Live yeast stability in rabbit digestive tract: consequences on the caecal ecosystem, digestion, growth and digestive health.

摘要

Live yeast Saccharomyces cerevisiae NCYC Sc 47 was added to the diet of weaning rabbits (35 d old) to analyse the effects on the caecal ecosystem (biotope and bacterial community), digestion and health status. Two levels of yeast (1 and 10 g/kg feed, group C1 and C10 corresponding to 106 and 107 CFU/g DM) were compared to a control group (C0) without live yeast addition. Three groups of 10 young rabbits were used in a first experiment to measure digestibility and caecal parameters and to calculate the yeast survival rate in the digestive tract. Growth performance and health status were studied on 3 further groups of 40 rabbits (Experiment 2). The live yeast concentration fell slightly after diet pelleting (0.1-0.5 log CFU/g DM), at 70-80 degrees C. The survival rate of yeast in digestive tract was high and increased from 90 to 97% (P<0.01) with increasing yeast supplementation. Live yeast addition did not modify the total tract digestibility of nutrients, or the growth performance. Mortality rate between 42 and 56 d of age was lower at the highest yeast level (C10: 4 dead on 40; P<0.05) compared to C0 and C1 groups (average 13/40). The structure of the caecal bacterial community was not modified after 11 d of yeast presence in the caecum, while the bacterial diversity tended to be higher (5.0 vs 5.4, P=0.10, for C0 vs [C1+C10]). The redox potential of the caecal content increased with yeast addition (-227 vs -251 mV, P<0.05 for C0 vs [C1+C10]), whereas the fermentation pattern and the caecal pH remain unaffected (meanly 5.88).Digital Object Identifier http://dx.doi.org/10.1016/j.anifeedsci.2012.01.012