively influences hatchability. At the cellular level, long-term egg storage induces cell death. This appears to be occurring both via necrosis and apoptosis. The result is higher embryonic mortality and, consequently, lower hatchability. In addition, long-term egg storage influences embryonic development and metabolism. Embryos of eggs stored long-term can be affected such that they do not initiate growth after proper incubation temperatures are provided; they initiate growth, but grow at a slower rate than eggs stored short term; and they are affected in both of the previously mentioned ways. Development of equipment to measure the embryonic metabolism of individually incubating eggs over the entire 21 d of incubation has provided further evidence that embryo metabolism has changed due to storage. One of the methods to reduce the negative effects of long-term storage has been to incubate eggs for short periods before storage. In both turkey and chicken eggs, this technique has been successful in improving the hatchability of long-term stored eggs. It is hypothesized that particular embryonic developmental stages are better able to survive long-term storage. Future research should focus on the mechanisms behind this improved ability to survive storage.

The ostrich (Struthio camelus) blastoderm and embryo development following storage of eggs at various temperatures

1. The gross morphology of blastoderms in fresh unstored ostrich eggs and in eggs subjected to different regimen of storage and incubation was studied. Then the effects of storage duration of eggs (1, 2 and 3 weeks) and storage temperature (15, 20 and 25 degrees C) on blastoderm and embryo development were investigated.2. Only incubation following overnight storage at 18 degrees C advanced blastoderm development (1.5-fold increase in diameter) to a stage comparable to hypoblast. 3. Storage of eggs at 15 or 20 degrees C did not affect blastoderm stage and size whereas, at 25 degrees C, the blastoderm doubled in size and appeared to have advanced to a primitive streak stage. Embryo development was reduced after 2 weeks of storage regardless of the storage temperature. 4. After oviposition and during pre-incubation storage the ostrich blastoderm develops progressively over time in a temperature-dependent manner towards the hypoblast stage and beyond but the viability of the blastoderm and embryo development is seriously compromised by 2 weeks of storage.

Accelerating embryonic growth during incubation following prolonged egg storage. 1. Embryonic livability

The hypothesis was proposed that shorter incubation periods and faster growth rates for long-stored eggs would improve embryonic survival and poult hatchling quality. Increased incubation temperatures were tested for their efficacy in improving embryonic livability in fertilized eggs stored for 15 d prior to setting in the incubator compared to controls stored for only 3 d. Two temperature treatments were applied. In experiment 1, a 37.8 degrees C set point for dry bulb temperature was used to accelerate development for the initial 2 wk compared to the controls at 37.5 degrees C. Following treatment, the accelerated embryos were returned to the same machine as the controls. In experiment 2, higher temperature exposure was only for the initial week of incubation. The temperature and storage treatments were in a completely random 2 x 2 factorial arrangement of treatments. At the completion of 28 d of incubation, survival rates of all treatments were determined by opening all nonhatching eggs to differentiate truly fertilized eggs from unfertilized. Hatchability was determined by dividing the total number of poults on a hatching tray by the number of fertilized eggs on a tray. Incubator trays were the experimental unit. Tissues were sampled in both experiments to verify treatment effects on growth and metabolism. Hatching times were observed at 4-h intervals during the actual hatching process beginning at 25 d of incubation. It was concluded that delayed growth and depressed metabolism of fertilized turkey eggs stored for 15 d can be compensated for by exposure to higher incubation temperatures for the initial 1 or 2 wk of incubation.

Prestorage incubation of long-term stored broiler breeder eggs: 1. Effects on hatchability

Two thousand eight hundred broiler breeder eggs were used to determine if prestorage incubation (PRESI) treatments of 0, 6, 12, or 18 h (at 37.5 C) could improve the hatchability of eggs stored (at 11.5 C) for 4 vs. 14 d. Embryonic development of 30 eggs was established after exposing the eggs to each PRESI treatment. The remaining eggs were cold-stored for 4 or 14 d and then incubated for 21 d. Unhatched eggs were broken open to determine fertility, and if fertile, stage of embryonic death was determined. Statistical significance was assessed at P < 0.05. Embryonic development significantly advanced (P = 0.00001) as the number of PRESI h increased. Therefore, embryos from each of the four PRESI treatments were placed into cold storage at different stages of development. Egg storage for 14 vs. 4 d significantly reduced the hatchability of all eggs set (58.4 and 88.2%, respectively). The PRESI treatments did not have a significant beneficial or detrimental effect on the hatchability of all eggs set for the eggs stored 4 d. However, in eggs stored for 14 d, PRESI for 6 h significantly improved hatchability of all eggs set (79.0%) when compared to eggs that were not PRESI (70.5%). The hatchability of all eggs set for eggs PRESI for 18 h and stored for 14 d was significantly reduced (9.1%) when compared to the other 14-d stored PRESI treatments. The results of this study provide evidence that embryos of eggs that have completed hypoblast formation (PRESI for 6 h) and are stored for 14 d have a survival advantage over embryos of 14-d stored eggs that have not been subjected to any PRESI treatments.