Failure to turn eggs during incubation: Development of the area vasculosa and embryonic growth

Abstract

Effect of turning of the egg during incubation on development of the area vasculosa of the chick embryo was investigated. The size of the area vasculosa was determined by two methods: direct measurement with calipers and measurement of a template cut from the eggshell by use of an automatic surface area recorder. The effects of turning and additionally the effects of lowered temperature (36°C) on both growth of the area vasculosa by day 7 and embryo growth by day 14 of incubation were investigated. The effects of turning during a critical period for turning, from 3 to 7 days of incubation, were also recorded. Generally, failure to turn eggs retarded growth of the area vasculosa. Turning during the critical period stimulated the extent of growth of the area vasculosa by day 7 of incubation and of subsequent embryonic growth by day 14. Incubation at low temperature resulted both in reduced expansion of the area vasculosa and retarded embryonic growth in a pattern similar to that observed for unturned eggs. It is suggested that turning stimulates development of blood vessels in the area vasculosa via localized increases in blood pressure. The effect of a reduced area vasculosa is considered to retard embryonic development through restricted nutrient uptake from the yolk. The prevailing hypothesis that turning prevents deleterious membrane adhesions is questioned in light of these observations. It is suggested that the physiological basis for the need for turning lies in maximizing the growth rate of the area vasculosa to maximize yolk use and embryonic growth rate.

Kaz (Anser anser) ve Tavuk (Gallus gallus domesticus) Yumurta Kabuğunun Embriyonik Gelişim Sırasında Taramalı Elektron Mikroskop ile Karşılaştırılması

“…It is required that poultry eggs are rotated during the development stages. Any mistakes during this process may cause of a decrease in oxygen uptake, delayed extra embryonic membranes, vascularization and embryonic development [3,4] . Generally, it is known that the yield of incubation rate of waterfowl is lower than that of chicken.…”

Electrolyte and Water Balance of the Early Avian Embryo: Effects of Egg Turning

“…Rate of growth of the area vasculosa of the yolk sac membrane during the ®rst third of incubation was slower in unturned eggs (Deeming, 1989b). Later in development the pattern of growth of the chorioallantoic membrane is disrupted in unturned eggs (Tullett and Deeming, 1987).…”

“…Later in development the pattern of growth of the chorioallantoic membrane is disrupted in unturned eggs (Tullett and Deeming, 1987). Failure to turn eggs also affects the volume of the allantois and amnion and slowed the rate of embryonic growth (Tazawa, 1980;Tullett and Deeming, 1987;Deeming, 1989aDeeming, , 1989bDeeming, , 1989cDeeming, , 1989dDeeming, , 1991. For various reasons, the protein content of amniotic¯uid is reduced in unturned eggs (Deeming, 1991) because less albumen proteins move through the sero-amniotic connection (Hirota, 1894;Deeming, 1991).…”

“…In eggs of the domestic fowl static incubation signi®cantly impairs the expansion of the area vasculosa. Deeming (1989b) measured the expansion of the area vasculosa from 3 to 8 days of incubation in turned and unturned eggs. Static incubation did not affect the area measured on day 3, but by day 5 and all subsequent days a lack of turning had signi®cantly reduced the expansion of the area vasculosa.…”

Effect of egg turning and incubation time on carbonic anhydrase gene expression in the blastoderm of the Japanese quail (Coturnix c. japonica)

“…Baggott et al (2002) suggested that in unturned eggs this 'depleted layer' would reduce the sodium available for ion transport by endodermal cells and thus decrease SEF formation. Alternatively, or in addition, it was suggested that the lower rate of expansion of the area vasculosa present in unturned eggs (Deeming, 1989a) might also reduce SEF mass. However, neither hypothesis provides a complete explanation of the occurrence in turned eggs of additional fluid at the time of maximum SEF mass (Babiker and Baggott, 1992).…”