a1 Department of Animal Sciences, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, POB 12, Rehovot 76–100, Israel
a2 Department of Poultry Science, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC 27695–7608, USA
Several factors may limit the development and viability of late-term embryos and hatchlings: 1 The nutrient content of the egg needed for the development of tissues and nutrient reserves (glycogen, muscle, yolk) of the embryo through to hatch; 2 The ability of the gastrointestinal tract to digest utilize nutrients from an external carbohydrate and protein-rich diet; and 3 The ability of chicks and poults to rely on the residual nutrients in the yolk sac during the first few days post-hatch. These limitations are manifested by in the “chick or poult quality” phenomena. Approximately 2% to 5% of hatchlings do not survive the critical post-hatch “adjustment” period and many survivors exhibit stunted growth, inefficient feed utilization, reduced disease resistance, or poor meat yield. These limitations can be alleviated by the administration of food in the hatchery immediately post-hatch, a technology termed “Early Feeding”, or by administration of food into the amnion of late term embryo, what we define as “In Ovo Feeding”. A great potential exists in “combining” the early feeding and the in ovo feeding methods. Since the modern broiler increases its body weight by 50-fold from hatch until market age at 42 days, the first few critical days of “adjustment” represent a much greater proportion of the bird's life span than in the past. Consequently, early feeding methods will have a great impact on overall growth and well-being of the bird, particularly as genetic selection for increased growth performance continues in the future.
(Received October 13 2003)
(Accepted October 25 2003)
This paper was first presented at the 14th European Symposium on Poultry Nutrition, Lillehammer, Norway, August 10–14, 2003