Performance, digestive disorders and the intestinal microbiota in weaning rabbits are affected by a herbal feed additive

[EN] A herbal feed additive (Digestarom(R), containing a mixture of onion, garlic, caraway, fennel, gentian, melissa, peppermint, anise, oak bark and clove) was fed to rabbit does and kits to study its impact on performance, post-weaning digestive disorders and intestinal microbiota. Two groups of 9 doe rabbits and their offspring, after weaning, were fed a standard diet without or with the addition of 300 mg Digestarom(R)/kg diet. Forty kits from each group were weaned at 28 d of age weighing 0.614±0.005 kg. They were caged in groups of four rabbits (10 cages/treatment) and fed the same diet as their mothers for 13 d. Weight gain and feed intake of the kits fed Digestarom(R) was 18 and 14% higher, respectively, than those fed control diet (P<0.001), with no differences in the feed conversion. Rabbits were killed 13 d after weaning and 10 healthy animals from the Digestarom(R) group and 10 healthy and 10 diseased animals from the control group were dissected. Healthy rabbits fed control diet and those fed Digestarom(R) showed closer intestinal digesta dry matter, pH and volatile fatty acid (VFA) profi les, compared to diseased animals. VFA concentration in the small intestine was higher (P=0.030) in the diseased animals of the control group compared with the healthy and Digestarom(R) fed rabbits. However, no differences were observed in VFA concentration in stomach or caecum contents. The fermentation profi le of diseased animals was characterised by a higher proportion of propionic, i- and n-valeric acids in the caecal contents (P<0.001), and an increased i-butyric acid concentration in the stomach and caecum contents (P=0.014), whereas n-butyric acid was reduced (P<0.033) compared with the healthy or Digestarom(R) fed rabbits. Denaturing gradient gel electrophoresis indicated a higher caecal bacterial diversity in the control rabbits compared with kits fed Digestarom(R) (P=0.008). The reduced evenness factor (P<0.010) also indicated that the bacterial composition