Nutritional genomics: a practical approach by early life conditioning with dietary phosphorus

Abstract

-The recent technologies that have led to the new field of functional genomics (how the genome of an organism regulates homeostasis and responds to stimuli) are providing a clearer understanding of how organisms interact with their environment and in particular their diet. We are beginning to learn how the diet may have long-term influence on performance and health. A form of epigenetic regulation has been recently described called fetal "programming". Fueled by epidemiological data the "fetal origins" hypothesis suggests that a poor in utero environment resulting from maternal dietary or placental insufficiency may "program" susceptibility in the fetus to cardiovascular or metabolic disorders. We have observed similar apparent programming by dietary manipulation in the chicken. When birds are challenged with a diet low in phosphorus (P) for 90 hours post-hatch they obtain the ability to better utilize P later in life. This increased retention of P from the diet can partially be explained by an enduring increase in the expression of the intestine-specific Na/P cotransporter (NaPcoT) gene during programming as well as later in life when fed P restricted diets. The resulting data provide the first evidence for neonatal programming of gene expression in an oviparous species.Key Words: epigenetics, functional genoimcs, nutrition, nutritional conditioning, poultry Genômica nutricional: uma abordagem prática pelo condicionamento com fósforo dietético nos primeiros anos de vida RESUMO -As tecnologias recentes que levaram ao novo campo da genômica funcional (como o genoma de um organismo regula a homeostase e responde aos estímulos) estão proporcionando uma compreensão mais clara de como os organismos interagem com seu ambiente e em especial a sua dieta. Nós estamos começando a aprender como a dieta pode ter influência a longo prazo sobre o desempenho e a saúde. Uma forma de regulação epigenética foi descrita recentemente chamada de "programação fetal". Alimentados por dados epidemiológicos da "origem fetal" hipótese sugere que um pobre no útero ambiente decorrentes da insuficiência alimentar ou placentária materna pode programar "suscetibilidade do feto de doenças cardiovasculares ou metabólicas. Tem-se observado programação aparente similar por manipulação dietética da galinha. Quando as aves são desafiadas com uma dieta baixa em fósforo (P) por 90 horas pós-eclosão, elas obtêm a capacidade de utilizar P melhor mais tarde na vida. Esta maior retenção de P da dieta pode ser parcialmente explicada por um aumento permanente na expressão do gene do cotransoprtador Na/P intestinal durante a programação, bem como mais tarde na vida quando alimentadas com dietas P restrito. Os dados obtidos fornecem a primeira evidência para a programação neonatal da expressão gênica em uma espécie ovípara.

Effects of dietary calcium and phosphorus deficiency and subsequent recovery on broiler chicken growth performance and bone characteristics

“…The bone mineralisation deficit showed the importance of the repletion phase for restoring the bone mineral criteria to acceptable values (Ashwell and Angel, 2010). The level of repletion (CC v. LC v. LM) did affect bone mineralisation.…”

“…Létourneau-Montminy et al (2008) have reported previously that bone mineralisation in chicks fed a marginally deficient diet for 10 days was restored by replenishing the mineral depletion over the next 11 days as a result of improved bone mineral deposition. Ashwell and Angel (2010) have suggested that an early deficiency could lead to an epigenetic imprinting effect that enhances Ca absorption capability. However, the deficiency began early in the Ashwell and Angel study (90 h after hatching) and even earlier (day 1, lasting through day 18) in a study by Yan et al (2005), compared with day 11 in our study.…”

“…Yan et al (2005) demonstrated that chickens fed diets deficient in calcium (Ca) and non-phytate phosphorus (nPP) during an early phase of growth (depletion) and later fed diet containing adequate levels of these minerals (repletion) exhibited better phosphorus and Ca utilisation and bone mineralisation. In fact, birds seem to respond to a decrease in Ca and nPP dietary content by increasing expression of mRNA encoding Ca transporters (Centeno et al, 2004;Bar, 2009) and phosphorus transporters (Ashwell and Angel, 2010) in the small intestine. Some authors have suggested that recommendations made by National Research Council (NRC) (1994) regarding dietary Ca and phosphorus for broiler chickens might exceed actual requirements (Angel et al, 2006;Létourneau-Montminy et al, 2010).…”

Bridging Gaps in the Agricultural Phosphorus Cycle from an Animal Husbandry Perspective—The Case of Pigs and Poultry

“…The mechanism by which environmental and maternal cues are transmitted may involve the epigenetic regulation of specific genes [38,39]. This may offer the possibility to induce different and stable phenotypes as findings in animal models revealed adaptive responses which facilitate considerable organismal plasticity [35,40,41]. In fact, due to selective dietary P challenges, the adaptive responses are thought to be associated with endocrine, paracrine and autocrine regulation of P homeostasis.…”

Epigenetics and phenotypic variability: some interesting insights from birds

“…For instance, phosphorus- or calcium-restricted diets during the early growing period trigger a compensatory adaptation of the chicken [101], possibly mediated by epigenetic mechanisms [102]. Although little is known about the underlying molecular mechanisms in birds, it seems that feed stress may alter gene transcription at least partly via epigenetic mechanisms.…”