The Effect of Light and Specific Gravity on Embryo Weight and Embryonic Mortality

Abstract

Eggs from Single Comb White Leghorn chickens were divided into two approximately equal groups with the range of specific gravities being present in each group. One group was incubated in a darkened Humidaire Hatchett while the other was incubated in an identical machine equipped with two 20 Watt fluorescent tubes which produced 8.3 X 10(3) ergs/cm.2-sec. at the surface of the eggs. The recommended temperature and humidity settings were used in both machines. After 7 days of incubation embryos from the lighted incubator were significantly (P less than .01) larger than those incubated in the dark. There were significantly more live embryos from low and high specific gravity eggs in the light than in the dark. There was no difference in embryonic mortality between groups for the eggs with intermediate specific gravities. Embryos from White Leghorn eggs incubated in the presence of light were significantly (P less than .01) larger on each day of incubation from day 2 through hatch. Eggs incubated in the lighted incubator hatched at 18 and 19 days and produced larger chicks than those hatched at 20 and 21 days in the dark.

The Effects of Lighted Incubation on Eggs with Pigmented and Nonpigmented Yolk

“…However, when comparing light and dark incubated eggs, regardless of yolk pigmentation, a 12 to 15 hr difference in mean hatch time was observed. Differences in hatch times of light versus dark incubated eggs were in agreement with a number of workers who have reported differences in hatch time due to lighted incubation of from 5 hr to 2 days (Walter and Voitle, 1972;Siegel et al, 1969;Coleman and McDaniel, 1975). However, the differences in hatching time reported in this study were not of the magnitude of Coleman and McDaniel (1975), who reported that White Leghorn eggs exposed to lighted incubation conditions comparable to those of this study hatched on the 18th and 19th day of incubation.…”

“…Since egg weight and hatch weight are known to be highly correlated (Halbersleben and Mussehl, 1922), a negative difference in hatch weights due to light treatment is indicated. This does not agree with Coleman and McDaniel (1975) or Walter and Voitle (1972), who reported chicks that hatched early in response to light were larger than those hatched at 21 days incubated in the dark.…”

“…Significant differences (P< .05) for percent hatchability were evident between light and dark incubated eggs with eggs incubated in die dark having the highest hatchability. These observations are not in agreement with Siegel et al (1969), who reported hatchability was unaffected by lighted incubation, nor do they agree with those of Coleman and McDaniel (1975), who reported an improvement in hatchability due to lighted incubation.…”

The Effect of Egg Shell Quality on Hatchability and Embryonic Mortality

“…Payne and Mc-Daniel (1958) found that turkey eggs with thin shells, as determined by specific gravity, did not hatch as well as those with thick shells. Coleman and McDaniel (1975) reported a highly significant increase in early embryonic mortality in eggs with low specific gravity. Rauch and Steinke (1953) presented data indicating that eggs with extremely thick or thin shells had increased embryonic mortality when compared with those of average thickness.…”

Physical Comparisons of Lighted Incubation in Avian Eggs

“…Conventional humidity and temperature controls were used. Embryos were harvested at 3 days incubation as described by Coleman and McDaniel (1975a). About 200 eggs were used.…”