Microbial programming: early postnatal microbial colonisation effects on subsequent health

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The gastrointestinal tract of animals is sterile at birth but is colonised almost immediately by bacteria present in the birth canal and in the surrounding environment. Initially only a small number of different bacterial species colonise the intestine, however, as the animal ages more than 400 different species are thought grow in this enviroment. A number of factors can affect the type of bacteria that colonise the intestine of neonatal animals in early life. Major factors include the bacterial species associated with the mother, bacteria in the environment (e.g. premature infant in an incubator versus full term baby), the type of diet (breast-fed versus formula) and use of antibiotics. There is evidence that the pattern of bacterial species colonising the neonatal intestine can have long term effects "programming" colonisation patterns and intestinal health later in life. For example, the increases in allergy, asthma and eczema in children in developed countries may be associated with their relatively "clean" pathogen-free environment compared with children in developing countries. In this project we will use neonatal piglets to investigate this concept of "microbial programming". The piglet is an excellent model for human infants and the results will also have implications for how we manage baby pigs to improve health. First we will analyse the bacterial DNA in intestinal contents to precisely determine the pattern of bacteria colonizing suckling pigs from birth to weaning. Next we will obtain germ-free piglets, expose them for 5 days to selected bacterial species identified in the suckling pig and then raise them normally. We will then determine whether the bacteria the pigs were exposed to in early life affects their intestinal bacterial populations and/or intestinal health at weaning. If a microbial programming effect is demonstrated it may be possible to develop strategies to modify the intestinal colonisation pattern in early life to promote a healthier intestine later.