Characterisation of the gastrointestinal bacterial community in pigs fed fermented liquid feed and dry feed: composition and fermentation capacity (phenotypic fingerprint).

Feeding pigs with fermented liquid feed (FLF) has been shown to reduce the number of enteropathogens such as Salmonella and Brachyospira hyodysenteriae as well as coliform bacteria in general in the gastrointestinal tract (GIT). Also the commensal bacterial populations have been shown to respond to the use of FLF, e.g. the total counts of anaerobes, including lactic acid bacteria are reduced. In the present work we demonstrate that the capacity to ferment a series of substrates (mainly low-molecular weight carbohydrates) is reduced in caecum, colon and faeces of pigs fed FLF compared to pigs fed dry feed. This reduction could be due to the fact that these substrates are partially depleted by fermentation in the liquid feed prior to entering the animal. Therefore nutrient availability may be limited in the large intestine of pigs fed FLF, which may again affect bacterial enzyme synthesis and growth and thus the possibility for pathogenic and zoonotic bacteria to establish.