Modulating intestinal cellular maturation and differentiation in broilers by in ovo feeding

Abstract

Mortality in a broiler flock will typically range from 4-5% of the population over the course of 6- 7 weeks in the U.S. and 7-8% of the population in Israel. Suboptimal intestinal maturation and functionality are one of the major factors that contribute to early age mortality and hinder flock body weight uniformity. The development of absorptive and secretory functions is orchestrated by differentiation of cells that arise from stem cells. Supplying compounds by in ovo feeding (IOF) during late embryogenesis provides nutrients that may change the dynamics of stem cell differentiation. We hypothesize that the introduction of specific nutrients or probiotics to the late embryonic chick via IOF will result in an acceleration of the maturation of the small intestine as measured by villus/crypt morphology and the number and distribution of absorptive and secretory cells. A chick that can absorb nutrients more efficiently by increasing the number of cells expressing nutrient transporters and resist enteric pathogens by increasing the number of cells expressing mucin and host defense peptides will be healthier at hatch. This chick may have less need for antibiotics and may show reduced early mortality. The objectives of this proposal are to: 1) develop a model for the development of putative stem cells and absorptive/secretory cells in the small intestine of the late embryonic and early post hatch broiler. 2) determine the ability of IOF of nutrients to modulate the population of differentiated cells in the intestine. 3) determine the ability of IOF of probiotics to modulate the population of differentiated cells in the intestine. 4) reduce early mortality and increase body weight uniformity by IOF of selected nutrients or probiotics. This proposal combines the IOF expertise of Zehava Uni (Hebrew University) with the RNAscope in situ hybridization technique of Eric Wong (Virginia Tech). Previous studies using quantitative PCR to examine expression of genes in the intestine were unable to identify specific cells expressing these genes. RNAscope allows the ability to identify putative stem, absorptive and secretory cells in the small intestine. Thus, we will be able to investigate the effect of IOF on the presence of intestinal absorptive and secretory cells at the cellular level. Understanding the mechanisms for intestinal development and function are key to maintaining peak growth and health of chickens and thus would be of great economic benefit to the poultry industry.