Reproductive maturity of turkey hens: egg composition, embryonic growth and hatchling transition

Abstract

Selection for body weight in commercial turkey strains has resulted in faster growing turkeys with improved feed efficiencies. These genetic gains, however, have come largely at the expense of reproductive fitness. In particular, considerable variability exists in early egg production. This variation greatly impacts egg composition, which in turn can affect embryonic growth and post-hatching transitions from an embryonic lipid-based metabolism to a glucose-based metabolism. Notably, embryos from young hens develop more slowly than embryos from older hens during the last week of incubation. Further studies have shown that these developmental differences are in part due to a proportional increase in yolk mass in eggs from older hens; which allows for a greater mass transfer of yolk lipid to the embryo during the final week of incubation. Hypothetically, developmental differences during incubation may contribute to problems that occur during the acclimation period after hatching, especially if hatchlings come from very young hens.

Estimating the most important criteria for hatching eggs as function of broiler breeders age

“…Characteristics related to hatchability, such as fertility, the time required to rupturing the internal and external membranes, and proper hatching can be influenced by the age of the female breeder (PEDROSO et al, 2005). It was also established that the embryo development is slower in the eggs of younger hens than in the eggs of older (APPLEGATE, 2002;YASSIN et al, 2009). This multi criteria concept allowed some prompt analysis of the process beyond the final score ( Figure 2): 1) the two analyzed ages had a tie on the criteria "Contaminated eggs" (in "Hatcher") and "Pipped but dead"; and 2) the only criterion that breeders of 56 week-old was better was "Pipped and alive."…”

“…Eggs laid by old breeders presented higher infertility and total embryo mortality, resulting in lower hatching percentage (ALMEIDA et al, 2008) and young breeders frequently lay eggs with greater embryo mortalities (APPLEGATE et al, 1998). Eggs from young female breeder have small yolk and consequently less yolk lipid available for the embryo (APPLEGATE, 2002). In old female breeders the increase in the eggs' weight lead to reduction of hatching capacity, as the embryos developed in larger eggs are less tolerant to the excessive heat that occurs in the end of the incubation period (ROCHA et al, 2008).…”

Effects of Intrayolk Sac Inoculation of Olive Oil on Physiological Adaptive Responses in Newly Hatched Broiler Chicks Subjected to Neonatal Fasting

“…However, in a companion paper published by Khorrami et al (2014) the mortality rate was increased significantly in the chicks received IYS inoculation of olive oil by nearly 10 percent during the first week. It has been shown that chicks must switch from utilizing yolk solids to digesting and absorbing carbohydrates, a transition which is often difficult and may explain why mortality is often high in the first week (Applegate, 2002). It seems that, the metabolic consequences of yolk fortification with exogenous lipids appeared later by retarded weight gain and greater mortality rates (Khorrami et al, 2014).…”

Effect of Disinfectants, Flock Physiological Status, Season and Storage Period of Broiler Breeder Eggs on Field Hatchability and Hatchery Operation Quality Under New-Salheya City Situation

“…Consistence with this explanation, our results showed that the percentages of early embryonic mortality and pipped eggs were highly significant (P< 0.0001) in eggs from 28 to 34 weeks old (before peak). Suarez et al, (1997), Applegate (2002) and Dudusola (2013) reported that eggs from young breeder hens have small yolk and consequently less yolk lipid available for the embryo, resulting in greater embryo mortalities.…”