Developmental Stability of Broiler Embryos in Relation to Length of Egg Storage Prior to Incubation

Abstract

The effects of storage of eggs for 0, 2, 8, 14, or 18 days prior to incubation, as measured by growth and developmental homeostasis of bilateral traits, were studied in broiler embryos. Data were obtained on hatchability, and for 10 embryos from eggs selected at random at 10, 14, and 18 days of incubation and at hatch from each storage period. Skeletal traits included lengths of left and right face, wing, tibia, femur, and shank as well as weights of the heart and left and right lungs. Eggs stored for 14 and 18 days had poorer hatchability than those stored for 0 and 2 days, with the 8-day storage group intermediate. There was a trend (P=0.08) for reduced lung weights of embryos from eggs stored for 18 days before incubation, whereas length of storage had no effect on heart weights. Femur and tibia lengths were affected by length of preincubation storage. Lengths of femur, tibia and shank differed among embryonic ages demonstrating that these bones grow at different rates during incubation. Polynomial equations are provided for size of traits. Developmental asymmetry of bilateral traits was influenced by length of preincubation storage and embryonic age. Relative asymmetry declined steadily from 10 days of incubation towards time of hatch.

Keywords

• chickens
• embryonic development
• leg bones
• relative asymmetry
• stress