The objectives of this study were to determine in vitro dry matter and energy utilization of hatchery waste products and to confirm whether in vivo energy digestibility of hatchery waste products could be estimated using in vitro data. Two in vitro assays were conducted for infertile eggs, unhatched eggs, culled chicks, and a mixture(20% dried infertile eggs, 20% dried unhatched eggs, and 60% dried culled chicks). In Exp.1, in vitro dry matter disappearance (IVDMD) of hatchery waste products was determined. In Exp.2, in vitro energy disappearance (IVED) was determined using undigested residues from Exp.1. The IVDMD of infertile eggs, unhatched eggs, culled chicks, and the mixture were 81.7, 88.7, 83.9, and 85.4%, respectively. The IVED of the test ingredients were 74.4, 85.1, 77.6, and 79.8%, respectively. Both IVDMD and IVED were greater in unhatched eggs compared with infertile eggs and culled chicks (p<0.05). In vivo energy digestibility was estimated well using prediction equations for hatchery waste products developed in the present study: In vivo energy digestibility(%) = 2.52 × IVDMD (%) – 133.95 with r2 = 0.70 and in vivo energy digestibility(%) = 1.63 × IVED(%) – 50.03 with r2 = 0.67. In conclusion, energy utilization of unhatched eggs was the greatest among test ingredients and energy utilization of hatchery waste products can be estimated using data from in vitro procedures.

ABSTRACT
 Introduction
 Materials and Methods
  1 Preparation of hatchery waste products
  2 In vitro dry matter disappearance
  3 In vitro energy disappearance
  4 Chemical analysis
  5 Calculations and statistical analyses
 Results and Discussion
 References

• Jung Yeol Sung(Department of Animal Science and Technology, Konkuk University)
• Sang Yun Ji(Animal Nutritional Physiology Team, National Institute of Animal Science, Rural Development Administration)
• Beob Gyun Kim(Department of Animal Science and Technology, Konkuk University) Corresponding author