Live yeast stability in the digestive tract of the rabbit: relationship with digestion, growth and digestive health.

Live yeast Saccharomyces Cerevisiae NCYC Sc 47 (Biosaf®) was added to the diet of wean ing rabbits to evaluate the effects on growth, feed eff ici ncy, health status, digestibility and caecal parameters. Two Biosaf® levels (1 and 10 g Biosaf®/ kg feed, group C1 and C10 corresponding to 10 6 and 10 CFU/g of DM in diet) were compared to a control gr oup (C0) without yeast addition. Thirty rabbits (3 groups of 10) were used to measure the d igestibility and caecal parameters and to calculate the yeast survival rate in the digestive tract. Gro wth performances and health status were studied on 120 rabbits (3 groups of 40 cages individually). In diet, live yeast concentration fell slightly (-0.2 to 0.5 log CFU/g DM) after pelleting, although the pel leting temperature was high (70-80°C). The survival rate of yeast in digestive tract was high and increased from 90 to 97% with yeast supplementation, but this did not affect the faecal digestibility or the caecal pH. However, redox potential (Eh) of the caecal content increased sign ifica tly with yeast addition. Mortality was 50% lower with the highest yeast addition (C10) compare d to C0 and C1 groups, while growth, intake or feed efficiency remained similar.