the study was conducted to determine the effects of turkey (meleagris gallopavo)egg weight on certain egg traits and hatching performance. a total of 178 turkey eggs comprising of three different egg weight groups below 60 g (g i), 61 to 69 g (g ii) and above 70 g (g iii) were used for this study. average egg weight (g), egg length (cm), egg breadth (cm) and egg volume (cm3) values increased wi...

In migratory birds, arrival date and hatching date are two key phenological markers that have responded to global warming. A body of knowledge exists relating these traits to evolutionary pressures. In this study, we formalize this knowledge into general mathematical assumptions, and use them in an ecoevolutionary model. In contrast to previous models, this study novelty accounts for both trait...

Numerous studies emphasize the potential indirect (genetic) benefits of polyandry in animals with resource-free mating systems. In this paper, we examine the potential for these benefits to fuel sexual selection and polyandry in the hermaphroditic ascidian Pyura stolonifera. Individuals were designated either sire (sperm producers) or dam (egg producers) at random and crossed in a North Carolin...

The Effect of Different Sources Selenium and Microencapsulation on Fertility Hatching Traits in Arbor Acres Broiler Breeder

Incubation temperature influences a suite of traits in avian offspring. However, the mechanisms underlying expression of these phenotypes are unknown. Given the importance of thyroid hormones in orchestrating developmental processes, we hypothesized that they may act as an upstream mechanism mediating the effects of temperature on hatchling phenotypic traits such as growth and thermoregulation....

The quality of eggs and the hatching traits of two slow-growing lines – La Belle (LB) and Bresse Gauloise (BB) reared under conventional or alternative system with pasture access were compared. The birds of both lines in the study were at the age of 27-37 weeks. Two-way ANOVA was used to assess the effect of the rearing system as well as the line on the quality characteristics of the eggs and h...

To understand how nest temperatures influence phenotypic traits of reptilian hatchlings, the effects of fluctuating temperature on hatchling traits must be known. Most investigations, however, have only considered the effects of constant temperatures. We incubated eggs of Takydromus septentrionalis (Lacertidae) at constant (24 degrees C, 27 degrees C, 30 degrees C and 33 degrees C) and fluctuat...

Many species alter the timing of hatching in response to egg or larval predators, pathogens, or physical risks. This plasticity depends on separation between the onset of hatching competence and physiological limits to embryonic development. I present a framework based on heterokairy to categorize developmental mechanisms and identify traits contributing to and limiting hatching plasticity, the...

Plasticity in the timing of transitions between stages of complex life cycles allows organisms to adjust their growth and development to local environmental conditions. Genetic variation in such plasticity is common, but the evolution of context-dependent transition timing may be constrained by information reliability, lag-time and developmental constraints. We studied the genetic architecture ...