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Three experiments were conducted to determine the effects of increased CO2 concentration during the first 3 d of incubation on albumen height and pH, embryonic mortality, and hatchability of broiler hatching eggs. Hatching eggs were obtained from commercial broiler breeder flocks of Ross 308 at 39 and 37 wk of age in Experiments 1 and 2, respectively. In Experiment 3, eggs were collected at 28 and 35 wk of age. Eggs were incubated under either standard conditions (Control-CO2) for the entire incubation or increased CO2 concentrations during the first 3 d of incubation (High-CO2) in 3 experiments. In Experiments 1 and 2, the CO2 concentration was gradually increased from the beginning of incubation onwards to reach 0.80% at 72 h by manual injection of CO2 into airtight laboratory incubators. In the control incubators, the CO2 concentration remained below 0.10% during the same period. Prior to setting, and at 3 d of incubation, the eggs were opened for albumen height and pH measurements in Experiments 1 and 2. In Experiment 3, the eggs were set in commercial incubators. During the first 3 d of incubation, the CO2 concentration was gradually increased to reach 0.70% at 72 h naturally (High-CO2). In the Control-CO2 incubator, the CO2 concentration remained below 0.10%. After 3 d, incubation was continued with the control incubator conditions for all eggs from both groups in the 3 experiments. The albumen height was not affected by CO2 treatment, but the treatment significantly decreased albumen pH at 3 d in Experiments 1 and 2 (P < 0.05). A greater CO2 concentration during early incubation reduced fertile hatchability due to increased early embryonic mortality by 2% in the 3 experiments (P ≤ 0.05). The differences in pH might provide one explanation why increased CO2 concentration during early incubation resulted in increased early embryonic mortality. These data indicated that at the beginning of the incubation, ventilation was necessary to prevent increases in CO2 concentration for optimum hatchability results. [ABSTRACT FROM AUTHOR]

The current study investigated the effect of chick body (rectal) temperature during the post-hatch handling period on body weight (BW) loss, yolk sac utilization, organ weights, and broiler live performance. Hatching eggs were obtained from a commercial flock of Ross 308 broiler breeders at 44 wk of age. A total of 384 chicks were separated into 3 groups during the 12 h post-hatch handling period: control, high and low temperature groups, with average body temperatures of 40.0, 42.6, and 38.1°C, respectively. Residual yolk sac weight was not affected by temperature group, whereas the weights of organs such as the heart, gizzard, proventriculus, and bursa of Fabricius were significantly lower in the high body temperature group than in the control and low body temperature groups. BW was significantly lower at placement in chicks in the high temperature group than in chicks in the control and low body temperature groups due to greater weight loss during the post-hatch handling period (P ≤ 0.05). Lower BW was maintained in the chicks in the high body temperature group than in the chicks in the other 2 groups until the end of the experiment at 35 d (P ≤ 0.05) because chicks in the high temperature group consumed less feed throughout the experiment (P ≤ 0.05). Feed conversion ratio (FCR) and mortality were numerically greater in the high body temperature chicks than in the control group, whereas FCR and the mortality in the low body temperature chicks were intermediate at 35 d. The results of the present study indicate that day-old chicks with high body temperatures (42.6°C) exhibited a greater percentage of BW loss due to dehydration and lower organ weights during the 12 h post-hatch handling period, which was followed by significantly poorer broiler performance. There were no significant differences in performance between the chicks in the control (40.0°C) and low (38.1°C) body temperature groups. In conclusion, day-old chicks are more sensitive to higher body temperatures than to lower temperatures during the post-hatch handling period. [ABSTRACT FROM AUTHOR]

The effects of temperature fluctuation during 7 d of storage on stage of blastoderm development, embryonic mortality, and hatchability of broiler hatching eggs were studied. Hatching eggs from 2 commercial flocks of Ross 308 broiler breeders at 27 and 50 wk of age, respectively, were randomly assigned to replicate chambers with either a constant temperature (Constant) of 18°C or a temperature that fluctuated (Fluctuated) over a 40 min period 3 times daily (0900 h, 1300 h, and 1700 h) between 18°C and 21°C. This latter treatment was intended to mimic the opening of an egg storage room door to add freshly collected eggs. The developmental stages of the blastoderm before and after storage were determined. At each flock age, there were 10 replicate trays of 60 eggs per egg storage temperature treatment set in a single stage incubator. All unhatched eggs were opened and examined macroscopically to determine fertility or embryonic mortality (early dead (0 to 7 d), middle + late dead (8 to 21 d plus pipped eggs), and to calculate percentage hatchability of fertile eggs. Embryonic development was advanced by flock age (P < 0.10) and fluctuating temperature treatment (P < 0.05). Blastoderm stages were determined according to Eyal Giladi and Kockav (EGK). The Fluctuated vs. Constant treatment exhibited an EGK of 9.8 vs. 9.1 (P < 0.05) in the young flock and EGK of 11.0 vs. 10.1 (P < 0.05) in the old flock. During 7 d of storage, Fluctuated temperature decreased early embryonic mortality (P < 0.05) in the eggs from the young flock but increased early embryonic mortality (P < 0.05) in the eggs from the old flock, which decreased (P < 0.05) hatchability of fertile eggs in the old flock. The fluctuating temperature conditions that did not negatively affect the younger flock eggs were not favorable for eggs from the older flock. [ABSTRACT FROM AUTHOR]

The effects of heating of eggs during stor-age, broiler breeder age, and length of egg storage on hatchability of fertile eggs were examined in this study. Eggs were collected from Ross 344 male x Ross 308 broiler breeders on paper flats, held overnight (1 d) at 18°C and 75% RH, and then transferred to plastic trays. In experiment 1, eggs were obtained at 28, 38, and 53 wk of flock age. During a further 10 d of stor-age, eggs either remained in the storage room (control) or were subjected to a heat treatment regimen of 26°C for 2 h, 37.8°C for 3 h, and 26°C for 2 h in a setter at d 5 of storage. In experiment 2, eggs from a flock at 28 wk of age were heated for 1 d of a 6-d storage period. Eggs from a 29-wk-old flock were either heated at d 1 or 5 of an 11-d storage period in experiment 3. In ex-periment 4, 27-wk-old flock eggs were heated twice at d 1 and 5 of an 11-d storage period. Control eggs stored for 6 or 11 d were coincubated as appropriate in each experiment. Heating eggs at d 5 of an 11-d storage pe-riod increased hatchability in experiment 1. Although no benefit of heating 28-wk-old flock eggs during 6 d of storage in experiment 2 was observed, heating eggs from a 29-wk-old flock at d 1 or 5 of an 11-d storage period increased hatchability in experiment 3. Further, heating eggs from a 27-wk-old flock twice during 11 d of storage increased hatchability in experiment 4. These effects were probably due to the fact that eggs from younger flocks had been reported to have many embry-os at a stage of development where the hypoblast had not yet fully developed (less than EG-K12 to EG-K13), such that heating during extended storage advanced these embryos to a more resistant stage. [ABSTRACT FROM AUTHOR]