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Saccharomyces cerevisiae yeast, an ally in rabbit health

It is now established that digestive flora contribute to the well-being and health of both human beings and animals.  INRA have shown that in the rabbit, the addition of S. cerevisiae yeast to their feed can interact with the natural microbial populations present in an animal and improve its health.

Une lapine et ses lapereaux. © NICOLAS Bertrand
Updated on 04/16/2013
Published on 02/12/2013

The importance of the intestinal microbiota

The flora of the digestive tract – or the intestinal microbiota – of animals is made up of a multitude of micro-organisms which interact together and also with their host. This complex ecosystem is the site of numerous exchanges and is essential to the satisfactory development of animals. It enables the better digestion of foods and the supply of vitamins that an animal is unable to synthesise, while constituting a barrier to any pathogenic agents that have been ingested. However, the functioning of the microbiota remains largely unknown, and the role of each microbial subpopulation in major physiological functions (nutrition, immunity, etc.) is the subject of considerable research.

Livestock farming, food transition and probiotics

The microbiota develops during the early days of life in parallel with maturation of the animal's digestive tract. The different microbial species are introduced through contact with other animals or with the environment. These phenomena allow a young animal to adapt to changes in its diet, to switch to greater dietary independence (e.g. in mammals, from maternal milk to the foods in its environment). In livestock farms, however, this food transition is problematic and may generate digestive disorders (diarrhoea, etc.), that can cause retarded growth or even be fatal in a large percentage of animals. This adaptive stress may have major economic consequences.
To overcome these problems and help the microbiota to adapt, supplementation with specific microbial strains (yeasts or bacteria) or probiotics is one of the solutions being studied.  However, the effects of such supplementation are not fully understood, and their mastery is not yet sufficient to achieve optimum efficacy.

S. cerevisiae and the caecal microbiota in the rabbit

During their research on the involvement of the microbiota in the nutrition of farmed animals, and its development in the young, scientists in the Joint Research Unit for Animal Tissues, Nutrition, Digestion, Ecosystems and Metabolism (TANDEM) focused in particular on the adaptation of young rabbits to their post-weaning diet. In the context of a thesis project sponsored in partnership by INRA, the University of Abobo-Adjamé (Abidjan, the Ivory Coast) and the company Lesaffre Feed Additives (Lille), the researchers studied the caecal microbiota of young animals, because this distal portion of the digestive tract is the site of intense microbial activity.
To achieve this, the team fed three groups of animals (weaned, 35 days old) with a standard diet supplemented or not with coated NCYC Cs47 yeast at a rate of 0 g/kg, 1 g/kg or 10 g/kg of feed (groups C0, C1 and C10, respectively), for 35 consecutive days. During this period, the researchers recorded various zootechnical parameters (initial and final weight, growth rate, mortality rate). Then, at the end of the growth period, the structure of the microbial populations was studied by the extraction of rDNA 16s and PCR (Polymerase Chain Reaction).
The scientists showed that the yeasts could travel through the digestive tract, and were able to withstand acidity in the stomach and digestive enzymes in the intestine to reach the caecum alive.  Yeast supplementation did not procure any improvements in the zootechnical performance of the animals, as the rearing conditions (feed, density of animals in cages, etc.) were optimum.  However, yeast supplementation at a rate of 10 g/kg feed did enable a 50% reduction in the incidence of digestive disorders in the young rabbits. The structure of bacterial communities in the caecum was little modified in the presence of live yeasts; the dominant bacteria remained the same, but biodiversity was slightly enhanced.  According to the researchers, this was indicative of a greater equilibrium in the bacterial community. The technique employed did not permit any further progress in identifying the bacterial strains which developed (which may have been fibrolytic strains digesting plant fibres).
At present, two thesis projects are under way to continue this work, which at a fundamental level is of considerable interest as it will help to clarify the role of the microbiota, while at a practical level it may contribute to enhancing the health and well-being of farmed animals.

Scientific contact(s):

  • Thierry GIDENNE (+33 (0)5 61 28 51 03) Joint Research Unit for Animal Tissues, Nutrition, Digestion, Ecosystems and Metabolism
Associated Division(s):
Animal Physiology and Livestock Systems
Associated Centre(s):

Find out more

  • Live yeast stability in rabbit digestive tract: Consequences on the caecal ecosystem, digestion, growth and digestive health. Kimse, M; Bayourthe, C; Monteils, V; Fortun-Lamothe, L; Cauquil, L; Combes, S; Gidenne, T. 2012. ANIMAL FEED SCIENCE AND TECHNOLOGY, 173 (3-4):235-243