Gut microbiota plays an important role for its host. It may provide additional nutrients from feed which could otherwise not be digested by the host, it may provide vitamins or other specific metabolites and it can also stimulate the gut immune system of its host. Finally, interactions among different microbiota members may restrict growth of harmful bacterial species. Development, composition and correct function of gut microbiota is therefore of utmost importance for its host.
Development of intensive animal production systems resulted in reduced chance of efficient transfer of microbiota from parent animals to their o spring; with chickens hatched in the clean environment of hatcheries as an extreme example. Absence of natural sources of healthy gut microbiota, suboptimal development of gut microbiota or modification of its composition by antibiotic therapy may affect the overall health status of individual animals, which can result in disorders difficult to associates with one particular reason. This is why we are interested in the composition of gut microbiota in chickens and pigs of different age or of different performance.
Our results point towards similarities and differences in the development of chicken and pig gut microbiota. In both species, the earliest gut coloniser is Escherichia coli and in both species, the abundance of E. coli significantly decreases after the first week of life. Next colonisers in pigs include representatives of Gram positive Firmicutes and Gram negative Bacteroidetes. Major families from phylum Firmicutes include Ruminococcaceae, Lachnospiraceae, Veilonellaceae and Lactobacillaceae. Major families from phylum Bacteroidetes include Bacteroidaceae dominating in suckling piglets and Prevotellaceae dominating in postweaning piglets and adult pigs. Porphyromonadaceae is the last common family present in pig gut microbiota (Fig. 1, left).
Development of gut microbiota in chickens from the second week of life is apparently different from pigs. In chickens in commercial production, different Gram positive Firmicutes dominate in the caecum. However, family composition is the same as in pigs and includes Ruminococcaceae, Lachnospiraceae, Lactobacillaceae and Veilonellaceae with representatives of Veilonellaceae appearing among the last ones. Gram negatives from phylum Bacteroidetes appear later, in approx. 1-month-old chickens. Unlike pigs, the first colonisers originate from the family Rikenellaceae, followed by Barnesiellaceae, Bacteroidaceae, Prevotellaceae and Porphyromonadaceae. ere is no developmental pattern or dominance of Bacteroidaceae or Prevotellaceae in chickens (Fig. 1, right). Interestingly, when we tested the development of gut microbiota in chickens which were in contact with an adult hen, the development was very fast and 1-week-old chickens had the same microbiota as the adult hen (Fig. 2). is clearly shows that also newly hatched chickens can be populated by adult microbiota composition but consequences for health status and overall performance are not known and are subject of current research activities within the PROHEALTH project.