The effects of hen's age and egg storage time on the frequency of occurrence of physical defects in turkey poults.

The aim of this study was to determine the effect of the interaction between hen's age and egg storage time on the frequency of occurrence and type of physical defects in turkey poults. The experimental materials comprised 6,048 eggs laid by BUT 6 turkey hens at 32, 38, 46, and 51 wk of age (1,512 eggs per week), which were randomly divided into 4 groups (378 eggs per group) and stored for different periods of time, i.e., 7, 10, 13, and 17 D. After incubation, poults were evaluated individually. Egg weight and the hatch-weight of poults increased with hen's age (P < 0.001). The relative body weight of poults, expressed as a percentage of egg weight, was highest in the group of the youngest hens (70.6%). Prolonged egg storage before incubation contributed to an increase in the percentage of poults with physical abnormalities (P < 0.001). Umbilical abnormalities were most common regardless of the week of the laying season and egg storage time.

The effect of dietary selenium source on embryonic development in Turkeys.

The objective of this study was to determine the effect of dietary selenium source on the growth and development of turkey embryos, and egg hatchability. White broad-breasted BUT Big 6 turkeys (1800 females and 150 males) were placed under optimum management conditions. Turkey diets were supplemented with organic selenium, and in the other with inorganic selenium, in the amount of 0.3 ppm. Eggs intended for incubation and examination were collected in week 2, 10, 18 and 23 of the laying season. The average egg weight was higher (p < or = 0.05) in laying hens fed a diet with organic selenium than in layers receiving inorganic selenium. The rate of yolk sac retraction was faster in embryos from the group fed a diet with inorganic selenium, and it reached 0.59 of the complete yolk sac on day 25 of incubation (p < or = 0.05). Selenium source had no effect on the hatching rates of fertilized eggs, which reached 79.61% and 79.84% in laying hens fed organic and inorganic selenium, respectively. In the flocks fed diets supplemented with organic selenium, dead embryos were more frequently characterized by problems with protein utilization (19.28%) and delayed pipping (10.83%). Embryo death rates at the first mortality peak were higher in layers fed inorganic selenium than in those receiving organic selenium (15% vs. 13.5%). The second embryo mortality peak occurred earlier (day 26) in laying hens fed inorganic selenium than in those fed organic selenium (day 28).