Changes in physicochemical parameters of duck eggs and extra-embryonic structures during incubation

Impact of storage period on hatching egg quality, extra-embryonic structures, embryo morphometry, hatchability, and Rosa 1 chick quality

Storage duration affects the biological value of hatching eggs. The study evaluated the composition and characteristics of hatching eggs from Rosa 1 hens, the morphometric traits of embryos and chicks, and hatching results based on storage time. A total of 1 200 hatching eggs were divided into three groups: NS (control, non-stored), S4 (stored up to day 4), and S7 (stored up to day 7). Storage conditions were 17 °C and approx. 60% relative humidity. Each group's egg quality was measured for 30 eggs. Weight loss during storage was monitored. Lysozyme activity and viscosity were analysed from fresh eggs and incubated eggs on days 7 and 14, using thin and thick albumen or amniotic fluid. Embryo morphometry was measured on days 7, 10, 14, and 18, and posthatching results and the quality of 1-day-old chicks were assessed. Eggs stored for 7 days (S7) had higher (P < 0.05) weight loss compared to the NS group. The proportions of eggshell and yolk increased (P < 0.05) after storage, and the yolk index decreased. Vitelline membrane strength was lower (P < 0.001) in the S4 and S7 groups than in the NS group. The lowest (P < 0.05) pH levels of thin, thick albumen and yolk were observed in the NS group. Lysozyme activity increased (P < 0.001) in the thin albumen of eggs in the NS and S4 groups and the thick albumen from the NS group than in others. On day 7 of incubation, group S7 showed higher (P < 0.05) lysozyme activity in thick albumen, with no activity in amniotic fluid. By day 14, lysozyme activity increased (P < 0.001) in group S7's thick albumen and S4 and S7 groups' amniotic fluid. Viscosity was highest (P < 0.05) in fresh eggs' thin and thick albumen from group S7, but on day 7, thick albumen viscosity was lowest. On day 14, amniotic fluid viscosity was higher (P = 0.009) in group S4 than in NS. Seven-day-old embryos in group S7 had lower (P = 0.004) weight than others. Eye diameter in S7 embryos was also smaller on days 7 and 18. On day 10, NS group embryos had shorter body diagonal lengths. Storage up to 7 days adversely affected hatching efficiency. Storage affected the navel area of 1-day-old chicks, with the highest neck length in male chicks from group S4 and the lowest in females from group S4. It is concluded that egg storage at 17 °C and 60% relative humidity could be limited to 4 days to maintain hatchability and qualitative features.

The typical developmental trajectory and energy requirements of Shitou goose during the embryonic stage

Low hatchability has been a persistent challenge in the goose industry. Establishing standard atlases and comprehending embryonic development patterns are essential to improving the hatching rates of goose eggs. However, comprehensive descriptions of normal atlases, embryonic development, and energy requirements in geese are lacking. In this study, a total of 120 fertile eggs from well-known large Shitou goose were incubated using 12 nesting purebred female geese. During hatching, both the temperature of the eggshells and the weight of eggs were recorded, and daily photographs of the embryos were captured to monitor their development closely. After hatching, counted the number of pores per unit area of eggshells by choosing eggs from without sperm, dead embryos, and normally hatched. Furthermore, 150 Shitou goose eggs were hatched by automatic incubator, with adjustments made based on observed normal developmental stages that incubated by female geese. The eggs were carefully opened to meticulously document embryonic morphology and create a detailed development map. Measurements were taken of the eye diameter, length of the lower beak, tarsometatarsus bone, and embryo length. Subsequently, an analysis was conducted to assess the calcium, phosphorus, crude protein, and crude fat content to study the energy requirements for embryo development. characteristics on the 7th, 15th, 23rd and 28th days of Shitou goose hatching corresponded to the 5th, 10th, 17th and 19th days of chicken egg incubation, respectively. These days were distinguished individually by "visible embryo's eye", "closure", "sealing the door", and "flashing hair". Besides, the hatch rate of the incubator reached 86.67%, and the cumulative water loss rate increased with embryo age. Notably, normally developing embryos displayed a significantly higher number of pores on the eggshell surface compared to dead embryos (P < 0.05). Additionally, embryonic body length, eyeball diameter, and lower beak length exhibited continuous growth until day 19 of incubation, while tarsometatarsus length increased steadily from days 12 to 31. Liver size measurement began on the 10th day of incubation, while both leg and chest muscles showed continuous growth from the 12th day. For energy demand, the embryo primarily relied on protein sourced from the egg yolk within the first 10 days of development. Afterward, the egg yolk provided both protein and fat for embryonic growth. In summary, this study has generated a comprehensive developmental map for Shitou goose embryos, offering valuable insights into their growth and morphological changes throughout the incubation period. This map can serve as a reference for optimizing machine incubation techniques to enhance goose egg hatching rates and provide fresh perspectives on the development of geese.

Quality characteristics, lysozyme activity, and albumen viscosity of fresh hatching duck eggs after a week's storage at various temperatures

The study aimed to analyze the qualitative features of Cherry Valley duck' hatching eggs during storage at different temperatures. Eggs were divided into 3 equal groups with 30 eggs each: fresh egg and stored at 7 °C and 17 °C within one week. Qualitative analyses of duck eggs were carried out, considering the morphological composition, physicochemical characteristics, lysozyme activity, and albumen viscosity. The highest weight of yolk and its percentage was found in the 17 °C group. The weight and percentage of albumen were significantly the highest in the group of fresh eggs. Higher egg weight loss was observed in the group stored at higher temperatures. Higher thick albumen height and Haugh units were found in fresh eggs and eggs stored at 7 °C. Different temperatures of egg storage did not affect lysozyme activity in thick and thin albumen. Stored eggs were characterized by lower albumen viscosity only at a shear rate of 10 rpm. The higher viscosity of thick albumen compared to thin ones was demonstrated at 10 and 20 rpm shear rates. The presented research results indicate a large diversity of selected qualitative indicators of hatching duck eggs, which may affect their storage and suitability for incubation.