Effects of epidermal growth factor on gastrointestinal development and function for improved growth and efficiency in poultry
Comprehensive research on epidermal growth factor (EGF), a potent mitogen for neonatal gastrointestinal development, has demonstrated its protective role in supporting and healing the gastrointestinal tract of mammalian models. However, EGF has not been thoroughly assessed for its ability to stimulate gastrointestinal development in neonatal chicks and subsequent impact on growth performance and nutrient utilization. Two experiments were conducted to evaluate the dose response of EGF supplementation on gastrointestinal development, health and function in broiler chickens. Experiment 1 incorporated EGF in starter diets fed to broiler chickens challenged with Eimeria and experiment 2 applied EGF in ovo during the late embryonic stage. Feeding EGF linearly increased body weight gain before Eimeria challenge (days 0-5) but had no effects on growth performance, intestinal histomorphology, or nutrient retention upon Eimeria challenge. Interestingly, EGF increased gene expression for certain digestive enzymes, nutrient transporters, tight junction proteins, and proliferating cell nuclear antigen in Eimeria-challenged birds, suggesting that EGF could potentially attenuate the negative effects of Eimeria. In ovo application of EGF had no effect on post-hatch growth performance, nutrient retention, and intestinal development; perhaps suggesting bioactivity of EGF as an intact protein may have been compromised by ubiquitous protective factors in amniotic fluid. In conclusion, further research to optimize biological and economic application of EGF may stimulate uptake in starter feeding programs.