Fermentability characteristics of different Saccharomyces cerevisiae cell wall using cat faeces as inoculum

摘要

Yeast cell wall are a source of prebiotics in animal nutrition, able to improve microbial functionin the large intestine. The purpose of this paper was to compare the fermentability of sixSaccharomyces cerevisiae (SC) cell wall obtained from three production processes (alcoholic,brewers and bakers). For each production process the two aliquots characterised by the highestthe lowest carbohydrate levels were selected. In order to perform the in vitro trial, each SC substratewas incubated at 39 C under anaerobic condition for 72 h, using cat faecal inoculum. Theresults showed that the production processes did not affect organic matter disappearance, whilesignificantly (p .01) influenced cumulative volume of gas which appeared the lowest for alcoholicsubstrates. The alcoholic SC substrate showed significantly highest (p .01) fermentationrate. All SCFA were affected by the production processes (p .01). In particular, brewers substratesshowed the highest acetate and butyrate production, while the fermentation of SC cellwall obtained by bakers showed the highest production of valerate, iso-butyrate and iso-valerate.Considering the high fermentability and acetate and butyrate production, the SC cell wallobtained by brewers seem more suitable to be used as prebiotic in cat diet. The bakers extractseems less advisable, due to its less fermentability at which corresponded the highest productionof gas and iso-butyrate and iso-valerate, which are considered the less desirable end-products.The study underlines that it is necessary to evaluate the fermentation characteristics ofthese ingredients before their use in diet formulation as source of prebiotics.