Nutritional effects of chestnut tannins in poultry and rabbit

This paper examines the nutritional effects of chestnut tannins, on poultry and rabbit and make some comparisons with ruminants and other monogastric animals.The use of antibiotic feed additives has been banned in the European Union (EU), and ongoing discussions to restrict their use outside the EU because of speculated risk for generating antibiotic resistance in pathogenic microbiota. Consequently, many approaches have been attempted to control or prevent the clinical diseases and maximize growth performance in poultry and rabbit. At present, the natural plant extracts, commonly used as feed flavouring, are being paid great attention to their natural antibiotics properties by the virtue of their advantage of being natural.Tannins contained into the chestnut wood (Castanea sativa) extract (CWE) represent some of several categories of phytochemicals antimicrobial that could have great potential effect.In order to evaluate the effects of chestnut extract on performances traits, meat composition, N and P balance in poultry and rabbit some trails have been carried out.In several study, chestnut extract inclusion up to 2.5 g/kg of diet had no significant influence on the apparent digestibility. In our study, growth performance generally fell in the standard range and CWE seemed to play a more favorable role in the younger broiler, both poultry and rabbit, than the older. CWE could modify the stability of the gastrointestinal microflora improving the competitive exclusion similarly to other plant extracts.The slaughtering data and meat composition showed no significant differences among the parameters examined both in poultry and rabbit. Moreover the mortality observed in rabbit fed diets containing CWE was significantly lower than the groups without CWE. It is possible to suppose that, in rabbits, CWE can modulate gut pH and prevent the development of the micro flora that causes enteropathy.In conclusion, the use of CWE did not influence the digestibility and carcass quality. The use of CWE had positive influence on growth performance, especially in young animal. Further research is needed to understand the mechanism of CWE in the gastrointestinal tract. Generally speaking, the study of the nutritional effects of tannins is complicated due to their great structural diversity and their wide presence into many different botanicals, this difficulty has led to a considerable confusion in the literature when it comes to determining their benefits or toxicity. Our study on a specific extract rich in tannins adds to the opinion that considers them as compounds that need to be studied individually considering as fundamental the botanical origin, Castanea sativa in this case.